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Imaging, data interpretation&audit, medico-legal, surface anatomy The IVC commences opposite the L5 vertebra. It is on the right side of the aorta, upwards beyond the aortic opening of the diaphragm and extends to the central tendon of the diaphragm, which it pierces at the level of T8. The IVC lies behind the portal vein near the pancreas and bile duct, and forms the posterior wall of the epiploic foramen of Winslow.Apertures in the diaphragm:Come Enter the AbdomenT8 inferior vena Cava (caval foramen)T10 oEsophagus (oesophageal hiatus)T12 Aorta (aortic hiatus)Each of the three holes have three structures passing through themCaval foramen – Inferior vena cava, right phrenic nerve, lymph nodesoEsophageal hiatus – Oesophagus, vagal trunks, left gastric vesselsAortic hiatus – Aorta, thoracic duct, azygous vein.left paravertebral spaceThe thoracic paravertebral space runs T1–T12 – its medial boundary is formed by the thoracic vertebrae and discs – at this point the vertebral foramina are also found with their corresponding nerve roots, posteriorly the ribs and transverse processes of the respective vertebrae as well as the superior costotransverse ligament, and anterolaterally the parietal pleural with the intercostal membranes a little more lateral to this.Within the space are intercostal vessels, the sympathetic chain and spinal nerves. Clinically this allows for a paravertebral block; in penetrating trauma these same structures would, of course, be at risk.transpyloric planeL1 is the correct level for the origin of the superior mesenteric artery. This level also corresponds to the level of the transpyloric plane: this is an imaginary transverse plane with a surface marking mid-way between the suprasternal notch and the pubic symphysis.The important anatomical relations of this site include – the origin of the superior mesenteric artery, the pancreatic neck, the first part of the duodenum, the pylorus, the renal hila, the duodenojejunal flexure, the gall-bladder fundus, the origin of the hepatic portal vein and the right and left flexures of the colon.The transpyloric plane is a convenient way to relate anatomical structures. It is an imaginary transverse plane with a surface marking mid-way between the jugular notch and the pubic symphysis. The important anatomical relations of this site include – the origin of the superior mesenteric artery, the pancreatic neck, the first part of the duodenum, the pylorus, the renal hila, the duodenojejunal flexure, the gall-bladder fundus, the origin of the portal vein, the transverse mesocolon and the splenic hilum. It crosses the right costal margin at the tip of the ninth (9th ) costal cartilage, the surface marking of the gall-bladder fundusL2L2 corresponds with the pancreatic head and ampulla of VaterT11This level corresponds with the upper liver and spleen.T10T10 is an important surface marker for the point at which the oesophagus passes through the diaphragm and forms to oesophageal–gastric junction.mid-inguinal pointThe mid-inguinal point is the surface marking for the femoral artery pulse. It is half way between the symphysis pubis and the anterior superior iliac spine. It does not correspond to the mid-point of the inguinal ligament, which is found half way between the anterior superior iliac spine and the pubic tubercle.inguinal canalThe boundaries of the inguinal canal are as follows:Anterior border – external oblique aponeurosisPosterior border – transversalis fascia, conjoint tendon (medial third of canal)Inferior border – inguinal ligamentSuperior border – external oblique aponeurosis, musculoaponeurotic arches of internal oblique and transverse abdominal, transversalis fascia.mid-point of the inguinal ligamentThe mid-point of the inguinal ligament lies at a point halfway between the anterior superior iliac spine and the pubic tubercle, and is the surface landmark of the deep inguinal ring. It is distinct from and lies laterally to, the mid-inguinal point, which lies halfway between the anterior superior iliac spine and the symphysis pubis and is the surface marking of the femoral pulse. When considering the anatomy of the inguinal region it is vital to remember this distinction. This can often lead to confusion, but the two are independent structures.Ureter relationshipsThe uterine artery crosses anterior and superior to the ureter near the lateral portion of the fornix. This relation is of surgical importance as the ureter is in danger of being damaged at the time of a hysterectomy. The point of crossing of the uterine artery and ureter is approximately 2 cm superior to the ischial spine. The ureter descends towards the pelvis anterior to the psoas major muscle but posterior to the gonadal artery. It then crosses anterior to the bifurcation of the common iliac artery at the level of the pelvic brim before descending posteroinferiorly along the lateral pelvic side wall.The testicular arteries arise from the aorta inferior to the renal arteries. Their initial course is retroperitoneal overlying psoas major. Eventually they cross obliquely anterior to the ureters to reach the inguinal ring. In its course the ureter passes beneath the vas deferens (male)male vs female pelvisThe general structure of the male pelvis is heavier and thicker than the female pelvis and has more prominent bone markings. The female pelvis is wider, shallower, and has both a larger superior and inferior pelvic aperture. The ischial tuberosities are farther apart in the female pelvis because of the wider pubic arch, and the sacrum is less curved in the female pelvis. This ensures a wider birth canal. In addition to this the obturator foramina are round in the male and oval in the female. The adaptations to the female pelvis compared with the male largely serve to ensure a wide and safe birth canal.McBurney’s pointThe appendix is usually attached to the caecum and located in the right iliac fossa with a surface anatomical marker of McBurney’s point – this is one-third of the way from the anterior superior iliac spine to the umbilicus.Bladder relationshipsIn males, the seminal vesicles lie in the rectovesical pouch, posterior to the posterior wall of the bladder. They are at risk of local invasion from posterior wall bladder tumours. The prostate gland is inferior to the bladder. The bulbospongiosus and corpus spongiosum are not directly