Pediatrics GIT Flashcards

Question

60) A 2-year-old girl is admitted with abdominal pain and vomiting. No history of trauma is provided. On examination, she is tachycardic and has upper abdominal tenderness. Ultrasound scan of the abdomen demonstrates an echogenic intramural mass in the duodenum in keeping with an intramural haematoma. There is mild proximal dilatation of the duodenum and a small amount of free fluid within the abdomen. What is the most likely underlying cause? a. duodenal diverticulum b. haemophilia c. pancreatitis d. Henoch–Scho¨ nlein purpura e. non-accidental injury

Answer 1

e. non-accidental injury Duodenal intramural haematoma is usually traumatic, particularly following bicycle-handlebar accidents and lap-belt injuries. However, it isalso commonly seen in non-accidental injury, where the mechanism of injury is thought to be a blunt blow to the abdomen that compresses the duodenum against the vertebral column. Trauma to the duodenum may result in duodenal rupture, intramural tear or, most commonly, intramural haematoma. Ultrasound appearances are of an echogenic intramural mass that becomes progressively hypoechoic with maturation of the haematoma. There may be associated deformity or obstruction of the duodenum. CT may demonstrate free intraperitoneal fluid, though free air and frank perforation are uncommon. Spontaneous intramural haematoma may occur in Henoch–Scho¨ nlein purpura, but other features of the condition would be expected to be present. It may occur with anticoagulant therapy and blood dyscrasia, but haemophilia in females is extremely rare. Duodenal diverticula may cause gastrointestinal bleeding, but this is usually intraluminal rather than intramural. Duodenal intramural haematoma has been described in association with pancreatitis but is very rare.

Answer 2

c. meconium plug syndrome Meconium plug syndrome is also known as small left colon syndrome and functional immaturity of the colon. It occurs most commonly in large infants and infants of diabetic mothers and is believed to be due to relativeimmaturity of bowel innervation. Characteristic features are of a dilated proximal colon with a calibre change at the splenic flexure and an empty descending colon. The functional obstruction is transient and usually self-limiting, and contrast enema may act as a stimulus for subsequent passage of (normal) meconium. Hirschsprung’s disease with a transition zone at the splenic flexure may mimic these findings, but the obstruction usually persists after contrast enema. Intussusception in this age group and at this site would be unusual. Meconium ileus and ileal atresia are causes of distal small bowel obstruction.

Answer 3

a. multifocal bowel wall thickening Henoch–Scho¨ nlein purpura is an acute systemic vasculitis that affects the skin, gastrointestinal tract, joints and kidneys. Children aged 3–10 years are predominantly affected, and may present with a purpuric rash on the extensor surfaces of the limbs, arthralgia and crampy abdominal pain with intestinal bleeding. Imaging demonstrates multifocal areas of bowel wall thickening due to intramural haemorrhage and oedema. Gastrointestinal complications include bowel infarction and perforation, as well as intussusception.

Answer 4

a. mesenteric rupture The most common mechanism for traumatic mesenteric rupture is a road traffic collision, although such an injury can occur in children following any blunt abdominal trauma, with handlebar injuries and child abuse being well-recognized causes. Use of a lap belt makes children more prone to the injury. Bowel perforation, infarction and active haemorrhage are indications for immediate surgery and can be identified on CT. Most of the remaining cases are treated conservatively. Free intraperitoneal air, extraluminal contrast or visible bowel wall defect is specific for perforation. Free fluid, haemorrhage and stranding are seen in perforation or mesenteric injury, with fluid at the root more likely to indicate the latter. Hyperattenuation of the pancreas, kidneys and bowel wall is a feature of hypoperfusion, along with small-calibre aorta and vena cava, and should not be mistaken for visceral injury.

Answer 5

a. viral gastroenteritis Most intussusceptions occur in childhood, usually between 6 months and 2 years of age. The vast majority are idiopathic or related to mucosal oedema and lymphoid hyperplasia following viral gastroenteritis. In the 5% of patients with a pathological lead point, causes include those listed above. Patients classically present with cramping abdominal pain, screaming episodes, ‘redcurrant jelly stools’ and a palpable abdominal mass. Most childhood intussusceptions are ileocolic. In contrast, a specific cause is identified in 80% of adult cases, and ileoileal intussceptions are more common than ileocolic.

Answer 6

c. abdominal radiograph (and chest radiograph if abdominal radiograph negative) Generally, in the case of ingested foreign bodies, a chest radiograph (including neck) at initial presentation is indicated. An abdominal radiograph is usually considered after 6 days only if there is doubt whether the foreign body has passed. However, if a sharp or potentially poisonous foreign body has been ingested, an abdominal radiograph is indicated at the time of presentation; a chest radiograph is indicated if the abdominal film is negative. Ingestion of disc batteries (small, coin-shaped batteries found in hearing aids, watches and calculators) may be associated with serious sequelae, particularly if the battery becomes lodged in the oesophagus, as is more likely with younger children and larger batteries. In this situation, leakage of alkaline material, and sodium hydroxide generated by electrolysis at the anode, can cause ulceration and perforation within a relatively short time. Radiography is indicated to locate the battery. If it lies within the oesophagus, emergency endoscopic removal is indicated. Batteries located beyond the oesophagus rarely require endoscopic removal, unless subsequent radiographs indicate delay in transit of the battery.

Answer 7

a. biliary atresia Congenital biliary atresia is a destructive inflammatory process resulting in atresia of the bile ducts, which presents in neonates with persistent jaundice. Diagnosis is usually made with a combination of liver biopsy and hepatobiliary scintigraphy with a 99mTc-labelled iminodiacetic acid (IDA) analogue. Phenobarbital is given for 5 days prior to imaging to stimulate biliary secretion. Normal findings are of activity within the small bowel due to biliary excretion by 60 minutes, but in biliary atresia no biliary clearance is seen by 24 hours. Patients with non-obstructive causes of neonatal jaundice usually demonstrate biliary clearance into the bowel during the first 24 hours. Choledochal cyst usually presents in children, and cholescintigraphy may be used to confirm that the cystic structure is connected to the biliary system. The 99mTc-labelled IDA analogue will fill the cyst, and may show prolonged retention depending on the degree of obstruction. Cystic fibrosis may be associated with steatosis and biliary cirrhosis. Physiological jaundice resolves spontaneously within 2 weeks

Answer 8

b. hepatoblastoma Hepatoblastoma is the commonest malignant liver tumour of early childhood, typically presenting before 3 years with pain, palpable mass, jaundice and weight loss, as well as precocious puberty due to hormone production. Tumours are typically large (average 10–12 cm) and appear to be heterogeneous with areas of calcification and necrosis. Metastases to the lung are common. Hepatocellular carcinoma is the second most common malignant liver tumour of children, but usually affects children over 5 years of age. Although it also commonly appears of heterogeneous echogenicity, calcifications are rare. Haemangiomas commonly appear hyperechoic on ultrasound scan and may contain calcifications, but are usually ,4 cm and are rarely seen in young children. Pyogenic abscess and choledochal cyst are typically hypoechoic lesions.

Answer 9

a. infantile haemangioendothelioma Infantile haemangioendothelioma is the commonest benign hepatic tumour occurring in the first 6 months of life, consisting of multiple sinusoidal vascular channels with surrounding connective tissue stroma. Patients typically present with an abdominal mass, or high-output cardiac failure secondary to arteriovenous shunting. Kasabach–Merritt syndrome (consumptive coagulopathy) is seen in 11% of patients. Typical CT features are of early peripheral enhancement and variable delayed central enhancement. Hepatoblastomas tend to occur in slightly older infants (peak 18–24 months) and congestive cardiac failure is not usually a feature. Mesenchymal hamartoma is a rare developmental liver tumour, which appears typically as a multiloculated cystic mass, but may appear solid and echogenic in infants due to innumerable microcysts. However, these are generally hypovascular lesions. Hepatocellular carcinoma is more commonly seen in older children and adolescents. Cavernous haemangiomas are rarely seen in young children.

