Dizziness and Syncope - YM



Dizziness and Syncope

Jong-Ling Fuh, MD

1. Vestibular Neuritis and Labyrinthitis

a. Etiology： viral infection of the vestibular nerve.

[pic] The vestibular nerve carries information from the inner ear about head movement. When one of the two vestibular nerves is infected, there is an imbalance between the two sides, and vertigo appears.

[pic] The virus that causes the infection is thought to be usually a member of the herpes family, the same group that causes cold sores in the mouth as well as a variety of other disorders.

b. Nnomenclature：neuritis（damage to the nerve）, neuronitis （damage to the sensory neurons of the vestibular ganglion）

c. Labyrinthitis

[pic] generally viruses cause the infection, but rarely labyrinthitis can be the result of a bacterial middle ear infection.

[pic] hearing may be reduced or distorted in tandem with vertigo.

[pic] Both vestibular neuritis and labyrinthitis are rarely painful -- when there is pain it is particularly important to get treatment rapidly as there may be a treatable bacterial infection or herpes infection.

d. Symptoms：dizziness or vertigo, disequilibrium or imbalance, and nausea. Acutely, the dizziness is constant. After a few days, sudden movements often only precipitate symptoms. A sudden turn of the head is the most common "problem" motion. While patients with these disorders can be sensitive to head position, it is generally not related to the side of the head, which is down, but rather just whether the patient is lying down or sitting up.

e. Pathology：Single case report--viral infection of Scarpa's ganglion (the vestibular ganglion). There was loss of hair cells, "epithelialization" of the utricular maculae and semicircular canal cristae on the deafferented side, and reduced synaptic density in the ipsilateral vestibular nucleus.

f. Vestibular neuritis often spares part of the vestibular nerve, the inferior-division. Because the inferior division supplies the posterior semicircular canal and saccule, even a "complete" loss on vestibular testing may be associated with some retained canal function.

g. Prevalence：About 5% of all dizziness (and perhaps 15% of all vertigo) is due to vestibular neuritis or labyrinthitis. It occurs in all age groups, but cases are rare in children.

h. Signs：spontaneous nystagmus, and unsteadiness Occasionally other ocular disturbances will occur such as skew deviation and asymmetric gaze evoked nystagmus.

i. Examination

[pic] Acutely, in uncomplicated cases, while a thorough examination is necessary, no additional testing is usually required.

[pic] It is not possible on clinical examination to be absolutely certain that the picture of "vestibular neuritis" is not actually caused by a brainstem or cerebellar stroke, so mistakes are possible. Nevertheless, this happens so rarely that it is not necessary to perform MRI scans or the like very often.

[pic] If symptoms persist beyond one month, reoccur periodically, or evolve with time, testing may be proposed. 

(a). an audiogram and an ENG. An audiogram is a hearing test to distinguish between vestibular neuritis and other possible diagnoses such as Meniere's disease and Migraine.

(b). MRI scan：if there is any reasonable possibility of a stroke or brain tumor. Occasionally one can visualize the inflammation of the vestibular nerve.

©. Blood tests for diabetes, thyroid disorders, Lyme disease, collagen vascular disease and syphilis are sometimes performed, looking for these treatable illnesses. However, it is rare that these are ever positive.

j. Treatment: The vestibular neuritis is treated symptomatically, meaning that medications are given for nausea (anti-emetics) and to reduce dizziness (vestibular suppressants).

k. Prognosis

[pic] It usually takes 3 weeks to recover from vestibular neuritis or labyrinthitis.

[pic] Some persons experience persistent vertigo or discomfort on head motion.

[pic] In the great majority of cases (at least 95%) vestibular neuritis it is a one-time experience. Rarely the syndrome is recurrent.

2. BENIGN PAROXYSMAL POSITIONAL VERTIGO (BPPV)

a. Etiology：otoconia which are small crystals of calcium carbonate derived from a structure in the ear called the "utricle", was collected within a part of the inner ear. While the saccule also contains otoconia, they are not able to migrate into the canal system. The utricle may have been damaged by head injury, infection, or other disorder of the inner ear, or may have degenerated because of advanced age.

b. Prevalence

[pic] About 20% of all dizziness is due to BPPV.

[pic] About 50% of all dizziness in older people is due to BPPV.

c. Symptoms： dizziness or vertigo, lightheadedness, imbalance, and nausea. Symptoms are almost always precipitated by a change of position of the head with respect to gravity. Getting out of bed or rolling over in bed is common "problem" motions. An intermittent pattern is common. BPPV may be present for a few weeks, then stop, and then come back again.

d. Causes

[pic] The most common cause of BPPV in people under age 50 is head injury.

