Certified Gastroenterology Registered Nurse (CGRN) — Questions and Answers

Question 1: Which endoscopic technique involves injecting a submucosal fluid cushion before resecting a large flat lesion en bloc?

Radiofrequency ablation
Argon plasma coagulation
Endoscopic submucosal dissection (ESD) (Correct answer)
Endoscopic mucosal resection (EMR)

Correct answer: Endoscopic submucosal dissection (ESD)

ESD uses submucosal injection to lift the lesion and specialized knives to dissect along the submucosal plane, enabling en bloc resection of large lesions.

Question 2: Ileostomy output exceeding 1,500–2,000 mL/day places patients at risk for which metabolic complication?

Hyponatremia, hypokalemia, and dehydration (Correct answer)
Metabolic alkalosis and hyperchloremia
Hypernatremia and hyperkalemia
Hypercalcemia and hyperphosphatemia

Correct answer: Hyponatremia, hypokalemia, and dehydration

High-output ileostomy causes loss of sodium-rich intestinal fluid, leading to hyponatremia, hypokalemia, and volume depletion with pre-renal azotemia.

Question 3: The hydrogen breath test is used clinically to diagnose which two conditions?

Gastroparesis and dumping syndrome
Lactose intolerance and small intestinal bacterial overgrowth (SIBO) (Correct answer)
GERD and achalasia
Celiac disease and Crohn's disease

Correct answer: Lactose intolerance and small intestinal bacterial overgrowth (SIBO)

Hydrogen breath testing after glucose or lactulose ingestion identifies SIBO (early H2 peak) or carbohydrate malabsorption (late H2 peak) like lactose intolerance.

Question 4: Self-expanding metal stents (SEMS) placed endoscopically in the colon are used as a bridge to surgery for which condition?

Diverticulitis with pericolic abscess
Malignant colonic obstruction (Correct answer)
Ischemic colitis
Sigmoid volvulus

Correct answer: Malignant colonic obstruction

Colonic SEMS decompress malignant large bowel obstruction, allowing bowel preparation and elective single-stage resection with anastomosis rather than emergency surgery with colostomy.

Question 5: What is the primary function of the ileocecal valve?

Regulate gastric emptying
Secrete digestive enzymes
Absorb vitamin B12
Prevent backflow of colonic contents into the ileum (Correct answer)

Correct answer: Prevent backflow of colonic contents into the ileum

The ileocecal valve prevents reflux of bacteria-laden colonic contents back into the small intestine.

Question 6: A Hartmann's procedure involves which surgical steps?

Sigmoid resection with end colostomy and closure of the rectal stump (Correct answer)
Anterior resection with primary anastomosis
Total colectomy with ileorectal anastomosis
Abdominoperineal resection with permanent colostomy

Correct answer: Sigmoid resection with end colostomy and closure of the rectal stump

Hartmann's procedure resects the diseased sigmoid/rectosigmoid, creates a proximal end colostomy, and closes the distal rectal stump as a blind pouch for later reversal.

Question 7: Which procedure is performed for refractory ascites in cirrhosis when patients fail repeated large-volume paracentesis?

Peritoneal dialysis catheter placement
Hepatic artery embolization
Splenectomy
Transjugular intrahepatic portosystemic shunt (TIPS) (Correct answer)

Correct answer: Transjugular intrahepatic portosystemic shunt (TIPS)

TIPS creates a low-resistance channel between the portal and hepatic veins, reducing portal pressure and decreasing ascites formation in refractory cases.

Question 8: Which test is the gold standard for diagnosing H. pylori infection in patients who have not taken PPIs or antibiotics recently?

Serology (IgG antibody)
Stool antigen test
Rapid urease test (CLO test)
Urea breath test (Correct answer)

Correct answer: Urea breath test

The urea breath test detects active H. pylori infection by measuring labeled CO2 after ingestion of urea, with high sensitivity and specificity.

Question 9: Which condition is characterized by iron-deficiency anemia, glossitis, koilonychia, and dysphagia due to an esophageal web in the postcricoid region?

Achalasia
Zenker's diverticulum
Plummer-Vinson (Paterson-Kelly) syndrome (Correct answer)
Diffuse esophageal spasm

Correct answer: Plummer-Vinson (Paterson-Kelly) syndrome

Plummer-Vinson syndrome features a cervical esophageal web, iron-deficiency anemia, and glossitis, predominantly in middle-aged women.

Question 10: Vitamin B12 absorption requires intrinsic factor and is completed in which GI segment?

Duodenum
Terminal ileum (Correct answer)
Proximal jejunum
Cecum

Correct answer: Terminal ileum

The B12–intrinsic factor complex binds to cubilin receptors exclusively in the terminal ileum for absorption by receptor-mediated endocytosis.

Question 11: Vancomycin administered orally is effective for Clostridioides difficile infection because:

It is absorbed systemically and reaches toxic bile acid concentrations
It remains in the intestinal lumen without systemic absorption (Correct answer)
It inhibits C. difficile spore formation in the liver
It stimulates intestinal mucosal immunity

Correct answer: It remains in the intestinal lumen without systemic absorption

Oral vancomycin is not absorbed from the GI tract, achieving high luminal concentrations that kill C. difficile directly in the colon.

Question 12: Iron absorption is primarily regulated at which level and is enhanced by which concurrent intake?

Renal reabsorption; calcium
Hepatic storage; vitamin B12
Intestinal enterocyte uptake; vitamin C (ascorbic acid) (Correct answer)
Bone marrow utilization; vitamin D

Correct answer: Intestinal enterocyte uptake; vitamin C (ascorbic acid)

Iron absorption is regulated by duodenal enterocytes and is enhanced by vitamin C, which keeps iron in the soluble ferrous (Fe2+) form for transport by DMT1.

Question 13: Which is the most common site for colorectal carcinoma in the United States?

Descending colon
Rectosigmoid region (Correct answer)
Transverse colon
Cecum

Correct answer: Rectosigmoid region

The rectosigmoid region accounts for approximately 55% of all colorectal cancers in the United States.

Question 14: Protein digestion begins in the stomach with pepsin and is completed in the small intestine; the final products absorbed by enterocytes are primarily:

Di- and tripeptides and free amino acids via specific transporters (Correct answer)
Large polypeptides via pinocytosis
Oligopeptides >10 residues via passive diffusion
Intact proteins via Fc receptor-mediated transcytosis

Correct answer: Di- and tripeptides and free amino acids via specific transporters

Brush-border peptidases hydrolyze oligopeptides to di/tripeptides and amino acids, which are then transported across enterocytes by PepT1 and amino acid transporters.

Question 15: Which is the most common primary malignancy of the liver in adults?

Angiosarcoma
Hepatoblastoma
Cholangiocarcinoma
Hepatocellular carcinoma (HCC) (Correct answer)

Correct answer: Hepatocellular carcinoma (HCC)

Hepatocellular carcinoma (HCC) accounts for approximately 75–85% of primary liver cancers and is strongly associated with cirrhosis and viral hepatitis.

Question 16: What is the most common cause of acute pancreatitis in the United States?

Medication-induced
Gallstones (Correct answer)
Chronic alcohol use
Hypertriglyceridemia

Correct answer: Gallstones

Gallstones are the leading cause of acute pancreatitis in the US, accounting for approximately 40–70% of cases.