Answer 10

b. mesenteric lymphadenitis Mesenteric lymphadenitis is an inflammatory process affecting the mesenteric lymph nodes; it is most frequently caused by viral infection but also by Yersinia enterocolitica and other pathogens. It affects children and young adults, and clinically mimics acute appendicitis. Imaging findings are of enlarged mesenteric lymph nodes, and ileal and colonic wall thickening. The normal appendix must be visualized to differentiate it from acute appendicitis. Features of acute appendicitis on ultrasound scan are of a blind-ending, non-compressible, tubular, aperistaltic, fluidfilled structure measuring over 6 mm in diameter. Mesenteric lymph nodes may also be seen anterior to the right psoas muscle, but tend to be smaller and fewer than in mesenteric lymphadenitis. Thickened bowel wall may be seen on ultrasound scan in Crohn’s disease, but this would be less likely in this age group. Symptomatic Meckel’s diverticulum usually presents in younger children with gastrointestinal bleeding. Small bowel duplication cyst usually presents

Answer 11

a. necrotizing enterocolitis Necrotizing enterocolitis is an acute inflammatory bowel condition seen predominantly in preterm infants. It usually presents 2–3 days after birth, with abdominal distension, vomiting and blood-stained stools. Plain film signs include distended small and large bowel, and bowel wall thickening, but the hallmark of the condition is pneumatosis intestinalis, seen in 80% of cases. This may be curvilinear (subserosal) or bubbly (submucosal) and may also be associated with portal venous gas. Hirschsprung’s disease is characterized by an aganglionic segment of distal colon, resulting in abnormal peristalsis and impaired evacuation of the colon. In this age group, it presents with failure to pass meconium, but is extremely rare in preterm infants. Meconium ileus and imperforate anus also present with failure to pass meconium. Pneumatosis intestinalis may be seen in association with mechanical obstruction resulting from these three conditions, but it is rare. It is not a feature of viral gastroenteritis.

Answer 12

A. prior administration of cimetidine Cimetidine, a histamine H2-receptor antagonist, may be used to increase uptake of[99 mTc] pertechnetate by inhibiting its secretion from gastric mucosa. Pentagastrinand glucagon have also been used to improve visualization, by stimulating uptake anddecreasing peristalsis respectively. Procedures such as colonoscopy and use of laxativesshould be avoided prior to the scan, as they may cause mucosal irritation. Potassiumperchlorate should not be used to block thyroid uptake, as it also blocks uptake ofpertechnetate by the gastric mucosa. The patient normally fasts for 3–4 hours and voidsprior to the study, as a full stomach or bladder may obscure an adjacent Meckel'sdiverticulum. Barium studies should be avoided for 3–4 days prior to the study, asattenuation by the barium may hamper interpretation.

Answer 13

(c) Henoch-Schonlein purpura Trauma (including NAI) is one of the leading causes of pancreatitis in the paediatric population. Other causes include cystic fibrosis, hyperlipidaemia syndromes, drugs, viral, hyperparathyroidism, hypercalcaemia, idiopathic, Pearson syndrome (mitochondrial disorder), Schwachman-Diamond syndrome, and anatomical anomaly (pancreas divisum).

Answer 14

(d) 99mTc-pertechnatate scintigraphy Pertechnatate studies are the most sensitive test (85%), although wireless capsule endoscopy has good potential. Pertechnatate is taken up by the ectopic gastric mucosa within the Meckel's. False +ve results include AVM, haemangioma, UC, Crohn's, appendicitis; false -ve results occur if the diverticulum contains no gastric mucosa.

Answer 15

(d) Hypovolaemic shock Hypovolaemic shock suggests ischaemic bowel, which would require surgical intervention, furthermore reduction should not be attempted in a sick infant and the patient should be appropriately resuscitated before any attempts at reduction are made. Other contraindications include pneumoperitoneum and peritonitis. The remaining options are not absolute contra-indications, but their presence reduces the chances of successful therapeutic reduction. Small bowel obstruction implies ischaemia or the presence of a tight intussusception. Free intraperitoneal fluid or fluid in the lumen surrounding the intussusceptum suggests oedema or ischaemia of the bowel. An older age (> 12 months) suggests a pathological lead point may be the aetiology, in which case resection may be necessary.

Answer 16

(e) Pneumoperitoneum NEC is the commonest GI emergency in premature infants. It is an infective/ ischaemic disorder of the neonatal gut in a compromised baby secondary to hypoxia. It typically presents at 2-3 days after birth and in 90% occurs before day 10. Treatment is normally conservative, surgery may be necessary due to perforation. Compared to adult patients, air in the portal system does not have such a grave prognosis. Late complications include intestinal strictures.

Answer 17

(c) Duplication cyst These cysts appear anechoic, displace the proximal duodenum supero-anteriorly. There is a double capsule: inner mucosa! Lining (hyperechoic) and outer rim of bowel wall (hypoechoic), this ·can be identified as the 'muscular rim' sign described. Choledochal cysts have 5 subtypes (type V = Caroli's disease). All bar type Ill involve the intrahepatic bile ducts. Choledochocoeles arise from the duodenal portion of CBD, but other features support a duplication cyst. In mesenteric lymphangioma there is a single wall.

Answer 18

(a) Haemangioendothelioma Infantile haemangioendothelioma typically presents in neonates (85% are diagnosed at 3 years).

Answer 19

(c) Normal The commonest plain film finding in malrotation is 'normal appearances', thus a 'normal' AXR cannot exclude malrotation. Other plain film findings of malrotation include ascites, bowel wall oedema (thumb-printing, due to SMV compression), evidence of ischaemic gut (due to SMA compression), duodenal obstruction (due to Ladd's bands), SBO, right-sided small bowel, left-sided caecum/ colon.

Answer 20

(e) Pyloric stenosis The 'double bubble' sign describes gas within the proximal duodenum and stomach. There is often a gasless distal abdomen due to obstruction in the duodenum. Pyloric stenosis causes obstruction at the level of the pylorus. In this condition, the duodenum is usually gas-free if gas passes into the duodenum it will also freely pass more distally.

Answer 21

(b) Duodenal atresia 13-50% may not have any US-detectable anomalies. Duodenal atresia is present in 50%, but is not detected before 22 weeks. Nuchal thickness is increased in 40% to < 3 mm at 10-13 wks, 5 mm at 14- 18 wks; CHDs are present in 40%. Other US findings include hydrops, echogenic bowel, pyelectasis, hypoplasia of the 5th digit, and 11 pairs of ribs.

Answer 22

(b) Ileum 15% of paediatric abdominal masses are duplication cysts, they can be found anywhere along the GI tract, commonest locations are: ileum (30-33%), oesophagus (17-20%), colon (13-20%), jejunum (10-13%), stomach (7%), pylorus (4%), duodenum (4-5%), ileocaecal junction (4%), rectum (4%).

Answer 23

(b) Pancreatic drainage is via the duct of Santorini Dorsal and ventral pancreas drain separately in to the duodenum via the minor and major papillae respectively.

Answer 24

(d) Oesophageal atresia with a distal tracheal fistula The most common type of oesophageal atresia is that associated with a distal tracheal fistula (type C in the Gross classification, and referred to as 'N' shape), which accounts for 75-80% of cases. Pure atresia occurs in 10%, TOF in 10% (type E, and referred to as 'H' shape); other forms are rare. Oesophageal atresia with no distal oesophageal bud is very rare and is not classified within the Gross system.

Answer 25

(b) It is easier to confirm reduction across the ilea-caecal valve Fluoroscopy has the 'rule of 3s': 3 feet above the table (pressure 120 mmHg), a maximum of 3 attempts with 3 mins/ attempt and 3 mins between attempts. Air reduction is now used in most centres and answers (a), (c), (d) and (e) list its advantages. The only disadvantage of air reduction is confirmation of reduction across the ileo-caecal valve, especially when gas is present in the ileum. Although there is also a small risk of tension pneumoperitoneum with air reduction, any potential peritoneal 'spill' following perforation will be less than with barium reduction.

Answer 26

(c) Involvement of all 3 layers of the abdominal wall Gastroschisis is a defect involving all 3 layers of the abdominal wall, and is located to the right side of the cord in 90% of cases. There is normal insertion of the umbilical cord, and a lower incidence of associated anomalies. Omphalocoele is herniation of intra-abdominal contents into the base of the umbilical cord, any organs may herniate, but liver herniation is typical +/- bowel. Omphalocoeles have a covering membrane.

Answer 27

(c) Pyloric muscle wall thickness of 4 mm Pyloric stenosis can be diagnosed clinically. US diagnostic criteria include: pyloric volume > 1.4 cm3, pyloric muscle wall thickness > 3 mm, pyloric canal length > 17 mm, pyloric transverse diameter > 13 mm when the pyloric channel is closed. In pyloric stenosis, a hypoechoic ring of hypertrophied muscle around the inner echogenic mucosa produces the 'target sign'. Peristaltic waves are increased and hyperdynamic in an attempt to overcome the obstruction.

