Chronic Diarrhea

Abstract

Diarrhea is common in clinical practice, and the ability to evaluate a patient who presents with diarrhea requires an understanding of the definition, pathophysiology, differential diagnoses, testing algorithms, and management strategies. Diarrhea can be defined in various ways, but generally is considered to represent an increase in frequency and/or fluidity of stool. Since stool weight is proportionally related to fiber intake, stool weight in excess of 200 g daily should be used with caution as the sole defining criteria of “diarrhea.” Chronic diarrhea has been defined as diarrhea lasting in excess of 4 weeks, whereas acute diarrhea typically lasts less than 2 weeks and is often self-limited.

Teaching Questions

• 1. A 28-year-old woman presents to the clinic for an evaluation of diarrhea that has been present for more than 2 years. She reports 4–5 bowel movements daily without blood. She describes cramping abdominal pain that is relieved after a bowel movement. She complains of mild bloating but no nausea or vomiting. Her weight has been stable and she denies nocturnal diarrhea. Past medical history is notable for depression and chronic headaches. She has been on sertraline for 5 years and takes acetaminophen as needed. There is no family history of gastrointestinal diseases or neoplasia. She has not responded to simple dietary interventions such as excluding caffeine, lactose, fructose, or extra fiber from her diet. Her examination is normal.

  Which one of the following is the next best step in management of this patient?

  • (A) Reassurance

  • (B) IgA tissue transglutaminase antibody

  • (C) Colonoscopy

  • (D) Stool bacterial cultures

  • (E) Trial of nortriptyline

• 2. A 52-year-old woman presents to the clinic for an evaluation of diarrhea that has been present for the past 3 months. She reports a history of travel to Mexico immediately prior to symptom onset. During her vacation, she had several days of diarrhea that was self-limited in nature. Symptoms recurred shortly after her return home. She reports 3–5 bowel movements daily associated with increased bloating and flatus. She denies fever, hematochezia, weight loss, or nocturnal stools. Her past medical history is significant for hypothyroidism and a cholecystectomy 3 years ago. Her only medication is levothyroxine. Examination is normal. Stool for bacteria (including Clostridium difficile) and ova and parasites is negative. Stool sodium is 40 mmol/L and stool potassium is 20 mmol/L.

  Which one of the following is the most likely diagnosis?

  • (A) Postinfectious irritable bowel syndrome

  • (B) Microscopic colitis

  • (C) Vibrio cholera infection

  • (D) Lactose malabsorption

  • (E) Bile salt-induced diarrhea

• 3. A 72-year-old man presents to the clinic for evaluation of diarrhea that has been present for 6 months. He describes 6–8 stools daily that are small in volume and associated with blood and mucous. He also describes bothersome tenesmus. He denies abdominal pain, fever, or weight loss. Past medical history is significant for hypertension, hyperlipidemia, and prostate cancer, for which he underwent prostatectomy and external beam radiation 4 years ago. Medications include hydrochlorothiazide, olmesartan, and atorvastatin. His last colonoscopy was at age 70.

  Which one of the following is the most likely diagnosis?

  • (A) Colorectal cancer

  • (B) Ischemic colitis

  • (C) Radiation proctitis

  • (D) Ulcerative proctitis

  • (E) Medication-induced colitis