PART 22 - Mike South



Part 22

ENT, EYE AND DENTAL DISORDERS

22.1

Ear, nose and throat, and head and neck surgery problems

B. Benjamin

Paediatric ear, nose and throat (ENT) disorders cover a wide field of congenital and acquired diseases of the ear, nose and paranasal sinuses, oral cavity, tongue, pharynx, larynx, tracheobronchial tree and oesophagus. They include craniofacial abnormalities, tumours and cysts of the head and neck, deafness and speech, language and communication problems. This section covers the common disorders.

The ear

The external auditory canal and the tympanic membrane are usually inspected (if necessary and if possible after removal of wax) using a handheld, battery-operated otoscope or a Seigle magnifying pneumatic speculum. An ENT specialist uses a slim, short telescope or a microscope for more detailed examination.

The external ear

Congenital abnormalities

Differences in the shape of the pinna are common – small ears, large ears, accessory skin tags and unusual configuration of the helix and antihelix – but usually no treatment is needed except for unsightly protruding ears, which can be corrected surgically. Major abnormalities of the external canal such as stenosis or atresia are sometimes associated with small, malformed pinnae, abnormalities of the ossicles and possibly hypoplastic inner ear abnormalities with consequent major hearing problems. When these anomalies affect both ears, hearing aids or reconstructive surgical procedures may be necessary.

Otitis externa

Swimming in contaminated or heavily chlorinated water predisposes the delicate skin lining the ear canal to infection with bacteria or fungi. Otitis externa causes itch, soreness, discharge and partial deafness. Treatment includes removal of debris by swabbing and/or syringing followed by careful drying and regular administration of appropriate antibiotic/steroid drops. Water in the ear should be avoided.

Severe pain and exquisite tenderness indicate acute localized or acute diffuse infection requiring systemic antibiotics, especially when there is surrounding cellulitis, lymphadenitis or generalized toxicity. ENT referral and hospitalization may be required in severe or intractable cases.

Wax

Black, brown, yellow or pale wax is a mixture of sebaceous material and ceruminous gland secretion combined with desquamated epithelium. Although normally removed by the self-cleaning chewing movement of the temporomandibular joint and evaporation, wax occasionally accumulates to occlude the canal, causing a hearing loss and a sensation of blockage. Obsessive parental attempts to ‘clean’ normal wax with cotton buds or a matchstick or repeated daily insertion of a hearing aid mould may cause impaction of the wax, requiring removal by syringing or use of special blunt probes and suction by an ENT specialist. Sometimes, in obstinate cases, wax must be removed under general anaesthesia with the aid of an operating microscope.

Foreign bodies

Foreign bodies such as beads, pips, pieces of paper, insects, etc. sometimes become lodged in the external auditory canal where they cause discomfort, pain and partial deafness. Occasionally they are discovered by chance. If attempts at careful extraction using a syringe or small grasping forceps are unsuccessful in a young or fractious child, referral to a specialist is indicated for removal, if necessary under general anaesthesia. Rough or ill-judged attempts at removal may cause damage to the tympanic membrane or the middle ear ossicles.

Injury of the tympanic membrane

Indirect trauma such as a slap or blow to the ear, a blast injury or impact with water can compress the column of air in the ear canal and rupture the tympanic membrane. Direct trauma may be caused by a cotton bud, hairpin or an incorrect syringing technique. There is pain, bleeding, deafness and some initial unsteadiness. On inspection, bleeding or a tear may be visible. The ear should not be cleaned and no drops should be given. Antibiotics are usually given to prevent infection. Almost all traumatic injuries will heal within a month or two: if not, a graft may eventually be necessary.

The middle ear

This air-containing, irregularly shaped, bony cavity is lined by mucous membrane and includes the mastoid air cells posteriorly and the eustachian tube anteromedially. The latter opens and closes on swallowing, yawning and blowing the nose and has an active mucociliary lining to cleanse, ventilate and maintain air pressure in the middle ear. Motion of the tympanic membrane and the lever action of the three small, articulated ossicles create an efficient transducer mechanism to transfer sound energy at the air–water interface. As the footplate of the stapes moves rapidly in the oval window, vibrations in air become wave motion in the perilymph fluid of the inner ear.

Acute suppurative otitis media

Acute suppurative otitis media (ASOM) is due to infection of part or all of the mucoperiosteum that lines the spaces of the middle ear. The diagnosis can be verified only by examination of the tympanic membrane.

It is much more common in infants and children than in adults, with a peak incidence under 2 years of age and again between 5 and 7 years. It is more common in winter and where there is overcrowding and malnutrition. About 50% of children will have experienced an attack before the age of 2 years and about 75% by the age of 3 years. This high incidence is apparently due to an immature immune response and increased frequency of upper respiratory tract infections in this age group. The overall incidence is also much higher in Aboriginal children in Australia.

Many factors predispose to middle ear infection:

• pre-existing middle ear effusion or ‘glue ear’

• infants and small children have a short, wide, straight eustachian tube, the dynamic protective function of which is less effective in minimizing middle ear contamination from the nasopharynx than the mature adult eustachian tube

• nasopharyngeal disease, such as seen with acute or chronic upper respiratory tract infection, enlarged infected adenoids and (to a lesser extent) tonsils or rhinosinusitis can act as a focus of infection

• coexistent chronic middle ear disease such as chronic otitis media or a pre-existing tympanic membrane perforation

• cleft palate or repaired cleft palate or other rarer craniofacial structural abnormality affects the normal opening by the palate muscles and the normal closure by the spring action of the cartilaginous portion of the eustachian tube

• contamination of the nasopharynx in babies being bottlefed in the recumbent position or in infants who are vomiting

• attendance at preschool or kindergarten with exposure to pathogens

• parental cigarette smoking

• deficiency of surface-tension-lowering substance, surfactant, in the tube

• abnormality of mucociliary action affecting the normal cleansing mechanism

• immunodeficiency syndromes.

In ASOM, the pathological sequence of events in the air spaces and mucosa of the middle ear proceeds rapidly with oedema, hyperaemia and exudate into the middle ear, more often than not following a head cold or upper respiratory tract infection. Inflammatory swelling occludes the eustachian tube. The serous fluid becomes purulent after secondary bacterial infection and causes bulging of the pain-sensitive tympanic membrane. The body’s natural defences, with or without assistance from antibiotics, usually achieve resolution. If not, the tympanic membrane continues to bulge, forming an area of ischaemic necrosis that ultimately ruptures.

The microbiology of ASOM primarily involves bacteria but in 5–10% viruses may play a role, usually paving the way for secondary bacterial invasion. Common organisms include Streptococcus pneumoniae, Streptococcus pyogenes, Branhamella catarrhalis, Haemophilus influenzae (especially in younger children), Staphylococcus aureus and some Gram-negative or mixed infections. About 30–40% of aspirates will yield no pathogen.

The clinical features of ASOM vary with the age of the child, the efficiency of the host defence and the effectiveness of treatment. Severe, throbbing pain in one or both ears is the commonest feature. There may be minor earache for an hour or two or a fulminating febrile illness with acute pain. These symptoms are often worse in the evening or at night when the child is lying down. Infants may present with fever, attempts to pull at the affected ear, irritability, vomiting and abdominal pain. Rupture of the tympanic membrane, with bloodstained then purulent discharge, relieves the pain and allows a culture and sensitivity to be obtained. If perforation occurs it usually heals within a few weeks.

The diagnosis is confirmed by the appearance of the tympanic membrane. However, many sick, irritable infants and smaller children are difficult, if not impossible, to examine, so in some cases a clinical diagnosis is made and treatment is commenced without visualization of the tympanic membrane.

The progression of ASOM can be divided into four stages:

1. Eustachian tube obstruction with a stuffy, blocked feeling of discomfort in the ear and a slightly retracted, pink tympanic membrane

2. Early infection with increasing earache, fever, and redness due to some mucoid or purulent material behind the tympanic membrane

3. Suppurative stage with severe local pain, constitutional symptoms and purulent exudate under pressure, leading to bulging of the tympanic membrane, which develops a yellowish colour with ischaemic necrosis prior to rupture

4. Resolution stage with dramatic lessening of pain and improvement of the tympanic membrane.

Treatment usually requires bed rest, adequate fluid intake, antipyretics and sufficient analgesic medication. Sometimes local warmth is helpful.

Although there is discussion about whether antibiotics are given too freely, many experienced physicians believe that antibiotics limit the disease, control pain and minimize possible complications. Others suggest that antibiotics should be withheld in non-severe cases pending further observation and given to those not recovering in 24–48 hours. It is generally agreed that children under 2 years of age should be treated with antibiotics rather than adopting a wait and see policy.

As a first-line treatment amoxicillin for 5–10 days is the drug of choice and is generally well tolerated. Erythromycin, sulfamethoxazole–trimethoprim or cefaclor are alternatives. Very occasionally a resistant or complicated infection requires myringotomy. Severe, otherwise uncontrolled infections require intravenous treatment in hospital.

There are no data to support the use of decongestants or antihistamines: in fact there is some evidence that they may be harmful. Topical antibiotic drops have no place in the treatment of acute suppurative otitis media.

The untoward sequelae of otitis media include:

• incomplete resolution with persistence of effusion (‘glue ear’)

• rarely, a ruptured tympanic membrane that will not heal. The chronic perforation will require grafting

• acute mastoiditis or its complications, which are still seen despite the use of antibiotics and usually present as a subperiosteal abscess behind the ear

• labyrinthitis with severe vertigo and vomiting

• intracranial complications, including lateral venous sinus thrombosis, extradural or subdural abscess, meningitis, cortical thrombophlebitis and intracerebral or intracerebellar abscess.