Answer 28

(c) Left-side down decubitus AXR Left-side down decubitus is the optimal view, it allows air to rise to the right lateral abdomen, which can then be seen between the liver edge and the abdominal wall; with right-side down films it is harder to detect free air due to presence of stomach/ splenic flexure. An erect CXR is likely to be impractical in a ventilated neonate. Signs on supine AXRs are often subtle (football sign, Rigler's sign, or air around the falciform ligament). In a cross-table lateral it will be hard to differentiate free air and distended bowel (both rise centrally).

Answer 29

(c) HIDA scintigraphy shows visualisation of tracer in bowel at 12 hours Both conditions have conjugated hyperbilirubinaemia. The findings of a normal (> 1.5 cm) or enlarged gallbladder supports neonatal hepatitis, however, either finding can be present in BA as the GB can appear normal if the atresia is distal (in 20%). There is no intrahepatic duct dilatation in BA due to panductal sclerosis. In HIDA scintigraphy BA has good hepatic visualisation within 5 mins, but no excretion into the bowel, and no tracer uptake seen by 24 hours; in neonatal hepatitis there is slow and reduced uptake of the tracer by the liver, but bowel activity is seen by 24 hours.

Answer 30

(e) The capsule contains two walls Duplication cysts can be located anywhere along the GI tract, the most common location is the terminal ileum, followed by oesophagus, duodenum, colon, jejunum and stomach. They represent 15% of paediatric abdominal masses, and may be detected on antenatal US. Small bowel cysts are usually located on the mesenteric side of the bowel, oesophageal ones are typically intra-luminal. The cysts have a double capsule made of the bowel wall and mucosa, they are typically non-communicating and calcification is rare.

Answer 31

(e) Meconium plug syndrome Meconium plug syndrome results from colonic inertia with subsequent inspissation of meconium. It typically presents in large babies, born to diabetic mothers, is not related to meconium ileus. Hirschsprung's disease is the key differential diagnosis and can have similar radiological appearances. However, meconium is rarely passed following contrast examination and the given history of a diabetic mother is a leader to meconium plug syndrome.

Answer 32

(e) Bleeding This is seen in over a quarter of cases. The remaining presentations are well-documented, but occur less commonly.

Answer 33

(a) Gastroschisis This can be differentiated from omphalocoele by its location (right paraumbilical as opposed to midline), lack of covering membrane and relatively small defect size. It is also less commonly associated with other congenital defects. It is difficult to reliably diagnose this condition until at least 20 weeks gestation

Answer 34

(a) Above the level of duodenal bulb, to the left of spine Malrotation is the abnormal position of the bowel due to a narrow mesenteric attachment following arrest of rotation and fixation in utero. The normal DJJ is at the ligament of Treitz, to the left of the vertebral (usually L 1) pedicle at a level above or equal with the duodenal bulb on a true AP film. In malrotation, the mesentery is short, thus the DJJ does not reach the ligament of Treitz.

Answer 35

(a) Annular pancreas The 'double bubble' sign is described and implies obstruction at the level of the duodenum. Duodenal atresia (not stenosis) is thecommonest cause (30%) and is associated with Down's. Annular pancreas is second commonest cause, others include: duodenal web/ diaphragm, pre-duodenal vein, midgut volvulus, and SMA syndrome..

Answer 36

(a) Cystic fibrosis Meconium ileus is the initial presentation in 10-15% of CF neonates, but over 90% of infants presenting with meconium ileus have CF (atresia of the pancreas or pancreatic duct are other causes). The 'soap bubble' appearance may be seen in the RIF and represents gas mixed with meconium. A water soluble contrast enema aids diagnosis (shows an unused 'micro' colon) and treatment (if unsuccessful, surgery is required).

Answer 37

(d) Perchlorate Tc-99m pertechnetate is the radiotracer used; cimetidine, pentagastrin and glucagon have been shown to improve the sensitivity of the test. Pentagastrin enhances tracer uptake in gastric mucosa, cimetidine 'traps' pertechnetate within the Meckel's, and glucagon reduces peristalsis, thus inhibits tracer washout. Potassium perchlorate given orally after the study protects the thyroid gland from accumulation of pertechnetate, however, if used prior to scanning it will block tracer uptake by gastric mucosa.

Answer 38

(d) US shows blood flow in the intussusceptum Vascular flow is a good sign - ischaemia is unlikely. A left-sided lesion is more difficult to treat, but the majority are ileocolic (75-95%) or ileo-ileocolic (9%); colocolic lesions are very rare. A short history (< 24 hours) suggfusts there will be less oedema and the intussusception is less likely to have passed through to the left colon. An older age (> 12 months) suggests a pathological lead point may be the aetiology. lntussusception is idiopathic in 95% of paediatric cases.

Answer 39

(a) Hirschsprung's disease Hirschsprung's disease presents in neonates with abdominal distension and failure to pass meconium. Proximal obstruction +/- perforation can be seen on AXR. The rectum is always involved, but the proximal extent of disease varies. The normal colon will be dilated. If the transition point lies near the recto-sigmoid junction, the rectum: sigmoid diameter ratio will be less than 1 (normal is > 1 :1 ). Retention of contrast medium on a delayed 24 hours film is a classical feature, but definitive diagnosis-is-by-biopsy.

Answer 40

Answer D: Congenital tracheobiliary fistula The finding of pneumobilia is key to thinking of the diagnosis.

Answer 41

3. a. Type B Congenital TE fistula and oesophageal atresia occur in approximately 1 in 4000 live births. They are divided into five subtypes, A to E. Type C is the most common, comprising 75% of all types and involves oesophageal atresia with a distal TE fistula. Type D involves oesophageal atresia with both proximal and distal TE fistula, and type E is a TE fistula without oesophageal atresia. Therefore types C to E do not typically present with gasless abdomen. Type B is oesophageal atresia with a proximal TE fistula; there is no communication between the trachea and the distal oesophagus, and therefore a gasless abdomen is typical. Type A is oesophageal atresia without TE fistula and therefore may also present with a gasless abdomen, but is not a listed option.

Answer 42

33. a. Prune belly syndrome Prune belly syndrome is a non-hereditary disorder occurring in males with a triad of abdominal wall muscular hypoplasia, bilateral cryptorchidism and distended nonobstructed ureters. Other associations include malrotation of the gastro-intestinal tract, intestinal atresia, cystic renal dysplasia, vesico–ureteric reflux, pulmonary hypoplasia and cardiac anomalies (including PDA, tetralogy of Fallot and VSD).

Answer 43

35. c. Duodenal atresia Duodenal atresia typically presents in the first few days of life with bilious vomiting, and is caused by failure of recanalisation of the duodenal lumen in the fetus. It is associated with Down’s syndrome, congenital heart disease and other gastro-intestinal disorders such as malrotation, annular pancreas and biliary atresia. The characteristic feature on abdominal X-ray is the double-bubble sign with dilatation of the stomach and duodenal cap.

Answer 44

36. c. Presence of blood flow within the intussusceptum The following criteria are associated with a lower rate of successful enema reduction: age less than three months or greater than five years, long duration of symptoms, passage of blood per rectum, significant dehydration, obstruction of the small intestine and visualization of the dissection sign during enema therapy.

Answer 45

36. a. Pyloric muscle wall thickness of 2mm Hypertrophic pyloric stenosis presents between four and six weeks of life with non-bilious vomiting, typically in first-born males. A palpable olive-shaped mass is a sign with reported sensitivity of up to 80%, but ultrasound is the most frequently used imaging modality. Typical ultrasound features include the target sign (central hyperechoic mucosa with surrounding hypoechoic pyloric muscle), the nipple sign (pyloric mucosa indenting the gastric antrum), pyloric canal length >16 mm, transverse pyloric diameter >13mm and pyloric muscle wall thickness >3 mm. Pyloric stenosis can be difficult to differentiate radiologically from infantile pylorospasm. Typically with pylorospasm the appearances change with time, and so if the pyloric muscle thickness is measured at less than 3mm this makes infantile pylorospasm the more likely diagnosis.

Answer 46

42. c. Presence of three lobes on the left The neonate has heterotaxy with right atrial isomerism, which is associated with bilateral trilobed lungs, and both atrial appendages are short and broad-based. It is also usually associated with bilateral SVC and bilateral eparterial bronchus.

Answer 47

46. a. Recent barium investigation Prior to adolescence a Tc-99m pertechnetate scan has a high pick-up rate for a Meckel’s diverticulum. This declines with increasing age as the test relies on the presence of ectopic gastric mucosa, which is less likely to be present in someone asymptomatic throughout childhood. A false negative result is most commonly due to insufficient mass of ectopic gastric mucosa within the Meckel’s diverticulum, but may also be seen with barium from recent investigation attenuating the gamma radiation, and dilution of intraluminal activity due to rapid bowel transit.

