American Board of Internal Medicine (ABIM) Certification Practice Exam

Which condition is likely in patients with chronic diarrhea and recent exposure to young children or contaminated water?

1. Clostridium difficile infection

2. Giardiasis

3. Rotavirus infection

4. Ulcerative colitis

The correct answer is: Giardiasis

The condition that is most likely in patients with chronic diarrhea who have had recent exposure to young children or contaminated water is giardiasis. Giardiasis is caused by the protozoan parasite Giardia lamblia, which is commonly found in contaminated drinking water and can be transmitted through fecal-oral contact, especially in settings where young children may be present. Transmission can occur when individuals consume water from lakes, streams, or even improperly treated municipal water supplies. Additionally, young children can carry the parasite and may not practice optimal hygiene, leading to easier transmission of the organism to adults. The symptoms of giardiasis often include chronic diarrhea, abdominal cramps, bloating, and weight loss, all of which align with the presentation described in the question. Other conditions listed have differing associations. For instance, Clostridium difficile infection is typically linked to antibiotic use and healthcare settings rather than direct transmission from children or water. Rotavirus, while it does cause gastrointestinal symptoms, is more prevalent in infants and young children, and its transmission is not primarily linked to contaminated water. Ulcerative colitis is a chronic inflammatory bowel disease that is not directly associated with recent exposure to water or young children but rather has complex genetic and environmental factors involved. Thus, gi