front 1 A patient with bowel obstruction is being evaluated for definitive management. Which situation most strongly supports surgical intervention? A. Functional ileus without ischemia | back 1 C. Mechanical obstruction or infarction |
front 2 Which combination of findings is most characteristic of intestinal obstruction? A. Tenesmus, jaundice, melena | back 2 B. Vomiting, constipation, distention |
front 3 Which group of conditions accounts for the large majority of mechanical intestinal obstructions? A. Hernias, adhesions, intussusception, volvulus | back 3 A. Hernias, adhesions, intussusception, volvulus |
front 4 Imaging confirms a mechanical bowel obstruction. Which statement best explains why the small intestine is most commonly involved? A. It has thinner serosa | back 4 B. It has narrower lumen |
front 5 A 54-year-old man develops a reducible groin bulge after heavy lifting. Which structure defines the protruding sac in a typical hernia? A. Mucosal diverticular outpouching | back 5 B. Serosa-lined peritoneal pouch |
front 6 Acquired abdominal hernias most commonly occur at which sites? A. Inguinal, femoral, umbilical, scars | back 6 A. Inguinal, femoral, umbilical, scars |
front 7 Hernias are the most frequent cause of intestinal obstruction in which setting? A. In children only | back 7 C. Worldwide |
front 8 Obstruction from a hernia most often results from: A. Mucosal ulceration | back 8 B. Visceral protrusion |
front 9 Which entrapped structure is most commonly involved in a hernia causing bowel obstruction? A. Appendix | back 9 C. Small bowel loop |
front 10 A painful inguinal hernia becomes nonreducible and tender. Pressure at the neck first impairs venous drainage, causing edema and stasis, followed by permanent trapping and then vascular compromise. Which sequence is most accurate? A. Infarction → strangulation → incarceration | back 10 C. Incarceration → strangulation → infarction |
front 11 A 46-year-old woman with prior pelvic surgery presents with crampy abdominal pain and vomiting. Fibrous bands are suspected to be tethering bowel loops to the abdominal wall. Which process most likely led to this obstruction? A. Adhesion formation | back 11 A. Adhesion formation |
front 12 Which clinical history most strongly predisposes to intra-abdominal adhesions? A. Peptic ulcer disease | back 12 B. Surgical procedure |
front 13 Fibrous bridges formed by adhesions may create closed loops through which bowel can slide and become trapped. This complication is best termed: A. Strangulation | back 13 C. Internal herniation |
front 14 A 70-year-old patient presents with acute abdominal distention, obstipation, severe pain, and signs of bowel ischemia. Imaging suggests twisting of bowel around its mesenteric attachment. Which diagnosis is most likely? A. Intussusception | back 14 B. Volvulus |
front 15 The pathophysiology of volvulus most directly causes: A. Secretory and osmotic loss | back 15 C. Luminal and vascular compromise |
front 16 Volvulus most commonly occurs in which location? A. Sigmoid colon | back 16 A. Sigmoid colon |
front 17 A 2-year-old child develops episodic abdominal pain and vomiting. Imaging suggests that one bowel segment has invaginated into the immediately distal segment after a wave of peristalsis. Which diagnosis is most likely? A. Volvulus | back 17 B. Intussusception |
front 18 Intussusception is best defined as: A. Twisting around mesentery | back 18 C. Telescoping into distal bowel |
front 19 Once the bowel segment becomes trapped in intussusception, ongoing peristalsis typically causes it to: A. Retract spontaneously | back 19 B. Pull mesentery along |
front 20 If untreated, intussusception may progress to: A. Fistula and pseudomembranes | back 20 C. Obstruction, vessel compression, infarction |
front 21 In idiopathic intussusception in infants and young children, which intervention can be both diagnostic and therapeutic? A. Colonoscopy | back 21 B. Contrast enema |
front 22 The majority of the gastrointestinal tract is primarily supplied by which set of arteries? A. Celiac, SMA, IMA | back 22 A. Celiac, SMA, IMA |
front 23 A pathology specimen shows necrosis limited to the mucosa and not extending beyond the muscularis mucosae. This is best classified as: A. Mural infarction | back 23 C. Mucosal infarction |
front 24 Infarction involving the mucosa and submucosa is best termed: A. Mural infarction | back 24 A. Mural infarction |
