Gen Emergency Surgery Flashcards

Question

25. An 88-year-old woman with severe chronic obstructive pulmonary disease presents with abdominal distension. A CT shows an obstructing apple core lesion of the sigmoid colon. She is also noted to have bilobar liver metastases. What is the most appropriate first line management? ``` A Caecostomy B Colonic stenting C Hartmann’s procedure D Sigmoid colectomy E Subtotal colectomy and end ileostomy ```

Answer 1

25. B Colonic stenting This is a frail patient with significant comorbidities, which would make any surgery very high risk. Even a loop colostomy is associated with significant morbidity and a small mortality rate. Stenting of the obstructing colonic lesion can achieve the same functional result as surgical decompression without the need for an operation and defunctioning colostomy. It can be used to allow time for work-up to definitive surgery or in an elderly patient, such as this, can provide good palliation. Lamah M, Mathur P, McKeown B, et al The use of rectosigmoid stents in the management of acute large bowel obstruction. J R Coll Surg Edinb 1998; 43:318–321.

Answer 2

26. B In low doses it increases renal blood flow Dopamine has varying dose-related effects due to α1-, β1- and dopaminergic activity: Low dose effects (at doses < 2 μg/kg/min) are predominantly renal. There is increased renal, cerebral, coronary and mesenteric blood flow with vasodilation because of agonistic action on dopamine receptors in these vascular beds. Intermediate dose effects (at doses 2–10 μg/kg/min) are predominantly cardiac. β1-agonist activity results in increased cardiac contractility and heart rate. The increased cardiac output and increased dopaminergic activity results in increased mesenteric perfusion. Slight α1-adrenergic activity may lead to a degree of peripheral vasoconstriction. High dose effects (at doses 10–20 μg/kg/min) are vasoconstrictive and cardiac. α1-Adrenergic activity causes marked peripheral vasoconstriction and a rise in blood pressure. There can also be renal and mesenteric vasoconstriction. At very high doses (> 20 μg/kg/min) the overriding adrenergic activity may cause extreme vasoconstriction, which can suppress dopaminergic renal vasodilation and deleteriously affect the renal and peripheral circulation. Holmes CL, Walley KR. Bad medicine: low-dose dopamine in the intensive care unit. Chest 2003; 123:1266–1275. Dopamine in cardiac failure and shock. BMJ 1977; 17:1563–1564.

Answer 3

27. C In pT4 melanoma (> 4 mm thickness) an excision margin of 2 cm is recommended For surgical excision of melanomatous lesions: • In pTis (melanoma in situ) an excision margin of 2–5 mm is recommended • In pT1 melanoma (0–1 mm thickness) an excision margin of 1 cm is recommended • In pT2 melanoma (1–2 mm thickness) an excision margin of 1–2 cm is recommended • In pT3 melanoma (2–4 mm thickness) an excision margin of 2 cm is recommended • In pT4 melanoma (> 4 mm thickness) an excision margin of 2 cm is recommended In patients with squamous cell carcinoma, a 4 mm margin is sufficient to remove microscopic tumor in over 95% of well-differentiated tumours which are < 2 cm in diameter. A wider margin of 6–10 mm is required for lesions > 2 cm in diameter, less-differentiated, or in high-risk locations (such as the scalp, ears, eyelids, nose, or lips). In cases of primary basal cell carcinoma (BCC), a 3 mm surgical margin adequately clears the tumour in 85% of patients with lesions under 2 cm. However, increasing the excision margin to 4–5 mm increases the peripheral clearance rate to 95%. In instances of recurrent BCC, margins of 5–10 mm have been recommended. Balch CM, Buzaid AC, Soong SJ, et al. Final version of the American Joint Committee on Cancer staging system for cutaneous melanoma. J Clin Oncol 2001; 19:3635–3648. Brodland DG, Zitelli JA. Surgical margins for excision of primary cutaneous squamous cell carcinoma. J Am Acad Dermatol 1992; 27:241–248. Burg G, Hirsch RD, Konz B, Braun-Falco O. Histographic surgery: accuracy of visual assessment of the margins of basal-cell epithelioma. J Dermatol Surg Oncol 1975; 1:21–24. Wolf DJ, Zitelli JA. Surgical margins for basal cell carcinoma. Arch Dermatol 1987; 123:340–344.

Answer 4

28. D Injection of cyanoacrylate glue Unlike oesophageal varices, bleeding from gastric varices is difficult to treat using band ligation because of difficult deployment in a retroflexed scope position. There are few controlled studies of medical therapy for gastric variceal bleeding and most evidence is extrapolated from what is known regarding the management of oesophageal varices. The best endoscopic therapy for fundal gastric variceal bleeding is injection of cyanoacrylate glue which hardens on contact with blood. Following healing, when the mucosa sloughs away the overlying glue ‘cap’ will also be shed. Complications include infection and embolism of glue particles (which are fortunately very rare). The glue can also harden inside the scope and this can damage the equipment. Feldman M, Friedman LS, Brandt LJ (eds). Sleisenger and Fordtran’s Gastrointestinal and Liver disease, 9th edn. Philadelphia: Saunders, 2010.

Answer 5

29. D Retroperitoneal, between the ovarian vessels and the renal veins Retroperitoneal varices occur between the mesenteric vessels and renal (or gonadal, or iliac) veins. However, in patients with infrarenal inferior vena cava obstruction, the ovarian (gonadal) vessels act as a collateral drainage for the systemic circulation by facilitating drainage form the internal iliac vessels to the left renal vein and the cava itself. However, this does not involve a portosystemic anastomosis. Other sites of collateralisation (between the portal and systemic circulations) include: • The rectum, where the superior rectal from inferior mesenteric vein anastamoses with the middle and inferior rectal veins/pudendal vein. • The paraumbilical region, where the left portal/paraumbilical vein anastomoses with the vestigial umbilical vein/superficial epigastric and caput medusa may result. • The distal esophagus, where the left gastric vein anastomoses with oesophageal branches of the azygous vein. • Intrahepatic, between the portal vein and the inferior vena cava.

Answer 6

30. A Clostridium difficile Alcohol-based hand rubs are less effective on soiled hands and are ineffective against C. difficile infection. Unfortunately, the hand rub is unable to kill the bacterial spores. World Health Organization (WHO). WHO Guidelines on Hand Hygiene in Health Care: First Global Patient Safety Challenge: Clean care is safer care. Geneva: WHO, 2009: 242–245.

Answer 7

31. A Addison’s disease This patient has biochemical evidence of metabolic acidosis with low bicarbonate, sodium and glucose and an elevated serum potassium. The normal range for serum glucose is 4–7 mmol/L (70–125 mg/dL). Addison’s disease (or adrenocortical insufficiency) results in reduced synthesis of mineralocorticoids and glucocorticoids. As a result of decreased glucocorticoid effects, there is a reduction in serum blood glucose. Because of decreased circulating cortisol, the kidney cannot excrete free water and hyponatraemia develops. Metabolic acidosis develops because of low aldosterone levels causing sodium loss in the urine, with H+ retention in the serum. Low aldosterone also leads to hyperkalaemia. Clinical symptoms which develop are mainly due to the low blood sugar (hypoglycaemic autonomic effects) and low sodium (hypotension). Ten S, New M, Maclaren N. Addison’s disease. J Clin Endocrinol and Metabl 2001; 86:2909–2922.

Answer 8

32. D Right hemicolectomy The patient requires a right hemicolectomy as the carcinoid of the appendix is > 2 cm in diameter. A right hemicolectomy shoud be considered if the appendix tumour is large (1–2 cm) or invades the serosa. If a right hemicolectomy is to be performed then a regional lymphadenectomy should also be considered. Ramage JK, et al. Guidelines for Management of Gastroenteropancreatic Neuroendocrine (including carcinoid) tumours. Gut 2005; 54(Suppl IV): iv1–iv16.

Answer 9

33. C Kruskall–Wallis test When answering a statistical question, it is important to select the correct test (Table 1.4). In this example, a test for an association between two continuous variables is sought. Satisfaction scores (notoriously difficult to attain reliability) are very unlikely to have normal distribution, and so median scores are applicable. Therefore, without assuming equal variances or normal distribution in the data, the Kruskal–Wallis test can be applied; where normal distribution and mean values are applied, ANOVA would be the correct test. The Mann–Whitney U test compares medians in two sets of continuous data; the 2-sided t-test compares means and the linear regression analysis is applicable in determining the contribution of multiple factors to one continuous outcome variable. Table 1.4 provides a simple overview for comparative statistical tests that should be easily remembered. Kirkwood BR, Sterne JAC. Non-parametric methods based on ranks. In: Kirkwood BR, Sterne JAC (eds). Essential Medical Statistics, 2nd edn. Oxford: Wiley-Blackwell, 2004: 345.