Question 17: Which laboratory finding is most consistent with acute pancreatitis?

Elevated serum lipase > 3× upper limit of normal (Correct answer)
Decreased serum bilirubin
Elevated serum alkaline phosphatase
Elevated serum albumin

Correct answer: Elevated serum lipase > 3× upper limit of normal

Serum lipase elevated more than three times the upper limit of normal is the most sensitive and specific marker for acute pancreatitis.

Question 18: Which modality is the preferred first-line imaging for suspected acute appendicitis in adult patients in the US?

CT scan of the abdomen/pelvis with IV contrast (Correct answer)
Ultrasound
Plain abdominal X-ray
MRI

Correct answer: CT scan of the abdomen/pelvis with IV contrast

CT abdomen/pelvis with IV contrast has the highest sensitivity (>95%) and specificity for diagnosing acute appendicitis in adults.

Question 19: Wilson's disease results from the toxic accumulation of which trace metal due to an ATP7B gene mutation?

Manganese
Iron
Copper (Correct answer)
Zinc

Correct answer: Copper

ATP7B encodes a copper-transporting ATPase; its dysfunction prevents biliary copper excretion, leading to copper deposition in the liver, brain, and cornea (Kayser-Fleischer rings).

Question 20: Short bowel syndrome most commonly causes diarrhea and malabsorption when the remaining small bowel is less than how many centimeters?

50 cm
200 cm
100 cm (Correct answer)
300 cm

Correct answer: 100 cm

Short bowel syndrome typically occurs when less than 100–150 cm of functional small intestine remains after resection, insufficient for adequate nutrient absorption.

Question 21: Which drug class is used as first-line prophylaxis for spontaneous bacterial peritonitis (SBP) recurrence in cirrhotic patients with ascites?

Antifungals
Aminoglycosides
Macrolide antibiotics
Fluoroquinolone antibiotics (e.g., norfloxacin) or trimethoprim-sulfamethoxazole (Correct answer)

Correct answer: Fluoroquinolone antibiotics (e.g., norfloxacin) or trimethoprim-sulfamethoxazole

Long-term norfloxacin or trimethoprim-sulfamethoxazole is used for secondary SBP prophylaxis in cirrhotic patients after a prior episode.

Question 22: Gastroparesis is most commonly associated with which systemic disease in US clinical practice?

Hypothyroidism
Diabetes mellitus (Correct answer)
Systemic lupus erythematosus
Rheumatoid arthritis

Correct answer: Diabetes mellitus

Diabetic autonomic neuropathy is the most common identifiable cause of gastroparesis, causing delayed gastric emptying due to vagal nerve dysfunction.

Question 23: Laparoscopic cholecystectomy is the gold standard for symptomatic cholelithiasis; which intraoperative injury is the most feared complication?

Common bile duct injury (Correct answer)
Cystic artery hemorrhage
Hepatic artery laceration
Bowel perforation

Correct answer: Common bile duct injury

Common bile duct injury occurs in approximately 0.3–0.5% of laparoscopic cholecystectomies and can cause biliary stricture, cholangitis, and significant morbidity.

Question 24: The Alvarado score is a clinical scoring tool used to assess the probability of which GI condition?

Acute cholecystitis
Acute pancreatitis
Bowel obstruction
Acute appendicitis (Correct answer)

Correct answer: Acute appendicitis

The Alvarado score uses symptoms, signs, and lab values (total 10 points) to stratify risk for acute appendicitis.

Question 25: Which electrolyte imbalance is most commonly seen with prolonged nasogastric suction or severe vomiting?

Hyperchloremic metabolic acidosis
Hyperkalemic metabolic acidosis
Hypokalemic, hypochloremic metabolic alkalosis (Correct answer)
Hypernatremic metabolic alkalosis

Correct answer: Hypokalemic, hypochloremic metabolic alkalosis

Loss of hydrochloric acid from gastric secretions depletes chloride and induces metabolic alkalosis, while secondary aldosterone activation causes renal potassium wasting.

Question 26: Wireless pH monitoring (Bravo capsule) is attached to the esophageal mucosa during EGD and records pH for how many days?

12 hours
48–96 hours (Correct answer)
24 hours
7 days

Correct answer: 48–96 hours

The Bravo capsule adheres to the esophageal wall and records pH over 48–96 hours, providing more physiologic data than catheter-based 24-hour studies.

Question 27: Diverticulosis most commonly affects which segment of the colon in Western populations?

Sigmoid colon (Correct answer)
Cecum
Ascending colon
Transverse colon

Correct answer: Sigmoid colon

In Western populations, diverticulosis predominantly affects the sigmoid colon due to high intraluminal pressures in this narrow-caliber segment.

Question 28: Courvoisier's sign — painless jaundice with a palpable, non-tender gallbladder — is classically associated with which condition?

Choledocholithiasis
Acute cholecystitis
Carcinoma of the head of the pancreas (Correct answer)
Primary sclerosing cholangitis

Correct answer: Carcinoma of the head of the pancreas

Pancreatic head carcinoma obstructs the common bile duct gradually, allowing the gallbladder to distend painlessly; stones cause chronic fibrosis and a non-distensible gallbladder.

Question 29: What does the acronym 'ERCP' stand for in GI endoscopy?

Esophageal Reflux Control Protocol
Endoscopic Rectal Cancer Procedure
Endoscopic Retrograde Cholangiopancreatography (Correct answer)
Endoscopic Retrograde Colonoscopic Polypectomy

Correct answer: Endoscopic Retrograde Cholangiopancreatography

ERCP stands for Endoscopic Retrograde Cholangiopancreatography, a procedure combining endoscopy and fluoroscopy to evaluate the biliary and pancreatic ducts.

Question 30: Cholestyramine is a bile acid sequestrant used to treat which type of diarrhea?

Infectious diarrhea from C. difficile
Bile acid malabsorption diarrhea (Correct answer)
Secretory diarrhea from VIPoma
Osmotic diarrhea from lactose intolerance

Correct answer: Bile acid malabsorption diarrhea

Cholestyramine binds bile acids in the colon, preventing them from stimulating fluid secretion, and is effective for bile acid malabsorption (e.g., post-ileal resection).

Question 31: The migrating motor complex (MMC) phase III is characterized by which activity?

Complete motor quiescence
Random, low-amplitude contractions
Intense, regular contractions sweeping the gut (Correct answer)
Irregular contractions

Correct answer: Intense, regular contractions sweeping the gut

Phase III MMC produces intense, cyclical contractions that sweep from stomach to ileum, clearing residual contents during fasting.

Question 32: Which of the following best characterizes Crohn's disease compared to ulcerative colitis?

Can affect any segment of the GI tract with skip lesions (Correct answer)
Involves only the rectum and sigmoid colon
Never causes fistulas or strictures
Causes continuous mucosal inflammation from rectum proximally

Correct answer: Can affect any segment of the GI tract with skip lesions

Crohn's disease is a transmural inflammation that can involve any part of the GI tract from mouth to anus with characteristic skip lesions.

Question 33: Peutz-Jeghers syndrome is characterized by GI hamartomatous polyps and mucocutaneous pigmentation, and carries increased risk of malignancy in which gene mutation?