Remember that otitis media has not been ‘cured’ until both the appearance of the tympanic membrane and the hearing have returned to normal. The recently introduced universal pneumococcal immunization programme in Australia may be helpful in preventing recurrent ASOM, particularly for children attending day school.

Clinical example

Emma, aged 3 years 8 months, complained of a ‘sore’ ear late in the afternoon, refused her dinner and later developed distressing pain and a fever of 39.4°C. The family doctor found a crying, upset, vomiting child and an agitated mother. Otoscopy showed a red, bulging tympanic membrane on the left and a thickened, pink membrane on the right. The advice was bed rest, fluids as tolerated, paracetamol, amoxicillin and a progress examination next day.

Note that acute suppurative otitis media causes severe pain, often worse in the evening. Both ears and the upper respiratory tract must be examined.

Glue ear or otitis media with effusion

A confusion of names have been applied to ‘glue ear’ but otitis media with effusion (OME) or secretory otitis media are those used most often. It is a common cause of repeated earaches, fluctuating mild to moderate conduction deafness and educational impairment.

The aetiology is uncertain but the ventilation, drainage and clearing mechanism of the eustachian tube is abnormal. Organisms similar to those found in ASOM can be cultured in 30–50% of cases – the effusion apparently follows incomplete resolution of ASOM. A mucoid, non-purulent effusion, containing leukocytes, dead or live bacteria, serum protein and mucus, accumulates in the middle ear. The effusion may be thin, thick, gelatinous or, in advanced cases, even ‘rubbery’.

The middle ear mucosa becomes oedematous and granular in appearance. Microscopically, the goblet cells and mucous glands increase dramatically in number and small cysts filled with watery or inspissated mucus can be seen in the thickened subepithelial layer, which is infiltrated by chronic inflammatory cells. It is now believed that biofilm (a blanket of bacteria in a very low metabolic state and enclosed in a polymeric matrix) in the middle ear may be a contributing factor in otitis media with effusion.

The clinical features of OME are common up to 8–10 years of age, are usually seen first in winter and are sometimes variable and unpredictable. Symptoms often follow a viral upper respiratory tract infection or incompletely resolved ASOM. Because at first there may be no symptoms the condition may remain unrecognized. Earache and deafness are the two important features.

Earache presents in two ways. Firstly, as a flare-up during an acute respiratory infection there may be typical ASOM with severe pain. Secondly, repeated ‘small’ earaches, lasting for minutes rather than hours, may wake the child at night or occur at school and settle quickly.

Deafness is often suspected by the parents or teacher or may be discovered at a routine screening hearing test. School performance is often affected: ‘doesn’t pay attention’, ‘can do better’ or ‘not concentrating’ are frequent remarks. Non-specific symptoms include poor school achievement, decreased learning skills, interference with language development, an adverse affect on emotional growth, irritability and personality changes. The child may be at an educational disadvantage. A few children become clumsy if their balance is mildly affected. Infants may be irritable, crying or constantly unsettled at night.

Recognition of physical signs in the tympanic membrane is often difficult for the inexperienced: a good pneumatic otoscope with magnification is invaluable. The common physical signs include:

• yellow or amber appearance of the tympanic membrane

• vascular dilatation, which is easier to see with magnification

• thickening and dullness of the tympanic membrane

• indrawing of the tympanic membrane, giving a concave appearance so that the handle of the malleus appears short

• in advanced cases there may be atelectasis in the middle ear with atrophy and thinning of the tympanic membrane.

Sluggish or poor movement of the tympanic membrane detected using a pneumatic otoscope is a most important physical sign. The thicker the fluid, the less the ‘bounce’. In children old enough to perform a pure tone audiogram (Fig. 22.1.1) a mild to moderate conduction deafness will be detected. Impedance tympanometry tests the bounce of the tympanic membrane and typically shows a ‘flat’ curve.

In many children OME will resolve without treatment over weeks or months. However, referral for specialist assessment is indicated:

• when infants and toddlers are persistently irritable, sleep poorly at night and rub or pull at their ears

• when older children have repeated earaches and/or persistent hearing loss.

There is no evidence that antibiotics, antihistamines, decongestants, mucolytics or antiallergy treatment have any significant beneficial effect.

In some cases, after adequate observation indicates that the effusion has been present for 3 months or more, myringotomy, suction removal of the fluid and insertion of tympanostomy tubes for middle ear ventilation/drainage is indicated. The tube remains in the tympanic membrane, functioning as a ‘temporary’ artificial eustachian tube providing sustained middle ear ventilation, discouraging recurrent effusions and promoting recovery, usually without any complications. The tube is extruded through natural mechanisms after 6–12 months but the effusion can recur. Insertion of the tubes may need to be repeated if the symptoms warrant it. In some children, predisposing causes such as infection and hypertrophy of the adenoids or upper respiratory tract mucosal disease or rhinosinusitis need treatment.

If untreated, the long-term irreversible complications of OME include atrophic thinning of the tympanic membrane, atelectasis of the middle ear space, damage to the middle ear mucosa, adhesive otitis media, retraction pockets, avascular necrosis of the incus and stapes, tympanosclerosis, cholesteatoma and cholesterol granuloma.

Clinical example

John’s mother was called to his school because he complained of earache and the teacher observed that he was not hearing well. She stated that her 6-year-old son had suffered four attacks of ‘ear abscess’ in the last 10 months. On examination, both tympanic membranes were dull and dilated vessels were seen to be running in a radial fashion. The tympanogram was ‘flat’. Referral to an ENT surgeon for treatment of glue ears was arranged. In fact, John had probably had otitis media with effusions (OME) for 10 months. Parents may be unaware of the hearing loss in OME. Variable deafness and ear infections almost always indicate OME.

Practical points

Possible sequelae of acute suppurative otitis media are:

• Complete resolution

• Residual ‘glue ear’ and minor deafness

• Acute mastoiditis or a complication of mastoiditis

• ‘Masked mastoiditis’

• Open chronic perforation

Chronic suppurative otitis media

In this condition the tympanic membrane is perforated. The patient complains of partial deafness and painless, recurrent or persistent discharge.

There are two types of chronic suppurative otitis media (CSOM):

• mucoperiosteal disease with a central perforation from pinhole size up to complete destruction of the tympanic membrane. The basic middle ear disease is chronic, persistent or intermittent infection with a purulent, sometimes profuse, discharge due to infection of the mucoperiosteum of the middle ear space. For this reason it is often called tubotympanic disease. Because complications are rare this is known as a ‘safe’ ear. A clean, dry, chronic, central perforation, whether large or small, is suitable for tympanoplasty, using fascia or perichondrium, usually waiting until the child is 7–8 years old. Grafting is successful in about 95%, prevents recurrent infections causing further damage, restores hearing and allows swimming without the risk of infection

• bony disease with a small marginal perforation at the superior bony edge of the tympanic membrane is usually associated with cholesteatoma and chronic, often smelly discharge. Complications are likely; hence this is an ‘unsafe’ ear.

A cholesteatoma is not a tumour but is a very slowly enlarging, pearl-like pocket of misplaced squamous epithelium accompanied by enzymatic destruction of the surrounding bone and ossicles. It is sometimes called atticoantral disease because of its position high in the middle ear.

Mucoperiosteal infection is usually controlled by repeated dry mopping or suction cleaning of the ear and use of appropriate topical antibiotic drops. Water must not get into the ear. The common organisms are Pseudomonas aeruginosa, Bacillus proteus and Escherichia coli. Therefore a chronic or intermittently discharging ear must not be neglected. Cholesteatoma and bony disease usually requires surgical mastoidectomy to remove the disease, combined with tympanoplasty to repair the tympanic membrane and reconstruct the ossicular chain to preserve hearing.

The complications of cholesteatoma include erosion and destruction of the ossicles, osteitis, petrositis, mastoiditis, labyrinthitis, facial nerve paralysis, thrombosis of the sigmoid venous sinus, meningitis, extradural, subdural or cerebral abscess and septicaemia. Some of these complications are life threatening.

Deafness

The accurate assessment of the type, degree and cause of deafness is essential for optimum treatment.

The type of hearing loss is usually described according to the site of pathology:

• ‘Conductive’ deafness. Sound vibrations are not conducted normally via the ear canal (for example, obstructing wax), the tympanic membrane (for example, perforation) or the ossicles (e.g. congenital malformation). Conduction deafness is usually treatable

• ‘Sensorineural’ deafness. There is malfunction of the sensory (cochlear) components (for example, rubella deafness) or the neural (retrocochlear) components (e.g. acoustic neuroma). Sensorineural deafness is often congenital, may be acquired and cannot be cured. If severe enough, sensorineural deafness requires a hearing aid for amplification, or consideration for cochlear implant.

Universal newborn screening for deafness. Language and communication will ultimately be better when deafness is identified early so that a hearing aid and a support programme can be provided. However, it has been difficult to assess the hearing of small children with the traditional informal and special testing techniques (described below) which require a child to be old enough for some cooperation. It is now hoped that universal hearing screening tests which are being introduced for the newborn in Australia will detect most congenital deafness.

When a sound is heard by the ear a tiny corresponding ‘echo’ can be measured by a computer using a small probe placed in a baby’s ear canal – the basis for a non-invasive screening technique called oto-acoustic emissions (OAE) testing. Because the test takes only a few minutes and does not rely on the participation of the baby it is suitable for newborn hearing screening. If the initial result is unreliable, for example if the baby is restless or irritable, further evaluation is necessary. A small number of babies will need referral for auditory brainstem response tests (see below), which can give more reliable information about the hearing

Certain ‘at risk’ criteria can be used to select babies, all of whom should have hearing screening tests soon after birth, usually before leaving hospital, including those with a family history of deafness, craniofacial abnormalities, exposure to ototoxic drugs and those who needed more than 48 hours in a neonatal intensive care unit.