Answer 10

34. A A significant difference (p-value = 0.05) has a likelihood of being due to chance in 1 in 20 A type I (α) error describes the likelihood of wrongly rejecting the null hypothesis. A p-value of 0.05 describes the chance that a seemingly positive finding is actually due to luck alone, and in fact, no real difference exists (0.05 is equivalent to 1 in 20 mathematically). It is clear that a power calculation has been carried out, based on the desired power and relevant difference which we wish to detect. The methodology described is that of a randomised controlled trial. In specially designed, pragmatic studies, either surgeon and/or patient preference may be accounted for, although this is not generally the case in controlled trials. Early stopping rules always apply, with patient safety paramount. If there is clearly a higher rate of complication with the new intervention, a trial is not justified, as the whole basis for its carrying one out is that of clinical equipoise and uncertainty. If a trial is underpowered, there may be too few subjects to correctly identify a real difference. This is a false negative or falsely retaining the null hypothesis, and represents a type II (β) error. Kirkwood BR, Sterne JAC. Non-parametric methods based on ranks. In: Kirkwood BR, Sterne JAC (eds). Essential Medical Statistics, 2nd edn. Oxford: Wiley-Blackwell, 2004: 425.

Answer 11

35. A Case–control study Here, we have a condition which we wish to link with a previous exposure. The question may be answered with a population level, longitudinal cohort study, following up children and recording details of any exposure, with rates of goitre later in life, to generate relative risk data. However, this is wholly impractical. It is more straightforward to answer this question by comparing two sets of odds ratios, to attribute the likelihood that someone with a condition has had a certain exposure, compared to the likelihood that someone free of the exposure has the condition. This does not imply causality, but degrees of relationship can be ascertained, and may provide justification for larger scale, longitudinal studies. Thus, the two sets of patients have different odds ratios generated. A randomised trial of exposure is simply unethical. An environmental study may act as a hypothesis-generating study during the early stages of studies. A meta-analysis may address the question, but would be unspecific to this surgeon's own population. It also traditionally pertains only to randomised controlled trials. Bhopal R. Concepts of Epidemiology: Integrating the Ideas, Theories, Principles and Methods of Epidemiology, 2nd edn. Oxford: Oxford University Press, 2008.

Answer 12

36. D Ensuring it represents a more general population Although external validity describes the applicability of trial data to the broader population, it is widely acknowledged that participants in randomised controlled trials (RCTs) are not typical patients. These patients self-select (selection bias) as being more interested/motivated around their healthcare issues, and their treatment will be different, regardless of protocols. The Hawthorne effect describes the change in behaviour, and potential outcomes, experienced by both participants and clinicians involved in trials, by the very fact they are aware of being studied. The other options simply describe best practice to ensure internal validity in any RCT, and so all must apply for the results to be valid and reliable in themselves. McCarney R, Warner J, Iliffe S, et al. The Hawthorne Effect: a randomised, controlled trial. BMC Med Res Methodol. 2007; 7: 30.

Answer 13

37. D Patients with prolonged hospital stays are at particular risk Although vancomycin is rarely associated with Clostridium difficile diarrhoea, it is more often used as a second line treatment, after oral metronidazole. Prolonged hospital admissions (and in particular, stays in the intensive care unit), are independently associated Clostridium difficile infection. The clinical presentation of this chapter ranges from mild diarrhoea, to severe pancolitis with pseudomembranes, sepsis and perforation. Examples of this are shown in the endoscopic (Figure 1.6) and postoperative (Figure 1.7) images. A low index of clinical suspicion is required for adequate infection control. Starr J. Clostridium difficile associated diarrhoea: diagnosis and treatment. BMJ 2005; 331:498–501.

Answer 14

38. B Formal diagnosis of malnutrition may be made with BMI ≤ 18 kg/m2 Guidelines state that nutritional screening should be offered to all patients at the point of admission and if a clinical concern arises at any time, then subsequently repeated weekly for inpatients. A routine method to accomplish this is the Malnutrition Universal Screening Tool (MUST) (Table 1.5), based on the patient’s body mass index (BMI), degree of unintentional weight loss, and effect of acute disease. This was developed to ensure a reliable, thorough and reproducible screening technique. Obese patients, as defined by BMI > 30, may still be malnourished in terms of loss of lean muscle mass, particularly in the acute illness phase. BMI ≤ 18 (or 20 with associated > 5% weight loss over 3–6 months), or weight loss > 10% in the same period are diagnostic. Patients require baseline trace elements to be checked only prior to commencement of parenteral feeding. Elia M. The ‘MUST’ report: Nutritional screeing for adults: a multidisciplinary responsibility. Redditch: Malnutrition Advisory Group of the British Association for Parenteral and Enteral Nutrition (BAPEN), 2003. National Institute of Clinical Excellence (NICE). Nutrition support in adults: oral nutrition support, enteral tube feeding and parenteral nutrition (CG32). London: NICE, 2006. Available at: http://www.nice. org.uk/CG32.

Answer 15

39. D Prevalence: risk of developing a new condition within a specified period This describes incidence not prevalence. Odds ratios and relative risks are frequently confused. Odds ratios pertain to retrospective data, working back from an event to assess the likelihood of having been exposed to a risk factor. They cannot be used to describe aetiology with certainty, and are useful in hypothesis generation and epidemiological studies. Relative risk ratios are calculated over prospective, longitudinal data, and reliably inform the strength of the relationship between exposure and outcomes. The absolute risk reduction is a numerical calculation, subtracting the risk rate in the control group from that in a study group. This may then be used to calculate the number needed to treat, which indicates the number of patients who require exposure to an intervention in order for any one patient to benefit. This is useful in economic modelling. See Straus et al (2010) for a readable guide to putting these numbers into practice. Straus SE, Richardson WS, Glasziou P, et al. Evidence Based Medicine: How to Practice and Teach EBM. 4th edn, London: Churchill Livingstone, 2010.

Answer 16

40. E Usual nutritional support should include adequate calories (total energy 25–35 kcal/kg/day) The daily calorie requirement must be adjusted for any acute illness episode, with 0.8–1.5 g protein/kg/day recommended. There is evidence to support the use of oral supplements towards improved outcomes, with absolute risk reduction of infection of 10% in one systematic review. When comparing enteral and parenteral nutrition in the same series, enteral nutrition was superior. However, overall quality of evidence is too poor to make definitive recommendations. Parenteral nutrition should only be considered when the gut is: • Unusable • Insufficient to achieve adequate absorption • Inaccessible • Non-functional • Leaking Otherwise, enteral feeding is always the route of choice. It generally offers better outcomes and fewer complications. In the context of starvation or malnutrition, refeeding syndrome may emerge on recommencement of feeding, particularly with enteral supplementation. This is a metabolic disturbance with rapid electrolyte imbalance, driven largely by a change in basal metabolic rate and insulin levels. It requires careful biochemical monitoring, and dietary phosphate and vitamin supplementation is usually prescribed to prevent this. Koretz RL, Avenell A, Lipman TO, Braunschweig CL, Milne AC. Does enteral nutrition affect clinical outcome? A systematic review of the randomised trials. American Journal of Gastroenterolgy 2007; 102:412–29.

Answer 17

41. A PaCO2 of > 7 kPa has been documented The PaCO2 need rise only to 6–6.5 kPa to confirm brainstem death. The other criteria are accurate. In the UK, brainstem death is defined as complete, irreversible loss of brainstem function, made according to well-defined criteria and preconditions, with reversible causes of apnoeic coma excluded, and brainstem areflexia and persistent apnoea confirmed. The cranial nerve reflexes tested are set out in Table 1.6. Pallis C, Harley DH. ABC of Brain Stem Death, 2nd edn. London: BMJ Books, 1996.

Answer 18

42. B Obese patients (BMI >30) should be excluded from day case lists Obese patients were originally excluded from day case surgery lists, with BMI limits varying considerably between units. A BMI of 30–40 was used as a cut-off, but increasingly even super-obese patients are being managed as day cases. It is now deemed acceptable to make this judgement on an individual patient basis. The other statements correctly describe defined criteria. Full details are available from the anaesthesic guidelines for day case surgery. Verma R, Alladi R, Jackson I, et al. Day case and short stay surgery: 2. Anaesthesia, 2011; 66:417–434.

Answer 19

43. A The caecum fails to descend to a subhepatic position during embryological development Malrotation (Figure 1.2), although commonly presenting in the first few months of life, may also present at a later stage, with 0.2% presenting much later in adulthood. Presenting in the neonatal period and the first few months of life, it constitutes a surgical emergency, and although baseline evaluation of biochemical and haematological indices are recommended, they should not delay surgery. Radiological investigations typically show a gasless abdomen, with a little stomach gas an isolated feature; contrast studies make the definitive diagnosis, normally demonstrating a ‘corkscrew’ duodenum with the duodenojejunal flexure lying to the right of the midline. It is normally an isolated abnormality and the child will go on lead a normal life following surgical correction. Youngson GG. Emergency abdominal surgery in infancy and childhood. In: Jones PF, Krukowski ZH, Youngson GG (eds). Emergency Abdominal Surgery 3rd edn, Boca Raton: CRC Press, 1998.