Answer 48

47. b. Meconium peritonitis These features are typical of meconium peritonitis. This is a chemical peritonitis secondary to bowel perforation in utero. The intraperitoneal meconium characteristically calcifies within 24 hours of perforation. Other features seen on ultrasound include fetal ascites,polyhydramnios and bowel dilatation.

Answer 49

48. b. Hirschsprung’s disease These features are typical of Hirschsprung’s disease. This is caused by absence of parasympathetic ganglion cells in the bowel wall. Meconium ileus typically shows an empty microcolon on water-soluble enema and colonic atresia shows a distal microcolon with obstruction at the point of atresia. Functional immaturity of the colon typically shows microcolon distal to the splenic flexure with an abrupt transition to mildly dilated proximal colon

Answer 50

57. a. Congenital biliary atresia Congenital biliary atresia is the most likely diagnosis. It has a slight female preponderance and typically presents in the neonatal period. Ultrasound features include a large coarse liver with increased periportal reflectivity. Biliary dilatation is not typical. In severe neonatal hepatitis, the features on Tc-99m HIDA scan can appear similar to biliary atresia with reduced extraction and excretion. However, the more common picture is one of reduced hepatic uptake.

Answer 51

58. c. Defect situated to the right of the midline Gastroschisis tends to be a small defect (often less than 2.5 cm in length) which occurs to the right of the midline. The herniated bowel does not have a peritoneal lining and floats freely within the amniotic fluid. Features suggesting exomphalos include the presence of other congenital anomalies, midline defect, fetal ascites, herniation of the liver, amnioperitoneal membrane covering the bowel and the defect covering a large extent of the anterior abdominal wall.

Answer 52

A Approximately half of all omphalocoeles are associated with other chromosomal abnormalities. Only 5% of cases of gastroschisis are associated with other congenital anomalies.

Answer 53

E The TOF is usually found above the level of the carina. Imaging is best performed in the prone position with a horizontal beam. Infants with an H-type fistula will have gas-filled bowel loops.

Answer 54

C Following contrast administration, there is centripetal and heterogeneous enhancement on CT. Calcification is common and present in 50% of plain abdominal radiographs. Hepatoblastoma tends not to be multifocal; this would make hepatocellular carcinoma a more likely diagnosis.

Answer 55

E Transverse pyloric diameter of greater than 11 mm Ultrasound criteria include canal length >16 mm, transverse pyloric diameter >11 mm, muscle wall thickening > 2.5 mm and increased gastric motility. A pylorus that does not open is associated with hypertrophic stenosis; however, it may also be seen in pylorospasm.

Answer 56

A ‘Corkscrewing’ of the duodenum and jejunum Malrotation predisposes patients to midgut volvulus, giving rise to the ‘corkscrew’ pattern.

Answer 57

B A contrast enema showing pellets of meconium within the terminal A contrast enema will demonstrate a microcolon, with reflux into the terminal ileum which should be small in calibre and demonstrate pellets of meconium. Reflux into the more proximal ileum will demonstrate a dilated

Answer 58

D Multiple low reflective areas with a central focus of high reflectivity in the The typical ultrasound findings represent bile duct lakes with the portal vein seen as a central echogenic dot.

Answer 59

D On ultrasound, the appendix appears larger than normal in CF. Ultrasound is a first line imaging investigation, and is very useful in picking up early stage liver cirrhosis and gallstones.

Answer 60

B Distal intestinal obstruction Distal intestinal obstruction presents in 10-15% of older CF sufferers and can be potentially fatal. Treatment is with oral Gastrografin and a Gastrografin enema.

Answer 61

B An ultrasound finding of hypoechoic, thickened bowel wall with echogenic areas would be supportive of the clinical diagnosis. The duodenum and jejunum are the commonest sites of involvement. However, intussusceptions tend to be located in the ileoileal region and are usually transient.

Answer 62

B A normal gallbladder which distends with fasting suggests an alternative diagnosis. Eighty per cent of infants with persistent neonatal jaundice will have biliary atresia or neonatal hepatitis. Decompression of biliary atresia is important for preventing cirrhosis.

Answer 63

A A persistent, solitary dilated loop is an indicator of impending perforation. Portal venous gas is seen in 10% of cases and is not always fatal. Its disappearance may indicate impending perforation.

Answer 64

D The risk of perforation during the procedure is around 5%. The success rate is 60% with a perforation rate of 5%-

Answer 65

C The umbilical vein drains into the left portal vein. The liver in the'newborn is less reflective than the kidney up to the age of 3—4 months. A patent umbilical vein after 2—3 weeks is not usual and is associated with portal hypertension.

Answer 66

C Meckel's diverticulum In adults, a minority of Meckel's diverticula contain gastric mucosa and can lead to GI bleeding. The diverticulum may also become inverted and act as a ‘lead point’ for an intussusception.

Answer 67

D In a positive study, the activity in the Meckel's diverticulum appears at the same time and same intensity as the gastric mucosa. In children the majority of Meckel's diverticula contain intestinal mucosa.

Answer 68

D On an enema, the aganglionic segment extends to the rectosigmoid Skip lesions and short segment disease are unusual and a biopsy is required for definitive diagnosis. The catheter balloon should never be inflated, as this runs the risk of perforation.

Answer 69

B Down's syndrome is present in 20—30% of patients with duodenal atresia. Trisomy 21 is seen in approximately 30% of patients with duodenal atresia/stenosis and an annular pancreas.

Answer 70

C Pneumatic reduction has a radiation dose lower than that of barium reduction. Studies have demonstrated that effective reduction and a lower radiation dose are achieved by using air reduction rather than barium.

Answer 71

D Meckel's diverticulum This angiographic finding is diagnostic of a Meckel’s diverticulum as it indicates that a remnant of the omphalomesenteric (vitelline) duct is present.

Answer 72

B Pass a nasogastric tube, then inject a small amount of air followed by a supine chest radiograph. A nasogastric tube is a very useful tool in suspected OA, but if the tube passes into the stomach it may have entered through a fistulous connection. However, if an NG tube curls up in a proximal air-filled oesophagus, OA is highly likely.

Answer 73

5. E. Infantile haemangioendothelioma. Also known as infantile hepatic haemangioma, infantile haemangioendothelioma is a vascular neoplasm and the most common benign hepatic tumor of infancy. It may be a solitary mass or multifocal, and most are diagnosed before the age of 1 year. The lesion itself runs a benign course, but life-threatening clinical complications may occur. These include high-output cardiac failure secondary to large arterio-venous shunts and Kasabach–Merritt syndrome of coagulopathy secondary to intratumoral platelet sequestration. On ultrasound the lesions are well-demarcated and are generally hypoechoic or of mixed echogenicity. On CT and MRI the enhancement pattern of the lesion is similar to adult haemangioma. There is intense early peripheral nodular enhancement, with centripetal progression on the later images. Hepatoblastoma rarely occurs in the newborn but can be seen in young infants. This tumour is distinguished by a heterogeneous rather than intense centripetal enhancement pattern and markedly elevated levels of alphafetoprotein (AFP) in 90% of patients. AFP level is rarely elevated in infantile haemangioendothelioma. Mesenchymal hamartoma of the liver, like infantile haemangioendothelioma, may also be found in the perinatal period. This benign tumour differs in imaging appearance from infantile haemangioendothelioma in that it usually appears as a multicystic, multilocular mass with enhancement of only the septa and solid portions. Less commonly, mesenchymal hamartoma may be predominantly solid, but it differs from infantile haemangioendothelioma in that it is hypovascular at dynamic contrast-enhanced imaging. Whilst metastases could occur in an infant (e.g. neuroblastoma), they would tend to be hypodense to normal liver on contrast-enhanced CT. Hepatoma is exceedingly rare in an infant and the imaging characteristics described would not be typical.

Answer 74

10. B. Longer dorsal duct draining via the minor papilla/shorter ventral duct draining via the major papilla. Pancreas divisum is the most common congenital anomaly of the pancreatic duct and has a prevalence of 4–10% of the general population. Although it is usually asymptomatic and an incidental finding, it can lead to recurrent episodes of pancreatitis in children and adults. By definition, the dorsal and ventral ducts fail to fuse during embryological development, which results in the following features seen at MRCP: (a) a prominent dorsal pancreatic duct, which drains directly into the minor papilla, and (b) a ventral duct, which does not communicate with the dorsal duct, but joins with the distal bile duct to enter the major papilla (ampulla of Vater). Typically, the ventral duct is short and narrow, while the dorsal duct normally has a larger caliber.

