Management of Chronic Diarrhea with Nocturnal Symptoms

Key Clinical Features and Diagnostic Approach

The presence of nocturnal diarrhea is a critical alarm feature that suggests organic rather than functional etiology, according to the European Society of Gastrointestinal Endoscopy 1, 2
A progressive course of worsening symptoms over 3 years indicates organic pathology, as suggested by the American Gastroenterological Association 1
Watery diarrhea with mucus suggests colonic inflammation or a secretory process, as indicated by the European Society of Gastrointestinal Endoscopy 1
Significant borborygmus may indicate malabsorption, bacterial overgrowth, or rapid transit, as noted by the American Gastroenterological Association 4, 1
Early satiety raises concern for small intestinal bacterial overgrowth (SIBO) or gastroparesis, according to the American Gastroenterological Association 4

Complete blood count is recommended to assess for anemia or infection, as suggested by the National Comprehensive Cancer Network 5
C-reactive protein or erythrocyte sedimentation rate are used as inflammatory markers, according to the American College of Gastroenterology 3
Coeliac serology, including tissue transglutaminase antibodies, should be obtained, as recommended by the American Gastroenterological Association 5
Thyroid function tests are necessary, as hyperthyroidism can cause secretory diarrhea, according to the Endocrine Society 2
Fecal calprotectin testing is recommended for patients under 45 years to exclude inflammatory bowel disease, as suggested by the European Society of Gastrointestinal Endoscopy 3

Bile acid diarrhea (BAD) testing using serum 7α-hydroxy-4-cholesten-3-one (C4) or ⁷⁵selenium homocholic acid taurine (SeHCAT) scanning is indicated for nocturnal diarrhea, as recommended by the Canadian Association of Gastroenterology 2, 6
Colonoscopy with biopsies is necessary due to the increased risk of microscopic colitis, according to the American Society for Gastrointestinal Endoscopy 2

Cholestyramine is the first-line bile acid sequestrant therapy (BAST) for confirmed bile acid diarrhea, as recommended by the Canadian Association of Gastroenterology 6
Budesonide 9 mg daily is the treatment of choice for active microscopic colitis, according to the American Gastroenterological Association 4
Rifaximin 550 mg three times daily for 14 days is used to treat confirmed SIBO, as suggested by the American College of Gastroenterology 4

Loperamide can be used cautiously while awaiting test results, but should be avoided if bloody diarrhea develops, as recommended by the Infectious Diseases Society of America 5, 7