Answer 20

44. E It most commonly occurs in an ileocolic segment of bowel The most common cause of paediatric intussusception is lymphoid hyperplasia in the Peyer’s patches of the gut. The most prominent such tissue occurs along the ileocaecal segment (Figure 1.8). Hence, this is not a congenital ‘lead point’ for the intussusception as such. Other possible lead points include Meckel's diverticulum and duplication cysts, as well as B lymphoma of the gut. Intussusception most commonly presents in the 2 months to 2 years age bracket. A high level of diagnostic accuracy is achieved with abdominal ultrasound, which may demonstrate the ‘target’ sign of bowel within bowel. Pneumostatic reduction is routinely attempted, unless the child already has signs of perforation/peritonitis, in which case theatre is essential. Prior to pneumatic reduction (‘air enema’), intravenous access and preparation for potential theatre should be assured. If it fails, operative reduction is often achieved, without the need to resect bowel. Youngson GG. Emergency abdominal surgery in infancy and childhood. In: Jones PF, Krukowski ZH, Youngson GG (eds). Emergency Abdominal Surgery, 3rd edn. Boca Raton: CRC Press, 1998: 82–135.

Answer 21

45. C Laparotomy in emergency theatre This patient requires an urgent laparotomy (the advanced trauma life support manual). He is haemodynamically unstable, with evidence of fluid loss (most likely blood) and peritonitis, indicating significant intra-abdominal injury. Scans will delay definitive management and may be dangerous in this context. No useful information will be gleaned from a FAST scan to supplement the clear clinical signs. Delayed pancreatitis is associated with blunt trauma to the same region. Catheterisation will take place perioperatively, irrespective of the pathology. American College of Surgeons. Abdominal Trauma in Advanced Trauma Life Support Manual, 6th edn. Chicago: American College of Surgeons, 1997.

Answer 22

46. B It may be attached to the umbilicus A Meckel’s diverticulum, the most common congenital abnormality of the small intestine, may be attached to the umbilicus. There may be other potential connections with a patent vitellointestinal duct with faecal fistula, or partial patency of the duct as a sinus to the umbilicus, with potential ongoing secretions. The presence of a Meckel’s may be undiagnosed lifelong, but it occurs in approximately 2% of the population. The three most common presentations include intestinal obstruction (40–50%), peptic ulceration (25%) and acute inflammation (20%), mimicking appendicitis. There is no indication to remove the lesion if discovered incidentally at surgery for another condition. Youngson GG. Emergency abdominal surgery in infancy and childhood. In: Jones PF, Krukowski ZH, Youngson GG (eds). Emergency Abdominal Surgery, 3rd edn. CRC Press, 1998: 82–135.

Answer 23

47. C Infants present with a hypochloremic, hypokalemic metabolic alkalosis Infantile hypertrophic pyloric stenosis is a common surgical problem, and often managed by the non-specialist paediatric general surgeon by way of Ramstedt’s pyloromyotomy (Figure 1.9). The precise aetiology remains unknown, but it tends to affect first-born males, some with a family history, at around 4–6 weeks of age. The vomiting is specifically non-bilious in nature. The child usually has been thriving, until insidious onset of vomiting, which then becomes projectile. The speed of presentation for medical help dictates the degree of metabolic disturbance, but the prolonged loss of gastric juices leads to an alkalosis, with potassium also lost in exchange for the kidney’s attempt to preserve chloride. Electrolyte correction, specifically of the hypochloraemia, and volume replacement must be carried out prior to surgical intervention, which may be delayed by a number of days if necessary. Recovery following the pyloromyotomy is normally straightforward. ``` Youngson GG. Emergency abdominal surgery in infancy and childhood. In: Jones PF, Krukowski ZH, Youngson GG (eds). Emergency Abdominal Surgery, 3rd edn. CRC Press, 1998: 82–135. ```

Answer 24

48. A A child with peritonitis should have volume resuscitation (≥ 20 mL/kg intravenous fluid) prior to surgery This describes the correct fluid resuscitation of any acutely unwell child. Prior to anaesthesia (in the context of sepsis/peritonitis) some volume resuscitation is always required. There is no absolute age below which a laparoscopic approach is contraindicated, but its use must depend on the expertise of the surgeon, with the small abdominal cavity and stretchy parietal peritoneum posing specific considerations. Despite there being fewer differential diagnoses in the paediatric presentation of appendicitis, the behaviour of the disease is different. This is especially true in the very young, and often presents at a more advanced stage (Figure 1.10). This perhaps in part reflects difficulties in communication causing a delay in reaching a diagnosis. Active observation, formally reported over 30 years ago, remains the most important diagnostic tool. There is no substitute for repeated reassessment of subjective and objective signs. No one serological or radiological test is entirely reliable. Advanced disease at presentation is not uncommon in the paediatric population – as much as in adult patients, and laparoscopic appendicectomy may be safely performed in the majority of cases. Jones PF. Active observation in the management of acute abdominal pain in childhood. BMJ 1976; 2:551–553.

Answer 25

49. B In pre-hospital care, utilise abbreviated initial resuscitation and rapid access to theatre This correctly describes the importance given to ‘source control’ in the damage control laparotomy. The severity of the injury requires this rapid approach, and evidence does support markedly improved survival in trauma centres practicing in this fashion. The approach dictates that the number of returns to theatre does not matter, and, to guard against abdominal compartment syndrome, an open abdomen managed with an appropriate closure device, is the most appropriate outcome from first, or even second surgery. Further, acidotic and coagulopathic patients do not benefit from prolonged surgical procedures, which would worsen physiological deterioration. The simple aims of stopping gross bleeding and controlling contamination apply. Cavity lavage is not a part of this approach. Brooks A, Mahoney P, Schwab CW. Critical Care of the Trauma Patient. In: Brooks A, Girling K, Riley B, Rowlands B (eds). Critical Care for Postgraduate Trainees. London: Hodder Arnold, 2005: 113–121. Johnson JW, Gracias VH, Schwab CW, et al. Evolution in damage control for exsanguinating penetrating abdominal injury. Journal of Trauma 2001; 51:261–269. Shapiro MB, Jenkins DH, Schwab CW, Rotondo MF. Damage Control: collective review. J Trauma 2000; 49:969–978.

Answer 26

50. D Log roll including checking spinal integrity and anal tone Within the advance trauma life support (ATLS) protocol, primary survey, and any immediate resuscitative measures work in parallel, and only once each of the five components of the primary survey are ‘stabilised’ may the trauma provider move on to the more detailed secondary survey. Primary survey includes: • Airway assessment and maintenance with C-spine control • Breathing assessment and ventilation if required • This includes assessment of respiratory rate and symmetry, with inspection, percussion and auscultation of the lung fields • Circulation with haemorrhage control • This is assessed via conscious level, skin color and pulse, with external haemorrhage identified and controlled • Disability: rapid assessment of neurological status • This is assessed via AVPU (Alert /responds to Voice /responds to Pain / Unresponsive) and pupillary responses • Exposure/environmental control • Full exposure of the patient, with re-warming as necessary ABCDE describes the order of priority, and, if a prior element deteriorates, the algorithm is repeated in order as required. Secondary survey is only instigated once the patient is stabilised and resuscitation is in progress – allowing more time for a detailed, systematic evaluation, of which the log roll and associated check is part. A focused assessment with sonography for trauma (FAST) scan of the abdomen is an adjunct to the secondary survey, but increasingly being replaced by CT. Airway and Ventillatory management. In: Advanced Trauma Life Support manual, 6th edn. Chicago: American College of Surgeons, 1997.

Answer 27

51. D Airway management – prepare for definitive orotracheal airway and have surgical airway kit ready This patient has an emergency need for definitive airway control. He is alert to painful stimuli and therefore he is unsuitable for a guedel airway. A nasopharyngeal airway is relatively contraindicated given the pattern of injuries (as would be a nasotracheal airway). If his airway is compromised by trauma, then a surgical airway may still be required, but a definitive orotracheal route is preferable with expertise available from anaesthetics. Until the airway is secured, there is little point in enhancing ventilation, and this is a secondary priority. However, until the airway is secured, every effort should be made to enhance oxygen delivery, and this may be carried out if enough personnel are available. It is not, however, the chief priority. Airway and Ventillatory management. In: Advanced Trauma Life Support manual, 6th edn. Chicago: American College of Surgeons, 1997.

Answer 28

52. A Alert cardiothoracic surgeons urgently If > 1500 mL is obtained on immediate drainage of a haemothorax, or > 200 mL per hour for 2–4 hours, there is a high likelihood that surgical exploration is required. There is nothing to indicate haemopericaridum (Beck’s triad consisting of elevated venous pressure, low arterial pressure and muffled heart sounds) so the options to assess cardiac tamponade are irrelevant. A chest CT may simply waste time because, depending on stability of other parameters, the cardiothoracic surgeons may not require this and may wish to proceed straight to theatre. Their expertise should be called upon immediately. Thoracic Trauma. In: American College of Surgeons: Committee on Trauma. Advanced Trauma Life Support Course: Student Manual, 6th Edn. Chicago: American College of Surgeons, 1997.