In infants with deafness not detected by screening tests or those developing deafness after the newborn period hearing loss is commonly suspected by the child’s mother (Fig. 22.1.2). The degree of loss is assessed by informal and special audiological methods according to age:

• in infants days or weeks old, the normal but non-quantitative response to a sudden loud sound is the ‘blink’ or ‘startle’ reaction (Fig. 22.1.3). This test is best done with the infant lightly asleep. However, the universal screening programmes using OAE above will, when fully introduced, be a better form of testing

• in special units, computerized electrophysiological tests are available to record small electrical changes evoked in the inner ear during transmission of acoustic signals. An accurate measure of function in the brainstem and the ear can be provided by electrocochleography and auditory brainstem tests in infants and children, including those with behavioural problems or multiple handicaps

• in babies from 4 months of age, normal head turning responses (Fig. 22.1.4) are elicited towards the side of a sound stimulus, which can be varied from a soft whisper to the jingle of keys or the crumple of paper. An approximate, clinical quantitative estimate of hearing can be obtained

• older toddlers can be assessed in specialized paediatric units by behavioural methods, observing the child’s reaction to ambient sounds or by conditioning them to respond to a puppet or peep show – known as condition-oriented response (COR) audiometry

• children of 3 or 4 years of age or older can usually cooperate so that a quantitative pure tone threshold audiogram (Fig. 22.1.1) can be obtained for different frequencies for both air conduction and bone conduction.

The cause of deafness determines the need for treatment. The many causes of conduction deafness each need specific attention, e.g.:

• removal of wax

• operation for congenital external ear canal atresia

• myringoplasty for tympanic membrane perforation

• ventilating tube for persistent otitis media with effusion

• reconstruction of congenital ossicular chain abnormality.

Approximately 1 baby in 1000 is born with severe deafness, and approximately 1 in 1000 infants become deaf before they have developed speech. In many cases the cause of sensorineural deafness is difficult to determine. The known causes can be considered in four groups, as below.

Prenatal hereditary deafness

This is transmitted by a dominant gene in 10%. If one parent carries the gene, up to 50% of children will be affected. There is a recessive gene in 90%, and in this situation both parents must carry the gene and 25% of children will be affected. Consanguinity increases recessive transmission. There is, therefore, sometimes a positive family history of deafness. There are many hereditary syndromes with hearing loss as a feature. Some examples include:

• Waardenburg syndrome – epicanthic folds, different-coloured irises, white forelock

• Usher syndrome – retinitis pigmentosa, epilepsy

• Pendred syndrome – sporadic thyroid disease

• Alport syndrome – progressive renal disease

• Hurler syndrome – gargoylism

• Fanconi syndrome – anaemia, skin pigmentation, skeletal deformities, mental retardation.

Prenatal acquired deafness

Damage in the first trimester can affect the developing cochlea. Detailed radiological imaging will define the Michel deformity, which is total absence, and the Mondini deformity, which is partial maldevelopment of the bony cochlea. The Scheibe deformity has a normal bony cochlea but damaged hair cells in the organ of Corti. Causes of prenatal acquired deafness include maternal infection such as rubella, cytomegalovirus, toxoplasmosis, herpes and congenital syphilis. Drugs that are ototoxic to the embryo include aminoglycosides, loop diuretics, quinine and thalidomide.

Perinatal acquired deafness

Causes include prematurity, prolonged or difficult labour, hypoxia, Rhesus incompatibility, kernicterus, ototoxins, infectious diseases and others.

Deafness in infancy and childhood

The common causes of acquired deafness at this age are mumps, measles, meningitis, traumatic fracture of the petrous bone through the inner ear or acoustic nerve, and patent cochlear aqueduct. Fortunately in these cases, if only one ear is affected, the handicap is not as devastating as with bilateral deafness.

Treatment of sensorineural deafness

Most deaf children have normal intellectual capacity and some usable residual inner ear function. The diagnosis must be made early and the child fitted with hearing aids or be considered for a cochlear implant. He or she should receive early and con-tinued auditory training. Many such deaf children learn to understand the spoken word, to develop intelligible speech and play an active role in society. However, the hearing of speech sounds does not guarantee normal understanding, as amplification may be accompanied by distortion and decreased intelligibility. Thus general practitioners, paediatricians and otologists have an enormous responsibility to take the mother’s suspicion of deafness seriously and arrange prompt investigation and assessment. Early diagnosis is the key to optimal outcome.

A geneticist should give advice to parents who have had a deaf child and who want to know the chances of having another – is the problem dominant deafness or recessive? The ability to identify previously undiagnosed cases of hereditary deafness on the basis of specific genetic testing has improved. DNA-based testing is available for the diagnosis of mutations that cause deafness, often those in the GJB2 gene which encodes the protein connexin 26. Up to 50% of those with non-syndromic deafness have mutations in the gap junction protein beta-2 gene.

The nose

Congenital conditions

Many congenital anomalies affect the nasal structures:

• craniofacial and external nasal malformations

• cleft lip, palate and face clefts

• haemangioma and vascular malformations

• dermoid, encephalocele, nasolacrimal duct cyst and other rare masses

• bilateral congenital choanal atresia poses the greatest threat to life because neonates, being obligate nose breathers, develop increasing cyanosis and even fatal asphyxia when their nasal airways are completely obstructed. However, if the baby cries and takes a breath through the mouth the obstruction is momentarily relieved until the mouth closes. Choanal atresia can be confirmed by failure to pass a 3  mm diameter plastic catheter through the nose into the oropharynx. The airway can be maintained using a Guedel oral airway or an endotracheal tube pending computed tomography (CT) assessment and surgical correction

• unilateral choanal atresia presents as persistent glairy discharge later in life.

Acute rhinosinusitis

Acute infective rhinosinusitis presents with purulent nasal discharge, nasal obstruction, pain and tenderness over the involved sinuses, and general malaise. The acute episode often follows an upper respiratory tract infection, swimming or diving and usually affects the maxillary sinuses, and in older children the ethmoid sinuses. Plain X-rays and CT are required only in difficult cases. Treatment is symptomatic, using decongestant nasal drops or oral decongestants and paracetamol. Antibiotics are given in severe, persistent, recurrent or complicated cases. Amoxicillin for 7–10 days to cover the common upper respiratory tract pathogens is the drug of first choice. In penicillin-hypersensitive patients use cefaclor, erythromycin or doxycycline (not in children under 8 years).

Infective rhinosinusitis in infants and children usually responds to medical treatment. Surgical drainage may be necessary for chronic disease or for acute complications such as subperiosteal abscess, periorbital cellulitis, osteomyelitis or intracranial spread.

Chronic rhinosinusitis

Chronic rhinitis often has an allergic basis, with secondary bacterial infection being common. In younger children it is aggravated by, or inseparable from, hypertrophy and infection of the adenoids. Swollen turbinates cause intermittent or persistent nasal stuffiness and catarrhal discharge. Therapy with antihistamines and pseudoephedrine may be helpful but symptoms are more often controlled with regular use of intranasal metered aerosol steroid spray. Nasal allergy, often with hay fever or asthma, may be traced to specific allergens, which should be avoided where possible. Desensitization can be considered in older children. In severe, persistent cases cautery, laser or surgical reduction of the inferior turbinates may provide substantial relief. Nasal polyps in children strongly suggest cystic fibrosis.

Nasopharyngeal tumours and cysts

Antrochoanal polyp, dermoid cyst, meningoencephalocele, glioma and chordoma are rare benign conditions. Nasopharyngeal angiofibroma is an uncommon locally destructive, non-metastasizing very vascular tumour occurring mostly in adolescent boys. It usually presents as frequent, often severe, epistaxes and nasal obstruction. Treatment is surgical removal after embolization of the feeding vessels, although some advocate radical radiotherapy. Rhabdomyosarcoma or lymphosarcoma are rare malignant nasopharyngeal tumours.

Trauma

Fracture or dislocation deformity of the external nose and nasal septum sometimes occurs during a difficult birth or after forceps delivery. The degree of displacement and nasal obstruction are occasionally severe enough to require correction in the neonatal period. Injuries of the nose, nasal bones and nasal septum occur commonly when toddlers fall during vigorous play and in older children during contact sports. Depressed, displaced nasal bones require correction within 10 days. Haematomas of the nasal septum should be drained and treated with antibiotics to minimize development of a septal abscess, which destroys cartilage and can lead to a saddle nose deformity.

Foreign bodies

Unilateral purulent, sometimes bloodstained nasal discharge in a young child suggests the presence of a foreign body, such as a bead, eraser, piece of vegetable or other material, until proven otherwise. Unreactive inorganic objects may remain undetected for months or years. The most dangerous foreign body is an alkaline battery, which emits a small current and leaks its caustic contents, rapidly causing local tissue necrosis; it must be treated as an emergency. Removal may require general anaesthesia.

Epistaxis

Bleeding from a prominent vessel on the anterior nasal septum (Little’s area) is common and is sometimes frightening for parents. It may be aggravated by accidental trauma, nose picking, nose blowing and infection. Occasionally epistaxis may be the presentation of a blood dyscrasia or a nasopharyngeal angiofibroma. First aid is to apply constant pressure to the side of the nose with a cold face cloth for at least 5 minutes. Packing with ribbon gauze controls many persistent cases. If the bleeding continues and the vessel can be identified, it can be thermally or chemically cauterized using topical anaesthesia in older cooperative children or under general anaesthesia in others.

Clinical example

Benjamin, aged 9, was struck on the nose by the seat of a swing while he was playing in the park. His nose bled, appeared ‘crooked’ and became swollen. He was taken to the casualty department, where the ENT registrar confirmed traumatic fracture of the nasal bones by clinical examination. Corrective surgery was arranged for later in the week.