front 25 Necrosis involving all layers of the intestinal wall, from the mucosa to the serosa. A. Mucosal infarction | back 25 C. Transmural infarction |
front 26 The most important risk factor for mesenteric arterial thrombosis is: A. Chronic pancreatitis | back 26 B. Severe atherosclerosis |
front 27 Obstructive emboli causing acute intestinal ischemia most commonly arise from: A. Hepatic veins and splenic cysts | back 27 C. Aortic atheromas or mural thrombi |
front 28 A 76-year-old woman develops abrupt cramping left lower abdominal pain, urgency to defecate, and bloody diarrhea. Which diagnosis is most likely? A. Acute colonic ischemia | back 28 A. Acute colonic ischemia |
front 29 Which portion of the GI tract is the most common site of ischemia? A. Stomach | back 29 B. Colon |
front 30 Which pair of sites are classic GI watershed zones? A. Cecum and ascending colon | back 30 C. Splenic flexure and rectosigmoid |
front 31 A bowel specimen shows a sharply demarcated segment of intensely congested, dusky purple-red intestine involving all wall layers. Which mechanism is most likely? A. Chronic venous congestion | back 31 B. Acute arterial obstruction |
front 32 In acute colonic ischemia, which finding most strongly suggests need for surgery? A. Guarding on examination | back 32 A. Guarding on examination |
front 33 Right-sided ischemic colitis is more severe primarily because it involves bowel supplied by the: A. Inferior mesenteric artery | back 33 C. Superior mesenteric artery |
front 34 Which statement about colonic ischemia is most accurate? A. Usually diffuse and continuous | back 34 C. Lesions are patchy, segmental |
front 35 A premature neonate develops abdominal distention and feeding intolerance, and imaging plus surgery reveal full-thickness bowel wall necrosis involving both small and large intestine. Which diagnosis is most likely? A. Angiodysplasia | back 35 B. Necrotizing enterocolitis |
front 36 The most severe bowel injury in necrotizing enterocolitis is: A. Mucosal edema | back 36 C. Transmural necrosis |
front 37 An older adult presents with intermittent lower GI bleeding. Colonoscopy shows malformed mucosal and submucosal vessels in the cecum. Which diagnosis best fits? A. Volvulus | back 37 B. Angiodysplasia |
front 38 A patient develops chronic bulky, frothy, greasy, yellow stool after an allogeneic hematopoietic stem cell transplant. Which condition could directly explain the malabsorption? A. Graft-versus-host disease | back 38 A. Graft-versus-host disease |
front 39 A patient has painful, bloody, small-volume diarrhea with tenesmus. Which term best describes this syndrome? A. Exudative diarrhea | back 39 C. Dysentery |
front 40 A hospitalized patient has watery diarrhea with isotonic stool losses that continue even when oral intake is stopped. Which diarrhea type is most likely? A. Malabsorptive | back 40 B. Secretory |
front 41 A young adult with lactase deficiency develops diarrhea after dairy intake, and symptoms improve completely during fasting. Which diarrhea mechanism is most likely? A. Secretory | back 41 D. Osmotic |
front 42 _____ diarrhea follows generalized failure of nutrient absorption, is associated with steaorrhea and is relieved by fasting A. Secretory | back 42 C. Malabsorptive |
front 43 _____ diarrhea is due to inflammatory disease characterized by purulent, bloody stools than continue during fasting A. Secretory | back 43 B. Exudative |
front 44 A 24-year-old woman develops chronic diarrhea, bloating, and weight loss after eating wheat-containing foods. Small-bowel biopsy suggests immune-mediated enteropathy. Which diagnosis is most likely? A. Environmental enteropathy | back 44 B. Celiac disease |
front 45 In celiac disease, gliadin peptides presented by HLA-DQ2/DQ8 primarily activate which immune cell? A. CD8+ T cells | back 45 C. CD4+ T cells |
front 46 Celiac disease most commonly involves which regions of the GI tract? A. Duodenum and jejunum | back 46 A. Duodenum and jejunum |
front 47 The malabsorption in celiac disease is most directly caused by: A. Pancreatic enzyme deficiency | back 47 D. Loss of brush border |
front 48 The most sensitive serologic test for celiac disease is measurement of IgA antibodies against: A. Endomysium | back 48 B. Tissue transglutaminase |
front 49 The most common malignancy associated with celiac disease is: A. Colonic adenocarcinoma | back 49 C. Enteropathy-associated T-cell lymphoma |
