Gastroenterology Exam Questions Flashcards
- Pancreatic enzymes are involved in digestion of protein. They are released as proenzymes into
the duodenal lumen where they are activated.
The enzyme that plays an important role in activating the proenzymes is:
A. carboxypeptidase.
B. chymotrypsin.
C. elastase.
D. lipase.
E. trypsin.
Answer E. Trypsin
Chymotrypsin is converted to trypsin by small intestine enzyme enterokinase. Activated trypsin further activates chymotrypsin and other proteases.
- A 2 year old boy is brought to the Emergency Department with a history of several days of rectal
bleeding. His mother first noticed reddish-coloured stools three days prior and since then has
changed a few nappies containing only blood. On examination the child is afebrile, alert and
playful and is eating well. He is tachycardic and abdominal examination is normal.
Which of the following investigations will most likely reveal the diagnosis?
A. Abdominal ultrasound.
B. Barium enema.
C. Gastroscopy.
D. Radionuclide scan.
E. Stool culture.
Answer D. Radionuclide scan.
Diagnosis in Meckel Diverticulum.
60% of complications arise in <2yr olds. Bleeding is painless. Diagnosed by 99m technetium pertechnetate (radionuclide) scan.
QUESTION 18
The initial luminal digestion of dietary starch by salivary and pancreatic amylase leads to the formation
of which disaccharide?
A. Fructose.
B. Galactose.
C. Glucose.
D. Maltose.
E. Sucrose.
Answer D. Maltose
Fructose, galactose and glucose are all monosaccharides.
Starch breakdown forms maltose which is the equivalent of two units of glucose.
Sucrose is formed of glucose and fructose.
Centre for Disease Control (CDC) body mass index (BMI) charts have been recommended as a
screening tool to identify individuals who are overweight.
Which of the following BMI’s define a child likely to be obese?
A. >25 kg/m2
B. >30 kg/m2
C. >85th percentile for age.
D. >85th <95th percentile for age.
E. ≥95th percentile for age.
Answer E. ≥95th percentile for age.
>85th <95th percentile is overweight, >95th is obese
Infliximab is effective in the treatment of Crohn’s disease. Its mode of action involves:
A. binding to tumour necrosis factor.
B. blockade of tumour necrosis factor receptors.
C. blockade of tumour necrosis factor secretion from inflammatory cells.
D. enhancement of hepatic metabolism of tumour necrosis factor.
E. inhibition of tumour necrosis factor production
Answer A. binding to tumour necrosis factor.
A two-year-old boy presents with a six week history of diarrhoea and lethargy. Clinical examination
reveals lower limb and periorbital oedema. Investigations show:
Normal liver function tests apart from albumin 22 g/L [35 - 50 g/L].
Urine analysis was normal.
Coagulation profile was normal.
What faecal test would confirm that the low albumin was related to gastrointestinal losses?
A. Alpha-1 antitrypsin.
B. Chymotrypsin.
C. Elastase.
D. Proalbumin.
E. Trypsin.
Answer A. Alpha-1 antitrypsin.
Protein losing enteropathy
Children with protein losing enteropathy have severe protein loss through the gut, resulting in low plasma protein levels (hypoalbuminemia). Causes include hypertrophic gastritis (Ménétrier’s disease), milk protein allergy, celiac disease, inflammatory bowel disease, giardiasis, intestinal lymphangiectasia, and right sided heart dysfunction (post-Fontan procedure).
Stool level of alpha-1 antitrypsin is an excellent screening test for protein losing enteropathy, as alpha-1 antitrypsin is a nondietary, serum protein synthesized in the liver. Its molecular weight of 50 kDa is similar in size to albumin (67 kDa), and it is resistant to intestinal and proteolytic digestion distal to the stomach.
Absorption of iron in the ferrous form (Fe 2+) occurs mainly in the:
A. stomach.
B. duodenum.
C. jejunum.
D. ileum.
E. colon
Answer B. duodenum
Most nutrients are absorbed in the duodenum and proximal jejunum. Bile salts and vit B 12 are absorbed in the terminal ileum.
Water is absorbed throughout the small intestine.
In infants with glucose-galactose malabsorption, ingestion of foods containing which of the following
carbohydrates is likely to cause severe diarrhoea and dehydration?
A. Fructose.
B. Mannitol.
C. Mannose.
D. Sorbitol.
E. Sucrose.
Answer E. Sucrose
Sucrose is a disaccharide which is broken down by sucrase to form glucose and fructose.
Sorbitol is a sugar alchohol obtained by the reduction of glucose.
Glucose + glucose = maltose
Glucose + galactose = lactose
Glucose + fructose = sucrose
Fructose + galactose = lactulose
Which of the following lipid-lowering drugs works primarily by the upregulation of low density
lipoprotein (LDL) receptor activity?