Bruising and swelling will rapidly hide the deformity. Careful palpation usually confirms the displacement without the need for X-ray.

The oropharynx

Acute sore throat (AST) in children is a common problem. The illness can be due to viral, bacterial, fungal or other infectious microorganisms or of unknown aetiology. Most children have a cold and nothing more and are better in less than a week. A number of questions arise. Is the infection due to a respiratory virus or to a bacterial infection? Is a throat swab useful? Are antibiotics justified? Is the sore throat a manifestation of a more serious systemic disease? Is admission to hospital necessary?

Arbitrary division of the acute infectious process into the descriptive ‘diagnostic’ categories rhinitis, nasopharyngitis, stomatitis, pharyngitis and tonsillitis is somewhat unsatisfactory because the inflammation often extends to overlap nearby areas. Nevertheless, the majority of patients with an acute sore throat can be described as having either acute ‘pharyngitis’ or ‘tonsillitis’.

Inflammation is widespread in the mucous membrane in ‘pharyngitis’ which can be caused by one of many viruses, whereas in more localized ‘tonsillitis’ the pathogen is usually either group A beta-haemolytic streptococcus (S. pyogenes) or a virus – adenovirus, Epstein–Barr virus (EBV) or Coxsackie A virus. The differentiation of bacterial from viral infection on clinical grounds is far from easy – often no more than an educated guess – because, for the most part, the symptoms and local signs accompanying AST correlate poorly with the presumed (or later proven) aetiological microorganism. Most acute upper respiratory tract infections that cause sore throat, fever and swallowing discomfort last 3–6 days, are viral and are mild in severity. They seldom warrant antibiotic treatment.

In approximately 50% of patients with acute sore throat beta-haemolytic streptococci can be isolated by surface throat culture; it seems reasonable to assume a cause and effect relationship. In fact this organism is more likely to be pathogenic when there are also local clinical findings of intense cellulitis of the uvula and soft palate and haemorrhagic palatal petechiae. Remember that 10–20% of otherwise normal children may be carriers of beta-haemolytic streptococci.

What, then, is acute tonsillitis? Acute tonsillitis has been defined clinically as a condition in which not only is inflammation mostly confined to the tonsils but the clinical features also include acute sore throat, fever, difficulty in swallowing, enlarged tender regional cervical lymph nodes, halitosis and constitutional symptoms such as lethargy, nausea and vomiting. Sometimes there is abdominal pain. Examination can show various appearances in tonsillitis:

• red mucosa over the tonsils and oedematous, generalized inflammation (parenchymatous tonsillitis)

• yellowish-white exudate in the crypts of the tonsils (follicular tonsillitis)

• the crypts become filled with ‘debris’, an exudate of desquamated epithelium and pus

• coalescence of these follicles can form a thin, white, non-confluent, patchy membrane that peels away without bleeding (membranous tonsillitis)

• the typical redness, oedema and purulent secretion (exudative tonsillitis). Note that this appearance is not necessarily diagnostic of streptococcal infection.

Acute sore throat is one of the commonest complaints seen in general practice. It is occasionally a manifestation of a serious systemic disease. A useful classification of causes includes:

• acute viral pharyngitis. Examples are coryza, influenza, parainfluenza, the viral exanthemas and infections with Coxsackie viruses (herpangina), the ECHO virus group and many others. Coryza (common cold, viral nasopharyngitis, viral catarrh) is usually caused by rhinoviruses and coronaviruses in winter and spring and by enteroviruses in summer and autumn and at other times by other viruses. Coryza is highly infectious. There is an initial burning sensation above the palate, then sore throat, which is generally not severe, minimal fever, stuffy nose, rhinorrhoea and conjunctivitis. It usually resolves in 4–5 days. Complications include acute sinusitis, otitis media and lower respiratory tract infections

• acute bacterial tonsillitis, often due to beta-haemolytic streptococci but occasionally to other bacterial organisms in immunocompromised patients. It seems also that adenoviruses and Epstein–Barr viruses may lie dormant in tonsils for years and can be activated by non-specific environmental factors such as fever, chilling and stress

• infectious mononucleosis (glandular fever), caused by the Epstein–Barr virus, has many manifestations. Acute sore throat is consistently a prominent feature

• thrush, due to Candida albicans and predisposed to by diabetes, general debility, immunosuppression, nutritional deficiency and disturbances in the normal flora due to prolonged administration of antimicrobial agents. There is a wide range of appearances but characteristically there are white, curd-like, adherent patches overlying inflamed mucosa on the gingival surfaces

• Vincent angina (also known as ulceromembranous gingivostomatitis), caused by a combination of the normal spirochaetes of the mouth and mixed anaerobic bacteria often in injured necrotic tissue of the gums, which provides the necessary anaerobic environment

• diphtheria is now uncommon yet it remains a potentially lethal acute infection, caused by Corynebacterium diphtheriae, which produces a powerful exotoxin. A sore throat is part of the much more serious systemic toxic illness

• aphthous stomatitis. The cause is unknown. These recurrent, non-infective, well demarcated, painful ulcers have an erythematous border and are usually in the anterior part of the oral cavity on the mucosa of the lips, mouth and gingivae and the borders of the tongue, but when they occur in the soft palate or the fauces the patient complains of sore throat

• patients with acute leukaemia, agranulocytosis, aplastic anaemia or HIV infection may present with an acute sore throat.

Approximately 50% of cases of acute sore throat are eventually proved to be bacterial. Pending the result of culture it would seem prudent to immediately treat with an antibiotic those children who are extremely ill or toxic, and to await the result of culture in other children.

Examination of the mouth and throat

Older children are examined sitting up in a chair or on a bed and younger children sitting on mother’s lap or lying on the bed. It may be helpful to have an assistant steady the head. A torch with a bright light and a wooden tongue depressor is usually used but, where available, a headlight and an angled metal tongue depressor will provide a better view of the oropharynx. The lips, buccal mucosa, teeth and gums, floor of the mouth and the tongue are examined and then the palate, tonsils and posterior pharyngeal wall.

In severely ill children, brief examination of the oropharynx will eliminate grossly enlarged tonsils, peritonsillar abscess, retropharyngeal abscess and the rare case of diphtheria. In suspected acute epiglottitis care must be taken not to worsen airway obstruction, and the oropharynx should only be examined under expert controlled conditions if epiglottitis is a significant possibility.

Throat swab and rapid antigen testing

Pharyngitis caused by adenoviruses or herpes simplex is generally indistinguishable from that caused by S. pyogenes. Viral studies are rarely helpful. The only way to confirm a bacterial infection and justify treatment is to identify the streptococcal organism using a rapid antigen test or to take a throat swab, if facilities for culture and laboratory identification are available. Although not diagnostic, at times a Gram stain for tentative identification would be a reasonable basis for the commencement of antibiotic therapy. Identification of S. pyogenes allows logical use of an antibiotic for those few who are judged to be unduly ill or those ‘at risk’ (see below under Antibiotics) and as a valuable reference in a patient who may later be suspected of having rheumatic fever.

Although seldom used, rapid immunological tests employ antiserum against group A streptococcal antigen. Streptococci obtained from a throat swab by chemical or enzymatic extraction are tested for agglutination using antibodies to group A Streptococcus. Such tests are reasonably accurate but the false-negative rate can be up to 30% – then a throat swab may be necessary.

A throat swab should preferably be taken before any antibiotics are given. Technique is important – with adequate exposure and illumination, sterile cotton wool swabs are rubbed vigorously on the areas of inflammation or exudate on the tonsils and posterior pharyngeal wall and put directly into a sterile container. Because the throat is normally colonized by many organisms, laboratory tests taking 24–48 hours are done to single out and identify the group A beta-haemolytic streptococcus. Remember, if diphtheria is a possibility the laboratory should be contacted as special tests are necessary.

Antibiotics

The difficult dilemma is that, although it might often seem reasonable to give antibiotics to a sick child with a sore throat, available evidence does not support their administration whether the infection is streptococcal or viral. When laboratory confirmation of a bacterial cause is available it is rational to give antibiotics to those at risk of remote complications such as post-streptococcal rheumatic fever or, less likely, acute glomerulonephritis. In others, the risk of these complications is not increased by delay in giving antibiotics for 24–48 hours: in fact treatment begun within 7–9 days of the onset is effective. Bear in mind that 10–20% of otherwise normal children may be carriers of S. pyogenes and that considerably fewer than 50% of cases of AST are eventually proved to be bacterial. In many cases no pathogen is isolated.

Antibiotics confer minimal worthwhile benefit (symptoms may last for 1 day less) over purely symptomatic treatment (rest, paracetamol and fluids) and are seldom effective in preventing suppurative complications except in high-risk groups. Nevertheless, pending the result of a throat swab, it might be prudent to immediately treat those who are unduly ill or toxic or those at risk, including diabetics, immunocompromised individuals and Aboriginal, Torres Strait and Pacific Islander children.

There are many proprietary ‘remedies’ available for upper respiratory infections and sore throat but none can be recommended. Throat lozenges, including those containing antibiotic, are of no use and antihistamine/decongestant preparations can lead to troublesome side effects.