in contact with the bladder. The perineal body is a midline perineal structure that is inferior to the bladder.Para-aortic lymph nodesThe testes (or the ovaries in women) develop in the embryological abdomen, and so lymphatic drainage follows the route of the gonadal vessels to arrive at the para-aortic lymph nodes. The lymphatic vessels for the testes travel in the spermatic cord and drain the testes into the lumbar nodes.External iliac lymph nodesLymph from the prostate and glans in men, and the cervix, upper vagina and clitoris in women drains here. The external iliac nodes also drain the fundus of the bladder, the inferior abdominal wall and the adductor region of the thigh. The external iliac nodes drain the lower limb.Inguinal lymph nodesThe scrotum drains to the inguinal nodes.Internal iliac lymph nodesThese receive lymphatic from the pelvic viscera and superior half of the rectum. They do not receive lymph drainage from the testis (or from the ovaries in women). The internal iliac nodes drain the pelvis and gluteal region.Sacral lymph nodesThese receive lymph drainage from the rectum and posterior wall of the pelvis.Superficial inguinal lymph nodesThe perineum and the external genitalia, including the scrotum and labia majora, drain to the superficial inguinal lymph nodes.deep perineal pouchIn men, the deep perineal pouch contains the membranous urethra, sphincter urethra, bulbourethral glands (on each side of the membranous urethra), deep transverse perineal muscles, internal pudendal vessels and dorsal nerves of the penis. The internal urethral sphincter is located at the inferior pole of the urinary bladder, not within the deep perineal pouch. The bulb of the penis itself lies in the superficial perineal pouch.superficial perineal fasciaThe superficial perineal fascia (Colles’ fascia) forms the inferior boundary for the superficial perineal pouch.episiotomyAn episiotomy is a perineal incision used in labour. The episiotomy has the effect of enlarging the distal birth canal – often the purpose is to prevent trauma to and damage of the perineal structures in breech or forceps delivery, in which there is a risk of this occurring.A midline episiotomy is made from the posterior vagina through the perineal body with a risk of damage to the external anal sphincter if extended too far. The rectum can also be damaged with this procedure.Most episiotomies are, however, posterolateral rather than midline – this procedure is safer and avoids the risk of damage to the external anal sphincter and rectum.suspects an odontoid peg fractureIn current practice a CT scan is the gold standard. Many hospitals include C-spine CT as standard with any head CT request, particularly in elderly patients. MRI is used to look for ligamentous injury, and also for cord abnormalities, and could be considered after a CT scan.An ‘open mouth’ view X-ray is the standard imaging technique used in plain imaging to look for possible peg fractures. However, with significant clinical/radiological concern, a CT scan is the investigation of choice. In a number of units, especially in the elderly, due to the availability of CT scanning, this has largely replaced plain radiographs as the initial diagnostic tool.odontoid peg (dens)The odontoid peg (dens) is an upward projection from the axis (C2). The peg has an articular facet at its front and forms part of a joint with the anterior arch of the atlas. The atlanto-axial joint (C1–C2) allows rotation. It is a non-weight-bearing joint. It is supported by a number of ligaments – the alar ligaments (from the side of the peg to the occipital condyle), the apical ligament (from the tip of C2 to the anterior margin of the foramen magnum), and the transverse ligament (which arches across the atlas to maintain the position of the peg).L5/S1 paracentral intervertebral disc bulgeParacentral intervertebral disc bulges usually impinge the transiting root. Paracentral disc bulges are the most common in the lumbar region. In this case it would be the S1 root, which can result in plantar flexion weakness, numbness on the sole of the foot in the S1 dermatome and an absent ankle jerk reflex. The S1 dermatome lies over the lateral malleolus.An absent ankle jerk implies some nerve root involvement, but on its own does not demand surgical intervention. Nerve root involvement is suggested by pain radiating below the knee. It is worse when the nerve is stretched, as with the sciatic stretch test, or when intra-abdominal pressure is raised, as with straining at stool, coughing or sneezing. Urinary retention is a worrying sign that can be consistent with cauda equina syndrome but it is sometimes secondary to pain, analgesic medication and bedrest. Before this can be assumed, a full neurological examination must be performed, and if there are concerns regarding a cauda equina syndrome then further investigations (eg lumbar-sacral MRI) must be carried out.concerns regarding a cauda equina syndromeA full neurological examination must be performed, and if there are concerns regarding a cauda equina syndrome then further investigations (eg lumbar-sacral MRI) must be carried out.The cauda equina starts at the level of vertebra L1/2 as the spinal cord terminates. The symptoms of cauda equina syndrome are classically urinary retention followed by overflow incontinence, bowel incontinence, bilateral sciatica and saddle anaesthesia.rolapsed intervertebral disc at the L4/5 interspaceA prolapsed L4–L5 disc presses on the L5 spinal nerve. The L5 dermatome lies over the anterior shin and dorsum of the foot.Collapse of a vertebral body secondary to osteoporosisOsteoporosis can cause painful collapse of vertebral bodies but rarely causes neurological symptoms and most often affects older women.spinothalamic tractPain and temperature are carried in the spinothalamic tract; these tracts carry contralateral sensation – a right-sided injury to the spinothalamic tract would therefore cause this sensory loss. The spinothalamic tract conveys pain, temperature, crude touch, itch, tickling and firm pressure sensations from one side of the body to the opposite side of the brain. The first neurone of the spinothalamic tract synapses in the posterior horn; the next neurone crosses to the contralateral side of the spinal cord and synapse in the thalamus (ventral posterolateral/ VPL nucleus), after ascending through the cord and brainstem; the