Board Review

A 25-year-old woman is evaluated for a 3-day history of diarrhea with four or five loose to watery stools per day. She has had mild to moderate abdominal cramps, intermittent nausea, and muscle aches but no fever, blood in the stool, or vomiting. She has had no recent travel outside her home town and has not recently been exposed to antibiotics. She is otherwise healthy and takes no medications.

On physical examination, temperature is 37.6 °C (99.7 °F), blood pressure is 110/70 mm Hg, and pulse rate is 85/min. She appears mildly ill. The abdomen is soft, nontender, and nondistended.

Which of the following is the most appropriate management?

A) Colonoscopy

B) Stool cultures

C) Stool testing for ova and parasites

D) Supportive care

Answer: D - Supportive care

Objective: Manage acute diarrhea.

Key Point

Because most cases of community-acquired diarrhea are self-limited, stool cultures or evaluation for ova and parasites are not required in most patients; studies may be indicated for symptoms lasting longer than 72 hours, particularly in patients with associated fever, tenesmus, or bloody stools.

The most appropriate management is supportive care. Most cases of acute diarrhea in developed countries are self-limited and due to a viral infection. In this otherwise healthy young woman with no alarm features (gastrointestinal bleeding, dehydration, fever, significant abdominal tenderness, recent antibiotic use), further testing is not indicated. Supportive measures, such as ensuring adequate oral fluid intake and using acetaminophen for muscle aches, are the only necessary intervention for most patients. Antimotility agents such as loperamide may be useful for patients with mild diarrhea, but they should not be used in patients with fever, significant abdominal pain, or bloody stools because they may worsen inflammatory diarrhea and increase the risk of complications such as toxic megacolon. Diarrhea in an otherwise healthy person lasting for more than 7 days suggests a parasitic or noninfectious origin and evaluation is appropriate.

Given this patient's age, absence of bleeding, and acute onset of symptoms, a colonoscopy is not indicated. A colonoscopy would be warranted if features of inflammatory bowel disease, such as blood in the stool, were present.

The diagnostic yield of bacterial stool culture for acute diarrhea is low (less than 3%); however, identification of a pathogen has important treatment and public health implications and may be useful in identifying and tracking a foodborne outbreak. Because most cases of community-acquired diarrhea are self-limited, stool cultures are not required in most patients; cultures may be indicated for symptoms lasting longer than 72 hours, particularly in patients with associated fever, tenesmus, or bloody stools.

Parasitic infection should be considered as a potential cause of diarrhea lasting for more than 7 days. Giardia lamblia and Cryptosporidium parvum are the most commonly identified parasitic agents definitively known to cause diarrhea in the United States. Amebiasis is relatively uncommon in the United States but can cause hemorrhagic colitis in travelers and may occur several years after return from an endemic area. Because this patient does not have a travel history and her symptoms are of short duration, stool testing for ova and parasites is not necessary at this time.

Sweetser S. Evaluating the patient with diarrhea: a case-based approach. Mayo Clin Proc. 2012 Jun;87(6):596-602. Link Out