Practical points

Features associated with an acute sore throat which should alert a perceptive medical attendant to a possible serious condition:

• Undue toxicity – the child appears sicker than might be expected

• Signs of respiratory distress, stridor or restlessness

• Difficulty swallowing or drooling

• Dehydration

• Marked or generalized lymphadenopathy

• Unilateral swelling in the pharynx

• Bruising or bleeding

• An adherent or obstructive membrane

Clinical example

The family doctor saw Andrew, a 7-year-old boy who had had a sore throat, difficulty in swallowing and fever for 2 days. The appearance in the throat was described as ‘tonsillitis’. An antibiotic was prescribed but when he was no better 3 days later it was changed to a different antibiotic. Again, Andrew was no better and in addition was complaining of feeling weak, with aching in the muscles and headache. Careful examination 8 days after the illness had commenced revealed tender, enlarged lymph nodes in the neck, axilla and inguinal region. His spleen was enlarged and tender. Blood tests were diagnostic of infectious mononucleosis.

An atypical sore throat needs caution about the diagnosis. Infectious mononucleosis is a systemic illness whose principal features are sore throat, fever, cervical (often generalized) lymphadenopathy and a feeling of malaise. Many organs in the body can be affected with protean manifestations. Antibiotics have no therapeutic value.

Indications for tonsillectomy and adenoidectomy

There is now reliable information to prove that the frequency of throat infections is reduced in selected patients undergoing these procedures. Operation is clearly indicated in a small number of children. There may be disagreement about the operation in individual cases and at times a second opinion may be in the best interests of the patient.

Indications for tonsillectomy

The indications for tonsillectomy are:

• repeated attacks of acute tonsillitis: at least three documented attacks a year for 2 years or more, making a minimum of 6 attacks in 2 years

• acute or chronic upper airway obstruction caused by enlarged lymphoid tissue. There may be an obstructive sleep pattern, even apnoea. Some cases with severe obstruction develop cardiac changes and cor pulmonale

• chronic tonsillitis. This usually applies to older children and adults

• peritonsillar abscess (quinsy). Two or more attacks are a definite indication for tonsillectomy

• biopsy excision for suspected new growth.

Indications for adenoidectomy

The indications for adenoidectomy are:

• enlargement causing severe nasal obstruction and breathing discomfort

• persistent discharge of infected mucopurulent material caused by large and infected adenoids

• possible benefit in repeated acute or chronic ear disease.

The tonsils and adenoids are often removed in a single, combined operation but there are clear indications for tonsillectomy alone or adenoidectomy alone. There is now greater awareness of the incidence and severity of obstructive sleep problems, which occur in an age range from 6 months to 10 years of age.

Contraindications to tonsillectomy and adenoidectomy

Tonsillectomy and/or adenoidectomy should not be performed if there is:

• a lack of staff or facilities to recognize and manage the potential complications

• recent respiratory tract infection, within the previous 2 weeks

• a systemic disorder, such as poorly controlled diabetes

• a bleeding disorder

• pharyngeal insufficiency, such as repaired cleft palate, submucous cleft palate or paralysis or paresis of the palate and so called ‘short’ palate. Adenoidectomy may cause or worsen escape of air through the nose (hypernasality), making speech difficult to understand.

Injuries of the tongue and oropharynx

Children with, for example, a pencil in the mouth may fall and injure the soft palate, tonsils or pharyngeal wall. At other times it is not uncommon for the teeth to lacerate the tongue and cause considerable bleeding. It is usually necessary to suture only the most severe of these injuries.

The larynx and trachea

Features of upper airway disease include:

• stridor: a prominent, audible manifestation of upper airway obstruction caused by turbulent airflow through a narrowed airway, usually the larynx or sometimes the trachea. It is most often inspiratory, sometimes expiratory and occasionally both

• other signs of partial or severe airway obstruction: tachypnoea, chest retraction

• cyanotic or apnoeic attacks

• husky, weak or absent cry

• repeated aspiration

• recurrent or atypical croup

• features of weakness, compression or stenosis of the trachea and/or bronchi.

Laryngomalacia

This is a common cause of stridor in infants. It is also appropriately called ‘floppy larynx’, both names implying collapse of the supraglottic tissues during inspiration. The cause is unknown. The features are intermittent inspiratory stridor, signs of upper airway obstruction, a normal cry and general health that is usually (but not always) normal. The features are often alarming to parents. As the condition is usually self-limiting there is seldom any need for treatment once a certain diagnosis has been established to differentiate laryngomalacia from the many other causes of stridor in infants. Occasionally, severe cases warrant laser removal of part of the redundant, floppy, supraglottic tissues.

Clinical example

Simon, aged 2 years and 6 months, ran to his mother in great distress, gasping for breath, coughing and crying. She rushed him to the nearby emergency department. The respiratory distress had lessened but pulse oximetry showed only 90% saturation. There was a wheeze and decreased air entry on the right side. An expiratory chest X-ray showed air trapping on the same side with shift of the mediastinum to the left. Simon was observed in the high-dependency ward until an impacted peanut was removed from the right main bronchus under general anaesthesia 90 minutes later. He made an uneventful recovery thereafter.

With inhalation of foreign bodies into major airways, if death does not occur in the first few minutes after inhalation, the situation usually improves but the implications remain serious. In this case the peanut, acting as a ball valve in the right main bronchus, let air into that side, but as the bronchus narrowed during expiration air was trapped in the lung.

Congenital and acquired subglottic stenosis

The reported incidence of subglottic stenosis has increased, partly because of the improved survival of premature babies who have been treated by prolonged intubation and partly because of more accurate diagnosis. Severe cases require tracheotomy and later repair by rib graft laryngotracheoplasty or even cricotracheal resection.

Vocal cord paralysis

Unilateral paralysis causes few symptoms in infants and children. Bilateral vocal cord paralysis is the cause of stridor in about 10% of infants with airway obstruction and is associated with a central nervous system anomaly (e.g. Arnold–Chiari malformation) in many cases. Tracheotomy is usually, but not always, required for bilateral paralysis.

Other causes of stridor

Laryngeal web, laryngeal atresia and laryngeal cleft are uncommon anomalies. Cysts causing clinical features include retention cysts, congenital cysts and cystic hygroma. Subglottic haemangioma is the commonest laryngeal tumour in infants and presents with inspiratory stridor in the first 6–8 weeks. The clinical features of tracheal obstruction are caused by tracheomalacia, tracheal compression by a vascular ring or other anomalies or congenital tracheal stenosis.

Investigations include X-rays, CT, contrast oesophagogram and ultrasound of the neck or mediastinum. Flexible laryngoscopy and direct laryngoscopy, bronchoscopy and possibly oesophagoscopy under general anaesthesia ultimately establish a firm diagnosis.

Acute inflammatory airway obstruction

Acute infectious diseases of the upper respiratory tract that cause airway obstruction fall into two groups:

• Oropharynx. Acute bacterial or viral infection with obstructive hypertrophy of the tonsils and adenoids; infectious mononucleosis causing obstructive enlargement of the tonsils and adenoids; peritonsillar abscess; retropharyngeal or parapharyngeal abscess and Ludwig’s angina

• Larynx and trachea. Acute laryngotracheobronchitis or croup; spasmodic croup; bacterial tracheitis; acute supraglottitis or epiglottitis (with a frighteningly rapid onset) and diphtheria. Some cases (especially patients with acute supraglottitis, epiglottitis or diphtheria) have critical, life-threatening airway obstruction, a situation that requires immediate recognition and transfer to a paediatric hospital for relief of airway obstruction, if necessary by endotracheal intubation or tracheotomy, and intensive care management.

Important advances in treatment of these diseases include more effective antibiotics, diphtheria immunization, diphtheria antitoxin, the use of racemic adrenaline (epinephrine) for croup, steroids for croup, Hib vaccine, which has dramatically reduced the incidence of H. influenzae supraglottitis and epiglottitis, and the use of intubation in place of tracheotomy.

Multiple respiratory papillomas

Papillomas are the most common benign growths in the larynx. Human papillomavirus (HPV) type 6, type 11 and occasionally type 16 cause papillomas in the respiratory tract, most often in the mucosa of the larynx. About two-thirds of patients are younger than 15 years and one-third older than 15 years, with the highest incidence before the age of 5 years. There is a tendency for recurrence after removal, although sometimes unexpected spontaneous improvement can occur. In infants, large obstructing masses may threaten life. There is a strong association between recurrent respiratory papillomas in infants and children and maternal condylomata acuminata or genital warts but transmission of HPV during passage through the birth canal is unlikely, as some infants have papillomas already in their larynx at birth.

Growth may be slow and persistent or irregular and unpredictable. The commonest presentation is a change in the cry or voice, sometimes with increasing airway obstruction, and often an erroneous diagnosis of asthma, laryngitis, bronchitis or croup has been made. Therefore, persistent or progressive huskiness in an infant or child should suggest the possibility of papillomas. The mainstay of treatment is repeated removal at microlaryngeal surgery under general anaesthesia, using forceps or the carbon dioxide laser, which is a precise modality attended by minimal bleeding, causing little pain and limited local scarring. Many adjunctive treatments have been tried because of frustration and recurrence of the tumour but none of these have proved beneficial over the long term. There is no tendency for regression or disappearance at puberty, as was formerly thought.

Ingested and inhaled foreign bodies

Foreign bodies in the pharynx and oesophagus

Children often swallow foreign bodies. Sharp objects such as fishbones can impact in the tonsils, base of the tongue or the pyriform fossa. More often objects such as coins, buttons, lumps of meat or vegetable, plastic or pins lodge somewhere in the oesophagus, usually at the upper end but occasionally at a site of pathological narrowing (stenosis). Some show on X-ray but, ultimately, if an impacted foreign body is suspected, oesophagoscopy is necessary. Remember most small smooth objects will pass through the oesophagus and the gastrointestinal tract and be recovered in the stools; however, ingestion of a small alkaline button battery is extremely destructive of surrounding tissue and must be treated as an acute emergency to prevent perforation of the oesophagus and mediastinitis.