Answer 29

53. D Noradrenaline is frequently the agent of choice in septic shock Noradrenaline is the most commonly used inotrope in sepsis with hypoperfusion, predominantly acting at α-adrenoceptors to produce vasoconstriction to counter the hypotension that results from peripheral vasodilatation. The description in (B) applies to dobutamine, which is used in cardiac failure to reduce afterload. Adrenaline stimulates both α- and β-receptors, with respective vasoconstriction and enhanced cardiac contractility. Afterload may be increased, along with myocardial oxygen demands, so that it is not a useful agent in cardiogenic shock. Glyceryl trinitrate is a useful agent in cardiac failure, but through increased availability of nitric oxide, preload is reduced due to vasodilatation and reduced venous return. Dopexamine, active at β2-receptors, aids in splanchnic perfusion, often in the context of cardiac failure. A concise summary of inotropic agents is given in Ashford and Evans (2001). Ashford R, Evans N. Surgical Critical Care. London: Greenwich Medical Media, 2001.

Answer 30

54. D Hyperthermia Massive transfusion is associated with the ‘lethal triad’ of hypothermia, coagulopathy and metabolic acidosis. This is classically described in the rapid deterioration of severely injured patients, leading to a significant mortality rate when present. Massive transfusion occurs when half of a patient’s circulating volume is transfused in a period under 24 hours. There is a requirement for close monitoring and optimisation of volume status and tissue oxygenation, as well as control of any bleeding or coagulation abnormalities. There may also be altered levels of ionised calcium or potassium, and the acid–base balance may be affected. There is a tendency for hyperkalaemia, hypokalcaemia and hypomagnesaemia (in part due to the citrate infused). British Committee for Standards in Haematology, Stainsby D, MacLennan S, et al. Guidelines on the management of massive blood loss. British Journal of Haematology 2006; 135:634–41. Gentilello LM, Pierson DJ. Update in non-pulmonary critical care: trauma critical care. American Journal of Respiratory and Critical Care Medicine 2001; 163:604–7.

Answer 31

55. A A heart rate of > 90 beats per minute and respiratory rate of > 20 breaths per minute are adequate diagnostic criteria for SIRS Although the definition of systemic inflammatory response syndrome (SIRS) is somewhat arbitrary, it represents the beginning of a potentially important continuum which may result in multiorgan failure if the process is not abated. SIRS is defined by the presence of two or more of the factors listed in Table 1.7. It was a working definition designed to help the early diagnosis of critically ill patients, derived from a consensus conference of physicians and intensivists in the USA around 20 years ago. SIRS is driven by the release and effect of inflammatory mediators such as interleukin-1 and 6, prostaglandins and leukotrienes, as well as catecholamines and insulin. Sepsis is the equivalent clinical state in the presence of bacteraemia. SIRS may occur in response to any systemic insult, such as major surgery, pancreatitis, trauma, etc. Organ dysfunction is frequently evident, but multiorgan dysfunction syndrome, and eventual multiorgan failure can result. Disseminated intravascular coagulation represents a failing haematological system and would not necessarily be seen in SIRS. Vasodilatation is characteristic, with nitric oxide mediated effects. American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference: definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Critical Care Medicine 1992; 20:864–74.

Answer 32

56. D Reduced blood pressure and cardiac output is an important side effect Reduced blood pressure and cardiac output is an important side effect of positive pressure ventilation. Increased preload with reduced venous return occurs because of the loss of negative pressure in the intrathoracic pump. Owing to reduced cardiac output, there is reduced renal blood flow, with reduced perfusion, urine output, and potential worsening of any acute injury in the context of acute illness. Although PaCO2 may arbitrarily be considered a reasonable threshold for consideration of ventillatory support, the decision to ventilate a patient is individual, and in the context of obstructive airways disease, this may be either non-critical, or relatively contraindicative, of support. Patients with injuries with raised intracranial pressure may be ventilated at low pressure and high frequency, to drive a reduction in CO2 which will then reduce cerebral blood volume, and consequently pressure. Through ventilation alone, intrathoracic pressure increase will lead to increased intracranial pressures. Through more rapid correction of hypoxia, hypercapnia and acidosis, ventilation decreases the endogenous catecholamine drive on the cardiovascular system. This subsequently reduces the impact of the body’s own stress response. Ashford R, Evans N. Surgical Critical Care. London: Greenwich Medical Media, 2001.

Answer 33

57. C Deceleration injury with shearing of spleen/kidney This patient is too stable for a significant aortic injury. The mechanism of injury is unlikely to produce a compression injury, whereas with correct seatbelt restraint, the abdominal organs are less likely to be injured than alternate areas around the girdle of the torso/long bones impacting. More information is available in the appendix of the advanced trauma life suppport (ATLS) manual, regarding mechanics and mechanisms of injury. Appendix 2: biomechanics of injury. In: Advanced Trauma Life Support manual, 6th edn. Chicago: American College of Surgeons, 1997.

Answer 34

58. B 4.5 L compound crystalloid over 8 hours, and the same again over the next 16 hours This patient has sustained 27% body surface, partial thickness burns (Figure 1.11). This is a significant volume burn (despite his apparent stability) and he is at risk of delayed metabolic sequelae. The goal of management is continued urine production around 1 mL/kg/h for the first day and to monitor this all patients require urinary catheters. The Parkland formula is used by the ATLS protocol, whereby % burn × kg weight × 4 = minimum volume to be infused in first 24 hours postburn. The first half of this volume should be given in the first 8 hours and the second half in the next 16 hours. If the patient appears volume deplete at the outset, these proportions may be varied, and may be titrated against urinary output. In this patient’s case, he requires: 27% × 80 kg × 4 = 8640 mL total fluid This equates to 4.32 L in first 8 hours, and the same in the subsequent 16 hours. The simple charts in Figure 1.11 provide an easy estimate for the % burn sustained – the higher surface area: volume ratio of children is important. Hettiaratchy S, Papini R. Initial management of a major burn: II–assessment and resuscitation. BMJ 2004; 329:101–103.

Answer 35

59. B Glasgow coma scale, PaO2: FiO2 ratio, serum creatinine The components of multiple organ dysfunction score (MODS) and sequential organ failure assessment score (SOFA) scoring systems are listed below: ``` MODS • Respiratory: PaO2: FiO2 ratio • Renal: serum creatinine • Hepatic: serum bilirubin • Cardiovascular: pressure adjusted heart rate, derived from the produce of heart rate and a pressure ratio • Haematological: platelet count • Neurological: Glasgow coma score ``` ``` SOFA • Respiratory: PaO2: FiO2 ratio • Renal: serum creatinine or urine output • Hepatic: serum bilirubin • Cardiovascular: hypotension • Haematological: platelet count ``` There are similarities between both the components and the uses of the scoring systems, both being used towards mortality predictions. For example, SOFA > 15 during an intensive therapy unit admission increases predicted mortality to 90%. For full scoring components and derivative scores see Brooks et al (2005). Brooks A, Sperry D. Epidemiology of Critical Care. In: Brooks A, Girling K, Riley B, Rowlands B (eds). Critical Care for Postgraduate Trainees. London: Hodder Arnold, 2005.

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60. C Placement of caval filter, then definitive surgical treatment of the leak This man has systemic compromise from his anastomotic leak. This will not settle with conservative management, and he therefore needs to return to theatre for control of sepsis and defunctioning. To do this safely, in the presence of a venous thrombosis, further prophylaxis against embolism is required. Emergency placement of a caval filter is also required. Low-molecular-weight heparin cannot be reversed, but this should neither preclude surgical intervention for his sepsis, nor filter placement. The evidence for filters is relatively weak but is outlined in a recent Cochrane summary. Young T, Tang H, Hughes R. Vena caval filters for the prevention of pulmonary embolism. Cochrane Summaries, 2010.

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61. A Abdominal compartment syndrome The inflammatory response and intra-abdominal swelling which occurs secondary to acute severe pancreatitis is driving the pathophysiology in this scenario. Abdominal compartment pressure may be estimated by elevation of a urinary catheter from the level of the pubis. A pressure above 12 cm is elevated and > 20 cm is diagnostic of abdominal compartment syndrome (ACS). By reducing abdominal blood flow and diaphragmatic movement, the secondary compromise in renal and respiratory function are worsened, and pose particular management problems in terms of ventilating the patient against this increased pressure. The renal impairment remains acute, but is more complex than a straightforward acute renal injury. The form of pancreatitis is immaterial to the pathological outcome here. This phenomenon is increasingly recognised, and actively managed, in the acute surgical patient, often using a vacuum assisted closure device (Figure 1.12). Anderson IA. Abdominal sepsis and abdominal compartment syndrome. In: Paterson-Brown S (ed), Core Topics in General and Emergency Surgery: A Companion to Specialist Surgical Practice, 4th edn. Philadelphia: Saunders Elsevier, 2009: 331–343.