front 50 Environmental enteropathy is most strongly associated with: A. Gluten ingestion | back 50 B. Poor sanitation |
front 51 A young boy has severe persistent diarrhea and multiple autoimmune disorders. Family history suggests an inherited syndrome. Which pattern best fits autoimmune enteropathy? A. Autosomal dominant | back 51 D. X-linked |
front 52 The severe familial form of autoimmune enteropathy caused by FOXP3 mutation is called: A. IPEX | back 52 A. IPEX |
front 53 FOXP3 mutations in IPEX most directly impair the function of: A. B lymphocytes | back 53 C. Regulatory T cells |
front 54 Abetalipoproteinemia is best described as an inherited inability to: A. Absorb gluten peptides | back 54 D. Secrete triglyceride-rich lipoproteins |
front 55 A peripheral smear in a patient with abetalipoproteinemia would most likely show: A. Schistocytes | back 55 B. Acanthocytes |
front 56 A 29-year-old patient has chronic abdominal pain and diarrhea. Endoscopy shows inflamed bowel separated by normal intervening mucosa. Which diagnosis is most likely? A. Ulcerative colitis | back 56 C. Crohn disease |
front 57 Which feature best distinguishes Crohn disease from ulcerative colitis? A. Transmural inflammation | back 57 A. Transmural inflammation |
front 58 A patient with inflammatory bowel disease develops enteroenteric fistulas and bowel wall fibrosis. Which diagnosis best fits? A. Ulcerative colitis | back 58 D. Crohn disease |
front 59 Which distribution is most typical of ulcerative colitis? A. Any GI segment | back 59 B. Colon and rectum |
front 60 Histology from an inflamed bowel segment shows noncaseating granulomas and transmural inflammation. Which disorder is most likely? A. Crohn disease | back 60 A. Crohn disease |
front 61 A patient with longstanding inflammatory bowel disease develops severe colonic dilation and systemic toxicity. Which disease is classically associated with this complication? A. Crohn disease | back 61 D. Ulcerative colitis |
front 62 Which gross feature is classically associated with Crohn disease? A. Continuous rectosigmoid disease | back 62 C. Creeping fat |
front 63 Ulcerative colitis is typically confined to which bowel layers? A. Muscularis and serosa | back 63 B. Mucosa and superficial submucosa |
front 64 A patient with Crohn disease develops recurrent obstructive symptoms from fibrosing bowel narrowing. Which treatment is often required? A. Surgical resection | back 64 A. Surgical resection |
front 65 A patient with severe ulcerative colitis undergoes total colectomy. What is the expected effect on the intestinal disease? A. Disease shifts to ileum | back 65 D. Intestinal disease is cured |
front 66 A 61-year-old woman has months of chronic nonbloody watery diarrhea. Colon imaging is normal, but biopsy shows inflammatory colitis. Which diagnosis is most likely? A. Ulcerative colitis | back 66 B. Microscopic colitis |
front 67 Which feature best characterizes microscopic colitis? A. Bloody diarrhea with masses | back 67 D. Normal radiology despite diarrhea |
front 68 A colon biopsy shows a dense subepithelial collagen band, increased intraepithelial lymphocytes, and mixed lamina propria inflammation. Which diagnosis is most likely? A. Lymphocytic colitis | back 68 C. Collagenous colitis |
front 69 Which histologic feature helps distinguish lymphocytic colitis from collagenous colitis? A. Transmural fissures | back 69 B. Normal collagen thickness |
front 70 Lymphocytic colitis has a strong association with: A. Celiac and autoimmune disease | back 70 A. Celiac and autoimmune disease |
front 71 A patient develops diarrhea after allogeneic hematopoietic stem cell transplantation. The stool is initially watery and later becomes bloody. Which diagnosis is most likely? A. Microscopic colitis | back 71 D. Intestinal graft-versus-host disease |
front 72 The most common histologic finding in intestinal graft-versus-host disease is: A. Dense subepithelial fibrosis | back 72 C. Crypt epithelial apoptosis |
front 73 A 68-year-old patient undergoing screening colonoscopy is found to have multiple saclike mucosal outpouchings in the colon that are acquired rather than congenital. These lesions are best classified as: A. True diverticula | back 73 C. Pseudodiverticula |
front 74 The pathogenesis of diverticular disease is most closely related to: A. Elevated intraluminal pressure | back 74 A. Elevated intraluminal pressure |