Clinical example

Simon, aged 2 years and 6 months, ran to his mother in great distress, gasping for breath, coughing and crying. She rushed him to the nearby emergency department. The respiratory distress had lessened but pulse oximetry showed only 90% saturation. There was a wheeze and decreased air entry on the right side. An expiratory chest X-ray showed air trapping on the same side with shift of the mediastinum to the left. Simon was observed in the high-dependency ward until an impacted peanut was removed from the right main bronchus under general anaesthesia 90 minutes later. He made an uneventful recovery thereafter.

With inhalation of foreign bodies into major airways, if death does not occur in the first few minutes after inhalation, the situation usually improves but the implications remain serious. In this case the peanut, acting as a ball valve in the right main bronchus, let air into that side, but as the bronchus narrowed during expiration air was trapped in the lung.

Foreign bodies in the larynx and tracheobronchial tree

The highest incidence of inhaled foreign bodies is in the second and third years of life and about 60% of deaths occur in children less than 4 years of age. Occasionally they lodge in the larynx or subglottic region but more often in one or other main bronchus. Diagnosis is made by awareness of the possibility and from a history of inhalation of a foreign body (a history of possible inhalation is present in about 65% of cases).

The clinical presentation may be:

• immediate, with sudden coughing, choking, gasping, spasm and cyanosis. Fortunately, few deaths occur in this stage

• delayed, with wheeze, chronic cough, atypical pneumonia, and chest X-ray changes (but about 20% show no abnormality). The foreign body may be found days, weeks or even months later

• symptomless. Although most foreign bodies will ultimately cause symptoms, occasionally some are found by chance on a chest X-ray or at endoscopy.

Only 5–10% of ingested foreign bodies impact in the larynx or subglottic region and then stridor, laryngospasm, dyspnoea, a husky voice, inspiratory wheeze or repeated atypical croup dominate the clinical picture. If death does not occur in the first few minutes after the foreign body is inhaled, the prognosis is good if the patient is promptly transported by road or air ambulance to a major paediatric unit where experienced personnel and adequate instruments are available. Ill-advised attempts at bronchoscopic diagnosis or removal by inexperienced surgeons or anaesthetists often worsen the situation.

Two-thirds of inhaled foreign bodies are nuts. Parents should be made aware that children under 4 years of age should be denied access to nuts, especially peanuts, in the hope that aspiration accidents will be minimized.

22.2

Eye disorders in childhood

J. E. Elder

A systematic approach to children’s eye disease allows rapid determination of the correct diagnosis or initiation of appropriate further investigation.

Visual development

A rapid sequence of anatomical and functional changes in the visual apparatus enables vision to develop from a very low level after birth to near adult levels by 12–18 months of age. At birth an infant has visual acuity of approximately 6/120 and by 12 months this has improved to about 6/12. This rapid development is the result of retinal maturation, myelination of the visual pathways, the ability to accommodate (change the focal length of the eye) and maturation within the visual cortex. The first three of these processes (retinal maturation, myelination and accommodation) are complete by 4–6 months of age. The maturation of the visual cortex occurs more gradually, over a 6–8-year period, with the most rapid phase being in the first 2 years. Anything that interferes with this gradual cortical maturation may result in the development of amblyopia, which is one of the commonest ophthalmic abnormalities of childhood (see Amblyopia, below).

Measurement of vision in children

Measurement of visual acuity in preverbal children presents a challenge. Asking the parent ‘Does your child see well?’ or ‘How well do you think your child sees?’ often gives useful information about an infant’s visual function. If a parent expresses concern about an infant’s vision, take note, as this concern is often well founded.

An understanding of normal visual behaviour is vital to estimating visual function in infancy. At birth, when alert, an infant should be able to fix on a face briefly. By 6 weeks of age most infants smile in a visually responsive fashion to a face. At this age the infant will also be able to follow a face or light through an arc of 90°. By 6 months of age an infant can reach for a small object and can actively follow objects in the visual environment. At 12 months of age a child should be able to reach and pick up tiny objects such as hundreds-and-thousands (‘sprinkles’).

More formal assessment of visual acuity becomes possible with the development of language. Children with specific language delay or more general intellectual delay will have difficulty with these tests of visual acuity. Picture-naming tests can be done by children between 2 and 3 years of age. Single letter-matching tests are within the abilities of most 3–4-year-olds. The standard Snellen chart test is often not performed well until the child is between 5 and 6 years of age. The vision should be tested for each eye individually. As with all testing in children, patience and an encouraging manner are vital to obtain the best results. Repeat the test on another occasion if the test results seem inaccurate.

The notation for documenting visual acuity is the Snellen fraction, e.g. 6/6. Most visual acuity tests use standard distances of 3 or 6  m between subject and chart. The numerator of the Snellen fraction is the distance from the chart while the denominator indicates which line on the chart was the smallest to be seen. If the vision is poor the subject should be brought closer to the chart. The vision then may be recorded as 2/18 or 1/60, etc., depending on how close the subject is to the chart and which line is read.

What level of vision is abnormal? (or, when to refer!)

This depends on the age of the child. An infant who is not fixing and following by 3–4 months, or reaching for small objects and tracking objects in the visual environment by 8–12 months, deserves further examination and investigation.

If the child is able to do a more formal test of acuity, a difference between the two eyes of two or more lines (that is 6/6 and 6/12) indicates the need for further assessment. In children less than 3 years of age vision of 6/18 or less in either eye should prompt referral and in children older than 3 years 6/12 is an acceptable cut-off for referral.

Assessment of a child with a possible eye problem

History

Prematurity, perinatal difficulties (e.g. birth asphyxia), significant syndromes (e.g. Down syndrome) and other sensory impairment (e.g. deafness) are associated with an increased risk of eye disease. Developmental delay often interferes with assessment of visual acuity, especially if language or intellect is affected. Common childhood eye problems such as strabismus and refractive errors have a clearly identified familial tendency, although the precise genetics are not well understood. Finally, the parents’ perception of a child’s visual function is important, particularly if there is concern that the vision is poor.

Examination

In keeping with paediatrics in general, observation without approaching or touching a child often supplies a great deal of information. By observation it is possible to rapidly determine an infant’s use of vision. Does the child smile at a face? Is the child looking around the room? If something moves, does the child look to it? If there is a noise, does the child look to the source of the noise? A blind child will become still and will often drop the head down while using hearing to further localize the source of the sound, but will not look towards this source.

Most eyelid, eyelash and ocular surface abnormalities can be detected readily by simple observation. Many intraocular abnormalities can be detected by examination of the ‘red reflex’. This is the red to orange colour seen within the pupil when the line of illumination and observation are approximately coaxial (that is, the same). This situation is most easily obtained by observing the child’s eye with a direct ophthalmoscope from a distance of about 1  m. It is then easy to compare the reflexes for the two eyes and the child is not threatened by the examiner getting too close. A dull or absent red reflex indicates an opacity, such as a cataract, in the normally clear media of the eye. A white reflex results from an abnormally pale reflecting surface within the eye, such as a white retinal tumour (retinoblastoma). While these intraocular disorders are rare, they are important in terms of the severe effect on vision or threat to life.

Misalignment of the eyes

Strabismus or squint is common in childhood and accurate assessment to confirm or refute the presence of misalignment is an important skill for anyone who deals with children.

Observation will confirm the presence of large-angle strabismus. However, a broad nasal bridge or prominent epicanthic folds will mimic milder degrees of strabismus, especially in younger infants. This situation is known as pseudostrabismus (Fig. 22.2.1). The epicanthic folds cover the sclera on the medial aspect of the globe while the lateral sclera is easily visible. This creates the appearance of misalignment, particularly when the child looks laterally. Examining the symmetry of corneal light reflections will help to avoid being misled by pseudostrabismus.

The cover test is by far the most reliable method of detecting strabismus. The cover test is done by first getting the child to fix on an object while the observer determines which eye appears to be misaligned. The eye that appears to be fixing on the object (and not misaligned) is then covered while the apparently misaligned eye is observed. If strabismus is present a corrective movement of the misaligned eye will be seen as this eye takes up fixation on the object of regard (Fig. 22.2.2). If no movement is seen then the eye is uncovered.

The cover test is then repeated but the other eye is covered this time and the eye that is not covered is again observed for a corrective movement and, if present, strabismus is confirmed. The test can be repeated as many times as necessary. If no movement is seen following repeated covering of either eye, then no strabismus is present. Care must be taken to let the child fix with both eyes open before covering either eye, otherwise normal binocular control may be prevented and a small latent squint (phoria) may be detected. Latent squints are normal variants and are of no significance.

Common eye problems in childhood

Amblyopia

Amblyopia is the cortical response to abnormal input from the eyes and is manifest as reduced visual acuity in one or both eyes. This abnormal input may result from a refractive (spectacle) error, a structural abnormality of the eye (e.g. cataract) or strabismus. Provided it is detected early enough, while the developing visual cortex is immature, amblyopia is treatable. Conversely, if the amblyopia is not treated before visual cortex maturation (about 7 years of age), it may not be reversible later in life. Detection of amblyopia is one of the major reasons for routine visual screening in childhood.

Common causes of amblyopia are strabismus and refractive errors. Refractive errors cause a poorly focused image to form on the retina and thus a poor-quality image to be transmitted to the cortex. Such input does not stimulate normal cortical development and amblyopia results. Strabismic (misaligned) eyes are not necessarily out of focus; however, if the cortex ‘paid attention’ to the image from each eye diplopia would result, as each eye is sending a different view of the world. In children, the immature visual cortex is capable of ignoring the image from one eye. If this situation is allowed to persist the cortex may completely ignore or suppress the input from a deviating eye and amblyopia will result.