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62. A Adhesions The history of Crohns’ disease is slightly misleading as there are no features here to suggest a ‘flare-up’ or recurrent disease. A more protracted history of pain or discomfort with increased bowel frequency and blood or mucus in the motions would be more classical and suggestive of active disease. Here the relevant history is of multiple laparotomies which will predispose the patient to the development of adhesions. Similar questions may push the candidate for a suitable management plan in the above clinical scenario. Most texts agree on a period (normally < 24 hours) of conservative management, including resting of the gastrointestinal tract, fluid resuscitation (with or without nasogastric aspiration or drainage if large volume or repeated vomits feature).

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63. F Gallstone ileus In patients aged over 65 years, gallstone ileus makes up approximately 25% of non-strangulated small bowel obstruction and carries a high mortality rate (approximately 15%). The unusual gas pattern seen here probably refers to pneumobilia (or gas in the biliary tree), and the opacification in the right lower quadrant is likely to represent a gallstone lodged in the terminal ileum. In conjunction with dilated fluid-filled loops of small bowel, these are classical radiographic findings associated with gallstone ileus. Despite this, the sensitivity of a plain radiograph for diagnosis of gallstone ileus varies from 40–70%.This compares to CT, which has a sensitivity and diagnostic accuracy of close to 100%. Maglinte DD, Reyes BL, Harmon BH, et al. Reliability and role of plain film radiography and CT in the diagnosis of small-bowel obstruction. Am J Roentgol 1996; 167:1451–1455. Reisner RM, Cohen JR. Gallstone ileus: A review of 1001 reported cases. Am J Surg 1994; 60:441–446. Rigler LG, Borman C, Noble JF. Gallstone obstruction: Pathogenesis and roentgen manifestations. JAMA 1941; 117:1753–1759.

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64. J Pseudomyxoma peritonei Pseudomyxoma peritonei (PMP) is a rare clinical entity (affecting approximately one individual per million population). It is a form of malignancy characterised by mucin production which can progress to fill the abdomen and compress hollow organs. When picked up intraoperatively, the findings are surprising as the volume of mucinous material can be quite marked. Some people develop symptoms as a result of direct compression but PMP is considered only borderline malignant due to its slow clinical progression. It is associated with appendixeal and mucinous ovarian tumours and should always be suspected in patients with these diagnoses. Treatment is usually based on minimising symptoms and ‘watchful waiting’, unless progression is marked or the symptoms dictate intervention. In such cases, the Sugarbaker procedure (peritonectomy) is used for debulking with postoperative chemotherapy (often intraperitoneally). National Institute for Health and Clinical Excellence (NICE).Complete cytoreduction for pseudomyxoma peritonei (Sugarbaker technique) IPG56. London: NICE, 2004. http://www.nice.org.uk/nicemedia/ live/11060/30806/30806.pdf

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65. B χ2 test When addressing a research question, it is important to differentiate between ‘parametric’ and ‘non-parametric’ data before selecting the appropriate method of description and the most accurate statistical test (Table 1.8). ‘Parametric’ refers to data which is normally distributed and follows Gaussian distribution, unlike ‘non-parametric’ data which is positively or negatively skewed. For practical purposes this can be determined by visualising the distribution of data on a histogram using a statistical package. Parametric tests of normally distributed data include (Student’s) paired t-test and independent t-test, which assess the distribution and central location of data between paired and unpaired cases respectively. χ2 testing is a comparison of proportions and is independent of whether data is normally distributed or not. However, it is restricted in its accuracy when values are low, and in such cases a Fisher’s exact test must be used.

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66. G Mann–Whitney U test The Mann–Whitney U test is a non-parametric statistical test used to assess whether two independent samples of observations have differing values. Contrast this with the Wilcoxon signed-rank test, which is a non-parametric statistical test for two related samples or repeat observations on a single sample.

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67. C Friedman’s test Friedman’s test is a non-parametric test also used to detect differences between several related samples, or in one sample across repeated time points. Kirkwood B, Sterne J. Essential medical statistics. Oxford: Wiley-Blackwell, 2003

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68. B Abdominal ultrasound Following laparoscopic cholecystectomy, complications are relatively common and imaging studies may be required to assess for the presence of a fluid collection (which may represent abscesses, bilomas, or haematomas). These will not always require intervention as a small collection is commonly seen in the postoperative period. The easiest way to assess non-invasively is through abdominal ultrasound, which will provide information on the presence and amount of any collection and can also describe its homogeneity. As a first line investigation it is also useful for identifying a retained stone or any biliary dilation. Thurley PD, Dhingsa R. Laparoscopic cholecystectomy: postoperative imaging. AJR 2008; 191(3): 794–801. Lohan D, Walsh S, McLoughlin R, Murphy J. Imaging of the complications of laparoscopic cholecystectomy. Eur Radiol 2005; 15: 904 –912. McAlister VC. Abdominal fluid collection after laparoscopic cholecystectomy. Br J Surg 2000; 87: 1126–1127.

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69. H CT of the abdomen Although this patient has had a recent hernia operation, the medical history of diverticular disease cannot be ignored, particularly in view of the tenderness. A CT of the abdomen with intravenous and oral contrast should be performed to reject or confirm a diagnosis of diverticulitis. Pericolic fat infiltration is a diagnostic feature. Chronic pain following hernia repair does not tend to occur as high as the iliac fossa or lower quadrant, unless there is large or small bowel involvement. Simmang CL, Shires GT. Diverticular disease of the colon. In: Feldman M, Friedman LS, Sleisenger MH (eds). Sleisenger and Fordtran’s gastrointestinal and liver disease: pathophysiology, diagnosis, management, 7th edn. Philadelphia: Saunders, 2002: 2100–2112. Shen SH, Chen JD, Tiu CM, et al. Colonic diverticulitis diagnosed by computed tomography in the ED. Am J Emerg Med 2002; 20:551–557.

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70. H CT of the abdomen If an anastomotic leak (and possible collection or abscess) is suspected, a CT of the abdomen and pelvis with intravenous, oral, and rectal contrast is indicated. This is a highly sensitive (95%) test for identifying abdominal or pelvic abscesses. It also affords the opportunity for CT-guided drainage, which is successful in up to 85% of patients. Gastrografin enema is another commonly used technique which will provide information on the presence of a leak, but will not demonstrate if there is a drainable collection and further imaging will be required. This patient has evidence of sepsis and the tenderness suggests there may be a collection or abscess. This will require drainage and, depending on the extent of the leak, and the integrity of the anastomosis, a laparotomy for drainage or defunctioning may be required. DuBrow RA, David CL, Curley SA. Anastomotic leaks after low anterior resection for rectal carcinoma: evaluation with CT and barium enema. Am J Roent 1995; 165:567–571. Nasirkhan MU, Abir F, Longo W, Kozol R. Anastomotic disruption after large bowel resection. World J Gastroenterol 2006; 12:2497–2504. Lucey BC, Maher MM, Boland GW, et al. percutaneous treatment by interventional radiologists of anastomotic leaks: basic concepts. Am J Roent 2002; 179:365–369.

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71. A Amyand’s Amyand is reported to have performed the first appendicectomy in 1735, on a patient with a perforated appendix situated in an inguinal hernia. This condition is very rare with an appendix in the sac of an inguinal hernia reported in approximately 1% of patients when the appendix is non-inflamed (and 0.08% when inflamed). Amyand C. Of an inguinal rupture, with a pin in the appendix coeci, incrusted with stone; and some observations on wounds in the guts. Phil Trans Royal Soc 1736; 39:329–342. D’Alia C, Lo Schiavo MG, Tonante A, et al. Amyand’s hernia: case report and review of the literature. Hernia 2003; 7:89–91.

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72. G Maydl’s A Maydl’s hernia occurs when a ‘W-shaped’ segment of small bowel occupies the hernia sac. The middle part is situated inside the abdomen and may become strangulated, as can also happen to the adjacent loops of small bowel (Figure 1.13). Ganesaratnam M. Maydl’s hernia: report of a series of seven cases and review of the literature. Br J Surg 1985; 72:737–738

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73. H Pantaloon A Pantaloon hernia is a combination of direct and indirect herniae. The hernial sacs bulge on either side of the inferior epigastric vessels like ‘pantaloons’. Mirilas P, Mouravas Y. Enigmatic images: inguinal hernia of a ‘third kind,’ pantaloon hernia, ‘direct pantaloon’ hernia, or direct hernia and supravesical hernia? Hernia 2010; 14:333–334.

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74. H Hepatitis B surface antigen Hepatitis B surface antigen (HBsAg) is a baseline diagnostic test to differentiate between ongoing or resolved hepatitis B in unwell patients. This test is used to determine the transmissibility of hepatitis B. Inaba N, Ohkawa R, Matsuura A, et al. Sexual transmission of hepatitis B surface antigen. Infection of husbands by HBsAg carrier-state wives. Br J Vener Dis 1979; 55(5): 366–368. Yuen MF, Wong DK, Lee CK, et al. Transmissibility of hepatitis B virus (HBV) infection through blood transfusion from blood donors with occult HBV infection. Clin Infect Dis 2011; 52:624–632.