front 75 Which dietary pattern most promotes progression of diverticular disease? A. High-protein diet | back 75 D. Low-fiber diet |
front 76 Which statement about diverticular disease is most accurate? A. Usually presents with obstruction | back 76 B. Most patients are asymptomatic |
front 77 A small left-sided colonic polyp is found on routine colonoscopy. Histology shows a benign epithelial proliferation without dysplasia. Which lesion is most likely? A. Hyperplastic polyp | back 77 A. Hyperplastic polyp |
front 78 Which feature best distinguishes a hyperplastic polyp from an adenomatous lesion? A. More common in rectum | back 78 C. No malignant potential |
front 79 Hyperplastic polyps are most commonly found in the: A. Cecum | back 79 D. Left colon |
front 80 A patient presents with rectal bleeding and mucus discharge. Endoscopy shows an inflammatory lesion on the anterior rectal wall. Which diagnosis best fits? A. Hyperplastic polyp | back 80 B. Solitary rectal ulcer syndrome pattern |
front 81 Which symptom pair is most characteristic of the inflammatory polyp/solitary rectal ulcer syndrome pattern? A. Hematemesis and melena | back 81 B. Rectal bleeding and mucus |
front 82 A 4-year-old child presents with intermittent painless rectal bleeding. Colonoscopy reveals a solitary rectal polyp composed of disorganized but mature tissue elements. Which diagnosis is most likely? A. Hyperplastic polyp | back 82 C. Juvenile polyp |
front 83 Juvenile polyps are best classified as: A. Hamartomatous polyps | back 83 A. Hamartomatous polyps |
front 84 Which presentation is most typical of a juvenile polyp? A. Watery secretory diarrhea | back 84 D. Rectal bleeding |
front 85 Juvenile polyps most often arise in the: A. Jejunum | back 85 B. Rectum |
front 86 A child has multiple hamartomatous colorectal polyps and a family history of similar lesions. Which syndrome should raise concern for future colonic adenocarcinoma? A. Lynch syndrome | back 86 C. Juvenile polyposis syndrome |
front 87 Juvenile polyposis syndrome is often associated with mutation in: A. SMAD4 | back 87 A. SMAD4 |
front 88 The major long-term malignancy risk in juvenile polyposis syndrome is: A. Gastric lymphoma | back 88 D. Colonic adenocarcinoma |
front 89 A teenager with dark pigmented macules on the lips is found to have multiple hamartomatous polyps throughout the GI tract. Which syndrome is most likely? A. Juvenile polyposis syndrome | back 89 B. Peutz-Jeghers syndrome |
front 90 In Peutz-Jeghers syndrome, hamartomatous polyps most often involve the: A. Small intestine | back 90 A. Small intestine |
front 91 Which gene is characteristically mutated in Peutz-Jeghers syndrome? A. SMAD4 | back 91 C. STK11 |
front 92 A screening colonoscopy identifies a neoplastic colonic polyp with epithelial atypia. Which histologic feature is the defining hallmark of an adenoma? A. Mucin depletion | back 92 B. Dysplasia |
front 93 Which statement about colonic adenomas is most accurate? A. They are usually inflammatory | back 93 D. They are most common neoplastic polyps |
front 94 Most colorectal adenocarcinomas arise from which precursor lesion? A. Adenoma | back 94 A. Adenoma |
front 95 A 1-cm pedunculated polyp is removed from the sigmoid colon. Histology shows crowded tubular glands without villous architecture. Which diagnosis is most likely? A. Villous adenoma | back 95 C. Tubular adenoma |
front 96 Which gross pattern is most typical of a villous adenoma? A. Small and pedunculated | back 96 D. Large and sessile |
front 97 A broad-based colonic adenoma causes chronic mucous stool losses with hypokalemia. Which lesion best fits? A. Tubular adenoma | back 97 B. Villous adenoma |
front 98 Which microscopic feature best characterizes a villous adenoma? A. Covered by villi | back 98 A. Covered by villi |
front 99 A polyp demonstrates both tubular glands and villous projections on histology. Which diagnosis is most appropriate? A. Tubular adenoma | back 99 C. Tubulovillous adenoma |
front 100 A right-sided colonic polyp is found to have premalignant potential despite lacking classic cytologic dysplasia. Which lesion is most likely? A. Juvenile polyp | back 100 B. Sessile serrated adenoma |
front 101 Which feature most strongly supports sessile serrated adenoma rather than tubular adenoma? A. Pedunculated architecture | back 101 C. Right-sided location |
