Review Of Related Disease (RRD) 5 Practice Exam

Greasy frothy stools signal fat malabsorption, or steatorrhea. The classic infectious cause among these options is giardiasis, due to Giardia lamblia, a protozoan parasite. Giardia attaches to the lining of the small intestine and disrupts fat digestion and absorption, so fats pass into the stool, producing bulky, pale, greasy, foul-smelling stools that may float and be frothy. This condition is typically acquired by ingesting cysts in contaminated water or food. Other choices tend to produce different stool patterns: bacillary dysentery (Shigella) causes bloody, inflammatory stools; pseudomembranous colitis (Clostridioides difficile) presents with watery diarrhea and pseudomembranes after antibiotic use; viral gastroenteritis usually causes vomiting and watery stools without fat malabsorption.