third neurone arises in the thalamus to pass to the cortex. Axons from the cervical region synapse medially while axons from the lumbar region synapse laterally. As the fibres decussate in the spinal cord, a lesion of the spinothalamic tract at the level of the spinal cord would lead to loss of pain sensations on the contralateral side, beginning one level below the level of the lesion.Dorsal columns of spinal cordDorsal columns carry ipsilateral fine touch, proprioception, vibration, 2-point discrimination, form recognition.It also ends in VPL (thalamus)superior orbital fissureThe superior orbital fissure lies at the apex of the orbit bounded by the greater and lesser wings of the sphenoid bone. A number of structures pass through from superior to inferior; lacrimal nerve (V1), frontal nerve (V1), superior ophthalmic vein, trochlear nerve, superior part of oculomotor nerve, nasociliary nerve (V1), inferior part of oculomotor nerve, abducens nerve, a branch of the inferior ophthalmic vein. The zygomatic nerve, a branch of the maxillary nerve (V2), enters the orbit via the inferior orbital fissure carrying sensory fibres and parasympathetics. This artery runs through the optic canal inferior laterally to the optic nerve, not through the superior orbital fissure.true vocal foldsThe true vocal folds have a stratified squamous epithelium, innervated by the recurrent laryngeal branch (CN X), and are formed by the vocal ligament (The free edge of the quadrangular membrane forms the false vocal cord). The cords are adducted by the lateral cricoarytenoid muscle, abducted by the posterior cricoarytenoid and tensed by tilting the thyroid cartilage downwards and forwards by contracting the cricothyroid muscle. All the laryngeal muscles are supplied by the recurrent laryngeal nerve except for cricothyroid, which is supplied by the external laryngeal nerve.visual lossA left-sided occipital haemorrhage will result in a right-sided homonymous hemianopia. There may or may not be macular sparing, depending if the occipital pole is spared or not. A left homonymous hemianopia would result from a right occipital lobe lesion/infarction.Bitemporal hemianopia is caused by a compressive lesion at the optic chiasma, typically either a pituitary adenoma or a craniopharyngioma. A central scotoma describes visual loss corresponding with the point of fixation most commonly caused by a lesion between the optic chiasm and the retina. Occipital lobe stroke typically results in a homonymous hemianopia contralateral to the side of the lesion. Macular or central field sparing can occur if the occipital pole remains intact through dual blood supply from a branch of the middle cerebral artery.Le fort fractureLe fort I fracture is a horizontal maxillary fracture including the alveolar ridge, inferior maxillary sinus and lateral nasal fractures. It results in a ‘floating palate’ – it separates the teeth from the upper face.Le fort II is a fracture through the posterior alveolar ridge, lateral maxillary sinus, inferior orbital rim and nasal bones. It results in a floating maxilla.Le fort III injuries describe a complex fracture that involves the nasofrontal suture, orbital wall, zygomatic arch, zygomaticofrontal suture and maxilla-frontal suture. It results in a ‘floating face.’ Base of skull fractureA base of skull fracture typically involves the temporal bone, occipital bone, sphenoid bone or ethmoid bone. If suspected, a CT head scan is indicated.Clinical signs include Battle’s sign, raccoon/panda eyes, cerebrospinal fluid (CSF) rhino/otorrhoea, haemotympanum, and cranial nerve palsy.Tripod fractureA ‘tripod’ fracture often involves the orbital floor as well as the lateral wall of the maxillary sinus, and a zygomatic arch fracture. A fluid level in the maxillary sinus represents blood and often directs you to the area concerned.head injurySubdural haemorrhage is common after falls in elderly patients on anticoagulation. It appears on CT scan as a crescenteric lesion concave to the skull.Extradural haemorrhage is typically associated with trauma but on CT scan appears as a convex lesion as it is limited by the cranial sutures. It can cross the midline.Subarachnoid haemorrhage is suspected when there is hyperattenuation of the subarachnoid space, most commonly around the circle of Willis. Intracerebral bleeds appear as hyperattenuation within the brain parenchyma In patients that have sustained a diffuse axonal injury the initial CT scan is often unremarkable.Radiation- relationsA CT scan of the abdomen and pelvis exposes a patient to 10 mSv of radiation, equivalent to 4.5 years of background radiation and associated with a 1 in 2000 increased lifetime additional risk of fatal cancer. A 1 in 1100 increased lifetime risk is associated with a myocardial perfusion scan. A CT of the head has a radiation dose of 2 mSv (lower radiation dose than CT abdomen and pelvis).A bone scan exposes a patient to the equivalent of two years of background radiation associated with an increased lifetime additional risk of fatal cancer of 1 in 5000. Cervical spine X-ray is associated with a 1 in 200 000 lifetime additional risk of fatal cancer. A chest X-ray exposes a patient to a small amount of radiation 0.02 mSv, which has a one in a million lifetime additional risk of fatal cancer. A lumbar spine X-ray would have an associated radiation risk of 1.3 mSv, nearly double an abdominal X-ray (equivalent of seven months of natural background radiation.)An abdominal X-ray is associated with a radiation dose of 0.7 mSV, which is approximately four months of background radiation. The smallest exposure is with limb and joint (except hip) X-ray with gives <0.01 mS (equivalent of <1.5 days of natural background radiation)One hip X-ray exposes a patient to 0.3 mSv, which is the equivalent of seven weeks of background radiation.4 months of equivalent background radiation would be from one pelvic X-ray, one abdominal X-ray or one thoracic spine X-ray.An intravenous urogram would have a radiation dose of 2.5 mSv.For paediatric patients, lifetime cancer risks are approximately doubled compared with adult patientsIn patients 70 year and older, the lifetime cancer risks for various imaging investigations are approximately 1/5 of that associated with the 16–69-year-old population. The UK average background radiation dose is 2.2 mSv per year, regional averages range from 1.5–7.5 