Treatment of amblyopia involves correcting any focusing errors with appropriate spectacles and forcing the brain to use the amblyopic eye by depriving the brain of clear input from the better-seeing eye, most commonly with a patch. Unfortunately, simply realigning strabismic eyes is not enough to overcome amblyopia secondary to strabismus.

Strabismus

A squint or misaligned eye is important to detect as it is frequently associated with amblyopia. Most childhood strabismus is the result of failure of binocular control at a cortical level within the central nervous system (CNS). Less commonly it is the result of cranial nerve lesions or extraocular muscle disease. In most children this CNS abnormality in eye movement control is an isolated abnormality with no other associated neurological or intellectual problems. However, children with widespread CNS abnormalities have an increased risk of developing strabismus. Down syndrome is a good example of this, with an approximately tenfold increase in the risk of developing strabismus.

The diagnosis of strabismus is outlined above and detailed consideration of the therapy of strabismus is beyond the scope of this chapter. The following is a brief description of the commoner patterns of strabismus seen in childhood and an outline of management.

Infantile esotropia

This is a large-angle convergent squint seen before 6 months of age. Strabismic amblyopia is common in infantile esotropia but refractive errors are rare. Patching followed by surgery is the most common initial treatment. Children with infantile esotropia need to be followed up throughout childhood, as about one-third need more than one operation and amblyopia can occur following apparently successful initial treatment.

Intermittent divergent strabismus

This occurs from 18 months of age onwards. It is often more noticeable on distance fixation and may be associated with closure of the deviating eye, especially in bright light. Amblyopia is uncommon, as the deviation is intermittent and presumably when the eyes are straight normal visual development proceeds. In some cases the divergence becomes more constant and in such situations surgery may be undertaken to improve alignment.

Accommodative esotropia

This occurs in children who are excessively long-sighted (hypermetropic). To overcome hypermetropia and focus a clear image on the retina, accommodative effort is used. Accommodation consists of the combination of changing focal length of the lens and converging the eyes (so that both are directed at the nearer object of regard). Thus in children with excessive hypermetropia there is increased focusing and at times excessive convergence; that is, a convergent squint (esotropia) appears as a result of the increased accommodative effort used by these children. Accommodative esotropia can be completely or partially corrected by prescribing glasses that compensate for the appropriate amount of hypermetropia. Amblyopia is often seen in association with accommodative esotropia and requires treatment. If glasses only partly correct the esotropia, surgery may be indicated to obtain optimal alignment.

Clinical example

A 3-year-old girl presented with a history of a worsening inward turn of her left eye over four months. The cover test confirmed a left convergent squint and the red reflex was normal in each eye. Subsequent assessment by an ophthalmologist confirmed the findings and her visual acuities were 3/3 in the right eye and 3/9 in the left with refraction showing she was long-sighted. When next seen 6 months later she was wearing glasses and had been patching her right eye 2 hours a day. Her eyes were straight to cover test and her parents reported that her left vision was slowly improving and that surgery was not going to be required in her case.

Refractive problems

Refractive problems are the result of defects in the focusing components of the eye. These defects include abnormality of corneal curvature (a frequent cause of astigmatism) and abnormalities of lens power and axial length of the eye (which may result in hypermetropia or myopia – short-sightedness). Children will rarely complain of poor vision related to refractive error. Rather, they readily accept the vision they have and get on with life. Children with high myopia will often manifest myopic behaviour (they will go very close to objects to look at them). Different refraction in either eye will often result in amblyopia because one eye will generally have a clearer image than the other and thus enable better cortical development for that eye.

Routine screening of visual acuity is the only reliable way of detecting the majority of refractive errors in children. In many countries there are both preschool and school entry tests of visual acuity for this reason. Such screening testing needs to be reliable, available to all of the target population and followed up with appropriate intervention when defects are identified. As cortical maturation of vision occurs at about 7 years of age, screening should ideally commence in 3–4-year-olds, before any amblyopia becomes difficult to reverse.

If a refractive error is suspected in a young child because of strabismus or poor visual acuity, then accurate and objective testing with cycloplegic retinoscopy is required. If a child is prescribed glasses, these should be worn the majority of the time.

Practical points

Vision assessment and strabismus

• The parents’ assessment of their infant child’s vision is often very accurate; if they are concerned their child is not seeing you should be concerned also

• Always try to gain as much information as possible by observation before actively engaging a child in an examination. Red reflexes can be observed from a distance. Urgent referral is required if an abnormal red reflex is found

• Children under 7 years of age will rarely complain of visual difficulty relating to refractive errors (reduced visual acuity). A vision screening programme is the most reliable method of detecting reduced visual acuity in children of this age

• Strabismus is a common cause of amblyopia. All suspected or confirmed strabismus should be referred to an ophthalmologist for further assessment and management

• Cover testing is the most accurate clinical method of diagnosing strabismus. When doing a cover test always make sure that the child is looking at a interesting fixation target – a small toy is useful for near fixation and a picture or larger toy for distance fixation

• Amblyopia is generally reversible if it is detected early and appropriate management is initiated

Watery and sticky eyes

This occurs commonly in infancy as the result of congenital nasolacrimal duct obstruction. About 10% of newborn infants have obstructed nasolacrimal ducts. This will present as a watery and sticky eye in the first few weeks of life. Despite the persistent discharge the eye is generally not red or inflamed. An inflamed eye suggests an alternative diagnosis such as infective conjunctivitis. If the obstruction persists, the lower lid will often become red and sometimes slightly scaly as a result of the skin being constantly moist.

The differential diagnosis includes trauma, conjunctivitis and infantile glaucoma. These conditions are all described below.

Most congenital nasolacrimal duct obstructions resolve spontaneously. Approximately 95% of cases have resolved by the time of the first birthday, with most doing so in the first 6 months. In persistent cases, probing under a general anaesthetic is recommended after 1 year of age.

Trauma

Trauma to the eye can take many forms. Physical trauma to the eye and surrounding structures may be blunt or sharp. Trauma can also result from radiation (thermal and electromagnetic) and chemical agents.

Direct blunt trauma to the eye may disrupt iris blood vessels, causing bleeding in the anterior chamber of the eye (hyphema), tear the iris, dislocate the lens, rupture the choroid and rarely rupture the eye wall (sclera) if the force is sufficient. Simple inspection of the eye will reveal most of these injuries and choroid and globe rupture may be suspected on the basis of the nature of the injury and associated poor vision. Referral to an ophthalmologist is necessary in these cases for confirmation of the injury and further management.

Sharp trauma may be due to a range of causes, from tiny objects such as a subtarsal foreign body causing a corneal abrasion, to fingernail scratches through to penetration of the eye by sharp objects such as a scissors blade or dart. Surface trauma can be diagnosed easily with the help of fluorescein staining and a cobalt blue light. Areas of epithelial abrasion will fluoresce green. If a round ulcer and/or vertical linear abrasions are seen, suspect a subtarsal foreign body and the upper lid should be everted. If identified, most subtarsal foreign bodies can be removed with a moistened cotton bud. Superficial trauma is treated with antibiotic ointment and a patch and daily review until any epithelial defect (ulcer or abrasion) is healed.

If the wall of the eye (cornea or sclera) has been penetrated, intraocular contents may prolapse out through the wound, the iris and pupil may appear distorted or the anterior chamber may be shallower than normal. Any suspected penetration of the eye must be referred to an ophthalmologist for further investigation and management. The eye should be protected with a cone that does not exert any pressure on the eye. If vomiting is likely or occurs an anti-emetic should be given to prevent further prolapse of intraocular tissue.

Thermal injuries to the eye itself are rare, as in most burn situations the eyelids are firmly closed and thus protect the eye. Facial burns may cause scarring that interferes with lid function, leading to exposure and drying of the eye’s surface. If a primary thermal injury to the eye is suspected, fluorescein dye should be used to detect any ulceration. If ulceration is found, treatment is with antibiotic ointment and a patch.

Radiation injuries to the eye are rare in childhood and most are the result of intentional irradiation as part of medical therapy for facial and ocular neoplasia. Typical injuries are cataract, dry eye syndrome, radiation retinopathy and optic neuropathy. These changes are seen some considerable time after the irradiation.

Chemical burns to the eye are unusual in childhood but potentially are very serious, especially if the chemical is alkaline. Many domestic cleaning agents are alkaline. Strong alkali will denature and dissolve protein and penetrate deeply into the surface of the eye. Acids tend to coagulate surface structures and this often prevents deeper penetration of the acidic chemical into the eye. Immediate first aid should consist of copious irrigation with water at the site of the accident and this should be continued for at least 10 minutes. Following adequate irrigation all chemical burns of the eye should be referred to an ophthalmologist.

Practical points

Blocked tear ducts and eye injury

• Most blocked tear ducts resolve spontaneously by 1 year of age

• Simple inspection with the addition of fluorescein staining will enable the diagnosis of most physical trauma to the eye

• All chemical injuries to the eye should be regarded as serious. Copious irrigation is the cornerstone of immediate management of all chemical injuries to the eye

Conjunctivitis

Conjunctivitis may result from infective, allergic or chemical agents interacting with the conjunctiva. Symptoms are itch, pain and irritation or a gritty sensation. Signs are epiphora (watering), discharge and erythema of conjunctiva and lids. The relative prominence of different symptoms and signs varies with the cause of the conjunctivitis (Table 22.2.1).

Conjunctivitis occurring in the first few weeks of life is generally bacterial and frequently acquired from the birth canal. Neisseria gonorrhoeae and Chlamydia trachomatis both cause a conjunctivitis with copious discharge and marked erythema in the neonatal period, termed ophthalmia neonatorum. Gonococcal conjunctivitis is serious because of the risk of spontaneous perforation of the cornea and resultant loss of vision and also the risk of more generalized sepsis. Chlamydial conjunctivitis is significant because of the risk of more generalized chlamydial sepsis. For accurate and prompt diagnosis of these infections, microbiological diagnosis and systemic as well as topical antibiotic therapy is needed. For culture, conjunctival swabs should be directly inoculated onto culture medium plates and conjunctival scrapings for Gram staining and immunofluorescent staining should be taken.