[pic] In older people, the most common cause is degeneration of the vestibular system of the inner ear.

[pic] In half of all cases, BPPV is called "idiopathic," which means it occurs for no known reason.

[pic] Viruses affecting the ear such as those causing vestibular neuritis, minor strokes such as those involving anterior inferior cerebellar artery (AICA) syndrome", and Meniere's disease are significant but unusual causes.

[pic] Occasionally BPPV follows surgery, where the cause is felt to be a combination of a prolonged period of supine positioning, or ear trauma when the surgery is to the inner ear.

e. Diagnosis：

[pic] Often, the diagnosis can be made with history and physical examination. Most other conditions that have positional dizziness get worse on standing rather than lying down (e.g. orthostatic hypotension).

[pic] Electronystagmography (ENG) testing may be needed to look for the characteristic nystagmus.

f. Differential Diagnosis：There are some rare conditions that have symptoms that resemble BPPV. Patients with certain types of central vertigo such as the spinocerebellar ataxias may have "bed spins" and prefer to sleep propped up in bed. These conditions can generally be detected on a careful neurological examination and also are generally accompanied by a family history of other persons with similar symptoms.

g. Prognosis：BPPV has often been described as "self-limiting" because symptoms often subside or disappear within six months of onset. Symptoms tend to wax and wane.

h. Treatment：The Epley maneuver is also called the particle repositioning, canalith repositioning procedure, and modified liberatory maneuver. It involves sequential movement of the head into four positions, staying in each position for roughly 30 seconds. It is very effective, with roughly an 80% cure rate. The recurrence rate for BPPV after these maneuvers is about 30 percent at one year, and in some instances a second treatment may be necessary.

3. Meniere's disease

a. History：In 1861, the French physician Prosper Meniere described a condition, which now bears his name. Meniere's disease is a disorder of the inner ear, which causes episodes of vertigo, tinnitus, a feeling of fullness or pressure in the ear, and fluctuating hearing loss.

b. Symptoms

[pic] preceded by fullness in one ear, hearing fluctuation or changes in tinnitus.

[pic] A Meniere's episode generally involves severe vertigo (spinning), imbalance, nausea and vomiting.

[pic] The average attack lasts two to four hours.

[pic] An unusual sensitivity to visual stimuli is common.

[pic] "otolithic crisis of Tumarkin"：a sudden fall that may occur without warning. These are attributed to sudden mechanical deformation of the otolith organs (utricle and saccule), causing a sudden activation of vestibular reflexes. Patients suddenly feel that they are tilted or falling (although they may be straight), and bring about much of the rapid repositioning themselves. This is a very disabling symptom as it occurs without warning and can result in severe injury. Often destructive treatment (e.g. labyrinthectomy or vestibular nerve section) is the only way to manage this problem.

[pic] Meniere's episodes may occur in clusters; that is, several attacks may occur within a short period of time. However, years may pass between episodes. Between the acute attacks, most people are free of symptoms or note mild imbalance and tinnitus.

c. Prevalence

[pic] affects roughly 0.2% of the population.

[pic] Meniere's disease usually starts confined to one ear but it often extends to involve both ears over time so that after 30 years, 50% of patients with Meniere's have bilateral disease. Some authors suggest that the prevalence of bilaterality is as low as 17%. Silverstein suggested that 75% of persons destined to become bilateral do so within 5 years.

d. Prognosis

[pic] In most cases, a progressive hearing loss occurs in the affected ear(s).

[pic] A low-frequency sensorineural pattern is commonly found initially, but as time goes on, it usually changes into either a flat loss or a peaked pattern.

e. Mechanism

[pic] result from fluctuating pressure of the fluid within the inner ear.

[pic] A system of membranes, called the membranous labyrinth, contains a fluid called endolymph. The membranes can become dilated like a balloon when pressure increases. This is called "hydrops". One way for this to happen is when the drainage system, called the endolymphatic duct or sac is blocked. In some cases, the endolymphatic duct may be obstructed by scar tissue, or may be narrow from birth. In some cases there may be too much fluid secreted by the Stria Vascularis.

[pic] Hydrops is not found in all persons with Meniere's disease, and hydrops is also commonly found (6%) on autopsy studies of persons who had no Meniere's type symptoms.