mSv.ARDSARDS is the most extreme manifestation of acute lung injury. It produces diffuse alveolar shadows on chest X-ray (CXR).It is important to be familiar of the diagnostic criteria of ARDS. The current definition is in the ‘Berlin Definition’ (2013). Key components:Acute (<1 week) onsetBilateral opacities consistent with pulmonary oedema on radiographSuch changes are not secondary to cardiac failure of fluid overload.Specific ventilatory requirements are a pa(O2)/FiO2 (PF) ratio <300 mmHg with a minimum of 5 cmH2O positive end-expiratory pressure (PEEP). [A normal PF ratio is approximately 500 mmHg and a PEEP of 5–15 cmH2O.]The final common pathway of ARDS involves neutrophil activation, and the release of inflammatory mediators and free radicals causing increased alveolar permeability. ARDS should be managed in an Intensive Therapy Unit (ITU)/High Dependency Unit (HDU) environment as rapid deterioration can occur requiring advanced circulatory support.Hilar lymphadenopathyIt is usually associated with sarcoidosis, tuberculosis, lymphoma, among other rarer differentials.technique to assess if there is an obstruction in the urinary tract?Technetium-99m (99Tcm) mercaptoacetyltriglycine (MAG3) is used in dynamic radio-isotope studies of the function of a kidney over a period of time. Progressive uptake of the isotope may occur in a dilated, but not obstructed, system. Intravenous injection of furosemide can then help with rapid clearance to demonstrate if any obstruction is present. As MAG3 has a faster clearance and smaller volume of distribution, it is replacing di-ethylene-triamine-penta-acetic acid (DTPA) in diuretic renography. It is important to note that MAG3 is preferred over DTPA in neonates, patients with impaired function, and patients with suspected obstruction, due to its more efficient extraction.CT urography, however, has become the modality of choice over the last decade. Common indications of CT urography include urinary calculus disease, haematuria, suspected renal or urothelial neoplasms. Non-contrasted MRI is not used to evaluate the urinary tract. However, MR urography provides superior visualisation (in terms of tissue contrast resolution, sensitivity for contrast enhancement) as compared with CT urography or conventional IVU. Furthermore, as MRI does not utilise ionising radiation, it is favoured in patient populations such as pregnant women, children or patients who require repeated studies of the urinary tract. Currently, it is mostly indicated in children and pregnant women with dilated systems. However it is contraindicated in patients with contrast allergies.Investigation by intravenous (iv) urography (IVU) involves serial abdominal X-rays after iv injection of contrast, therefore allowing visualisation of the renal parenchyma, calyces, pelvis as well as the collecting system. IVU has been largely replaced by CT urography, as the latter gives both anatomical and functional information, although with a relatively higher dose of radiation.An Ultrasound Scan (USS) does not assess the functional status of the kidneys. However it is useful in assessing anatomy, as well as detecting abnormalities such as tumours, cysts, abscesses, fluid collection in or around the kidneys, as well as the size, location and shape of the kidneys.Mandibular fracturesMandibular fractures are among the commonest facial fracture, given its prominence on the face. Fractures usually obey the ‘ring bone rule’, meaning that a fracture at one point usually indicates a corresponding fracture elsewhere. Approximately 50% of mandibular fractures are bilateral. Therefore multiple fractures are the norm. Malocclusion of the teeth commonly occurs, temporo-mandibular joint (TMJ) dysfunction occurs with condylar fractures. CT scanning is the imaging of choice after plain X-rays in planning reconstruction. Plain radiography may be helpful in diagnosis of facial fractures, but CT is the gold standard for planning reconstructive surgery. Magnetic resonance imaging will provide detailed images however it is less readily available than CT scanning.X-rays consistent with osteoarthritisThese are the four features typically found on X-rays consistent with osteoarthritis: joint space narrowing, osteophytes, subchondral cysts, subchondral sclerosisOsteophytes are bony projections associated with degenerative joint disease. Subchondral cysts are fluid filled areas inside the bone of joints and are a feature of osteoarthritis. Subchondral sclerosis occurs as a result of cartilage loss in degenerative joint disease and appears as increased density on X-ray.Bone scansBone scans reveal metastases by detecting function changes in osteoblastic–osteoclastic activity and bony vascularity. This function is unaffected by the presence of bony sclerosis (or lysis), which is determined by the relationship between the osteoclastic and osteoblastic remodelling processes.Bone scans are non-specific, and increased uptake of 99Tcm-labelled phosphate is found in areas with active bone turnover – eg fractures, infection, local tumour or healing bone after necrosis. Therefore clinical correlation with history, examination and, if necessary, routine X-rays are essential.Bone scans produce images of the whole skeleton. These substances have a half-life of 6.2 h, and the radiation dose compares favourably with skeletal survey. They are a sensitive, cheap and rapid method for screening for skeletal metastases, but are in fact limited in the level of details, or to distinguish between metastases or non-malignant lesions, eg fractures, infection. They show destructive lesions with bone loss of >50% of bone material. They show destructive lesions > 1.5 cm in diameter.Blunting of costophrenic anglesThe costophrenic angles are the lateral areas on a chest X-ray between the ribs and the diaphragm. The costophrenic angle area is usually seen as a very clearly defined ‘sharp’ angle on a chest X-ray. Blunting is cause by fluid in the angle. Some causes for blunting of the costophrenic angle include pleural effusion, lower lobe atelectasis, lower lobe pneumonia, empyema, haemothorax, pulmonary oedema and extensive pneumoconiosis (because of pleural thickening). An amoebic liver abscess may also cause blunting of the costophrenic angle due to direct irritation of the diaphragm, precipitating an inflammatory pleural effusion.chest Xray-Hiatus herniaA hiatus hernia occurs