A 3-year-old girl is brought to the emergency department with abrupt-onset vomiting followed by frequent, large-volume, watery diarrhea for the last day. She has no prior medical conditions but has not received recommended vaccinations. Temperature is 37.8 C (100 F). Physical examination shows mild dehydration. The abdomen is soft and mildly tender to palpation throughout. Bowel sounds are increased. Polymerase chain reaction testing of the stool sample yields a virus with a segmented, double-stranded RNA genome. Which of the following pathologic findings is most likely to be present in this patient?

Question

A 3-year-old girl is brought to the emergency department with abrupt-onset vomiting followed by frequent, large-volume, watery diarrhea for the last day.  She has no prior medical conditions but has not received recommended vaccinations.  Temperature is 37.8 C (100 F).  Physical examination shows mild dehydration.  The abdomen is soft and mildly tender to palpation throughout.  Bowel sounds are increased.  Polymerase chain reaction testing of the stool sample yields a virus with a segmented, double-stranded RNA genome.  Which of the following pathologic findings is most likely to be present in this patient?

Quizplus · Accepted Answer

Rotavirus is a segmented, nonenveloped, double-stranded RNA virus that is primarily transmitted via the fecal-oral route. It is a major cause of infectious diarrhea in children worldwide and typically presents in those age <5 with acute, self-limited fever and watery diarrhea that may lead to dehydration and electrolyte abnormalities. Rotavirus vaccination is protective and has resulted in a dramatic reduction in disease incidence. Rotavirus invades the villous epithelium of the duodenum and proximal jejunum. Infection causes diarrhea via multiple mechanisms including villous blunting (loss of absorptive capacity), proliferation of secretory crypt cells (secretory diarrhea), and reduced brush border enzymes (accumulation of unmetabolized disaccharides in the small intestine lumen). Rotavirus-induced diarrhea is noninflammatory; therefore, fecal leukocytes and erythrocytes are not typically seen. Repeat infections are often less severe than initial infection due to the generation of protective secretory IgA against rotaviral antigens. (Choice B) Clostridioides difficile infection causes exotoxin-mediated damage to the large intestine mucosa, leading to the development of yellow-white pseudomembranes. Cases are most common after recent antibiotic therapy and usually present with watery diarrhea, fever, and abdominal pain. C difficile is a spore-forming, gram-positive bacterium. (Choice C) Entamoeba histolytica is an anaerobic parasite that commonly causes dysentery and extraintestinal disease (eg, liver abscess) in the developing world. Gastrointestinal infection usually results in bloody stools and fever; colonic visualization classically reveals flask-shaped ulcers (ie, with overhanging edges) in the cecum and ascending colon. (Choice D) Whipple disease is caused by the gram-positive bacillus Tropheryma whipplei. Histopathology of the small intestine classically shows foamy macrophages in the lamina propria. Manifestations usually include arthralgias and chronic diarrhea with malabsorption and weight loss. (Choice E) Typhoid strains of Salmonella pass through enterocytes and invade macrophages in the intestinal submucosa and Peyer patches. Inflammation and necrosis of Peyer patches can lead to life-threatening gastrointestinal bleeding and perforation. Educational objective: Rotavirus is a common cause of self-limited childhood diarrhea in unvaccinated individuals. It infects villous enterocytes in the duodenum and proximal jejunum and results in villous blunting, proliferation of secretory crypt cells, and a loss of brush border enzymes; this results in watery diarrhea without fecal leukocytes.

A 3-Year-Old Girl Is Brought to the Emergency Department with Abrupt-Onset