Answer 75

15. D. Duodenal-jejunal corkscrew appearance on an upper GI contrast study. In individuals with malrotation, the mesenteric attachment of the midgut, particularly the portion from the duodenal-jejunal junction to the caecum, is abnormally short. The gut is therefore prone to twist counterclockwise around the superior mesenteric artery and vein—midgut volvulus. Options A to C are all imaging findings in malrotation, but not specifically that midgut volvulus has occurred. With regard to option E duodenal obstruction can, of course, be seen with midgut volvulus, but obstruction may also occur due to obstructive bands and there is also an increased risk of congenital duodenal anomalies in malrotation, such as duodenal atresia, stenosis, and webs. It is the finding of an abnormally located duodenal-jejunal flexure and a corkscrew appearance to the duodenum and proximal jejunum that is the most specific for malrotation complicated by midgut volvulus.

Answer 76

19. B. Diffuse fatty infiltration and fibrosis. Pancreatic insufficiency is almost invariable in patients who have the delta F508 mutation for CF. The most commonly described imaging abnormality in patients with CF is diffuse fatty infiltration and fibrosis. While pancreatic cysts are described, their size does not usually exceed a few millimetres. Larger pancreatic cysts have only been described in a few patients and complete replacement of the pancreas by macrocysts is very unusual.

Answer 77

24. E. Duodenal web. A duodenal web is classically associated with the ‘windsock sign’ seen on an upper GI contrast study. Over time, the web or diaphragm passively elongates as a result of continual peristalsis, to form the windsock configuration of an intraluminal duodenal diverticulum. Duodenal atresia is commonly associated with the ‘double bubble’ appearance on AXR. The atresia is most commonly just distal to the ampulla of Vater. Associated anomalies are common, such as congenital heart disease, Down’s syndrome, and malrotation. Midgut volvulus is usually a complication of malrotation. The AXR may be normal, gasless, or show signs of duodenal/high small bowel obstruction. The upper GI contrast study shows an abnormal position of the duodenal-jejunal flexure (to the right of midline) or duodenal obstruction in severe cases. More often the volvulus is intermittent, when the ‘corkscrew’ appearance is classical, due to clockwise twisting of the jejunum around the superior mesenteric artery. Annular pancreas and preduodenal portal vein are exceedingly rare. In preduodenal portal vein (persistent left vitelline vein), the portal vein lies in an abnormal position anterior to the duodenum and may cause compression. However, in this entity, the primary obstruction is more usually due to an associated obstructing duodenal lesion, such as an intraluminal membrane or web, and not to the abnormal position of the vein.

Answer 78

29. C. Neonatal hepatitis. Physiological jaundice of the newborn usually resolves within 2 weeks and thus is unlikely to be the cause in this case. It is also unconjugated, as is jaundice secondary to hypothyroidism. Caroli’s disease (type V of the Todani choledochal cyst classification) would typically have an abnormal ultrasound, demonstrating cystic dilatation of the intrahepatic bile ducts. The key distinction in this question is between biliary atresia and neonatal hepatitis. The question stated that the ultrasound was normal and visualization of a normal-sized gallbladder has been said to favour neonatal hepatitis. However, 20% of patients with biliary atresia may have a normal sized gallbladder, which also empties after a feed. Despite this, in the presence of a suggestive clinical picture, an absent or small gallbladder in the fasting state, a gallbladder with irregular and echogenic walls, or a large gallbladder that does not empty post feed are highly suggestive of biliary atresia. Distinction can be clarified with a HIDA scan. In early biliary atresia prior to cirrhosis, there is rapid extraction of radionuclide from the bloodstream, which persists and accumulates in the hepatic parenchyma with failure of excretion into the gut. Thus, visualization of isotope activity within the gut excludes the diagnosis of biliary atresia. In severe or late biliary atresia, hepatocyte function eventually deteriorates, resulting in sluggish tracer uptake by the hepatocytes. Patients with neonatal hepatitis often have decreased parenchymal extraction and clearance of radioisotope from the bloodstream but tracer does reach the intestines.

Answer 79

34. E. Duplication cyst. The most common location for duplication cysts is in the terminal ileum. This is followed by oesophagus, duodenum, and stomach. Duplication cysts contain both mucosal and muscle layers. On ultrasound, the mucosa is represented by an inner echogenic line and the muscle as an outer hypoechoic layer. The cyst is usually anechoic, unless complicated by haemorrhage or infection. Lymphangiomas, mesenteric, and omental cysts are rare. On ultrasound, they are usually anechoic, unless complicated by debris, haemorrhage, or infection. The wall is usually thin and does not have the double layer associated with duplication cysts. Ovarian cysts arise from the pelvis and will not have the layered wall appearance of a duplication cyst.

Answer 80

45. D. Hepatoblastoma. This is the most common primary malignant hepatic tumour in children (approximately 80%). Most cases occur below the age of 3 years. Serum alphafetoprotein is elevated in 70–90%. The imaging features are as described. Calcification is seen in approximately 50%. HCC is the next most common malignant liver tumour and has two peaks in childhood, at 2–4 years and 12–14 years. Serum alphafetoprotein is also elevated in approximately 80%. Imaging features are similar to those seen in an adult population, i.e. larger tumours are of heterogeneous echogenicity on ultrasound and on biphasic CT they show arterial enhancement with rapid washout on the portal venous phase. Undifferentiated embryonal sarcoma (UES) is the third most common liver malignancy and is most common between the ages of 6 and 10 years. Serum alphafetoprotein levels are normal. The imaging hallmark of this tumour is the discrepancy between its appearance on ultrasound and that on CT. Ultrasound is used to confirm the solid nature of this tumour, which typically is isoechoic or hyperechoic. On CT, UES is seen as a well-circumscribed, multiseptate, fluidattenuating lesion. Enhancement of solid-appearing septa and a pseudocapsule may be seen. Mesenchymal hamartoma is the second most common benign hepatic lesion (to haemangioendothelioma). It is usually seen under the age of 2 years. Serum alphafetoprotein is not elevated. The typical ultrasound appearance is a multiseptate, cystic mass. Less commonly, the solid component of the lesion can be more predominant, with multiple smaller cysts giving the lesion a Swiss-cheese appearance. The usual CT finding is of a multilocular cystic mass with enhancing septa of varying thickness. Angiosarcoma is not usually seen in children, but is a rare, highly vascular and highly malignant, hepatic tumour of adults.

Answer 81

49. E. A pyloric channel length of 12 mm. Ultrasound is the primary imaging modality used for the diagnosis of hypertrophic pyloric stenosis, although the criteria are generally applied to infants of 6 weeks and older. These include muscle thickness >3 mm, pyloric channel length >14 mm, pyloric thickness (serosa to serosa) >10 mm, failure of the pylorus to open with pyloric elongation and displacement, as well as retrograde or hyperperistaltic gastric contractions. A pyloric ratio, which is the ratio of the wall thickness to the pyloric diameter, above 0.27 is stated to be 96% sensitive for the diagnosis. The standard measurements above are not always applicable to neonates and real-time assessment to look for passage of fluid from the stomach into the duodenum becomes more important.

Answer 82

54. C. The umbilical cord inserting at the apex of the hernia. Omphalocele is the total failure of the midgut to return to the peritoneal cavity during the tenth week of gestation. The contents may vary from a single loop of small bowel to the entire GI tract, including the liver. An omphalocele can be differentiated from a gastroschisis (rupture of the abdominal wall) because in an omphalocele, the herniated structures are covered by peritoneum and amnion, and the umbilical cord inserts at its apex. In gastroschisis, there is a normally positioned umbilicus and the hernia is through a paraumbilcal defect. Because this (probably ischaemic) rupture of the abdominal wall occurs after the bowel has returned to the peritoneal cavity, the protruding viscera are not covered in peritoneum. The contents of the hernia in gastroschisis include stomach, midgut, and occasionally portions of the urinary tract. In omphalocele, there may be associated congenital cardiac anomalies and there is also an association with Beckwith Wiedeman syndrome. There is a low incidence of additional anomalies in gastroschisis.

Answer 83

59. C. Pancreatic duct dilatation. In cases of acute pancreatitis in children, the echogenicity of the pancreas on ultrasound is not ahelpful diagnostic feature and pancreatic enlargement is absent in 50% of the patients. The most useful diagnostic feature is dilatation of the pancreatic duct (>1.5 mm at 1–6 years of age, >1.9 mm at 7–12 years, and >2.2 mm at 13–18 years). Pancreatic ductal dilatation may also be seen in chronic pancreatitis. Pancreatic atrophy and parenchymal Calcifications are more typically associated with chronic disease.