when part of the alimentary tract, typically the stomach, slips through the oesophageal hiatus in the diaphragm to lie within the thoracic cavity. A chest X-ray will typically reveal a retrocardiac opacity with an air fluid level. It does not cause pulmonary oedema and therefore blunting of the costophrenic angle does not occur.Mediastinal lipomatosis- chest X-rayMediastinal lipomatosis is a rare, genetic condition characterised by the presence of multiple lipomata within the mediastinum. This can cause blunting of the cardio-phrenic angle, but not the costophrenic angle as this does not correspond to the location of the mediastinum.Idiopathic pulmonary fibrosis- chest X-rayIdiopathic pulmonary fibrosis does not cause blunting of the costophrenic angle. It produces interstitial ground-glass shadowing on plain radiography.Traumatic aortic disruption (aortic rupture)Traumatic aortic disruption, a time-sensitive injury, is a common cause of sudden death after an automobile collision or a fall from great height. A complete tear through the tunica intima, media and adventitia usually leads to rapid exsanguination and death. In aortic rupture survivors, immediate death is prevented due to the vascular continuity maintained by a pseudoaneurysm within an intact adventitial layer or a mediastinal haematoma. A large mediastinal haematoma may shift the trachea to the right. This condition has a variable course ranging from a relatively clinically silent period due to the contained rupture (pseudoaneurysm), to rupture of the pseudoaneurysm, exsanguination and death. Radiographic findings may include a widened mediastinum, obliteration of the aortic knuckle, deviation of the trachea to the right, obliteration of the space between the pulmonary artery and the aorta (obscuration of aorto-pulmonary window), depression of the left main stem bronchus, deviation of the oesophagus (nasogastric tube) and fractures of the first or second rib or scapula. False-positive and false-negative findings occur with each radiographic sign and, rarely (1–2%), no mediastinal or initial chest X-ray abnormality is present in patients with great vessel injury. While conventional digital subtraction angiography has historically been the gold standard investigation, CTA has now replaced it as the first line investigation, not only due to it being non-invasive but also on account of better delineation of the poorly opacifying false lumen, intramural haematoma and end-organ ischaemia. MRI has been reserved for follow-up examinations. Rapid non-contrast imaging techniques may see MRI having a larger role to play in the acute diagnosis, particularly in patients with impaired renal function. It has similar sensitivity and specificity to CTA and transoesophageal echocardiogram (TOE) but suffers from limited availability and the difficulties inherent in performing MRI on acutely unwell patients. Transoesophageal echocardiography (TOE) has very high sensitivity and specificity for assessment of acute aortic dissection, but due to limited access and invasive nature, it has largely been replaced by CTA. Transthoracic echocardiography has a limited role in the assessment of traumatic aortic disruption and the patient will require CTA.gold standard test for DVTAscending contrast venography Duplex Doppler US is used far more readily in practice, however the gold standard test for deep vein thrombosis remains the ascending contrast venography. 125I-labelled fibrinogen scanning is at a research stage onlyUltrasound DopplerUltrasound uses sound waves to create an image. With Doppler scanning this produces a dynamic picture and is used to evaluate blood flow through a vessel. Ultrasound is more difficult in patients with high body mass indices (BMIs).first-line investigation in patients with acute renal colicNon-contrast CTKUB is now the first-line investigation in adult patients that are not pregnant when they present with acute renal colic. It is now recommended over intravenous urogram as it is a more sensitive test and has a similar radiation dose.Ultrasound KUB would be used as the first-line imaging modality to investigate a patient presenting with renal colic if they are pregnant or in children. Most renal stones are radio-opaque and can therefore be seen on plain abdominal X-ray. But this is not a very sensitive way of diagnosing renal stones and would not be the first-line investigation for a patient presenting with renal colic.traumatic diaphragmatic injury- visualising the anatomy of the diaphragmMRI is more accurate in visualising the anatomy of the diaphragm. It is very sensitive and specific and so is the investigation of choice. Surgical repair is necessary, even for small tears, because the defect will not heal spontaneously. Diaphragmatic injuries result from either blunt or penetrating trauma. A traumatic diaphragmatic rupture is more commonly diagnosed on the left side, perhaps because the liver obliterates the defect or protects it on the right side. In addition, the appearance of bowel, stomach or a nasogastric (nasogastric tube (NG)) tube is more easily detected in the left side of the chest. Right diaphragmatic ruptures are rarely diagnosed in the early post-injury period. The liver often prevents herniation of other abdominal organs into the chest. This, however, may not be representative of the true incidence of laterality and autopsy studies have revealed that left-sided and right-sided ruptures occur almost equally. Blunt trauma produces large radial tears measuring 5–15 cm, most often at the posterolateral aspect of the diaphragm. In contrast, penetrating trauma usually create only small linear incisions or perforations, which are less than 2 cm in size and may often take some time, even years, to develop into diaphragmatic hernias. If a laceration of the left diaphragm is suspected, an nasogastric tube (NG) tube should be inserted. If the tube appears in the thoracic cavity on the chest film, the need for special contrast studies can be eliminated. Minimally invasive endoscopic procedures (thoracoscopy) may be helpful in evaluating the injury to the diaphragm in indeterminate cases.screening for abdominal aortic aneurysmAll men at the age of 65 years are offered an ultrasound to screen for abdominal aortic aneurysm. At this time if an aneurysm is detected between 3-4.4 cm, then annual screening will take place with ultrasound. As