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75. G Hepatitis B surface antibody Hepatitis B surface antibody (anti-HBsAg) is a test to assess response to immunisation in healthcare workers. Such ‘at-risk’ groups of people receive three vaccinations of the the hepatitis B surface antigen (HBsAg) at 1 and 6 months intervals. The hepatitis B surface antibody usually becomes measurable in the serum about 4 weeks after HBsAg is no longer measurable. When antibody is present, it suggests that the infection is no longer active and the subject is immune to hepatitis B infection. It is therefore used to determine the need for further vaccination. Pasko MT, Beam TR. Persistence of anti-HBs among healthcare personnel immunized with hepatitis B vaccine. Am J Public Health 1990; 80:590–593.

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76. A Hepatitis C virus (HVC) polymerase chain reaction (PCR) HCV PCR is a test used by hepatologists and virologists to monitor hepatitis C treatment by measuring the expression of HCV RNA. Urdea MS, Wuestehube LJ, Laurenson PM, Wilber JC. Hepatitis C diagnosis and monitoring. Clinical Chemistry 1997; 43:1507–1511.

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77. J Magnetic resonance cholangiopancreatography (MRCP) This patient has recurrent upper abdominal pain, with a recent ultrasound showing stones in the gallbladder. She is apyrexial with normal inflammatory markers and is therefore unlikely to have cholecystitis or cholangitis. With grossly abnormal liver function test values, she is likely to have ductal stones. There seems little value in repeating an ultrasound scan as the only difference to management would be if it clearly demonstrated ductal stones with dilatation requiring decompression. MRCP utilises magnetic resonance imaging to examine the biliary and pancreatic tree in great detail, although it does not offer any therapeutic options. Compared to an invasive procedure like ERCP, there is very minimal mortality or morbidity with MRCP. Performing this procedure will provide information on the presence of any ductal stones and will therefore guide the need for further treatment. A major limiting factor in patients undergoing MRCP is that some will require a subsequent ERCP regardless. Kaltenthaler E, Vergel YB, Chilcott J, et al. A systematic review and economic evaluation of magnetic resonance cholangiopancreatography compared with diagnostic endoscopic retrograde cholangiopancreatography. Health Technol Assess 2004; 8:iii, 1–89.

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78. D ERCP with balloon trawl with or without sphincterotomy This woman presents with acute cholecystitis and a dilated common bite duct (CBD) (based on her ultrasound findings). She will require a cholecystectomy at some point, but her biliary tree needs decompressed and this should be performed with endoscopic retrograde cholangiopancreatography (ERCP) This patient is high risk as her CBD is dilated beyond 10mm. As with other high-risk patients (with cholangitis or pancreatitis) she should undergo ERCP +/– duct decompression. Up to a third of such patients will have no evidence of a gallstone at ERCP and further tests may be required at a later date. Mesenas SJ. Does the advent of endoscopic ultrasound sound the death knell for endoscopic retrograde cholangiopancreatography (ERCP)? Ann Acad Med Singapore 2006; 35:89–95.

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79. G Laparoscopic cholecystectomy with on-table cholangiogram This patient is at low risk of gallstone-related complications and should proceed to cholecystectomy without further preoperative diagnostic procedures. He should also have an intraoperative cholangiogram (IOC) to demonstrate any distal common bite duct (CBD) or pancreatic duct stones.

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80. H Pilonidal sinus Pilonidal disease can be asymptomatic, or may present with an abscess or discharging sinus tract (most commonly in the natal cleft region). It occurs due to ingrowing hairs and is more common in male, hirsute patients who sit for prolonged periods. Søndenaa K, Andersen E, Nesvik I, Søreide JA. Patient characteristics and symptoms in chronic pilonidal sinus disease. Int J Colorectal Dis 1995; 10:39–42.

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81. B Anal fissure An anal fissure is a small tear or ulcer at the anal verge (normally in the 6 o’clock position). It has been suggested it is due to ischaemia with impaired healing due to a combination of increased sphincter tone, fibrotic scarring and repeated mechanical injury. When an anal fissure develops, it may cause severe sharp pain on defaecation which can last for hours afterwards. There may also be fresh blood on the toilet paper or in the pan after defaecation. A sentinel pile (a skin tag distinct from a haemorrhoid) is a common marker of an anal fissure and also prognosticates that it may be difficult to manage conservatively. Ayantunde AA, Debrah SA. Current concepts in anal fissures. World J Surg 2006; 30:2246–2260

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82. C Fistula-in-ano The discharge of fluid in this patient’s case represents a fistula. Fistula-in-ano is a feature of the chronic stage of abscess formation and can occur due to simple cryptoglandular infection or trauma, Crohn’s disease tuberculosis, cancer or radiation. The external opening can be used to locate the internal opening by following Goodsall’s rule. Approximately 90% of fistulae with an external opening anterior to the midline will open into the anal canal anteriorly (in a radial fashion). Fistulous openings posterior to the midline will follow a horseshoe shape to open posteriorly in the midline (Figure 1.15). Goodsall DH. Anorectal Fistula. In: Goodsall DH, Miles WE. Diseases of the anus and rectum, part I. London: Longmans, Green, 1900:92.

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83. J Teratoma Testicular neoplasms commonly present following a minor scrotal injury. The patient who self-examines may feel a new lump which he attributes to the injury. Commonly, the lesion is pre-existing and was previously too small or asymptomatic to be noticed in the absence of regular examination. A raised serum β-human chorionic gonadotropin (β-hCG) and α-fetoprotein is diagnostic of a testicular germ cell (non-seminomatous) tumour. Dunzendorfer U, Jurincic C. Quantification of alpha-fetoprotein and beta-HCG in testis tumor patients. Urol Int 1987; 42:248–253.

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84. B Epididymal cyst Epididymal cysts are benign, fluid-filled swellings in the head of the epididymis which do not usually require treatment. They are normally distinct from the testicle and transilluminate brightly. Walsh TJ, Seeger KT, Turek PJ. Spermatoceles in adults: when does size matter? Arch Androl 2007; 53:345–348.

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85. F Idiopathic scrotal oedema Acute idiopathic scrotal oedema is a relatively rare cause of an acute scrotum. It is characterised by a rapid onset of marked oedema (with or without erythema), without any tenderness. The child is normally apyrexial and all diagnostic tests are negative. The aetiology of this condition is unknown although helminth infection has been postulated as a cause. Galejs LE, Kass EJ. Diagnosis and treatment of the acute scrotum. Am Fam Physician 1999; 59:817–824. Klin B, El-Kholi N, Ashour K, et al. Acute idiopathic scrotal edema in children—revisited. J Pediatr Surg 2002; 37:1200–2

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86. D Excision of cyst This patient is likely to have an epididymal cyst, although it may represent a more sinister lesion. Simple epididymal cysts are normally treated conservatively unless they change or the patient becomes symptomatic. In such cases surgery, in the form of excision, is recommended. Newer techniques to treat epididymal cysts have started to emerge including the use of sclerotherapy under ultrasound guidance. Pierie S, Agresti P, Morucci M, et al. A therapeutic alternative in the treatment of epididymal cysts: percutaneous sclerotherapy. Radiol Med 2003; 105:462–470.

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87. F Immediate surgical exploration This adolescent should be suspected to have a testicular torsion and merits immediate surgical exploration. The diagnosis is suspected on history and examination findings but should be confirmed by operation. If a viable testicle is found it should be untwisted and fixed in that position. Classically a testicular torsion presents in infants and adolescents with sudden onset severe scrotal pain. The testicle may be tender and lying high in the scrotum. The chance of testicular salvage decreases as the duration of torsion increases. A torsion less than 6 hours is almost always viable whereas a torsion over 24 hours is never viable. Williamson RCN Torsion of the testis and allied conditions. Br J Surg 1976; 63:465–476. Coggon D, Nelms M. Incidence of testicular abnormalities. Lancet 1984: 747. Murphy FL, Fletcher L, Pease P. Early scrotal exploration in all cases is the investigation and intervention of choice in the acute paediatric scrotum. Pediatr Surg Int 2006; 22:413–416.

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88. K Testicular vein embolisation This patient has a varicocoele which is an abnormal dilation of the testicular vein due to defective valves, compression or obstruction. Approximately 98% develop on the left side because of the 90°angle of insertion of the testicular vein into the left renal vein. On the right the drainage is directly into the inferior vena cava. Examination findings are likened to a ‘bag of worms’. When patients are symptomatic and desire treatment the most common method is by radiological embolisation of the testicular vein. Pryor JL, Howards SS. Varicocele. Urol Clin North Am 1987; 14:499–513. Kuroiwa T, Hasuo K, Yasumori K, et al. Transcatheter embolization of testicular vein for varicocele testis. Acta Radiol 1991; 32:311–314.

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89. G Mittelschmerz Mittelschmerz is mid-cycle lower abdominal or pelvic pain which can occur suddenly and may be present for several days. Diagnosis is one of exclusion whereby ultrasound scan normally reveals no abnormal findings or a trace of pelvic fluid. Krohn PL. Intermenstrual pain (the ‘Mittelschmerz’) and the time of ovulation. BMJ 1949; 7, 1:803–805.