MLH1/MSH2 (mismatch repair genes)
APC gene
SMAD4 gene
STK11 (LKB1) gene (Correct answer)

Correct answer: STK11 (LKB1) gene

Peutz-Jeghers syndrome is caused by germline mutations in STK11 (LKB1), a tumor suppressor gene on chromosome 19p.

Question 34: Which electrolyte is primarily absorbed in the colon via aldosterone-regulated sodium channels (ENaC)?

Potassium
Sodium (Correct answer)
Magnesium
Calcium

Correct answer: Sodium

Aldosterone upregulates epithelial sodium channels (ENaC) and Na+/K+-ATPase in colonocytes, driving sodium reabsorption and potassium secretion.

Question 35: Transjugular intrahepatic portosystemic shunt (TIPS) procedure is contraindicated in patients with which condition?

Severe or overt hepatic encephalopathy (Correct answer)
Refractory ascites
Hepatorenal syndrome type 1
Recurrent variceal bleeding on beta-blockers

Correct answer: Severe or overt hepatic encephalopathy

Pre-existing severe hepatic encephalopathy is a contraindication to TIPS because shunting additional portal blood past the liver worsens ammonia clearance.

Question 36: Lactulose is used in the management of hepatic encephalopathy through which primary mechanism?

Directly chelating ammonia in the portal circulation
Acidifying the colon to trap ammonium and reduce bacterial ammonia production (Correct answer)
Reducing intestinal transit time to decrease ammonia absorption
Increasing renal excretion of ammonia

Correct answer: Acidifying the colon to trap ammonium and reduce bacterial ammonia production

Lactulose is metabolized by colonic bacteria to lactic and acetic acids, lowering pH and converting NH3 to NH4+, which is poorly absorbed and excreted in stool.

Question 37: Which imaging test is preferred for detecting liver metastases in colorectal cancer follow-up in the United States?

Transabdominal ultrasound alone
Nuclear bone scan
CT abdomen/pelvis with IV contrast or MRI with liver protocol (Correct answer)
Plain abdominal X-ray

Correct answer: CT abdomen/pelvis with IV contrast or MRI with liver protocol

Contrast-enhanced CT or MRI with liver protocol provides the highest sensitivity for detecting hepatic metastases during CRC surveillance.

Question 38: The MELD score used to prioritize liver transplant candidates incorporates which combination of laboratory values?

Bilirubin, INR, and creatinine (Correct answer)
AST, ALT, and platelet count
ALT, AST, and albumin
Bilirubin, albumin, and prothrombin time

Correct answer: Bilirubin, INR, and creatinine

The MELD score is calculated from serum bilirubin, INR, and creatinine (with sodium added in MELD-Na), reflecting hepatic synthetic function and renal status.

Question 39: Argon plasma coagulation (APC) is most commonly used endoscopically to treat which condition?

Gastric antral vascular ectasia (GAVE / 'watermelon stomach') (Correct answer)
Anastomotic leaks
Esophageal varices
Submucosal GI tumors

Correct answer: Gastric antral vascular ectasia (GAVE / 'watermelon stomach')

APC delivers non-contact thermal coagulation and is first-line treatment for GAVE (gastric antral vascular ectasia), ablating the vascular ectasias responsible for chronic GI blood loss.

Question 40: Which bowel preparation is most commonly used before colonoscopy in the United States?

Sodium phosphate enema only
Castor oil
Polyethylene glycol (PEG) electrolyte solution (Correct answer)
Saline laxative tablets alone

Correct answer: Polyethylene glycol (PEG) electrolyte solution

Polyethylene glycol-based solutions (e.g., GoLYTELY) are the most widely used colonoscopy prep due to safety and efficacy across patient populations.

Question 41: Which finding on colonoscopy requires removal and is considered a premalignant lesion?

Hyperplastic polyp <5 mm in the rectum
Normal mucosa with prominent vessels
Subepithelial lipoma
Tubular adenoma (Correct answer)

Correct answer: Tubular adenoma

Tubular adenomas are adenomatous polyps with dysplastic epithelium and malignant potential, requiring polypectomy.

Question 42: Terlipressin is used in hepatorenal syndrome and variceal bleeding; what is its mechanism of action?

Stimulates hepatic albumin synthesis
Blocks beta-1 adrenergic receptors in the heart
Vasoconstrictor that reduces splanchnic blood flow via V1 vasopressin receptors (Correct answer)
Blocks aldosterone receptors in the kidney

Correct answer: Vasoconstrictor that reduces splanchnic blood flow via V1 vasopressin receptors

Terlipressin is a vasopressin analogue that constricts splanchnic vasculature, reducing portal pressure and increasing renal perfusion in hepatorenal syndrome.

Question 43: Zenker's diverticulum is a pulsion diverticulum that forms at which location?

Sigmoid colon
Midesophagus
Duodenum
Pharyngoesophageal junction (Killian's triangle) (Correct answer)

Correct answer: Pharyngoesophageal junction (Killian's triangle)

Zenker's diverticulum protrudes posteriorly through Killian's triangle between the thyropharyngeus and cricopharyngeus muscles.

Question 44: The APACHE II score is used to assess severity and predict mortality in which GI condition?

Colorectal cancer staging
Acute liver failure
Acute pancreatitis (Correct answer)
Upper GI bleeding

Correct answer: Acute pancreatitis

APACHE II (along with Ranson criteria and BISAP) is used to stratify severity and predict outcomes in acute pancreatitis.

Question 45: A patient with celiac disease who ingests gluten will show damage primarily to which intestinal structure?

Peyer's patches
Intestinal villi (Correct answer)
Brunner's glands
Crypts of Lieberkühn

Correct answer: Intestinal villi

Celiac disease causes immune-mediated villous atrophy in the small intestine, reducing absorptive surface area and leading to malabsorption.

Question 46: Which of the following features distinguishes acute mesenteric ischemia from other causes of acute abdomen?

Normal WBC count
Pain out of proportion to physical exam findings (Correct answer)
Severe rebound tenderness at onset
Diarrhea preceding pain

Correct answer: Pain out of proportion to physical exam findings

A classic hallmark of acute mesenteric ischemia is severe abdominal pain that is disproportionately greater than the physical examination findings.

Question 47: Non-selective beta-blockers (e.g., propranolol, nadolol) are used in cirrhosis primarily to prevent which complication?

First and recurrent variceal hemorrhage (Correct answer)
Hepatic encephalopathy
Spontaneous bacterial peritonitis
Hepatorenal syndrome

Correct answer: First and recurrent variceal hemorrhage

Non-selective beta-blockers reduce portal pressure by decreasing cardiac output (β1) and causing splanchnic vasoconstriction (β2), preventing variceal bleeding.

Question 48: Endoscopic band ligation is the preferred endoscopic treatment for acute bleeding from which source?

Dieulafoy's lesion
Esophageal variceal bleeding (Correct answer)
Mallory-Weiss tear
Peptic ulcer bleeding

Correct answer: Esophageal variceal bleeding

Endoscopic variceal band ligation (EVL) is the first-line endoscopic treatment for acute esophageal variceal hemorrhage, and is also used for secondary prophylaxis.

Question 49: In irritable bowel syndrome (IBS), which diagnostic criteria are currently used?

Harvey-Bradshaw index
Truelove-Witts criteria
Manning criteria
Rome IV criteria (Correct answer)

Correct answer: Rome IV criteria

The Rome IV criteria define IBS as recurrent abdominal pain at least 1 day/week for 3 months, associated with defecation or stool changes.