A. Cholestyramine.
B. Clofibrate.
C. Colestipol.
D. Nicotinic acid.
E. Simvastatin.
Answer E. Simvastatin.
Simvastatin is a HMG CoA reductase inhibitor leading to upregulation of LDL receptors in the liver, in turn increasing catabolism of plasma LDL and lowering plasma concentration.
Cholestyramine and colestipol are resins that bind with bile acids and are excreted in faeces.
Clofibrate promotes conversion of VLDL to LDL, reducing VLDL levels.
Nicotinic acid inhibits the synthesis of VLDL.
What is the commonest cause of failure to thrive in infancy in developed countries?
A. Chronic organ failure.
B. Gastrooesophageal reflux.
C. Inadequate intake.
D. Malabsorption.
E. Recurrent infection.
Answer C. Inadequate intake.
A four-year-old boy was playing with his brother and accidentally swallowed a coin. Initially there was
some coughing and spluttering but he subsequently settled. An X-ray taken at the Emergency
Department four hours later shows the coin to be at the lower oesophagus just above the
gastrooesophageal junction. What is the most appropriate next step?
A. Barium swallow.
B. Domperidone.
C. Endoscopic removal.
D. Oral fluid bolus.
E. X-ray in 48 hours.
Answer C. Endoscopic removal
According to Up To Date….if object has not passed out of oesophagus by 24 hours, should be removed endoscopically.
If patient is symptomatic or duration is unknown, should be removed immediately.
An eight-week-old ex-premature baby with congenital hypothyroidism fails to respond to an adequate
dose of thyroxine given regularly. The baby is breast fed and is on nutritional supplements. Which of
the following nutritional supplements is most likely to affect absorption of thyroxine?
A. Folic acid.
B. Iron.
C. Phosphate.
D. Vitamin A.
E. Vitamin D.
Answer B. Iron.
A 14-year-old has recently been diagnosed with anorexia nervosa. She has a body mass index (BMI)
of 15 kg/m2. She was commenced on nasogastric feeds. The level of which of the following
electrolytes is most likely to fall if calories are given too rapidly?
A. Calcium.
B. Chloride.
C. Magnesium.
D. Phosphate.
E. Sodium.
Answer D. Phosphate
Refeeding Syndrome
In significantly malnourished patients, the initial stage of oral, enteral, or parenteral nutritional replenishment causes electrolyte and fluid shifts that may precipitate disabling or fatal medical complications. The refeeding syndrome is marked by:
- Hypophosphatemia
- Hypokalemia
- Hypomagnesemia
- Vitamin (eg, thiamine) and trace mineral deficiencies
- Volume overload
- Edema
Hypophosphatemia is the hallmark of the syndrome and predominant cause of the refeeding syndrome.
The pathogenesis of hypophosphatemia begins when stores of phosphate are depleted during episodes of AN and starvation. When nutritional replenishment begins and patients are fed carbohydrates, glucose causes release of insulin, which triggers cellular uptake of phosphate (and potassium and magnesium). Insulin also causes cells to produce a variety of depleted molecules that require phosphate (eg, adenosine triphosphate (ATP) and 2,3-diphosphoglycerate), which further depletes the body’s stores of phosphate. The lack of phosphorylated intermediates causes tissue hypoxia and resultant myocardial dysfunction and respiratory failure.
A 16-year-old female was diagnosed with ulcerative colitis at the age of 12. Her disease was fairly
well controlled, initially with steroids and subsequently on maintenance salazopyrine. Over the last six
months she complained of poor concentration, tiredness and vague upper abdominal pain. Blood
investigation done by her general practitioner showed:
Alanine aminotransferase (ALT) 80 IU/L [<55 IU/L]
Alkaline phosphatase (ALP) 660 IU/L [30 - 120 IU/L]
Gamma glutamyltransferase (GGT) 332 IU/L [0 - 40 IU/L]
Total Bilirubin 6 μmol/L [<8 μmol/L]
Antinuclear antibody (ANA) + ve (titre 1:80)
Anti-smooth muscle antibody –ve
Anti-liver kidney microsomes –ve
What condition does this patient most likely have?
A. Autoimmune hepatitis.
B. Cholelithiasis.
C. Non-alcoholic steatohepatitis (NASH).
D. Sclerosing cholangitis.
E. Viral hepatitis.
Answer D. Sclerosing cholangitis
Patients with UC are at risk of developing sclerosing cholangitis. Half of patients are asymptomatic. Fatigue and pruritis most common symptoms.
Lab tests show a cholestatic picture, with raised ALP predominant, and fluctuating GGT due to transient blockage. AST and ALT are usually <300. Anti ANA and anti SMA antibodies may also be raised.
