Q&A Medicine>>>>>Gastroenterology
Question 42#

A 24-year-old woman presents with a history of diarrhea. She reports returning 2 months ago from a church-affiliated hiking trip. Since returning, she has developed diarrhea, abdominal pain, and increased flatulence. Of note, she just finished taking one of her friend’s ciprofloxacin for 7 days without any improvement.

Which of the following antibiotics should be prescribed to this patient?

A. Ampicillin
B. Metronidazole
C. Cefazolin
D. Extend the course of ciprofloxacin

Correct Answer is B

Comment:

Metronidazole. The patient in this question is presenting with classic giardiasis caused by Giardia lamblia. The Internal Medicine shelf examination might ask a similar question that offer clues to the diagnosis of giardiasis (history of recent travel, exposure to river water, or day care centers). This organism is common in unsanitary conditions and most often transmitted via water (although it can also be transmitted via food). In this condition, the organism (trophozoites) sticks to the mucosa of the gut and causes malabsorption. This causes diarrhea (patients typically note foul-smelling watery stools), flatulence, abdominal pain, and sometimes weight loss. Diagnosis can be confirmed with stool studies looking for ova and parasites. Treatment is with oral metronidazole. (A, C, D) These antibiotics are not used in the treatment of giardiasis. Although ciprofloxacin is usually the best antibiotic in infectious diarrhea, it is not helpful in giardiasis.