Question 50: Which medication is used to treat hepatic encephalopathy by reducing gut bacteria that produce ammonia, without being significantly absorbed systemically?

Vancomycin
Metronidazole
Rifaximin (Correct answer)
Neomycin

Correct answer: Rifaximin

Rifaximin is a minimally absorbed antibiotic that reduces ammonia-producing gut bacteria and is preferred for preventing recurrent hepatic encephalopathy.

Question 51: Roux-en-Y gastric bypass (RYGB) achieves weight loss primarily through which mechanism?

Pure malabsorption by bypassing 80% of the small intestine
Increased gastric acid production accelerating emptying
Restriction and hormonal changes (reduced ghrelin, altered GLP-1/PYY) with mild malabsorption (Correct answer)
Vagal nerve transection causing anorexia

Correct answer: Restriction and hormonal changes (reduced ghrelin, altered GLP-1/PYY) with mild malabsorption

RYGB restricts stomach volume, reduces ghrelin (hunger hormone), and alters gut hormones (GLP-1, PYY) to improve satiety and insulin sensitivity, with modest malabsorption.

Question 52: Which type of viral hepatitis is transmitted via the fecal-oral route and does NOT cause chronic infection?

Hepatitis C
Hepatitis D
Hepatitis B
Hepatitis A (Correct answer)

Correct answer: Hepatitis A

Hepatitis A is transmitted by the fecal-oral route and causes only acute infection, with no chronic carrier state.

Question 53: Anorectal manometry is the first-line diagnostic test for which condition in adults?

Internal hemorrhoids
Rectal prolapse
Fecal incontinence and Hirschsprung disease evaluation (Correct answer)
Rectal cancer staging

Correct answer: Fecal incontinence and Hirschsprung disease evaluation

Anorectal manometry assesses sphincter pressures and the rectoanal inhibitory reflex, making it key for evaluating fecal incontinence and Hirschsprung disease.

Question 54: Endoscopic mucosal resection (EMR) is appropriate for polyp removal when the lesion is confined to which layer of the GI wall?

Mucosa and superficial submucosa (sm1) (Correct answer)
Adventitia
Muscularis propria and serosa
Deep submucosa (sm2/sm3) and beyond

Correct answer: Mucosa and superficial submucosa (sm1)

EMR safely resects lesions confined to the mucosa and superficial submucosa (sm1) where lymphovascular invasion risk is low; deeper invasion requires surgery.

Question 55: Over-the-scope clips (OTSC, 'bear claw clips') are used in endoscopy primarily for which indication?

Full-thickness closure of GI perforations and treatment of refractory hemorrhage (Correct answer)
Biliary stone extraction
Dilation of esophageal strictures
Marking lesion margins before surgery

Correct answer: Full-thickness closure of GI perforations and treatment of refractory hemorrhage

OTSC devices close full-thickness GI wall defects (perforations, fistulas) and achieve hemostasis for bleeding that fails standard through-the-scope clips.

Question 56: What is the approximate transit time of contents through the entire colon in a healthy adult?

6–12 hours
2–4 hours
24–72 hours (Correct answer)
5–7 days

Correct answer: 24–72 hours

Normal colonic transit takes approximately 24 to 72 hours, though this can vary widely with diet and activity.

Question 57: Which enzyme converts trypsinogen to active trypsin in the duodenum?

Enterokinase (enteropeptidase) (Correct answer)
Elastase
Carboxypeptidase A
Chymotrypsin

Correct answer: Enterokinase (enteropeptidase)

Enterokinase (enteropeptidase), a brush-border enzyme, cleaves the activation peptide from trypsinogen to generate trypsin.

Question 58: Endoscopic retrograde cholangiopancreatography (ERCP) is considered first-line therapy for which condition?

Pancreatic pseudocyst drainage
Common bile duct stones (choledocholithiasis) (Correct answer)
Suspected cholangiocarcinoma biopsy only
Screening for pancreatic cancer

Correct answer: Common bile duct stones (choledocholithiasis)

ERCP with sphincterotomy and stone extraction is the standard of care for choledocholithiasis causing biliary obstruction or cholangitis.

Question 59: After a Roux-en-Y gastric bypass, patients are at increased risk for deficiency of which nutrients requiring lifelong supplementation?

Iron, vitamin B12, calcium, vitamin D, and folate (Correct answer)
Omega-3 fatty acids and lutein
Vitamin C and zinc only
Vitamin A and phosphorus

Correct answer: Iron, vitamin B12, calcium, vitamin D, and folate

RYGB bypasses the duodenum and proximal jejunum (key sites for iron, calcium, B12, and folate absorption), requiring lifelong supplementation of these micronutrients.

Question 60: Which antibody is most characteristic of primary biliary cholangitis (PBC)?

Anti-mitochondrial antibody (AMA) (Correct answer)
Anti-nuclear antibody (ANA)
Anti-smooth muscle antibody (ASMA)
pANCA

Correct answer: Anti-mitochondrial antibody (AMA)

Anti-mitochondrial antibodies (AMA), particularly M2 subtype, are present in over 90% of PBC cases and are highly specific.

Question 61: Alosetron is a 5-HT3 antagonist approved for IBS with diarrhea (IBS-D) in women; which serious adverse effect restricts its use?

Ischemic colitis and severe constipation (Correct answer)
Severe hepatotoxicity
Agranulocytosis
QT prolongation and arrhythmias

Correct answer: Ischemic colitis and severe constipation

Alosetron carries a black box warning for ischemic colitis and severe constipation, restricting it to women with severe IBS-D who fail other therapies.

Question 62: Which type of fiber is most effective at lowering LDL cholesterol by binding bile acids in the intestinal lumen?

Soluble viscous fiber (psyllium, beta-glucan) (Correct answer)
Insoluble fiber (cellulose)
Lignin
Resistant starch

Correct answer: Soluble viscous fiber (psyllium, beta-glucan)

Soluble viscous fibers form gels that bind bile acids, reducing their enterohepatic reabsorption and forcing the liver to convert more cholesterol to new bile acids.

Question 63: Which imaging modality is the first-line study for suspected acute cholecystitis?

Right upper quadrant ultrasound (Correct answer)
MRI/MRCP
Hepatobiliary iminodiacetic acid (HIDA) scan
CT scan of the abdomen

Correct answer: Right upper quadrant ultrasound

Abdominal ultrasound is rapid, inexpensive, and radiation-free, with high sensitivity for gallstones and signs of cholecystitis (wall thickening, pericholecystic fluid, sonographic Murphy's sign).

Question 64: Metoclopramide is a prokinetic agent used in gastroparesis; which receptor does it primarily antagonize to enhance gastric emptying?

Serotonin 5-HT4 receptor
Muscarinic M3 receptor
Histamine H2 receptor
Dopamine D2 receptor (Correct answer)

Correct answer: Dopamine D2 receptor

Metoclopramide antagonizes dopamine D2 receptors in the GI tract and CNS, enhancing gastric antral contractions and accelerating gastric emptying.

Question 65: Which condition is associated with the triad of esophageal dysmotility, esophageal dilatation, and failure of the lower esophageal sphincter to relax?