Answer 84

60. B. Type B. Tracheoesophageal fistulae are classed depending on the communications present between the trachea and the oesophagus. In types A–D the mid-portion of the oesophagus is absent. Type A are not truly fistulae, but consist of an absence of the mid-portion of the oesophagus. In type B the proximal oesophageal bud communicates with the trachea and in type C it is the distal bud that has a tracheal fistula. Type C is the most common subtype. Both proximal and distal buds have fistulous connections with the trachea in type D. Type E (or H type) tracheoesophageal fistulae have complete trachea and oesophagus with a fistulous connection between them resembling the letter H.

Answer 85

64. C. Water-soluble contrast enema. This is rarely, if ever, indicated in the acute phase of necrotizing enterocolitis (NEC). It may be used for the evaluation of the presence of strictures, usually approximately 6–12 months after the acute phase of NEC. Supine AXR is the primary method used to evaluate NEC. A ‘jumbled’ pattern may be seen secondary to bowel wall oedema, which either compresses the lumen in some areas or causes an ileus appearance in other areas. Pneumatosis may be seen, which is either ‘bubbly’ or linear. This can lead to air in the portal venous system, which does not appear to alter the morbidity or mortality. Perforation may occur and this may be demonstrated on the supine AXR by Rigler’s sign (air on both sides of the bowel wall) or the ‘football sign’ (air outlining the falciform ligament). The left lateral decubitus and supine cross-table AXRs may both be used to detect small quantities of free air. Abdominal ultrasound may be helpful in the acute setting of NEC, as it can depict intraabdominal fluid, bowel wall thickening, assess bowel wall perfusion, and may also detect small quantities of free air and portal venous gas.

Answer 86

69. B. Gastric mucosa. The most sensitive and specific evaluation for a Meckel’s diverticulum is a 99mTc pertectnetate scan. This is positive only if gastric mucosa is present (in approximately 20% of patients). However, ectopic gastric mucosa is present in nearly all cases of Meckel’s diverticulum that bleed, as it is the ulcerated ectopic gastric mucosa that is the source of the haemorrhage. Ectopic pancreatic and colonic mucosa can occur in a Meckel’s divericulum, but are not typically associated with haemorrhage. Ectopic thyroid tissue is not usually found in a Meckel’s diverticulum. Other complications of a Meckel’s diverticulum include obstruction (either volvulus or intussusception) and diverticulitis.

Answer 87

C. Lipomatous pseudohypertrophy of the pancreas. The history is one of undiagnosed cystic fibrosis (CF), with respiratory disease and pancreatic exocrine dysfunction. Pancreatic involvement in CF initially produces inhomogenous attenuation, then low attenuation, and then complete fatty infiltration and replacement. Microcysts may develop and some of these may become small macroscopic cysts demonstrable with CT. There may be scattered calcifications. On ultrasound, there is increased diffuse echogenicity in keeping with fatty infiltration and fibrosis. CF is a major cause of pancreatic exocrine failure in childhood. Pancreatic abnormalities are seen in 85–90% of CF patients. However, the disease progresses to pancreatitis in less than 1% of CF patients. It predisposes to pancreatic cancer. Shwachman–Diamond syndrome is a rare congenital disorder characterized by pancreatic exocrine insufficiency, bone marrow dysfunction, and skeletal abnormalities. Patients usually present in infancy or early childhood with malabsorption and recurrent infections. Imaging reveals pancreatic lipomatosis.

Answer 88

1 Answer C: Hirschsprung disease Hirschsprung disease is the absence of parasympathetic ganglia in the muscle and submucosal layers of the colon. It usually presents in the first six weeks of life of a full-term infant. It is very rare in preterm infants. Eighty per cent involve the rectosigmoid.

Answer 89

Answer D: Pyloric transverse diameter 15 mm and presence of the cervix sign The `cervix sign' is the indentation of muscle mass on the fluid-filled antrum in longitudinal section and is seen in pyloric stenosis. Maximal dimensions of the canal on USS are 17 mm in length, 3 mm wall thickness, 13 mm in diameter and volume of 1.4 cu cm.

Answer 90

Answer A: Ileocolic intussusception This is a classic age and history for intussusceptions and the most common site type is ileocolic.

Answer 91

Answer C: Meckel's diverticulum Meckel's diverticulum is due to persistence of the omphalomesenteric duct, which normally obliterates in utero. Fifty per cent contain ectopic mucosa, which is usually gastric but may be pancreatic or colonic. This can demonstrate technetium uptake similar to normal stomach mucosa. It is therefore very important that the entire abdomen is imaged on the camera simultaneously to demonstrate simultaneous uptake.

Answer 92

9 Answer D: Right paraumbilical abdominal wall defect

Answer 93

21 Answer B: Distal intestinal obstruction syndrome Otherwise known as meconium ileus equivalent, distal intestinal obstruction syndrome occurs in children and adolescents with cystic fibrosis. It occurs due to impaction of inspissated stool in the distal ileum and proximal colon.

Answer 94

27 Answer B: Intussusception There are many causes of false positive Tc-99m pertechnetate studies which include: ectopic gastric mucosa, enteric duplication, Barrett's oesophagus, arteriovenous malformations, haemangiomata, hypervasculartumour, aneurysm, duodenal ulcer, ulcerative colitis, Crohn's disease, appendicitis, intussusception, bowel obstruction and urinary tract obstruction. Ileal rotation, haemorrhage and rapid bowel transit are causes of a false negative study.

Answer 95

32 Answer A: Good hepatic activity within five minutes and no visualisation of bowel at six hours or 24 hours The DISIDA nuclear scintiscan is 90-97% sensitive and 60-94% specific for biliary atresia. In addition it shows delayed clearance from the cardiac pool and increased renal excretion and bladder activity.

Answer 96

36 Answer C: Blood flow within the intussusceptum on colour Doppler The `target' sign is due to the hyperechoic mesentery of the intussusceptum surrounded by hypoechoic and hyperechoic rings of the intussuscipiens and is classic for intussusception. It is not a predictor of reducibility. Fluid inside the intussusception is associated with irreducibility and ischaemia. The absence of blood flow within the intussusceptum is suggestive of bowel necrosis

Answer 97

39 Answer C: Oesophageal atresia without tracheoesophageal fistula The inability to pass a feeding NG tube is suggestive of oesophageal atresia; it is seen coiled in the oropharynx on chest radiograph. Neonates with tracheoesophageal fistulae tend to aspirate during feeding with coughing and choking.

Answer 98

Answer B: Duodenal atresia Duodenal atresia is the most common cause of congenital duodenal obstruction. Twenty-five per cent of neonates with atresia have Down syndrome as in this case.

Answer 99

42 Answer C: Duodenal atresia This is the most common cause of congenital duodenal obstruction. It is associated with Down's syndrome.

Answer 100

57 Answer D: Haemangioendothelioma This is the most common benign hepatic tumour seen in infants under six months old. It commonly presents with congestive heart failure due to high-output circulation. They can be solitary or multiple. Haemangioendotheliomas have a natural history of regression within 12-18 months and the initial management is medical.

Answer 101

Answer D: Congenital biliary atresia It is best diagnosed with cholescintigraphy which shows good hepatic uptake but no biliary excretion. Triangular fibrous cord at porta hepatis seen on ultrasound is pathognomonic

Answer 102

68 Answer D: Laparotomy These findings are consistent with necrotising enterocolitis (NEC). Congenital heart disease is a risk factor for NEC. Gas in the portal venous system can be transient and does not necessarily imply a hopeless outcome.

Answer 103

Answer A: Annular pancreas Annular pancreas is a relatively common congenital anomaly wherein a ring of normal pancreatic tissue encircles the duodenum secondary to the abnormal migration of the ventral pancreas. It is associated with other congenital abnormalities in 75%; including Down syndrome. In a neonate it usually presents with duodenal obstruction and the obstruction is at D2 in 85% of cases.

Answer 104

69 Answer C: Supine An abnormal position of the duodenojejunal flexure on a barium meal confirms the diagnosis of malrotation, most commonly to the right of the spine.

Answer 105

Answer E: Diffuse pancreatic atrophy.

Answer 106

1 Answer D: Pyloric transverse diameter of 20mm Pyloric stenosis manifests itself between two and eight weeks of life and is more common in boys. Positive findings on ultrasound include: * pyloric muscle wall thickness >3 mm * pyloric canal length >17 mm * pyloric transverse diameter >13 mm * exaggerated peristaltic waves * delayed gastric emptying.