front 102 A colonic polyp shows dysplastic glands that have penetrated through the basement membrane but remain confined to the lamina propria. Which diagnosis is most appropriate? A. Invasive adenocarcinoma | back 102 C. Intramucosal carcinoma |
front 103 Intramucosal carcinoma is defined by extension of dysplastic epithelium into the: A. Lamina propria or muscularis mucosae | back 103 A. Lamina propria or muscularis mucosae |
front 104 Why does intramucosal carcinoma have little to no metastatic potential? A. It remains cytologically bland | back 104 D. It is confined to mucosa |
front 105 What is the usual treatment for intramucosal carcinoma arising in a polyp? A. Chemoradiation | back 105 B. Polypectomy alone |
front 106 Familial adenomatous polyposis is best described as which syndrome? A. APC-associated adenomatous polyposis | back 106 A. APC-associated adenomatous polyposis |
front 107 Which finding is required for diagnosis of classic familial adenomatous polyposis? A. At least 10 polyps | back 107 D. At least 100 polyps |
front 108 Colorectal adenocarcinoma develops in ____% of untreated FAP patients | back 108 100 |
front 109 The standard preventive treatment for classic familial adenomatous polyposis is: A. Annual polypectomy | back 109 C. Prophylactic colectomy |
front 110 After colectomy for FAP, which medication class can reduce polyps in the residual rectum? A. NSAIDs | back 110 A. NSAIDs |
front 111 MYH-associated polyposis is caused by: A. Monoallelic APC deletion | back 111 D. Biallelic MYH mutation |
front 112 Compared with classic FAP, MYH-associated polyposis typically shows: A. Greater rectal involvement | back 112 B. Fewer polyps |
front 113 Lynch syndrome is most strongly associated with which underlying defect? A. APC inactivation | back 113 D. Mismatch repair defect |
front 114 Which statement about Lynch syndrome-associated colon cancer is most accurate? A. Usually arises in rectum | back 114 D. Tends to be right-sided |
front 115 Lynch syndrome is associated with colorectal cancer and: A. No extracolonic cancers | back 115 C. Several extracolonic cancers |
front 116 Which statement about colorectal adenocarcinoma is correct? A. Rare GI malignancy | back 116 D. Most common GI malignancy |
front 117 Colorectal adenocarcinoma develops through which two major molecular pathways? A. STK11 and FOXP3 | back 117 B. APC and microsatellite instability |
front 118 A right-sided colon cancer is most likely to present with: A. Iron deficiency anemia | back 118 A. Iron deficiency anemia |
front 119 A patient with colon cancer has occult blood loss, crampy abdominal pain, and altered bowel habits. Which tumor location is most likely? A. Transverse colon | back 119 C. Left colon |
front 120 Which factors are most important in determining prognosis in colorectal adenocarcinoma? A. Tumor size and grade | back 120 D. Invasion depth and nodal spread |
front 121 The most common site of metastasis from colorectal adenocarcinoma is the: A. Liver | back 121 A. Liver |
front 122 A 48-year-old patient presents with painful rectal bleeding that worsens with defecation. Which underlying mechanism most directly explains hemorrhoid formation? A. Mucosal autoimmune injury | back 122 B. Elevated venous pressure |
front 123 Which presentation is most characteristic of hemorrhoids? A. Pain and rectal bleeding | back 123 A. Pain and rectal bleeding |
front 124 Hemorrhoids are classified anatomically as: A. Mucosal or transmural | back 124 D. Internal or external |
front 125 Acute appendicitis is most often initiated by: A. Villous mucin secretion | back 125 C. Luminal obstruction |
front 126 The key early pathogenic event in acute appendicitis is: A. Reduced lymphatic drainage only | back 126 B. Increased intraluminal pressure |
front 127 In acute appendicitis, rising intraluminal pressure most directly compromises: A. Venous outflow | back 127 A. Venous outflow |
front 128 Which histologic finding establishes the diagnosis of acute appendicitis? A. Submucosal fibrosis | back 128 C. Muscularis propria neutrophils |
front 129 Appendiceal neuroendocrine tumor. Which statement is most accurate? A. Usually highly aggressive | back 129 D. Usually benign |
front 130 The most common tumor of the appendix is: A. Mucinous cystadenoma | back 130 C. Neuroendocrine tumor |
front 131 Appendiceal neuroendocrine tumors are usually: A. Infiltrative and high grade | back 131 B. Well differentiated |