Eosinophilic esophagitis
GERD
Achalasia (Correct answer)
Diffuse esophageal spasm

Correct answer: Achalasia

Achalasia is caused by degeneration of myenteric plexus neurons, leading to impaired LES relaxation and aperistalsis of the esophageal body.

Question 66: Which liver enzyme is considered most specific for hepatocellular damage?

AST (aspartate aminotransferase)
ALT (alanine aminotransferase) (Correct answer)
GGT (gamma-glutamyl transferase)
Alkaline phosphatase

Correct answer: ALT (alanine aminotransferase)

ALT is more liver-specific than AST because AST is also found in muscle, heart, and kidneys, whereas ALT is predominantly hepatic.

Question 67: Infliximab and adalimumab are anti-TNF agents used in IBD; which is administered as an intravenous infusion rather than subcutaneous injection?

Golimumab
Adalimumab
Certolizumab pegol
Infliximab (Correct answer)

Correct answer: Infliximab

Infliximab is a chimeric monoclonal antibody administered by IV infusion, whereas adalimumab and other anti-TNF agents are given subcutaneously.

Question 68: The gold standard test for diagnosing gastroparesis is:

Gastric emptying scintigraphy (nuclear medicine scan) (Correct answer)
Wireless motility capsule
Upper GI series (barium swallow)
CT abdomen with contrast

Correct answer: Gastric emptying scintigraphy (nuclear medicine scan)

Gastric emptying scintigraphy using a standardized radiolabeled solid meal (e.g., Tc-99m sulfur colloid egg meal) is the diagnostic gold standard for gastroparesis.

Question 69: Peyer's patches, lymphoid aggregates important for gut immunity, are found predominantly in which GI segment?

Duodenum
Jejunum
Ileum (Correct answer)
Cecum

Correct answer: Ileum

Peyer's patches are concentrated in the distal ileum where they sample luminal antigens via specialized M cells.

Question 70: Hepatorenal syndrome (HRS) is best defined as:

Acute kidney injury from NSAID use in a cirrhotic patient
Obstructive nephropathy secondary to biliary calculi
Functional renal failure occurring in advanced liver disease without another identifiable renal cause (Correct answer)
Contrast-induced nephropathy in a patient with cirrhosis

Correct answer: Functional renal failure occurring in advanced liver disease without another identifiable renal cause

HRS is a functional renal vasoconstriction in advanced cirrhosis or acute liver failure, occurring when no intrinsic renal disease, obstruction, or nephrotoxin explains the renal impairment.

Question 71: Which serum tumor marker is most commonly elevated in pancreatic adenocarcinoma and used for monitoring treatment response?

CA-125
CA 19-9 (Correct answer)
Alpha-fetoprotein (AFP)
Carcinoembryonic antigen (CEA)

Correct answer: CA 19-9

CA 19-9 is the primary serum marker used in pancreatic cancer; while not diagnostic alone, elevated levels support diagnosis and serial measurements track treatment response.

Question 72: Ondansetron belongs to which drug class and acts by blocking which receptor to control nausea and vomiting?

Antihistamine; H1 receptor
NK1 antagonist; substance P receptor
Dopamine antagonist; D2 receptor
5-HT3 antagonist; serotonin receptor (Correct answer)

Correct answer: 5-HT3 antagonist; serotonin receptor

Ondansetron is a selective 5-HT3 serotonin receptor antagonist that blocks vagal afferent signals triggering the vomiting center.

Question 73: Sucralfate is an aluminum-containing drug used to treat peptic ulcers; what is its primary mechanism?

Forms a protective polymer barrier over ulcer craters at low pH (Correct answer)
Blocks histamine H2 receptors
Inhibits the proton pump
Neutralizes gastric acid directly

Correct answer: Forms a protective polymer barrier over ulcer craters at low pH

Sucralfate polymerizes in acidic conditions and adheres to ulcer craters, forming a cytoprotective barrier that resists acid, pepsin, and bile.

Question 74: On MRCP or ERCP, primary sclerosing cholangitis (PSC) characteristically shows which finding in the bile ducts?

Smooth diffuse dilation of the common bile duct
Intrahepatic gallstones
A beaded, multifocal stricture pattern (Correct answer)
Single dominant stricture at the hilum

Correct answer: A beaded, multifocal stricture pattern

PSC produces multifocal strictures alternating with normal or dilated segments, creating the classic 'beaded' appearance on cholangiography.

Question 75: Which laboratory pattern is most characteristic of hereditary hemochromatosis?

Elevated alkaline phosphatase with low albumin
Elevated serum ferritin and transferrin saturation >45% (Correct answer)
Low serum copper with elevated ceruloplasmin
Positive anti-mitochondrial antibodies

Correct answer: Elevated serum ferritin and transferrin saturation >45%

Hemochromatosis causes progressive iron loading; elevated ferritin and transferrin saturation >45% are the hallmark screening findings, confirmed by HFE gene mutation testing.

Question 76: Portal hypertension leads to esophageal varices primarily through which mechanism?

Direct erosion of the esophageal mucosa by bile acids
Development of portosystemic collateral vessels to decompress elevated portal pressure (Correct answer)
Splenomegaly compressing the esophagus
Increased lymphatic pressure causing vessel dilation

Correct answer: Development of portosystemic collateral vessels to decompress elevated portal pressure

When portal pressure rises, blood is shunted through portosystemic collaterals, including submucosal esophageal veins, forming varices.

Question 77: Enteral nutrition is preferred over TPN whenever possible due to all of the following EXCEPT:

Preserves gut microbiome diversity
Maintains intestinal mucosal integrity
Reduces infectious complications
More convenient for outpatient administration (Correct answer)

Correct answer: More convenient for outpatient administration

TPN bags are typically administered at home or hospital via central lines on a scheduled infusion, whereas enteral feeding requires tube placement and pump management — neither is clearly more convenient.

Question 78: During upper endoscopy (EGD), the Z-line (squamocolumnar junction) is normally located at approximately how many centimeters from the incisors?

50–55 cm
40–50 cm
25–30 cm
35–40 cm (Correct answer)

Correct answer: 35–40 cm

The gastroesophageal junction and Z-line are typically found at 35–40 cm from the incisors in adults of average height.

Question 79: Hereditary hemochromatosis most commonly results from a mutation in which gene, leading to iron overload and hepatic cirrhosis?

ATP7B
SERPINA1
HFE (Correct answer)
CFTR

Correct answer: HFE

Most hereditary hemochromatosis in the US is caused by the C282Y homozygous mutation in the HFE gene on chromosome 6p.

Question 80: Which sphincter, located at the gastroesophageal junction, is primarily responsible for preventing gastroesophageal reflux?

Lower esophageal sphincter (Correct answer)
Upper esophageal sphincter
Pyloric sphincter
Ileocecal valve

Correct answer: Lower esophageal sphincter

The lower esophageal sphincter (LES) maintains a high-pressure zone that prevents reflux of gastric contents into the esophagus.

Question 81: Toxic megacolon is a life-threatening complication most commonly associated with which condition?

Diverticulosis
Severe ulcerative colitis or Clostridioides difficile colitis (Correct answer)
Celiac disease
Irritable bowel syndrome

Correct answer: Severe ulcerative colitis or Clostridioides difficile colitis

Toxic megacolon is defined as non-obstructive colonic dilation >6 cm with systemic toxicity, most often complicating severe UC or C. diff colitis.