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90. F Mesenteric adenitis The family history of inflammatory bowel disease is a distractor here as there are no gastrointestinal symptoms. This boy is likely to have mesenteric adenitis secondary to his recent upper respiratory viral illness. Mesenteric adenitis commonly mimics appendicitis but as this patient is hungry and thirsty, it can be reasonably safe to exclude appendicitis as a potential cause. Rao PM, Rhea JT, Novelline RA. CT diagnosis of mesenteric adenitis. Radiology 1997; 202:145–149.

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91. L Terminal ileal Crohn’s disease Crohn’s disease can affect any part of the gastrointestinal tract from the mouth to the anus. The main symptoms of terminal ileal Crohn’s disease are diarrhoea, abdominal pain and weight loss. The inflammation can lead to the development of a mass and malaise, lethargy, anorexia, nausea and vomiting may also feature. Shariff U, Narula H, Speake W, Brown S. Terminal ileal Crohn’s disease: conservative surgeon and aggressive physician? Colorectal Dis 2009; 11:522–523.

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92. D Decompression of tension pneumothorax In this patient, the hyper-resonance and tracheal deviation is diagnostic of a tension pneumothorax. This occurs when the air leak into the pleural space increases to the point, where it pushes the mediastinum (including trachea) to the opposite hemithorax. There can be pressure on the cava with a massive decrease in cardiac output. The treatment here is emergency needle thoracostomy to decompress the thorax prior to insertion of a formal intercostal chest drain. Barton ED. Tension pneumothorax. Curr Opin Pulm Med 1999; 5:269.

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93. K Thoracotomy In a trauma situation a positive pericardiocentesis is an indication for an emergency thoracotomy. Although a pericardiocentesis may have some benefit, it is essentially a diagnostic and temporizing procedure. The cause of the bleeding in the pericardial space needs to be addressed and this requires a thoracotomy. In the above patient’s case, the positive focused assessment with sonography for trauma (FAST) scan for pericardial blood should have been enough to have mandated a thoracotomy, although the pericardial decompression may have been a lifesaving measure. Cothren CC, Moore E. Emergency department thoracotomy for the critically injured patient: Objectives, indications, and outcomes. World Journal of Emergency Surgery 2006, 1:4.

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94. H Laparotomy Patients with a penetrating injury who are haemodynamically unstable require immediate operation. This includes those patients who are ‘non-responders’ and those who only transiently respond to fluid bolus administration. There should not be a delay for unnecessary investigations or interventions. In junctional injuries (such as chest/abdomen) a decision must be made on which cavity to expose first. If at laparotomy there is no identified source of bleeding a thoracotomy should be performed (and vice versa). In the above patient’s case, with exposed omentum the peritoneum has clearly been breached and the first course of action is to perform a laparotomy. Biffl WL. Management guidelines for penetrating abdominal trauma. Current Opin Crit Care 2010; 16:609–617. Henneman PL. Penetrating abdominal trauma. Emerg Med Clin North Am 1989; 7:647–666.

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``` 95. F 6 The Child–Pugh classification uses five variables (albumin, bilirubin, international normalised ratio, severity of ascites and encephalopathy), and each is scored between one (most normal) and three (most abnormal). The sum of the five scores generates the Child–Pugh score ranging from 5–15 (Table 1.9). The score corresponds to a Child–Pugh grade of A, B or C which can be used to classify the prognosis for the patient. The patient in this question will score 1 for all of the above fields except for bilirubin (2). This gives a total score of 6 which is equivalent to Child–Pugh class A (Table 1.10). ``` Child CG, Turcotte JG. Surgery and portal hypertension. The liver and portal hypertension. Philadelphia: Saunders. 1964: 50–64. Pugh RN, Murray-Lyon IM, Dawson JL, et al Transection of the oesophagus for bleeding oesophageal varices. Br J Surg 1973; 60:646–649.

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A 1 This patient has an Imrie score of 1, because of his elevated blood glucose. The Imrie score is a modification of the Glasgow criteria, used to assess the severity of acute pancreatitis. It is a composite of eight separate parameters, each scoring 1 if positive. A total score > 3 in the first 48 hours is predictive of severe pancreatitis and is associated with a worse prognosis. By adjusting the titles of the measured parameters a useful acronym can be used, ‘PANCREAS’: Partial pressure oxygen < 8.0 kPa Age > 55 years Neutrophilia: white blood cell count >15 × 109/L Calcium < 2.0 mmol/L Renal: urea > 16 mmol/L Enzymes: lactate dehydrogenase > 600 U/L Albumin < 32 g/L Sugar: glucose > 10 mmol/L

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97. E 5 The Rockall scoring system (Table 1.11) uses the above criteria to identify patients at risk of adverse outcome following an upper gastrointestinal bleed. The clinical features (age, shock and comorbidity) and endoscopic findings (active bleeding and pathological cause) generates a score between 0 and 11.

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98. C Calciphylaxis Patients with end stage renal failure may develop calciphylaxis which is deposits of calcium in the small and medium sized vessels. These can present as painful plaques with surrounding purpura which can progress to ischaemic skin lesions with areas of necrotic skin. Necrotic components are typically dark bluish purple or completely black and leathery. Nigwekar SU, Wolf M, Sterns RH, Hix JK. Calciphylaxis from nonuremic causes: a systematic review. Clin J Am Soc Nephrol 2008; 3:1139–43. Wilmer WA, Magro CM: Calciphylaxis: emerging concepts in prevention, diagnosis, and treatment. Semin Dial 2002; 15:172–186.

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99. A Acanthosis nigricans Acanthosis nigricans is a dermatological condition which presents with hyperpigmented, thickened skin, which is most marked over body flexures. It is associated with malignancy and in a study of 277 cases (by Rigel et al) 56% had gastric carcinomas in 55.5%, 18% had another form of intra-abdominal malignancy and 27% had various other malignancies. Rigel DS, Jacobs MI. Malignant acanthosis nigricans: a review. J Dermatol Surg Oncol 1980; 6:923–927.

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100. G Lentigo maligna Lentigo maligna is a melanoma in situ which is normally found as a slow growing pigmented lesion on sun exposed areas. It is considered a precancerous lesion which grows slowly over many years. The lifetime risk of malignant transformation ranges from 2.2–4.7%. Cohen, LM. Lentigo maligna and lentigo maligna melanoma. J Am Acad Dermatol 1996; 33:923–936.

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101. C Amiloride Amiloride (like spironolactone) is a potassium sparing diuretic which blocks the sodium channels in the distal convoluted tubules and collecting ducts, thereby inhibiting sodium reabsorption. Salt and water are lost in the urine, whereas potassium is retained and this may result in hyperkalaemia. McNay JL, Oran E. Possible predisposition of diabetic patients to hyperkalemia following administration of potassium-retaining diuretic, amiloride (MK 870). Metabolism. 1970; 19:58–70.

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102. M Simvastatin Statins are absolutely contraindicated in pregnancy because of the suspected risk to the fetus. As statins inhibit cholesterol production (which is required for fetal development) there is a risk of teratogenesis and the development of the VACTERL syndrome. However, other groups have suggested, there is no evidence that exposure to simvastatin increase the rate of congenital abnormalities in pregnant women. Edison RJ, Muenke M. Mechanistic and epidemiologic considerations in the evaluation of adverse birth outcomes following gestational exposure to statins. Am J Med Genetics 2004; 131:287–298. Pollack PS, Shields KE, Burnett DM, et al. Pregnancy outcomes after maternal exposure to simvastatin and lovastatin. Birth Defects Res A Clin Mol Teratol 2005; 73:888–896.

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103. L Noradrenaline The main categories of adrenergic receptors relevant to vasopressor activity are the α1-, β1-, and β2-adrenergic receptors and the dopamine (δ) receptors. Dopamine has varying effects on receptors depending upon the dose used (Table 1.12). • α1-adrenergic agonism leads to peripheral arteriolar vasoconstriction. • β1-adrenergic agonism leads to increased heart rate and force of contractility. • β2-adrenergic agonism leads to bronchial smooth muscle and skeletal muscle relaxation. • (δ) dopaminergic agonism leads to increased renal blood flow at low doses. At higher doses there are also cardiac and vasoconstrictive effects. Müllner M, Urbanek B, Havel C, et al. Vasopressors for shock. Cochrane Database Syst Rev 2004; CD003709.

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104. B α-fetoprotein Serum α-fetoprotein (AFP) can be used to diagnose, and guide the treatment of hepatocellular carcinoma (HCC). Normal serum values are under 10 ng/mL, but they can be elevated in hepatitis to values as high as 100 ng/mL. In previously well individuals a serum AFP > 400 ng/mL is diagnostic of HCC. However, in those with ongoing liver disorders (e.g. hepatitis) a value of > 4000 ng/mL is required to diagnose HCC. AFP is useful in assessing the response to treatment for HCC. Following complete tumour removal, the AFP level should normalise. If it subsequently elevated it suggests a tumour recurrence. Zhou L, Liu J, Luo F. Serum tumor markers for detection of hepatocellular carcinoma. World J Gastroenterol 2006; 12:1175–1181.