the size of the aneurysm increases, the interval may shorten to 6 monthly surveillance.Facial X-rays usually taken for facial injuriesFour facial X-rays are usually taken: Waters’ view (posterior–anterior (PA) with cephalad angulation), Caldwell (PA view), lateral view occipito-submentovertex viewWaters’ view tends to show all facial structures the best, hence Water’s view is helpful in the diagnosis of facial fractures but less helpful when planning a surgical intervention.Pancreatic pseudocystsPancreatic pseudocysts can develop the following attacks of acute pancreatitis. They take 3–6 weeks to mature and usually present with low-grade fever, leucocytosis, chronic abdominal pain and/or persistent rise in serum amylase. If very large they can cause gastric outlet obstruction. The investigation of choice is computed tomography (CT) of the abdomen, which enables the size and location of the collection to be determined. Often they are managed conservatively, but if very symptomatic they can be treated initially with percutaneous (with imaging guidance), internal or external drainage. If recurrence occurs, formal surgical drainage via cystogastrostomy or cystenterostomy are options.most suggestive of cholecystitis on ultrasound scanningUltrasound is the preferred initial modality in the investigation of right upper quadrant pain. It is more sensitive than hepatobiliary iminodiacetic acid (HIDA) scintigraphy and computed tomography (CT) in the diagnosis of acute cholecystitis. The most sensitive ultrasound finding in acute cholecystitis is the presence of cholelithiasis in combination with the sonographic Murphy’s sign. Gall-bladder wall thickening (>3 mm) and pericholecystic fluid are secondary findings in acute cholecystitis. [A normal gall-bladder is thin walled (<3 mm) and anechoic on ultrasound.]Bosniak classificationThe Bosniak classification system of renal cystic masses divides renal cystic masses into five categories based on imaging characteristics on contrast-enhanced CT. It is helpful in predicting a risk of malignancy and suggesting either follow up or treatment.Bosniak 1 are simple cysts with a rounded wall. They are not malignant and require no further follow up.Bosniak 2 lesions are minimally complex with a few thin septa or calcifications and are non-enhancing. They do not require further follow up.Bosniak 2F lesions are minimally complex but have an increased number of septa when compared with Bosniak 2 (that are minimally thickened with nodular or thick calcifications). They do require imaging surveillance although there are no guidelines on this, ~5% will be malignant.Bosniak 3 lesions are indeterminate with ~55% malignant. They appear with thick nodular multiple septa and enhance.Bosniak 4 lesions are clearly malignant solid masses with large cystic or necrotic areas.arithmetic meanThe arithmetic mean is the sum of the observations divided by the number of observations(For example: 3+1+1+2+12+1+7+2+4+1+2+4+1+3+1)/15=45/15 = 3.average deviationThe average deviation is a measure of dispersion, calculated by taking the arithmetic mean of the absolute values of the deviations of the functional values from some central value, usually the mean or median.modeThe mode is the most commonly occurring value. For example: 3, 1, 1, 2, 12, 1, 7, 2, 4, 1, 2, 4, , 1, 3, 1 – in the above example ‘1’.geometric meanThe geometric mean is the nth root of the product of the observations and is only used when the observations are positively skewed and can be assumed to have a log-normal distribution.median deviationIt is the value that divides the observations into two equal halves when they are arranged in order of increasing valueFriedman's two-way ANOVAThis statistical test is used for non-parametric data and aims to understand if there is an interaction between the two independent variables on the dependent variable.Student’s t-testStudent’s t-test is used to examine the difference between sample means, suitable for normally distributed dataChi-squaredThis statistical test is used for non-parametric data. Observations are classified into mutually exclusive classes and the null hypothesis gives the probability that any observation falls into the corresponding classes. Kruskall–WallisThis test is also used for non-parametric data. It is used for comparing two or more independent samples of equal or different sizes.Mann–WhitneyThis statistical test is for non-parametric data to compare two sample means from the same population. It can be used as an alternative to the independent t-test when data are not normally distributed.type I errorA type I error (false-positive result) occurs if the null hypothesis is rejected when it is actually true (eg the treatments are interpreted as having different effects when they do not).Experimental design errorAn experimental design error would be likely to result in statistical bias – factors that will influence the results have not been subject to adequate control measures.Observer bias errorObserver bias occurs when for example knowledge of the type of treatment being given or received alters the perception of its effect. For example a patient knowingly given a placebo for pain relief may over-rate their pain.Selection bias errorSelection bias occurs when patients are allocated to the interventions sequentially so it is known in advance which treatment the next patient recruited will receive so a clinician may pre-select a specific patient for a particular intervention.Type II errorA type II error is a false-negative result and occurs if the null hypothesis is accepted when it is actually false (eg the treatments are interpreted as having equal effects when they are actually different).Clinical governanceClinical governance involves seven pillars, one of which is clinical audit:Service user, carrer and public involvement.Risk management.Clinical audit.Staffing and staff management.Education and training.Clinical effectiveness.Clinical information.Lead-time biasLead-time bias occurs when screening advances the date at which diagnosis is made. This, therefore, lengthens the calculated survival time without necessarily altering the date of death. Length bias can also affect screening programmes. This is the tendency for screening to detect a disproportionate number of cancers that are slow-growing and have a better prognosis anyway.Detection biasDetection bias occurs when a