Question 82: Dumping syndrome after gastric surgery is classified as early or late; late dumping (1–3 hours postprandially) is caused by:

Bile reflux into the esophagus
Bacterial overgrowth in the gastric remnant
Rapid fluid shifts into the intestinal lumen causing hypotension
Reactive hypoglycemia from excessive insulin release (Correct answer)

Correct answer: Reactive hypoglycemia from excessive insulin release

Late dumping is caused by rapid carbohydrate absorption triggering excessive insulin secretion, leading to reactive hypoglycemia 1–3 hours after eating.

Question 83: Colonic fermentation of undigested carbohydrates by bacteria produces which gases responsible for flatulence?

Carbon dioxide, hydrogen, and methane (Correct answer)
Oxygen and nitrogen
Carbon monoxide and argon
Ammonia and sulfur dioxide

Correct answer: Carbon dioxide, hydrogen, and methane

Colonic bacteria ferment dietary fiber and unabsorbed carbohydrates to produce CO2, H2, and CH4 as gaseous byproducts.

Question 84: A patient presents with watery diarrhea, hypokalemia, and achlorhydria (WDHA syndrome). Which tumor is most likely?

Insulinoma
Gastrinoma
Glucagonoma
VIPoma (Correct answer)

Correct answer: VIPoma

VIPoma (Verner-Morrison syndrome) secretes vasoactive intestinal peptide, causing profuse watery diarrhea, hypokalemia, and achlorhydria.

Question 85: Total parenteral nutrition (TPN) is indicated when patients cannot tolerate enteral nutrition; which of the following is a known complication of long-term TPN?

Hypokalemia resistant to supplementation
Hypoglycemia unresponsive to dextrose
Intestinal-failure-associated liver disease (IFALD) (Correct answer)
Hyperalbuminemia

Correct answer: Intestinal-failure-associated liver disease (IFALD)

Long-term TPN bypasses the gut and can cause intestinal atrophy and intestinal-failure–associated liver disease (formerly TPN-associated cholestasis/cirrhosis).

Question 86: What is the standard first-line pharmacologic treatment for autoimmune hepatitis?

Sofosbuvir/velpatasvir antiviral therapy
Cholestyramine
Ursodeoxycholic acid
Prednisone with or without azathioprine (Correct answer)

Correct answer: Prednisone with or without azathioprine

Corticosteroids (prednisone) alone or combined with the steroid-sparing agent azathioprine achieve remission in the majority of autoimmune hepatitis patients.

Question 87: Mesalamine (5-ASA) is the first-line therapy for mild to moderate disease in which condition?

Pouchitis after IPAA
Crohn's disease of the small bowel
Ulcerative colitis (Correct answer)
Microscopic colitis

Correct answer: Ulcerative colitis

Mesalamine is the cornerstone of induction and maintenance therapy for mild-to-moderate ulcerative colitis due to its topical anti-inflammatory effect on the colonic mucosa.

Question 88: The Forrest classification is used to guide endoscopic management of which condition?

Staging of colorectal cancer at colonoscopy
Severity of esophageal varices
Grading of Barrett's esophagus dysplasia
Risk stratification of peptic ulcer bleeding lesions (Correct answer)

Correct answer: Risk stratification of peptic ulcer bleeding lesions

The Forrest classification grades peptic ulcer stigmata (Ia–IIc) from active arterial spurting to clean base, predicting rebleeding risk and guiding endoscopic therapy.

Question 89: Endoscopic ultrasound (EUS) is the most accurate modality for staging which malignancy?

Esophageal and gastric cancer (T and N staging) (Correct answer)
Colon cancer
Small bowel adenocarcinoma
Hepatocellular carcinoma

Correct answer: Esophageal and gastric cancer (T and N staging)

EUS provides high-resolution imaging of the esophageal and gastric wall layers for T staging and adjacent lymph nodes for N staging.

Question 90: Proton pump inhibitors (PPIs) work by irreversibly inhibiting which enzyme in gastric parietal cells?

H+/K+-ATPase (proton pump) (Correct answer)
Gastrin receptor
Carbonic anhydrase
Histamine H2 receptor

Correct answer: H+/K+-ATPase (proton pump)

PPIs covalently and irreversibly bind the H+/K+-ATPase enzyme, blocking the final step of acid secretion in parietal cells.

Question 91: The myenteric (Auerbach's) plexus lies between which two muscle layers of the GI tract?

Submucosa and circular muscle
Mucosa and submucosa
Circular muscle and longitudinal muscle (Correct answer)
Longitudinal muscle and serosa

Correct answer: Circular muscle and longitudinal muscle

Auerbach's plexus is located between the inner circular and outer longitudinal layers of the muscularis externa, controlling peristalsis.

Question 92: Which agent is the first approved for fecal microbiota transplantation (FMT) by the FDA for recurrent C. difficile infection?

Vancomycin
Bezlotoxumab
Fidaxomicin
Rebyota (fecal microbiota, live-jslm) (Correct answer)

Correct answer: Rebyota (fecal microbiota, live-jslm)

Rebyota (RBX2660) received FDA approval in 2022 as the first approved microbiota-based live biotherapeutic for recurrent C. difficile infection.

Question 93: In the stomach, which cell type secretes pepsinogen, the precursor to the proteolytic enzyme pepsin?

Parietal cells
Mucous cells
G cells
Chief cells (Correct answer)

Correct answer: Chief cells

Chief (zymogenic) cells in the gastric fundus and body secrete pepsinogen, which is activated to pepsin by acidic pH.

Question 94: Which cells in the gastric mucosa produce intrinsic factor?

Chief cells
Mucous neck cells
Parietal cells (Correct answer)
G cells

Correct answer: Parietal cells

Parietal cells secrete both hydrochloric acid and intrinsic factor, which is essential for vitamin B12 absorption.

Question 95: Chylomicrons transport dietary lipids from the enterocyte to systemic circulation via which route?

Portal vein directly to the liver
Intestinal lacteals → mesenteric lymphatics → thoracic duct → systemic circulation (Correct answer)
Bile acid recycling via enterohepatic circulation
Direct absorption into capillaries and portal vein

Correct answer: Intestinal lacteals → mesenteric lymphatics → thoracic duct → systemic circulation

Chylomicrons enter lacteals (intestinal lymphatics), travel through mesenteric lymphatics and the thoracic duct, and enter the bloodstream at the left subclavian vein.

Question 96: What is currently the most common cause of chronic liver disease in the United States?

Hepatitis B
Hepatitis C
Non-alcoholic fatty liver disease (NAFLD) (Correct answer)
Alcoholic liver disease

Correct answer: Non-alcoholic fatty liver disease (NAFLD)

NAFLD, strongly linked to obesity, insulin resistance, and metabolic syndrome, has surpassed other etiologies to become the most prevalent chronic liver disease in the US.

Question 97: Fecal calprotectin is most useful for distinguishing which two conditions?

Celiac disease vs. lactose intolerance
Inflammatory bowel disease vs. irritable bowel syndrome (Correct answer)
Colorectal cancer vs. diverticulitis
Hepatitis vs. cirrhosis

Correct answer: Inflammatory bowel disease vs. irritable bowel syndrome

Fecal calprotectin is a sensitive noninvasive marker of intestinal inflammation, helping differentiate organic IBD from functional IBS.