Bacterial conjunctivitis occurring outside the first few weeks of life in children is usually the result of relatively innocuous organisms (e.g. Staphylococcus spp. and Haemophilus spp.) Microbiological investigation is not usually indicated and a broad-spectrum topical antibiotic should be prescribed (such as neomycin/polymyxin or chloramphenicol). Concern has been raised about topical chloramphenicol preparations because of a perceived risk of secondary agranulocytosis. It is the author’s belief that this risk is extremely low but does exist and should not stop short-term use of topical chloramphenicol.

Viral conjunctivitis is relatively common at all ages and clinically may be very difficult to differentiate from bacterial conjunctivitis. The discharge may be somewhat less with viral conjunctivitis. Viral conjunctivitis is frequently associated with upper respiratory tract infection symptoms. If the aetiology is uncertain, topical antibiotics as for bacterial conjunctivitis should be used.

Allergic conjunctivitis is common in children of all age groups and has itch as its most prominent symptom. House dust mite, grass and other plant pollens are common allergens that precipitate allergic conjunctivitis. Therapy depends on the severity of the symptoms. If mild, cold compresses may be all that is needed. For more severe symptoms soothing topical astringent agents that include a topical antihistamine are helpful. In more persistent and severe cases topical sodium cromoglycate and steroid preparations may be indicated. Topical steroid should be used with the supervision of an ophthalmologist because of the risk of significant side effects, including cataract and glaucoma.

Clinical example

A 4-year-old boy presented with a 12-hour history of a red and watery eye. He complained of pain and his parents had not observed any discharge. Examination revealed a red eye with no obvious trauma or foreign body on the surface of the eye. Fluorescein staining demonstrated a round ulcer on the upper part of the cornea. On everting the upper eyelid a small foreign body was found and was removed with a moistened cotton bud. The ulcer was treated with antibiotic ointment and a pad and healed in 1 day.

Lid infections

These are common in children and most arise in the skin appendages of the eyelids (lash follicles and meibomian glands). Infection of a lash follicle is called a stye (or hordeolum externum) and acute infection of a meibomian gland is known as hordeolum internum. Unless there is significant secondary erythema of the surrounding lid, topical and systemic antibiotics are not indicated. Occasionally, severe preseptal cellulitis will follow a focal lid infection and systemic (often intravenous) antibiotics will then be needed for treatment.

More chronic inflammation of a meibomian gland is known as a chalazion. This is generally the result of sterile chemical inflammation rather than infection and occurs when the contents of a meibomian gland escape into the lid following blockage of the opening of the gland at the lid margin. A chalazion will appear as a lump in the substance of the lid and is often not particularly inflamed in appearance. Topical antibiotics seldom hasten resolution. Warm compresses may give symptomatic relief and help drainage. Chalazia may persist for many months. Some will discharge through the conjunctiva or the skin. On occasions surgical drainage is indicated for a persistently inflamed and large chalazion.

Practical points

Conjunctivitis and chalazion

• Neonatal conjunctivitis may be sight-threatening and a threat to the newborn infant’s health. Immediate investigation with appropriate treatment is needed

• If a child does not have itch as a major symptom then allergic conjunctivitis is unlikely. Think of other causes of conjunctivitis in this situation

• Most chalazia are not infected and redness and swelling is the result of sterile inflammation. Consequently topical and oral antibiotics are of little use in treatment. Most chalazia resolve spontaneously

Ptosis

Ptosis, also called blepharoptosis, is a droopy upper eyelid and results from innervational or muscular defects of the levator superioris or Muller muscles. Innervational defects include third cranial nerve palsy, Horner syndrome (sympathetic nervous system) and myasthenia gravis. Congenital ptosis is the commonest muscle defect causing ptosis in children. Ptosis will cause visual defects when the lid is so low that it occludes the visual axis or if it induces astigmatism by altering the corneal curvature. Ptosis is also a cosmetic concern in that it may make an affected child look sleepy or dull. Surgical correction is possible in most cases.

Learning difficulties

Learning difficulties are common in school-age children and are the result of a neurobiological disorder, i.e. brain dysfunction. The majority of reading difficulties are the result of defects in phonological awareness. It is commonly assumed that there may be a visual abnormality that contributes to or even causes the learning difficulty. This assumption is ill founded and arises because vision is so obviously involved with activities such as reading and writing. Children with learning difficulties are no more or less likely to have visual problems than children without evidence of learning problems. Rather than expending effort on therapies for perceived ocular abnormalities, parents should be encouraged to take an educational approach to their child’s learning difficulties.

Visual handicap

Visual handicap in childhood may be the result of ocular and/or cortical visual abnormalities and may be associated with other abnormalities, e.g. deafness, motor defects and intellectual defects. Intervention and support for a particular child needs to be planned after a thorough assessment of the child’s visual and associated handicaps. From a purely visual point of view, interventions may include mobility training, low vision aids, such as magnifiers and closed circuit television, and training in alternative means of communication, such as ‘reading’ braille and using a computer to write.

The presence of additional handicap such as deafness or an intellectual deficit compounds the situation and necessitates skilled intervention over many years to achieve optimal outcomes.

Rare but important eye problems in childhood

These are mentioned briefly because prompt recognition enables early treatment and optimal outcomes.

Poor vision in infancy

This first comes to attention when a child fails to achieve normal milestones of visual development (see Measurement of vision in children, above). If the cause of severe visual impairment is within the eye, sensory nystagmus will develop at about 3–4 months of age. This nystagmus is often slow and somewhat pendular rather than jerky in appearance. Severe visual loss secondary to CNS abnormality does not cause nystagmus. Causes of poor vision in infancy include:

• cataracts

• albinism

• retinal colobomas

• infantile glaucoma

• congenital retinal dystrophy

• retinoblastoma

• delayed visual maturation

• cortical visual impairment.

Prompt recognition is vital as there may be a treatable cause (e.g. cataracts) and, even if no treatment is possible, early and appropriate intervention minimizes the negative effects of severe visual impairment on general development.

Cataract

A cataract is any opacity within the lens. Bilateral congenital cataracts will often cause poor vision in infancy, while unilateral congenital cataract may go unrecognized, as one eye has normal vision. Both bilateral and unilateral congenital cataracts are treatable if diagnosed early. Cataracts are detected readily by inspection of the red reflex with the direct ophthalmoscope.

There are numerous causes of congenital cataracts, including: hereditary (dominant, recessive and X linked); metabolic (e.g. galactosaemia); association with systemic syndromes (e.g. Down syndrome), and congenital infection (e.g. rubella embryopathy). Many, especially unilateral cataracts, are idiopathic.

Retinoblastoma

This is a rare childhood cancer arising within the retina. Sporadic and hereditary forms are recognized. The sporadic form is the result of two separate mutations that negate the action of the retinoblastoma (Rb) gene within a single retinoblast cell, and thus is always unilateral. The hereditary form arises when the first of these two mutations occurs in one Rb gene within a germ cell (most often a sperm). The second mutation occurs within the retinoblast. As all retinoblasts descended from an affected germ cell have the first mutation, by chance more than one retinoblastoma will usually develop and hence the hereditary form is often, but not always, bilateral.

Retinoblastoma most often presents with leukocoria (white pupillary reflection: the white tumour is seen immediately behind the lens), strabismus, poor vision, or a known family history of retinoblastoma. Prompt recognition is vital as early treatment will increase the possibility of preserving vision and life. With current treatments the 5-year survival of this childhood cancer is about 98%.

Glaucoma

Glaucoma in infancy presents with a cloudy and enlarged cornea with associated epiphora (watery eye) and photophobia. It may be unilateral or bilateral and is usually an isolated ocular abnormality. If unrecognized it will result in severe and untreatable visual loss over weeks to months. Prompt diagnosis allows surgical treatment, which controls the glaucoma in the majority of cases.

Colobomas

These defects result from failure of complete fusion of the embryonic fissure of the developing eye between the fourth and sixth week of gestation. If the optic nerve or macular area of the retina is involved then vision will be significantly affected. An iris coloboma may or may not be present in association with a visually more important posterior pole colobomas. Colobomas are not treatable.

Practical points

Further important considerations

• Learning difficulties are seldom the result of simple eye problems

• Examine the red reflexes of all infants suspected of having poor vision and all infants with strabismus. An abnormal red reflex in this situation may be due to retinoblastoma and urgent referral is mandatory

• Think glaucoma if a child has one eye that bigger than the other. Then look for co-existing clouding of the cornea and seek history of watery eye and photophobia

The eye in paediatric systemic disease

The following is a brief account of the common ocular features of some paediatric systemic diseases.

Extreme prematurity

Marked prematurity gives rise to eye problems by interfering with the orderly development of retinal blood vessels. This disorder is known as retinopathy of prematurity (ROP). Mild ROP is seen in 30–50% of infants weighing less than 1250  g at birth and then regresses without ill effect on vision. In some infants the ROP progresses and a fibrovascular proliferation develops within the eye that detaches the retina, with resultant loss of vision.

Excess oxygen administration to premature infants has been known to be a potent cause of severe ROP since the 1950s. Curtailment of oxygen use to amounts sufficient to limit respiratory and neurological sequelae has greatly reduced the incidence of blinding ROP but has not completely prevented it. In general it is the sicker and smaller infants that are still at risk of severe ROP.

Screening of at-risk infants (birth weight ................
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