phenomenon is more likely to be observed for a particular set of study subjects. This may lead to a false inflation of a particular phenomenon being observed in a particular group because the study authors are more likely to look for it within a set group.Interobserver biasThis occurs when the researcher subconsciously influences the experiment due to cognitive bias, in which judgement may alter how an experiment is carried out.Population biasPopulation bias or sampling bias arises when some members of a population are more likely to be included in a study than others, leading to systematic differences between the population being studied and the general population.modified Glasgow ScoreA point is recorded for each criteria below. A score of 3 or more indicates a severe attack and ideally should have an intensive care unit (ITU) review/ monitored in ITU. This patient scores 3 based on pa(O2), glucose and albumin levels:pa(O2) < 7.9 kPaage > 55 yearsneutrophils: WCC > 15 × 109/lcalcium < 2 mmol/lrenal function: urea > 16 mmol/lenzymes: AST/ALT > 200 IU/l or LDH > 600 IU/lalbumin < 32 g/lsugar: glucose > 10 mmol/lclearance of the substanceClearance (ml/min) is calculated using the formula C= (U × V)/P where U = urine concentration in mg/ml, V = urine production in ml/min, P = plasma concentration in mg/ml.null hypothesisThe null hypothesis assumes that there is no difference in the means of the groups. Therefore when P < 0.05 the null hypothesis can be rejected and it can be stated that there is a statistical difference between the means of the groups.inaccuracy of the pulse oximeterArrhythmias, hypotension, vasoconstriction, abnormal haemoglobin or pigments (eg bilirubin), movement, poor tissue perfusion and nail varnish can all affect pulse oximetry readings. Anaemia or polycythaemia will not affect the accuracy of the reading values, but these factors should impact the interpretation of these values. For example, an anaemic patient who has saturations of 99% will have fewer haemoglobin molecules, meaning that total oxygen content may still be significantly decreased although the saturations will not reflect this. Carboxyhaemoglobin will also cause a reading to be falsely high – pulse oximetry should be interpreted with caution in these patients.Levels of evidence1a Systematic reviews (with homogeneity) of RCTs1b Individual RCTs (with narrow confidence interval)1c All or none RCTs2a Systematic reviews (with homogeneity) of cohort studies2b Individual cohort study or low quality RCTs (eg <80% follow-up)2c ‘Outcomes’ research; ecological studies3a Systematic review (with homogeneity) of case–control studies3b Individual case–control study4 Case series (and poor quality cohort and case–control studies)5 Expert opinion without explicit critical appraisal, or based on physiology, bench research or ‘first principles’.Randomised controlled trial (RCT)decreased, normal or raised anion gap:The anion gap is the difference between the primary measured cations (sodium and potassium) and primary measured anions (chloride and bicarbonate). The degree of difference between the measured cations and anions aids in determining the cause of a metabolic acidosis.Anion gap = ([Na+] + [K+]) ? ([Cl–] + [HCO3–]) (all units mmol/l). a decreased anion gap (< 6 mEq/l):hypoalbuminaemiaplasma-cell dyscrasiamonoclonal proteinbromide intoxicationnormal varianta normal anion gap (6–12 mEq/l):loss of bicarbonate (ie, diarrhoea)recovery from diabetic ketoacidosisileostomy fluid losscarbonic anhydrase inhibitors (acetazolamide, dorzolamide, topiramate)renal tubular acidosisarginine and lysine in parenteral nutritionnormal variant.an elevated anion gap (>12 mEq/l):methanoluraemiadiabetic ketoacidosispropylene glycolisoniazid intoxicationlactic acidosisethanol ethylene glycolrhabdomyolysis/renal failurePaget’s disease of the bonePaget’s disease of the bone is characterised by excessive breakdown and remodelling of bone. It is characterised by excessive osteoclastic and osteoblastic activity. Blood results in Paget’s disease characteristically reveal an elevated ALP with normal calcium and phosphate.Secondary hyperparathyroidismIn chronic renal failure, secondary hyperparathyroidism is an appropriate response to low calcium levels that occur due to low calcitriol levels, which is produced in the kidneys. Phosphate is high as it cannot be cleared from the kidneys. ALP is elevated in high turnover renal osteodystrophy due to increased osteoblast activity.Primary hyperparathyroidismPrimary hyperparathyroidism is usually caused by a tumour (parathyroid adenoma, or more rarely, parathyroid adenocarcinoma) within the parathyroid gland. It causes raised calcium, as opposed to low calcium as seen in these blood results. Bloods results typically show raised parathyroid hormone (PTH) and raised calcium and can be treated by surgical removal of one more parathyroid glands.Tertiary hyperparathyroidismTertiary hyperparathyroidism refers to excessive secretion of parathyroid hormone (PTH) after a long period of secondary hyperparathyroidism. It occurs as a state of autonomous parathyroid function due to persistent parathyroid stimulation. It would result in hypercalcaemia. The blood results shown above reveal hypocalcaemia and therefore are not caused by tertiary hyperparathyroidism.OsteoporosisOsteoporosis is a chronic condition that results in reduced bone density. It does not however cause changes in serum levels of calcium and phosphate, and does not cause elevated ALP as is seen in these blood results.advantage of a cross-over studyThe advantage of a cross-over study design is that the same individuals receive a sequence of different treatments therefore reducing the errors associated with individual differences. Most cross-over designs have a ‘balance’ in which all subjects should receive the same number of treatments and participate for the same period of time.Gaussian distributionThe Gaussian distribution is more usually referred to as the normal distribution and is characterised by being ‘bell shaped’ (unimodal) and symmetrical about its central value. In a Gaussian distribution the mean, median and mode are equal. This situation is characteristic of the bell-shaped distribution.Jehovah’s witnesses.In any emergency setting the patient should be managed using an ABC approach. In this case the child is in grade IV shock which requires immediate blood