Autoimmune hepatitis
Type 1 (classic) - raised ANA &/or SMA
Type 2 - Anti LKM (Liver/Kidney microsomal antibody)
Cholelithiasis
Patients often asymptomatic, may present with biliary colic, normal physical exam and normal lab results. Pts might c/o diaphoresis, N&V.
NASH
Hepatic inflammation that histologically is indistinguishable from alcoholic steatohepatitis. Most patients are asymptomatic. Some may c/o fatigue, malaise, and vague right upper abdominal discomfort. LFTs may indicate raised AST and ALT.
Viral Hepatitis
Pts with viral hepatitis present more acutely with jaundice a predominant feature. In viral hepatitis, raised autoantibodies not a typical feature. Most liver enzymes will be raised.
A term born infant presents to the Emergency Department at five days of age with a six hour history of
bilious vomiting. The parents report that he passed a normal stool 12 hours beforehand. On
examination, he has mild abdominal distension and his perfusion is decreased, with a capillary refill
time of three seconds. Plain abdominal X-ray is normal.
Which of the following investigations is most likely to be diagnostic?
A. Abdominal ultrasound.
B. Air enema.
C. Barium enema.
D. Barium meal.
E. Computed tomography scan of the abdomen.
Answer D. Barium Meal
Presentation is likely to be a volvulus or obstruction. Barium meal is best way to diagnose. Air enema is diagnosic and therapeutic for intussusception. Barium enema for Hirschsprungs disease. CT is not indicated as first line.
A two-year-old boy was brought to the Emergency Department after he passed a large amount of
blood per rectum. He was a previously healthy boy and on clinical examination he appeared pale but
alert. He was not in any distress, his heart rate was 160 beats/minute and his systolic blood pressure
was 70 mmHg. Examination revealed a soft but mildly distended abdomen. There was no localised
tenderness or palpable mass. He continued to pass maroon coloured clots during the examination.
Initial haemoglobin was 70 g/L [105 – 135 g/L].
What is the most likely diagnosis?
A. Allergic colitis.
B. Duodenal ulcer.
C. Intussusception.
D. Meckel diverticulum.
E. Rectal polyp.
Answer D. Meckel Diverticulum.
Meckels is associated with painless PR bleeding in an otherwise well child.
Allergic colitis occurs in infancy with similar presentation of blood tinged or mucousy stools in otherwise well baby. Duodenal ulcer presents with pain and possibly malena. Intussusception has bouts of severe pain, mass in the abdomen and assoc with red current jelly stool if severe/late stage. Rectal polyp assoc with pain, constipation, diarrhoea and bleeding.
A six-month-old infant drinks 1000 ml of a standard cow milk formula daily. Approximately how much
energy does the child get per day from his milk intake?
A. 200 kcal (840 kJ)
B. 500 kcal (2100 kJ)
C. 670 kcal (2820 kJ)
D. 810 kcal (3400 kJ)
E. 1000 kcal (4200 kJ)
Answer C. 670 kCal (2820kJ)
Standard formulas provide approx 280kJ/100mL (67 kCal)and 1.5g protein per 100ml.
Energy requirments at 0-6 months 115kcal/kg/day, 6-12 months 95kcal/kg/day.
A 15-year-old boy presents with dysphagia and regurgitation of undigested food. His barium swallow images are shown below.
What is the most likely diagnosis?
A. Achalasia.
B. Eosinophilic oesophagitis.
C. Peptic stricture.
D. Tracheo-oesophageal fistula.
E. Vascular ring.
Answer A. Achalasia
Primary achalasia is a disease of unknown etiology in which there is a loss of peristalsis in the distal esophagus and a failure of lower esophageal sphincter (LES) relaxation with swallowing (main cause of symptoms). Can occur at any age, before adolescence is rare.
Barium swallow will show
- Dilation of the esophagus
- Narrow esophagogastric junction with “bird-beak” appearance caused by the persistently contracted LES
- Aperistalsis
- Poor emptying of barium
Eosinophilic Oesophagitis
Ring-like areas of narrowing on barium swallow
TOF
Presents with coughing/aspiration symptoms in infancy.
Vascular Ring
Vascular rings are congenital anomalies of the aortic arch that result in compression of the tracheobronchial tree and/or esophagus, leading to respiratory and gastrointestinal symptoms. Barium swallow demonstrates a posterior indentation of the esophagus in all vascular rings except for the pulmonary sling, in which an anterior indentation and increased space between the trachea and esophagus are found.
Malrotation with midgut volvulus is a potentially life threatening condition in otherwise healthy infants. Which of the following best describes the normal rotation of the bowel that occurs during embryogenesis?