front 132 A surgeon removes a dilated appendix distended by accumulated mucin. Which diagnosis best fits this gross description? A. Appendiceal mucocele | back 132 A. Appendiceal mucocele |
front 133 An appendiceal mucocele may reflect either simple obstruction or: A. Ischemic infarction | back 133 C. Mucinous neoplasm |
front 134 A patient with progressive abdominal distention undergoes surgery, and the peritoneal cavity is found to be filled with tenacious, semisolid mucin. Which diagnosis is most likely? A. Sterile peritonitis | back 134 C. Pseudomyxoma peritonei |
front 135 A patient develops chemical inflammation of the peritoneum after leakage of bile during abdominal injury. Which diagnosis best fits? A. Pseudomyxoma peritonei | back 135 B. Sterile peritonitis |
front 136 Also known as idiopathic retroperitoneal fibrosis or Ormond disease, is characterized by dense fibrosis that may extend to involve the mesentery: A. Peritoneal mesothelioma | back 136 D. Sclerosing retroperitonitis |
front 137 A patient has fibroinflammatory retroperitoneal disease suspected to be part of a systemic immune-mediated process. Which association is most likely? A. STK11-related syndrome | back 137 C. IgG4-related disease |
front 138 Which lesion is a primary malignant tumor of the peritoneal lining? A. Peritoneal mesothelioma | back 138 A. Peritoneal mesothelioma |
front 139 A patient develops profuse watery diarrhea after exposure to contaminated water. The responsible organism produces diarrhea primarily by which mechanism? A. Mucosal invasion with ulceration | back 139 C. cAMP-mediated chloride secretion |
front 140 Cholera toxin most directly causes intestinal fluid loss by activating: A. CFTR-dependent chloride secretion | back 140 A. CFTR-dependent chloride secretion |
front 141 A traveler presents with massive painless watery diarrhea and severe dehydration. The stool is described as gray-white flecks in liquid. Which description is classic? A. Currant-jelly stool | back 141 B. Rice-water stool |
front 142 Which organism is a common bacterial enteric pathogen and is strongly associated with both reactive arthritis and Guillain-Barré syndrome? A. Vibrio cholerae | back 142 C. Campylobacter jejuni |
front 143 Which postinfectious extraintestinal complication is classically associated with Campylobacter jejuni? A. Toxic megacolon | back 143 C. Reactive arthritis |
front 144 A febrile patient has painful bloody diarrhea after ingesting contaminated food. These are gram-negative unencapsulated, nonmotile, facultative anaerobes that belong to the Enterobacteriaceae family and are closely related to enteroinvasive E. coli: A. Cholera | back 144 D. Shigellosis |
front 145 Shigellosis most characteristically involves which intestinal regions? A. Duodenum and jejunum | back 145 C. Ileum and left colon |
front 146 Which management approach is most appropriate for shigellosis? A. Antidiarrheals to limit fluid loss | back 146 D. Antibiotics; avoid antidiarrheals |
front 147 A 23-year-old patient develops fever and abdominal symptoms after eating undercooked poultry and eggs. Which source most strongly supports salmonellosis? A. Contaminated meat, poultry, eggs, milk | back 147 A. Contaminated meat, poultry, eggs, milk |
front 148 A patient with enteric fever has ileal lymphoid hyperplasia on pathology. Enlargement of which structure is classically associated with typhoid fever? A. Crypt abscesses | back 148 B. Peyer patches |
front 149 A febrile traveler is suspected of having typhoid fever. Which skin finding, if present, would support the diagnosis? A. Erythema nodosum | back 149 C. Rose spots |
front 150 During the febrile phase of typhoid fever, which diagnostic study is most likely to be positive? A. Blood cultures | back 150 A. Blood cultures |
front 151 A patient develops enterocolitis after consuming pork and raw milk during the winter. Which organism is most strongly suggested by this epidemiologic pattern? A. Shigella sonnei | back 151 B. Yersinia enterocolitica |
front 152 Which exposure pattern is most classically associated with Yersinia infection? A. Shellfish and seawater | back 152 D. Pork, raw milk, water |
front 153 Yersinia most directly initiates intestinal invasion by targeting which specialized epithelial cell? A. M cell | back 153 A. M cell |
front 154 Yersinia adhesins promote host cell attachment by binding to: A. E-cadherin | back 154 C. β1-integrins |
front 155 Which statement about E. coli is most accurate? A. Gram-positive cocci | back 155 D. Gram-negative bacilli |