[pic] Abnormally enlarged fluid pathways into the ear such as the vestibular aqueduct or cochlear aqueduct may also be associated with Meniere's like symptoms. Enlarged vestibular aqueducts are one of the most commonly identified inner ear bony malformations in children with sensorineural hearing loss of unknown cause. The vestibular aqueduct extends from the medial wall of the vestibule to the posterior surface of the petrous temporal bone. Most persons with enlarged vestibular aqueducts with ear disorders have hearing loss, but occasionally there is an association with vestibular problems.

[pic] Recently attention has been mainly focused on the immunologic function of the endolymphatic sac -- immune disease may contribute to a substantial percentage of Meniere's disease.

[pic] For the most part the underlying cause of Menieres disease is unknown. It is most often attributed to viral infections of the inner ear, head injury, a hereditary predisposition, and allergy.

[pic] Conventional thought is that repeated attacks of Meniere kill hair cells in the inner ear. This is a gradual process over years, but frequently resulting in unilateral functional deafness. Cochlear (hearing) hair cells are the most sensitive. Vestibular hair cells seem more resilient but there is also a slow decline in the caloric response in the diseased ear over roughly 15 years.

[pic] Mechanical disruption of the inner ear is also likely with dilation of the utricle and saccule of the ear being a well-known pathological finding of Meniere disease. The saccule may dilate so that in later stages, it is adherent to the underside of the stapes footplate. This mechanical disruption and distortion of normal inner ear structures may result in the gradual onset of a chronic unsteadiness, even when patients are not having attacks. Finally, it also seems likely that there may be rupture of the suspensory system for the membranous labyrinth. This might create some mechanical instability of the utricle and saccule and consequently some chronic unsteadiness.

f. Prevalence

[pic] affects about 2 out of 1000 people.

[pic] The majority of people with Menier's disease are over 40 years of age, with equal distribution between males and females.

g. Diagnosis

[pic] is based on a combination of the right set of symptoms (usually episodic dizziness and hearing disturbance)

[pic] hearing tests (audiometry) which document that hearing is reduced after an attack, and then gets better, and exclusion of alternative causes.

[pic] an ENG test, several blood tests (ANA, FTA), and an MRI scan of the head. Electrocochleography (ECOG) is helpful in difficult cases.

h. Treatment

[pic] Between attacks, medication may be prescribed to help regulate the fluid pressure in your inner ear, thereby reducing the severity and frequency of the Meniere's episodes. Diamox is the most common medication for this purpose. Verapamil (typical dose: 120 SR) sometimes reduces the frequency of attacks.

[pic] The hydrops diet regimen will probably be recommended.

[pic] In extremely severe cases, treatments that deaden the inner ear such as gentamicin injections or surgery may be considered. This is a last resort for persons who have severe attacks, which are disabling. At present, gentamicin is favoredfor most instances where destructive treatments are being considered. Injections of gentamicin are given through the eardrum, through a small hole or through a small tube. This procedure allows one treat one side alone, without affecting the other. Typically about four injections are given, over a period of a month. Dizziness may reoccur one year later, requiring another series.

[pic] surgical treatment - vestibular neurectomy or vestibular nerve section is very effective in eliminating vertigo but much higher risk than gentamicin injection.

[pic] Another operation, called a labyrinthectomy is recommended in persons who have lost all usable hearing or in whom vestibular nerve section is considered too dangerous. Again, this procedure seems most applicable to situations where gentamicin has failed.

[pic] A third procedure, the endolymphatic shunt procedure, is used by some doctors to relieve pressure in the inner ear.

4. Perilymph Fistula

a. Etiology

[pic] an abnormal opening in fluid filled inner ear.

[pic] There are several possible places that there can be an opening-- between the air-filled middle ear/mastoid sinus, into the intracranial cavity, or into other spaces in the temporal bone. In most instances it is a tear or defect in one or both of the small, thin membranes between the middle and inner ears. These membranes are called the oval window and the round window. Another possible location for an abnormal communication is in the bone of the ear (the otic capsule).

b. Symptoms

[pic] pressure in the ear or loud noises which can cause strong vertigo, nystagmus, vertigo, imbalance, nausea, and vomiting.

[pic] Some people experience ringing or fullness in the ears, and many notice a hearing loss.

[pic] Valsalva induced dizziness -Some people with fistulas find that their symptoms get worse with coughing, sneezing, or blowing their noses, as well as with exertion and activity.

[pic] Tullio's phenomenon：use of ones own voice or a musical instrument will cause dizziness

c. Prevalence：Whatever the cause, perilymph fistula is a very rare condition compared to most other causes of dizziness and hearing loss.

d. Cause

[pic] Head trauma is the most common cause of fistulas, usually involving a direct blow to the ear.