Answer 107

14 Answer B: Meconium ileus Meconium ileus presents with small bowel obstruction secondary to meconium impacted in the distal ileum. Almost all patients with meconium ileus have cystic fibrosis. It is the earliest clinical presentation of meconium ileus (10-15% of cystic fibrosis patients present with meconium ileus).

Answer 108

14 Answer A: Gastric duplication cyst This two-layered appearance is classic of gastric duplication cyst. Sixty-five per cent are in the region of the greater curvature. Most present in infancy with 75% being detected before the age of 12 years.

Answer 109

Answer A: Cystic fibrosis Cystic fibrosis affects the gastrointestinal tract in the majority of patients and manifestations include: meconium plugging, meconium ileus, distal intestinal obstruction, gastro-oesophageal reflux, thickened duodenal folds, small bowel dilatation, colonic stricturing, microcolon and pneumatosis intestinalis.

Answer 110

17 Answer A: Tc-99m pertechnetate Meckel's diverticulum is a persistence of the omphalomesenteric duct and is the most common congenital abnormality of the gastrointestinal tract. Tc-99m pertechnetate is >85% sensitive and >95% specific for Meckel's diverticulum.

Answer 111

24 Answer B: Hydrostatic reduction at 120 mmHg A rule of threes usually applies: maximum three attempts for three minutes, allowing three minutes between attempts. The pressure should be approximately 120 mmHg. (The colonic bursting pressure is approximately 200 mmHg.).

Answer 112

a Abdomen distended by bowel gas

Answer 113

30 Answer B: Intestinal atresia The description is that of gastroschisis. Gastroschisis has associated anomalies in 5 %, most of which are intestinal atresia or stenosis. Omphalocoele has a high incidence of associated anomalies including chromosomal, genito-urinary, cardiac (particularly VSD), neural tube defects, IUGR and Beckwith-Wiedemann syndrome.

Answer 114

31 Answer B: Free intra-abdominal air In necrotising enterocolitis, pneumatosis intestinalis is seen in 80%. Gas in the portal vein can be seen, is frequently transient and does not imply a terrible outcome as it would in adults. Pneumoperitoneum is a poor prognostic factor and usually requires immediate surgery.

Answer 115

36 Answer D: Intussusception Intussusception is the invagination of a segment of bowel (intussusceptum) into the lumen of the adjacent bowel (intussuscipiens). Ninety-five per cent of cases are idiopathic in children.

Answer 116

39 Answer C: Duodenojejunal junction low and in the midline All of the above are found in malrotation. The most common findings associated with the diagnosis of malrotation are: duodenum and jejunum to the right of the spine, corkscrew duodenum and jejunum and the duodenojejunal junction low and in the midline.

Answer 117

43 Answer C: Fibrolamellar hepatocellular carcinoma This is a subtype of hepatocellular carcinoma found in older children and adolescents, which is less aggressive. The central scar can calcify

Answer 118

46 Answer C: Pneumoperitoneum These are all radiological findings seen in necrotising enterocolitis. This is an ischaemic bowel disease secondary to hypoxia, perinatal stress and infection. It is the most common gastrointestinal emergency in premature infants. Portal venous gas is often a transient feature.

Answer 119

56 Answer A: `Triangular cord' sign in porta hepatis This is due to fibrous tissue and is pathognomonic for biliary atresia. The other options can all be seen in both neonatal hepatitis and biliary atresia.

Answer 120

61 Answer A: Hereditary spherocytosis Gallstones are rare in neonates without predisposing factors. These include: total parenteral nutrition, furosemide, short gut syndrome, obstructive congenital biliary anomaly, dehydration and haemolytic anaemia.

Answer 121

69 Answer A: Rectal duplication cyst These account for 4% of all gastrointestinal tract duplications; 20% of patients develop perianal fistulae.

Answer 122

8 Answer C: Oesophageal atresia without tracheo-oesophageal fistula The diagnosis is made incidentally in this instance, as the patient has not required feeding yet. Nasogastric tubes are passed routinely when the neonate is intubated. The nasogastric tube does not pass into the stomach and coils in the neck. The lack of air within the abdomen differentiates it from patients with a tracheooesophageal fistula.

Answer 123

9 Answer D: Appendicitis The appendix is frequently not visualised in appendicitis due to retrocaecal position, the inability to compress the abdomen adequately or prior perforation.

Answer 124

13 Answer E: Fusiform cyst beneath the portal hepatis, separate from the gallbladder The clinical and ultrasound findings are those of a choledochal cyst. This is the most common congenital lesion of the gallbladder and is a segmental dilatation of the common bile duct. It does not involve the gallbladder or cystic duct.

Answer 125

27 Answer B: Intussusception Other findings on abdominal radiograph include an abdominal soft-tissue mass in the right upper quadrant, normal appearances and small bowel obstruction.

Answer 126

30 Answer B: Henoch-Schonlein purpura This is a hypersensitivity-related acute small-vessel vasculitis, which often begins as an upper respiratory tract infection. It causes a proliferative glomerulonephritis with IgA deposits & can lead to renal insufficiency & rarely to end-stage renal disease.

Answer 127

34 Answer C: Malrotation of the ileum The other options can all give false positive results. False negative results can be caused by a recent barium enema, irritable bowel in the right lower quadrant causing rapid transit or presence of only a small amount of ectopic gastric mucosa.

Answer 128

34. (b) Pancreas divisum This is the most common anatomical variant of the pancreas and is due to failure of fusion of the ventral and dorsal pancreatic buds. As a result, the main dorsal pancreatic duct drains through the minor papilla while the ventral pancreatic duct with the common bile duct drains through the major papilla.

Answer 129

49 Answer A: Acute splenic sequestration crisis This occurs in patients with sickle cell disease when the intrasplenic veins become obstructed leading to a sudden trapping of a large amount of blood in the spleen.

Answer 130

61 Answer B: Pyloric stenosis This occurs most frequently in boys aged three to six months and presents with non-bilious vomiting.

Answer 131

63 Answer C: Midgut malrotation Midgut malrotation usually presents within the first month of life with bilious vomiting. The pathognomonic finding of midgut malrotation is an abnormally positioned ligament of Treitz with the duodenojejunal junction lying to the right or below the expected normal position, shown on a barium meal. Duodenal atresia obstructs near the ampulla of Vater and results in bilious vomiting in the first 24 hours of life. Plain radiograph findings of duodenal atresia are of a `double bubble' sign of a dilated stomach and duodenal bulb with no gas seen distally.

Answer 132

66 Answer C: Necrotising enterocolitis Necrotising enterocolitis is the most common surgical emergency in neonates. Inflammation and mucosal ulceration of the bowel leads to widespread trans- mural necrosis.

Answer 133

68 Answer E: Passing inferiorly from the umbilicus to the pelvis then turning cranially to lie with the tip at T9 An umbilical artery catheter (UAC) should run into the pelvis via the umbilical artery to the iliac artery before turning superiorly to the aorta. An umbilical venous catheter will pass immediately superiorly. The tip of a UAC should not be positioned close to the origin of a major vessel T10-L3 due to risk of thrombosis.

Answer 134

70 Answer D: Rhabdomyosarcoma of the biliary tract This a rare tumour, most commonly arising from the common bile duct. It is more common in males.

Answer 135

1. (d) Meckel’s diverticulum The 99mTc pertechnetate scan demonstrates ectopic gastric mucosa which bleeds giving rise to symptoms.

Answer 136

3. (a) Intussusception This is a common surgical emergency in children less than 1 year of age. Ultrasound can accurately diagnose and assess bowel viability. Hypertrophic pyloric stenosis occurs at a much younger age and does not present with bleeding per rectum. Other options are also unlikely, with the given ultrasound appearances.

Answer 137

4. (b) Ultrasound This is the most useful investigation as it can not only accurately diagnose intussusception but also assess bowel viability and reducibility

Answer 138

6. (e) Malrotation with volvulus Bilious vomiting in newborn infants is most likely to represent malrotation with midgut volvulus. The duodenojejunal flexure is on the right and CT or ultrasound demonstrates a ‘whirl sign’ of superior mesenteric vein and mesenteric vessels around the superior mesenteric artery.

Answer 139

8. (e) Duodenal atresia The ‘double bubble’ sign can be seen in duodenal atresia, midgut volvulus or annular pancreas, but the absence of gas in the rest of abdomen suggests underlying duodenal atresia. Duodenal atresia is also associated with Down’s syndrome and maternal hydramnios. Annular pancreas usually presents at a later age (if symptomatic). Midgut volvulus is seen in young infants. Some gas is seen distal to duodenum. Choledochal cyst is seen in children and young adults with biliary symptoms.