Question 98: What is the recommended first-line treatment for acute esophageal variceal bleeding?

TIPS procedure as primary intervention
Balloon tamponade with a Sengstaken-Blakemore tube alone
Endoscopic band ligation combined with IV octreotide (Correct answer)
Emergency surgical portosystemic shunt

Correct answer: Endoscopic band ligation combined with IV octreotide

Endoscopic band ligation with concurrent IV octreotide (to reduce splanchnic blood flow) is the standard first-line treatment for acute variceal hemorrhage.

Question 99: Which hormone, released by S cells in the duodenum, stimulates pancreatic bicarbonate secretion?

Gastrin
Cholecystokinin
Motilin
Secretin (Correct answer)

Correct answer: Secretin

Secretin is released in response to acid entering the duodenum and stimulates pancreatic duct cells to secrete bicarbonate-rich fluid.

Question 100: Which procedure allows real-time visualization and biopsy of the bile ducts using a miniaturized endoscope passed through a duodenoscope?

Endoscopic ultrasound (EUS)
Transabdominal cholangiography
Intraoperative cholangiogram
Per-oral cholangioscopy (SpyGlass) (Correct answer)

Correct answer: Per-oral cholangioscopy (SpyGlass)

Per-oral cholangioscopy (e.g., SpyGlass system) enables direct visualization and targeted biopsy of biliary strictures through the working channel of a duodenoscope.

Question 101: The Whipple procedure (pancreaticoduodenectomy) removes which structures?

Pancreatic tail, spleen, and left colon
Head of pancreas, duodenum, gallbladder, and distal common bile duct (Correct answer)
Entire pancreas, stomach, and duodenum
Distal pancreas and stomach only

Correct answer: Head of pancreas, duodenum, gallbladder, and distal common bile duct

The classic Whipple resects the pancreatic head, entire duodenum, gallbladder, distal common bile duct, and often the distal stomach.

Question 102: Which scoring system is used at 48 hours to predict severity and mortality in acute pancreatitis?

APACHE II score only
Glasgow-Blatchford score
BISAP score only
Ranson's criteria (Correct answer)

Correct answer: Ranson's criteria

Ranson's criteria evaluate 11 parameters (5 at admission, 6 at 48 hours); a score ≥3 indicates severe disease with significantly increased morbidity and mortality.

Question 103: Barrett's esophagus is defined as replacement of normal squamous epithelium in the distal esophagus with which type of epithelium?

Intestinal metaplastic (columnar) epithelium (Correct answer)
Stratified squamous epithelium
Transitional epithelium
Ciliated pseudostratified epithelium

Correct answer: Intestinal metaplastic (columnar) epithelium

Barrett's esophagus is the presence of intestinal metaplasia (goblet cells) in the distal esophageal mucosa, a precursor to adenocarcinoma.

Question 104: Helicobacter pylori infection is most strongly associated with ulcers in which location?

Jejunum
Duodenal bulb (first part of duodenum) (Correct answer)
Gastric fundus
Esophagus

Correct answer: Duodenal bulb (first part of duodenum)

H. pylori colonizes the gastric antrum and is the leading cause of duodenal ulcers, especially in the duodenal bulb.

Question 105: A patient undergoes total proctocolectomy with ileal pouch-anal anastomosis (IPAA) for ulcerative colitis; what is the most common late complication of the pouch?

Pouchitis (Correct answer)
Pouch-vaginal fistula
Anastomotic stenosis
Pouch adenocarcinoma

Correct answer: Pouchitis

Pouchitis, a non-specific inflammation of the ileal reservoir, occurs in up to 50% of patients with IPAA and is the most common long-term complication.

Question 106: In hepatic encephalopathy, which neurotoxic substance primarily accumulates due to failed hepatic clearance?

Urea
Ammonia (Correct answer)
Creatinine
Bilirubin

Correct answer: Ammonia

Ammonia, normally converted to urea by the liver, accumulates in hepatic failure and crosses the blood-brain barrier, causing encephalopathy.

Question 107: Which hepatitis virus is transmitted via the fecal-oral route and never causes chronic infection?

Hepatitis D
Hepatitis C
Hepatitis B
Hepatitis A (Correct answer)

Correct answer: Hepatitis A

Hepatitis A is transmitted fecal-orally, causes self-limited acute illness, and does not establish chronic infection or a carrier state.

Question 108: Brunner's glands, which secrete alkaline mucus to protect the duodenal mucosa, are located in which layer?

Submucosa (Correct answer)
Mucosa
Muscularis externa
Serosa

Correct answer: Submucosa

Brunner's glands are submucosal glands unique to the duodenum that secrete bicarbonate-rich mucus.

Question 109: Which vitamin deficiency classically results from fat malabsorption and causes night blindness and xerophthalmia?

Vitamin A (retinol) (Correct answer)
Vitamin C (ascorbic acid)
Vitamin B12 (cobalamin)
Vitamin B1 (thiamine)

Correct answer: Vitamin A (retinol)

Vitamin A deficiency, common in fat malabsorption states, impairs rhodopsin regeneration in rod cells, causing night blindness and keratinization of the cornea (xerophthalmia).

Question 110: Secretory diarrhea is characterized by which feature that distinguishes it from osmotic diarrhea?

Diarrhea persists during fasting (Correct answer)
Stool osmotic gap >125 mOsm/kg
Relief with a gluten-free diet
Stool volume <200 mL/day

Correct answer: Diarrhea persists during fasting

In secretory diarrhea, active ion secretion continues regardless of oral intake, so diarrhea persists even when the patient fasts.

Question 111: Which scoring system is used to grade the severity of esophageal varices and predict bleeding risk?

Rockall score
MELD score
AIMS65 score
Child-Pugh score (Correct answer)

Correct answer: Child-Pugh score

The Child-Pugh score (incorporating bilirubin, albumin, PT, ascites, encephalopathy) predicts hepatic reserve and risk of variceal bleeding in cirrhosis.

Question 112: Chronic alcoholic pancreatitis is most characteristically identified on imaging by which finding?

Pancreatic ductal calcifications and parenchymal fibrosis (Correct answer)
Groove between the duodenum and pancreatic head
Cystic lesions throughout the pancreas
Autoimmune enlargement of the pancreatic head

Correct answer: Pancreatic ductal calcifications and parenchymal fibrosis

Chronic alcoholic pancreatitis classically produces intraductal calcium deposits (calcifications) and progressive fibrotic replacement of the exocrine parenchyma, visible on plain films and CT.

Question 113: The hepatopancreatic ampulla (ampulla of Vater) is the site where which two ducts join before entering the duodenum?

Cystic duct and common bile duct
Hepatic duct and cystic duct
Common bile duct and main pancreatic duct (Correct answer)
Hepatic duct and pancreatic duct

Correct answer: Common bile duct and main pancreatic duct

The common bile duct and the main pancreatic duct (of Wirsung) unite at the ampulla of Vater before emptying into the duodenum.

Question 114: Primary sclerosing cholangitis (PSC) is most strongly associated with which inflammatory bowel disease?

Ulcerative colitis (Correct answer)
Microscopic colitis
Crohn's disease
Ischemic colitis

Correct answer: Ulcerative colitis

PSC occurs in approximately 5% of patients with ulcerative colitis and is characterized by fibro-inflammatory strictures of bile ducts.