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105. E Cancer antigen (CA) 19-9 This assay was originally developed to diagnose colorectal cancer, but in current practice it is more commonly used for patients with pancreatic cancer. The upper limit of normal for the CA19-9 assay is 37 U/mL and in the early stages of pancreatic cancer the blood levels are often normal, so it is not a useful screening test. The overall sensitivity of this assay is ~80% with a specificity of approximately 90%. When tumours generate blood levels of CA19-9 > 1000 U/mL it is often an indication that the tumour is unfortunately unresectable. Steinberg W. The clinical utility of the CA 19-9 tumor-associated antigen. Am J Gastroenterol 1990; 85(4): 350–355.

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106. M Human chorionic gonadotrophin Three tumor markers are used in men with testicular germ cell tumors; the beta subunit of human chorionic gonadotropin (β-hCG), α-fetoprotein (AFP) and lactate dehydrogenase (LDH). The most commonly used markers are AFP and β-hCG. AFP is never elevated in pure seminomas and β-hCG is only elevated in approximately a quarter of cases. AFP and β-hCG are both elevated in about 80% of non-seminomatous germ cell tumors (NSGCTs). LDH is not used as a diagnostic test but high levels are predictive of decreased survival. Laguna MP, Pizzocaro G, Klepp O, et al EAU Working Group on Oncological Urology. EAU guidelines on testicular cancer. Eur Urol 2001; 40(2):102–10. Weissbach L, Bussar-Maatz R. HCG-positive seminoma. Eur Urol 1993; 23 (Suppl) 2:29–32.

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107. A Duodenal atresia Duodenal atresia is a failure of embryological development which results in the closure, or absence, of part of the duodenum. It occurs in 1;2500 live births and infants normally present with early onset of (commonly bilious) vomiting. The diagnosis of duodenal atresia can be confirmed by plain abdominal radiography or ultrasound which demonstrates the classical ‘double bubble sign’. There is a significant association with Down’s syndrome, as approximately 20–40% of all infants with duodenal atresia have Down’s syndrome and approximately 8% all infants with Down's syndrome have duodenal atresia. Correctional surgery is always necessary. Nixon HH. Duodenal atresia. Br J Hosp Med 1989; 41:134–140. Brimblecombe FS, Moore HD. Duodenal atresia and stenosis in infants. Ann Surg 1970; 172:991–995. Joppich I, Kellnar S. Surgery of atresia of the gastrointestinal tract. Chirurg 1996; 67(6):576–83.

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108. I Meconium ileus Cystic fibrosis (CF) is an autosomal recessive disorder which presents with meconium ileus in 10–20% of patients. The highly viscous meconium can lead to intestinal obstruction which is suggestive of the diagnosis of CF. The majority of infants (90%) presenting with meconium ileus are subsequently diagnosed with CF. Del Pin CA. Management and survival of meconium ileus. A 30-year review. Ann Surg 1992; 215:179–185.

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109. E Hirschsprung's disease Hirschsprung’s disease is congenital aganglionosis of the distal colon as a consequence of abnormal faetal development and neural crest migration. The myenteric (Auerbach) plexus and the submucosal (Meissner) plexus are both affected which leads to decreased peristalsis in the affected segment. The anus is always involved and aganglionosis normally extends proximally for a short distance. Hirschsprung’s disease should be considered in a newborn with delayed passage of meconium, or a child with constipation since birth. Other symptoms include abdominal distension and vomiting. Most infants pass meconium by 24 hours and if there is none by 48 hours, a rectal examination should be performed. There may be explosive stools after an examining finger is gently placed in the rectum. Definitive diagnosis is normally made by performing a rectal suction biopsy. Coran AG, Teitelbaum DH. Recent advances in the management of Hirschsprung’s disease. Am J Surg 2000; 180:382–387. Whitehouse FR, Kernohan JW. The myenteric plexus in congenital megacolon. Arch Int Med 1948; 82:75.

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110. C Forest plot A Forest plot is a visual method used in meta-analysis to display the relative strength of treatment effects in multiple studies examining the same specific question. It normally has a left hand column containing the names of the studies (in chronological order) and a right hand column which displays the treatment effect as an odds ratio. A square with horizontal lines is used to represent the odds ratio and the confidence interval (this is normally numerically represented adjacent to the diagram). The size of each square represents its weight in the overall analysis (Figure 1.16). A vertical line representing no effect (at odds ratio =1) is plotted. A cumulative metaanalysis line is also plotted (below as a dotted line). The meta-analysed measure of effect is plotted as a diamond where the points represent the confidence intervals. Lewis S, Clarke M. Forest plots: trying to see the wood and the trees. BMJ 2001; 322:1479. Kirkwood RB, Sterne JC. Essential medical statistics, 2nd edn. Oxford: Wiley-Blackwell, 2003: 376–377.

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111. H p-value A type I error is a false positive. In statistical terms this means the test identifies a difference or a finding, when none actually exists. The rate of this error is noted as ‘α’, and is equivalent to the statistical significance. In studies a p-value is quoted as the significance level, or the chance of a type I error. In layman’s terms when interpreting a p-value it is best to think of it as the odds that the test would have produced the same result through chance alone. Grunkemeier GL, Wu YX, Furnary AP. What is the Value of a p Value? Ann Thorac Surg 2009; 87:1337–1343. Kirkwood RB, Sterne JC. Essential medical statistics, 2nd edn. Oxford: Wiley-Blackwell, 2003: 376–377.

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112. F Likelihood ratio A likelihood ratio (LR) is a measure of diagnostic accuracy and normally refers to a test or an investigation. When considering a clinical finding, the LR is the probability of that finding in patients with disease, divided by the probability of the same finding in patients without disease: LR = Probability of finding in patients with disease Probability of finding in patients without disease For example, in patients with suspected diverticulitis, if the physical sign of ‘left iliac fossa (LIF) tenderness’ is present in 90% of patients with confirmed diverticulitis, and 30% without diverticulitis (i.e. because of urinary sepsis, pelvic inflammatory disease, etc.), then the LR for ‘LIF tenderness’ in detecting diverticulitis is 3.0 (90% divided by 30%). A LR > 1 suggests strongly for the diagnosis of interest and the greater the number, the more convincingly the finding suggests that disease. LR < 1 argues against the diagnosis of interest and the closer to 0, the less likely the disease. McGee S. Simplifying likelihood ratios. J Gen Int Med 2002; 17: 647–650. Kirkwood RB, Sterne JC. Essential medical statistics, 2nd edn. Oxford: Wiley-Blackwell, 2003: 376–377.

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113. A Case–control study There is a population of patients with an adverse outcome, and knowledge of the hypothesised risk factor. Although a longitudinal series would provide firm evidence of causal relationship, it would be possible to test his hypothesis by case-matching patients with, and without incisional hernias at 1 year postoperative, and constructing odds ratios relative to body mass index data in 2 x 2 tables. Straus SE, Glasziou P, Richardson WS, Haynes RB. Evidence-based medicine: how to practice and teach it, 4th edn. London: Churchill Livingstone, 2010.

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114. F Meta-analysis This describes an opportunity to perform a meta-analysis of available accrued trial data, with the cumulative numerical output being standard approach for meta-analysis. Straus SE, Glasziou P, Richardson WS, Haynes RB. Evidence-based medicine: how to practice and teach it, 4th edn. London: Churchill Livingstone, 2010.

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115. E Longitudinal cohort series This scenario describes an opportunity to demonstrate the value of rigourous, longitundinal data in adding to the evidence base. Often, data pertaining to ‘real life’ practice, and effectiveness, rather than overall efficacy data generated from randomised controlled trials, are highly useful and applicable to daily practice, and should not be overlooked in generating levels of evidence in guidelines and recommendations (Table 1.13).

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116. A χ2 test This scenario is going to compare two categorical groups (men, women) by a specific categorical outcome (readmission: yes/no). This requires a comparison of proportions in a 2 x 2 table. If numbers were very small, the Fisher’s exact test should be used instead. Standard statistical programmes usually compute both test statistics in the appropriate setting, and the output advises which one should be applied based on variance.

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117. E Mann–Whitney U test In this scenario two categories of patients, laparoscopic and open surgery, are to be compared by a continuous outcome (which is unlikely to have a normal or parametric distribution). A non-parametric test comparing location of central tendency (median and interquartile range); the Mann-Whitney U test should be used. This is the non-parametric equivalent of the t-test. If data had been paired (i.e. patients matched by sex, tumour stage, and only varying by operative approach), then the Wilcoxon sign rank test would need to be used instead.

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118. C Kruskal–Wallis test This third scenario compares a continuous variable between four categories of patients. The continuous variable outcome is likely to exhibit highly skewed distribution. It is safest to assume the data is not normally distributed and use non-parametric testing. The Kruskal–Wallis test should be used unless the pain data are normally distributed. In such an unlikely situation, the ANOVA test should be used. The Kruskal–Wallis test may be thought of as the Mann–Whitney U test for more than three groups.