Answer 140

18. (b) Biliary atresia Jaundice persisting beyond 1 month is usually due to biliary atresia of neonatal hepatitis. A choledochal cyst is seen in 5% of cases. These conditions have similar clinical and biochemical presentations. Ultrasound will be normal in hepatitis and biliary atresia, but no bowel activity is seen with HIDA scan on delayed images in biliary atresia.

Answer 141

32. (a) Necrotising enterocolitis Ischaemic bowel disease secondary to hypoxia, perinatal stress and infections. The terminal ileum is commonly involved and the bowel loops show wall thickening and intramural air. Gas may be seen in the porto-venous system in the liver.

Answer 142

33. (a) Meconium ileus Meconium ileus is almost diagnostic of cystic fibrosis and presents in neonates. Family history of CF may be present. The abnormally thick meconium obstructs the ileum and a water soluble enema may relieve the impaction. This disorder produces the smallest of microcolons because the obstructing meconium leaves the colon unused. Meconium plug syndrome is also known as functional immaturity of the colon. It is a temporary functional obstruction which often occurs at the splenic flexure, and is a common cause of neonatal obstruction.

Answer 143

34. (b) Meconium peritonitis This is a sterile chemical peritonitis, secondary to perforation of bowel resulting in prenatal leak of meconium into the peritoneal cavity. This is usually secondary to bowel obstruction and perforation in utero. Meconium peritonitis usually results in intraperitoneal calcifications, which may be focal, cystic or generalised. On plain films, the primary finding is calcifications. On ultrasound there may be cysts with echogenic walls (calcifications) containing meconium. Calcifications usually disappear over months or years.

Answer 144

38. (a) Hirschsprung’s disease This is a functional colonic obstruction characterised by an aganglionic hypertonic distal segment of bowel with associated proximal dilatation. Radiographic demonstration of the transition zone between the dilated proximal ganglionic segment bowel and the non-dilated distal aganglionic bowel is the most reliable diagnostic feature of Hirschsprung’s. Other features include a corrugated or sawtooth rectosigmoid, abnormal rectosigmoid index (normally the sigmoid should not be bigger than the rectum) and delayed evacuation of contrast medium. 38. (a) Hirschsprung’s disease This is a functional colonic obstruction characterised by an aganglionic hypertonic distal segment of bowel with associated proximal dilatation. Radiographic demonstration of the transition zone between the dilated proximal ganglionic segment bowel and the non-dilated distal aganglionic bowel is the most reliable diagnostic feature of Hirschsprung’s. Other features include a corrugated or sawtooth rectosigmoid, abnormal rectosigmoid index (normally the sigmoid should not be bigger than the rectum) and delayed evacuation of contrast medium.

Answer 145

40. (a) Hepatoblastoma This is the most common primary malignant hepatic tumour in children occurring before 3 years of age. There is an association with Beckwith–Wiedemann syndrome. On CT there is a heterogeneous contrast enhancement whilst on MRI, the tumour is usually heterogeneously hyperintense on T2. Hepatocellular carcinoma, metastases and hemangioendothelioma are very rare in this age group.

Answer 146

42. (c) Hypertrophic pyloric stenosis Ultrasound is diagnostic of this condition, including an elongated pyloric canal (> 15 mm) and thick pyloric muscle (> 3 mm).

Answer 147

Answers: (a) Not correct (b) Not correct (c) Not correct (d) Correct (e) Not correct Explanation: Hypertrophic pyloric stenosis is typically seen in first born males with peak incidence between 2 and 6 weeks of age. It is rarely seen in premature infants. To make a diagnosis on ultrasound the pyloric canal length should be 17mm, pyloric wall thickness at least 3 mm and transverse diameter of pylorus at least 13 mm.

Answer 148

Answers: (a) Correct (b) Not correct (c) Correct (d) Correct (e) Correct Explanation: Abdominal involvement in non-Hodgkin’s usually presents with a mass typically at ileocaecal region or intussusception causing obstruction. Splenic involvement is seen in less than 40% of cases at presentation.

Answer 149

Answers: (a) Not correct (b) Correct (c) Correct (d) Not correct (e) Correct Explanation: The H type trachea-esophageal fistula is seen only in 10% cases. Upper esophageal atresia with a fistula between lower esophagus and trachea is the most common type (85%). Duodenal duplication cysts are usually situated along the concave border where they may cause duodenal obstruction, biliary obstruction or pancreatitis

Answer 150

Answers: (a) Correct (b) Correct (c) Not correct (d) Not correct (e) Correct Explanation: Meckel’s diverticulum located at the antimesenteric border of the ileum. Best investigation diagnosed Meckel’s diverticulum in children is a radionuclide technetium 99 pertechnetate scan.

Answer 151

Answers: (a) Not correct (b) Not correct (c) Correct (d) Not correct (e) Correct Explanation: Hepatoblastomas typically present as an abdominal mass in an asymptomatic child under 2 yrs of age. Hepatocellular carcinoma presents over 4 yrs of age. Both hepatoblastomas and hepatocellular carcinoma cause elevated alpha-fetoprotein levels. Hepatoblastomas are associated with hemihypertrophy and Beckwith-Wiedemann syndrome. Calcification is present in 50% cases of hepatoblastomas.

Answer 152

Answers: (a) Correct (b) Not correct (c) Not correct (d) Not correct (e) Correct Explanation: In intussusception plain films can be normal in 50% cases with highest incidence between 3 months and 4 years of age. In children 95 % intussusception are idiopathic with no lead point.

Answer 153

Answers: (a) Correct (b) Not correct (c) Correct (d) Not correct (e) Not correct Explanation: Double bubble sign is also seen in duodenal stenosis, annular pancreas and preduodenal portal vein. In bifid CBD insertion bowel gas may not be seen distal to atretic segment. 1/3rd of cases are associated with Down’s syndrome.

Answer 154

Answers: (a) Not correct (b) Correct (c) Correct (d) Correct (e) Not correct Explanation: A normal DJ flexure lies to the left of spine at the same level as or more superior to the duodenal bulb. In malrotation the DJ flexure (ligament of Treitz) is abnormally positioned. In malrotation the caecum is generally malpositioned in the right upper quadrant or in the left side of abdomen. In 20% of patients with malrotation caecum is normally positioned.

Answer 155

Answers: (a) Not correct (b) Correct (c) Not correct (d) Correct (e) Not correct Explanation: Chronic liver disease is present in 25% of adults with cystic fibrosis and the severity increases with age. Pancreatic calcification is seen in 8% of the patient’s on radiography. MRI depicts the calcification poorly. Microgallbladder is a common finding. In patients with cystic fibrosis, the gallbladder is typically small, trabeculated, contracted and poorly functioning. It often contains echogenic bile, sludge and cholesterol gallstones

Answer 156

Answers: (a) Correct (b) Not correct (c) Not correct (d) Not correct (e) Correct Explanation: Omphalocoele is usually associated with other anomalies in over 80% cases, with umbilical cord insertion at the apex and covered by peritoneum and amnion

Answer 157

Answers: (a) Not correct (b) Correct (c) Not correct (d) Not correct (e) Correct Explanation: NEC is predominantly a disease of premature infants weighing less than 2 kgs. Very premature infants develop NEC until 2nd or 3rd week of life or later. Most infants however develop NEC in first few days of life. NEC is a serious neonatal disease of unknown etiology, involving predominantly the distal ileum and proximal colon characterized by mucosal or transmucosal necrosis of part of the intestine which may progress to perforation.

Answer 158

Answers: (a) Correct (b) Correct (c) Not correct (d) Not correct (e) Correct Explanation: The pathognomonic finding of Hirchsprung disease on contrast enema is a transition zone between normal and aganglionic bowel i.e. abnormally small rectum and distal colon to a dilated normal proximal colon. However in 25% of patients transition zone is not seen which does not rule out Hirchsprung disease. In a normal patient rectum has the largest luminal diameter of the left sided colon. When rectum alone is involved the sigmoid colon has larger diameter than rectum.

Answer 159

Answers: (a) Not correct (b) Correct (c) Not correct (d) Correct (e) Not correct Explanation: OA and TOF are associated with anomalies in the VACTERL group. OA is also associated with other atresias like duodenal atresia and imperforate anus. OA and TOF include a spectrum of anomalies involving trachea and esophagus. The most common type is N type i.e. proximal OA and distal TOF. H type is TOF without OA thus a gasless stomach is not possible.