products for life-saving treatment. Following the Children’s Act of 2005 it would not be necessary to make the child a ward of the court to administer life-saving treatment and in these scenarios where the child is less than 12 or older but lacking capacity the doctor must act in the best interests of the child.In cases with a child younger than 12 or older children that lack capacity, medical treatment or surgery cannot be performed without parent or guardian consent, unless for life-saving treatment when the doctor can act in the best interests of the child and in this case administer the blood transfusion.A consent form signed in an out-patients’ department 6 months preoperatively is technically valid but it is strongly advisable to obtain the signature again on admission. The surgeon can clarify the patient’s initial consent and reconfirm this by signing the relevant section on the day of surgery. The patient does not have to re-sign.It would be best practice to hold a further discussion with the patient, as there has been significant delay, to check their understanding and offer them another opportunity to ask any additional questions. On the consent form there is an additional section labelled confirmation of consent that can be signed as evidence that this has been done. A signature on a consent form, following a documented balanced discussion of alternative treatments, risks and benefits often indicates completion of the consent process. It is good practice to reconfirm consent on the day of surgery and offer opportunity for questions. If a significant delay has occurred between initial consent and the day of surgery, reconfirming consent by signing the relevant section of the consent form is good practice.Appraisals are carried out between yourself and a colleague who has been trained as an appraiser. Medical appraisers come from a variety of backgrounds and include locums and salaried general practitioners in primary care settings and staff and associate specialist doctors in secondary care settings. An annual appraisal is mandatory for doctors working within the NHS and is part of the 5 yearly process of revalidation. Feedback from colleagues in the form of either multi-source feedback, or 360 degree feedback is an essential component of revalidation done every 5 years. It does not necessarily need to be included at every appraisal.brainstem death testingThis is correct, brainstem death testing should be carried out twice by two doctors, both 5 years post-registration, one of whom must be a consultant and neither should be a member of the transplant team.Gillick competenceGillick competence states ‘as a matter of Law the parental right to determine whether or not their minor child below the age of 16 will have medical treatment terminates if and when the child achieves sufficient understanding and intelligence to understand fully what is proposed’.guidanceNICE issues evidence-based guidance and advice forinterventional procedures health technologiesclinical practicepublic healthsocial careThe General Medical Council issues guidance on good medical practice. and medical ethics.ingle-blinded trialsn single-blinded trials, patients are randomly allocated to treatment or placebo/standard groups. Typically the patient is unaware to which treatment group they have been allocated, but the assessor will know. When both the assessor and patient are aware of the treatment being given then the study is not blinded. If the patient and the assessor are unaware of what treatment has been given this would be a double-blinded trial.child abuseWhile there are no pathognomonic signs of child abuse some fractures raise a higher suspicion. These include single fracture with multiple bruises, multiple fractures of different ages, metaphyseal and/or epiphyseal injuries, rib fractures, new periosteal bone formation and skull fractures in association with intracranial injury.. Red flags of child abuse include long bone fracture in a child who is not yet walking, multiple fractures in various stages of healing, corner fractures, posterior rib fractures and transphyseal separation of the distal humerus. Children suspected of being abused should be admitted to hospital and appropriate child protection professionals informed. Anterior rib fractures are uncommon in a child and should raise the suspicion of non-accidental injury, however with the appropriate history of trauma this may be accidental. In non-accidental injury it is classically the postero-medial ribs that fracture. Hip dislocation in a child who is not yet walking is not usually a presentation of child abuse. It could represent a condition such as developmental dysplasia of the hip in which the acetabulum is too shallow and the femoral head is not held tightly in place making it more prone to dislocation.LPAAn LPA is a legal document that may be made by a person (known as a donor) in anticipation of losing the mental capacity to make decisions for themselves. The document must be registered with the Office of the Public Guardian (OPG) to be valid. An ‘attorney’ or ‘attorneys’ are appointed to make decisions over either property and financial affairs, health and welfare affairs, or both. An attorney acting under a health and welfare LPA must act in the donor’s best interests when deciding upon medical treatments.referred to the coronerAny death thought to have been caused by an industrial disease or industrial poisoning should be referred to the coroner. Recent surgery should also be referred to the coroner, particularly if it relates to the patient's death.Notifiable diseases have to be reported to the Consultant in Communicable Disease Control (CCDC). They do not need to be referred to the coroner.Deaths from AIDS or an HIV-related illnesses do not need to be reported to the coroner unless they meet another reason for reporting; unknown cause of death, violent or unnatural death, sudden and unexplained death, not visited by a medical practitioner in their final illness, medical certificate unavailable, not seen by a doctor who signed the medical certificate within 14 days before death or after they died, death during an operation or before the person came out of anaesthetic or medical certificate suggesting that the death may have been caused by an industrial disease or industrial poisoning. ................
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