A. Clockwise 180 degrees.
B. Clockwise 270 degrees.
C. Counterclockwise 90 degrees.
D. Counterclockwise 180 degrees.
E. Counterclockwise 270 degrees.
Answer E. Counterclockwise 270 degrees.
The addition of starch to oral rehydration solution increases water absorption by which mechanism?
A. Aquaporin transport.
B. Colonic fermentation.
C. Enterohepatic reabsorption.
D. Sodium-glucose co-transport.
E. Sodium-Potasium ATPase.
B. Colonic fermentation.
The sodium coupled co-transport with glucose is the basis of ORT as it drags water along behind it. Addition of resistant starch to ORS increases colonic fermentation (bacteria break starch down to short chain fatty acids). The colon which was unable to absorb water can do so with via short chain fatty acis.
In which segment of the gastrointestinal tract is most of dietary iron absorbed?
A. Distal ileum.
B. Duodenum.
C. Jejunum.
D. Proximal ileum.
E. Stomach.
B. Duodenum
Iron and Folate are absorbed in the duodenum and Vit B12 is absorbed in the terminal ileum.
Supplementation with which of the following micronutrients has been shown to be most effective in the treatment of chronic diarrhoea in malnourished children?
A. Cyanocobalamin.
B. Folic acid.
C. Iron.
D. Magnesium.
E. Zinc.
E. Zinc.
Zinc reduces severity and duration of persistent diarrhoea and recommended by WHO to be supplemented in diarrhoeal illness in developing countries. Also noted to decrease severity and duration in acute diarrhoea.
The optimal method of rehydration in children with gastroenteritis is widely accepted to be through the use of Oral Rehydration Solution because it optimises the absorption of both water and electrolytes in appropriate quantities.
Which of the following best describes the mechanism by which water is absorbed from the
gastrointestinal lumen?
A. Activation of adenylate cyclase.
B. Active transport via sodium - glucose cotransporter.
C. Active transport via sodium - water cotransporter.
D. Passive diffusion across an osmotic gradient.
E. Utilisation of sodium - potassium ATPase pump.
Answer D. Passive diffusion across an osmotic gradient.
Water absorption is passive depending upon the osmotic gradient that is dictated by sodium transport via the following three principal mechanisms:
- Na/H exchangers
- Electrochemical gradient
- Sodium-coupled transport with carrier organic solutes (eg, glucose)
Which vitamin B complex nutritional deficiency is most likely to cause angular cheilosis and glossitis?
A. Cobalamin.
B. Folate.
C. Niacin.
D. Riboflavin.
E. Thiamin.
Answer D. Riboflavin
- Cobalamin (B12) Irritability, hypotonia, developmental delay, developmental regression, and involuntary movements. Hyperpigmentation of knuckles and palms.
- Folate - megaloblastic anemia and hypersegmentation of neutrophils. Nonhematologic manifestations include glossitis, listlessness, and growth retardation.
- Niacin (B3) - Pellagra (the 4 D’s - diarrhoea, dermatitis, dementia and death).
- Riboflavin - (B2) - cheilosis, glossitis, keratitis, conjunctivitis, photophobia, lacrimation, corneal vascularization, and seborrheic dermatitis.
- Thiamin - (B1) - Peripheral neuritis, decreased DTR, loss of vibration sense, cramping legs.
According to the diagram shown above, the most common type of oesophageal atresia is:
A. a.
B. b.
C. c.
D. d.
E. e.
Answer A. a.
Oesophageal atresia with distal tracheoesophageal fistula accounts for 84%. Type C next most frequent (8%) with oesophageal atresia without tracheoesophageal fistula.
A five-year-old boy presents with multiple ulcerated skin lesions (as shown) with raised margins, which commenced as pustular lesions associated with fever a week prior to presentation. Pyoderma gangrenosum is confirmed by skin biopsy. Which of the following is most likely to be associated with this skin lesion?

A. Chronic granulomatous disease.
B. Human immunodeficiency virus (HIV) infection.
C. Inflammatory bowel disease.
D. Pseudomonas septicaemia.
E. Systemic lupus erythematosis.
Answer C. Inflammatory bowel disease.
1/2 of pts with pyoderma gangrenosum have underlying systemic disease, most commonly inflammatory bowel disease, haematological disorders and arthritis.
A six-year-old patient with coeliac disease undergoes dual sugar intestinal permeability testing. Two sugars, rhamnose and lactulose, are administered orally and the subsequent urinary excretion is measured over five hours. Rhamnose is actively absorbed by the small intestinal villus, whereas lactulose is absorbed via passive paracellular transport.
Which of the following findings in urine indicate poor adherence to a gluten-free diet?
Answer B. Rhamnose decreased, lactulose normal
Rhamnose absorption in decreased due to damage to small intestinal villi, lactulose continues to be absorbed by passive transport as this is not affected by damage caused by gluten.