front 156 The heat-labile toxin of ETEC causes diarrhea by increasing intracellular: A. cAMP | back 156 A. cAMP |
front 157 ETEC heat-stable toxins resemble guanylin and stimulate which pathway? A. Adenylate cyclase, increased cAMP | back 157 C. Guanylate cyclase, increased cGMP |
front 158 The pathogenesis of Clostridioides difficile colitis most often begins with: A. Viral invasion of enterocytes | back 158 B. Antibiotic disruption of microbiota |
front 159 Which gross or endoscopic finding is classically associated with Clostridioides difficile colitis? A. Creeping fat | back 159 B. Pseudomembranes |
front 160 Which combination is a classic risk profile for Clostridioides difficile colitis? A. Antibiotics, hospitalization, advanced age | back 160 A. Antibiotics, hospitalization, advanced age |
front 161 Which diagnostic approach is preferred for suspected Clostridioides difficile colitis? A. Routine stool culture | back 161 C. Toxin detection |
front 162 A patient with confirmed Clostridioides difficile colitis requires treatment. Which regimen is appropriate based on the material provided? A. IV ceftriaxone | back 162 B. Oral metronidazole or vancomycin |
front 163 Has become the most common cause of diarrhea worldwide A. Rotavirus | back 163 C. Norovirus |
front 164 Norovirus most commonly spreads through: A. Tick bites only | back 164 B. Food, water, person-to-person |
front 165 This encapsulated virus with a segmented, double-stranded RNA genome is highly prevalent and a significant cause of diarrheal deaths worldwide. A. Rotavirus | back 165 A. Rotavirus |
front 166 Pediatric diarrhea, can affect immunocompromised patients: A. Astrovirus | back 166 D. Adenovirus |
front 167 A 6-year-old child develops bloating, foul-smelling stools, and lactose intolerance after a camping trip. Which organism most likely caused decreased brush-border enzymes, including lactase? A. Giardia lamblia | back 167 A. Giardia lamblia |
front 168 The diarrhea caused by Giardia lamblia is best classified as: A. Exudative diarrhea | back 168 C. Malabsorptive diarrhea |
front 169 Which diagnostic test is most appropriate for suspected giardiasis based on the material provided? A. Blood culture | back 169 B. Stool cyst immunofluorescence |
front 170 A patient with AIDS develops profuse nonbloody watery diarrhea. The organism causes sodium malabsorption, chloride secretion, and increased intestinal permeability. Which pathogen is most likely? A. Giardia lamblia | back 170 C. Cryptosporidium |
front 171 Which stool finding is most useful for diagnosing cryptosporidiosis? A. Stool ova | back 171 B. Stool oocysts |
front 172 A patient has watery diarrhea from a parasite that causes both sodium malabsorption and chloride secretion. Which infection is most likely? A. Pinworm infection | back 172 B. Cryptosporidiosis |
front 173 A child develops cough, transient pulmonary symptoms, and later intestinal parasitic infection. Which helminth classically migrates through the lungs before maturing in the intestine? A. Enterobius vermicularis | back 173 C. Ascaris lumbricoides |
front 174 Which parasite is most associated with an eosinophil-rich inflammatory reaction during tissue migration? A. Ascaris lumbricoides | back 174 A. Ascaris lumbricoides |
front 175 A patient remains chronically infected because larvae hatch within the intestine and repeatedly reinvade the host. Which organism has this autoinfective cycle? A. Ascaris lumbricoides | back 175 D. Strongyloides |
front 176 Which pair of parasites both include a lung migration phase in their life cycle? A. Giardia and pinworm | back 176 B. Ascaris and Strongyloides |
front 177 A patient from a resource-limited setting has fatigue and chronic microcytic anemia. Endoscopy shows worms attached in the duodenum causing superficial erosions. Which infection is most likely? A. Strongyloidiasis | back 177 C. Hookworm infection |
front 178 Hookworm causes chronic iron deficiency anemia primarily because the worms: A. Induce hemolysis directly | back 178 B. Suck blood in duodenum |
front 179 A child has intense nighttime perianal itching. Which parasite most likely causes this by depositing eggs on the perirectal mucosa? A. Giardia lamblia | back 179 C. Enterobius vermicularis |
front 180 Which transmission route is most characteristic of pinworm infection? A. Hand-to-mouth spread | back 180 A. Hand-to-mouth spread |