[pic] following rapid or profound changes in intracranial or atmospheric pressure, such as may occur with SCUBA diving. Forceful coughing, sneezing or straining as in lifting a heavy object may rarely cause a fistula.

[pic] Ear surgery, particularly "stapes" surgery, often causes fistula.

[pic] present from birth (usually in association with deafness)

[pic] cholesteatomas

[pic] superior canal dehiscence syndrome：the bone between the ear and brain area is missing or thin. Roughly 2% of persons at autopsy are found to have thinning of bone, which is thought to predispose them to this syndrome.

e. Examination

[pic] A fistula test - recording of eye movements while pressurizing each ear canal with a small rubber bulb.

[pic] A positive test is good grounds for surgical exploration.

[pic] In window fistulae, a positive test may consist only of a slight nystagmus after pressurization.

[pic] In superior canal dehiscence, a strong nystagmus may be produced.

[pic] Positive pressure or Valsalva against pinched nostrils produces downbeating nystagmus, with a torsional fast phase consistent with stimulation of the affected ear.

[pic] Negative pressure or Valsalva against a closed glottus may produce upbeating nystagmus and nystagmus beating with the torsional fast phase in the opposite direction.

[pic] Audiometry and an "ENG" - to establish the side, and to exclude other potential causes of symptoms. Audiometry may show a sensorineural hearing loss.

[pic] An ECOG (ectrocochleography) - diagnose Meniere's disease, which is a common alternative source of pressure sensitivity.

[pic] An MRI and/or a temporal bone CT scan - to exclude other possibilities.

[pic] CT of the temporal bone is very accurate in identifying canal fistulae. CT should be done of the temporal bone with at least 1 mm resolution.

[pic] MRI is not the best test for fistulae because it doesn't show the bone and resolution is not as good as CT scan. However, MRI is the best way of showing other possibly confounding problems such as tumors or multiple sclerosis plaques.

[pic] CT cisternography with a spinal injection of a contrast material - to detect CSF leak. The head is tilted down for 3 minutes with the patient prone, and a CT scan is done with high resolution cuts (spiral), in the coronal plane immediately after the prone positioning, to cover the frontal sinus through the mastoid sinus region.

[pic] Air in the labyrinth (pneumolabyrinth) is the most convincing finding of fistula.

[pic] Middle ear effusions may also be suggestive of fistula.

f. Treatment

[pic] In many cases, a window fistula will heal itself if your activity is restricted. In such cases, strict bed rest is recommended for one week or more to give the fistula a chance to close.

[pic] It is usual to wait 6 months before embarking on surgical repair, given that hearing function is reasonable and is stable or improving.

[pic] With respect to air travel, while it is certainly safest to avoid air travel altogether, in some instances it may be unavoidable. In this case, we suggest using a nasal decongestant at least one half hour prior to landing.

[pic] If a patient has a canal fistula, the symptoms are significant and have not responded to the conservative approach outlined above, or if the patient has a progressive hearing loss, surgical repair of the fistula may be required. For canal fistulas, surgery generally involves plugging of the canal. For a window fistula surgery involves placing a soft-tissue graft over the fistula defect in the oval and/or round window. Otic capsule fistula does not, in general, heal by itselves. Unfortunately, surgical procedures are not well worked out. Patients are often reoperated when it is decided that the graft has failed.

5. Motion Sickness

a. Symptoms/sign：nausea, disorientation and fatigue that can be induced by head motion. The first sign is usually pallor. Yawning, restlessness and a cold sweat forming on the upper lip or forehead often follow. As symptoms build, an upset stomach, fatigue or drowsiness may occur. The final stages are characterized by nausea and vomiting.

b. Prevalence

[pic] Nearly anyone can be made motion sick by an appropriate stimulus, except for individuals with no vestibular system.

[pic] prevalence was about 28%

[pic] females were more susceptible than males

[pic] Individuals with more active occupations are less susceptible.

c. Mechanism：In order for the body to determine where it is at all times, the brain combines visual information, touch information, inner ear information, and internal expectations. Under most circumstances, the senses and expectations agree. When they disagree, there is conflict, and motion sickness can occur.

d. Acquired susceptibility

[pic] Persons with an inner ear disturbances, especially a recent one, may be intolerant to activity in general

[pic] People with migraine are apt to get motion sick.

[pic] Persons with rare, central nervous system disorders of the part of the brain that processes signals from the inner ear may also be unusually susceptible to motion sickness.

e. mal de debarquement ：Certain individuals who are constitutionally susceptible to motion sickness and can develop seasickness on ships, and a prolonged land sickness, when they get off the ship.

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