Question 115: The Boston Bowel Preparation Scale (BBPS) scores each of the three colon segments from 0 to 3; what is the minimum acceptable total score for an adequate colonoscopy?

5
3
9
6 (Correct answer)

Correct answer: 6

A BBPS total score of ≥6 (with no individual segment score <2) is generally considered adequate preparation for colonoscopy.

Question 116: Capsule endoscopy is considered the first-line test for suspected bleeding in which GI region?

Esophagus
Small bowel (mid-GI) (Correct answer)
Stomach
Rectum

Correct answer: Small bowel (mid-GI)

Video capsule endoscopy is the first-line investigation for obscure GI bleeding or suspected small bowel pathology beyond the reach of standard endoscopes.

Question 117: Azathioprine and 6-mercaptopurine are thiopurine immunosuppressants used in IBD; deficiency of which enzyme leads to toxic drug accumulation?

Dihydropyrimidine dehydrogenase (DPYD)
Thiopurine methyltransferase (TPMT) (Correct answer)
Cytochrome P450 2C19 (CYP2C19)
Uridine diphosphate glucuronosyltransferase (UGT)

Correct answer: Thiopurine methyltransferase (TPMT)

TPMT deficiency impairs thiopurine methylation, causing accumulation of cytotoxic thioguanine nucleotides and severe bone marrow suppression.

Question 118: Which segment of the colon has the highest rate of water and electrolyte absorption?

Transverse colon
Sigmoid colon
Ascending (right) colon (Correct answer)
Descending colon

Correct answer: Ascending (right) colon

The ascending colon absorbs the majority of water and electrolytes from liquid ileal effluent, producing semi-solid stool.

Question 119: The most dreaded early complication of esophagectomy is anastomotic leak; what is the preferred initial management of a cervical anastomotic leak?

Observation with NPO status alone
Broad-spectrum antibiotics and opening of the neck wound for drainage (Correct answer)
Immediate return to the operating room for surgical repair
Endoscopic stent placement only

Correct answer: Broad-spectrum antibiotics and opening of the neck wound for drainage

Cervical anastomotic leaks are managed by opening the neck incision to allow drainage, along with antibiotics and enteral feeding via jejunostomy.

Question 120: Which layer of the GI tract contains blood vessels, lymphatics, and the submucosal (Meissner's) plexus?

Muscularis externa
Submucosa (Correct answer)
Mucosa
Serosa

Correct answer: Submucosa

The submucosa houses Meissner's plexus along with blood vessels, lymphatics, and connective tissue.

Question 121: Which antibiotic regimen is currently recommended for first-line H. pylori eradication in the United States (clarithromycin-resistant regions)?

Ciprofloxacin + metronidazole for 10 days
Bismuth quadruple therapy (PPI + bismuth + tetracycline + metronidazole) for 10–14 days (Correct answer)
Metronidazole monotherapy for 14 days
Amoxicillin + clarithromycin for 7 days

Correct answer: Bismuth quadruple therapy (PPI + bismuth + tetracycline + metronidazole) for 10–14 days

Due to rising clarithromycin resistance, bismuth quadruple therapy for 10–14 days is recommended as first-line H. pylori treatment in most US regions.

Question 122: Charcot's triad — fever, right upper quadrant pain, and jaundice — is the classic presentation of which condition?

Acute pancreatitis
Ascending cholangitis (Correct answer)
Acute cholecystitis
Hepatic abscess

Correct answer: Ascending cholangitis

Ascending cholangitis results from biliary obstruction with bacterial superinfection, producing Charcot's triad; the addition of hypotension and confusion forms Reynolds' pentad in severe cases.

Question 123: Percutaneous endoscopic gastrostomy (PEG) is contraindicated in which clinical situation?

Dysphagia due to neurologic disease
Short-term nutritional support after abdominal surgery
Recurrent aspiration pneumonia with a patent GI tract
Uncorrectable coagulopathy or severe ascites (Correct answer)

Correct answer: Uncorrectable coagulopathy or severe ascites

PEG placement is contraindicated with uncorrectable coagulopathy, severe thrombocytopenia, or tense ascites due to risks of hemorrhage and peritoneal leak.

Question 124: Lubiprostone and linaclotide are used to treat constipation-predominant IBS (IBS-C); what is their shared mechanism?

Block opioid receptors in the gut
Inhibit bile acid reabsorption
Inhibit colonic motility
Stimulate intestinal chloride secretion, increasing luminal fluid (Correct answer)

Correct answer: Stimulate intestinal chloride secretion, increasing luminal fluid

Both lubiprostone (ClC-2 activator) and linaclotide (GC-C agonist) increase intestinal chloride and fluid secretion, softening stool and accelerating transit.

Question 125: The crypt of Lieberkühn contains which cell type that acts as the intestinal stem cell niche regulator?

Enterocytes
Paneth cells (Correct answer)
Goblet cells
Enteroendocrine cells

Correct answer: Paneth cells

Paneth cells reside at the base of intestinal crypts, secreting defensins and supporting the local stem cell microenvironment.

Question 126: The hepatic portal vein receives blood from all of the following EXCEPT:

Superior mesenteric vein
Hepatic veins (Correct answer)
Splenic vein
Inferior mesenteric vein

Correct answer: Hepatic veins

Hepatic veins drain blood OUT of the liver into the inferior vena cava; they do not contribute to the portal vein.

Question 127: Bile is stored and concentrated in the gallbladder, which can increase bile concentration by how much compared to hepatic bile?

2–5 fold
50–100 fold
10–20 fold (Correct answer)
5–10 fold

Correct answer: 10–20 fold

The gallbladder absorbs water and electrolytes, concentrating bile 10- to 20-fold relative to freshly secreted hepatic bile.

Question 128: Fat-soluble vitamins (A, D, E, K) are primarily absorbed via which mechanism in the small intestine?

Pinocytosis via intestinal macrophages
Active transport via SGLT1
Facilitated diffusion via GLUT5
Incorporation into micelles and passive diffusion into enterocytes (Correct answer)

Correct answer: Incorporation into micelles and passive diffusion into enterocytes

Fat-soluble vitamins are solubilized in bile acid micelles, then passively diffuse across the enterocyte brush border and are packaged into chylomicrons.

Question 129: Which GI hormone inhibits gastric acid secretion and is released by D cells in the gastric antrum?

Cholecystokinin
Ghrelin
Somatostatin (Correct answer)
Gastrin

Correct answer: Somatostatin

Somatostatin from D cells inhibits gastrin and histamine release, thereby suppressing gastric acid secretion.

Certified Gastroenterology Registered Nurse (CGRN)

The CGRN exam, administered by the American Board of Certification for Gastroenterology Nurses (ABCGN), validates the knowledge and clinical skills of registered nurses specializing in gastroenterology and endoscopy nursing practice across four core domains.

Questions

35 min

Time Limit

70%

To Pass

Checking for saved progress...

Exam Rules

You can skip questions and return to them later
Flag questions for review before submitting
No feedback shown until you submit the entire exam
Unanswered questions count as wrong — answer everything
10 pretest questions are mixed in and don't affect your score
Timer auto-submits when time runs out
Your progress is auto-saved every 30 seconds