Defecation

Importance: Chronic diarrhea is defined as loose or watery stools lasting longer than 4 weeks and affects approximately 6% to 7% of adults in the US. More than 90% of patients with chronic diarrhea have a noninfectious etiology.

Observations: The most common causes of chronic, noninfectious diarrhea are irritable bowel syndrome with diarrhea (IBS-D) and functional diarrhea. IBS-D typically presents with recurrent abdominal pain relieved or worsened after defecation. Functional diarrhea is a condition in which more than 25% of bowel movements in the preceding 3 months are loose or watery, but it is not associated with significant abdominal pain. Chronic diarrhea due to a small-bowel source, such as celiac disease or small intestinal bacterial overgrowth, is typically associated with large-volume diarrhea and weight loss, with or without steatorrhea. Celiac disease is an autoimmune condition defined by enteropathy precipitated by exposure to dietary gluten in genetically predisposed individuals, and small intestinal bacterial overgrowth is characterized by excessive bacteria in the small bowel. Chronic diarrhea due to colon pathology, such as bile acid diarrhea and microscopic colitis, typically presents with frequent, low-volume stools, with or without urgency and excess mucus. Bile acid diarrhea is characterized by excess bile acids in the colon, and microscopic colitis is characterized by chronic inflammation on colon biopsies despite normal endoscopic appearance. Evaluation of chronic diarrhea includes serological testing for celiac disease (tissue transglutaminase immunoglobulin A, along with total immunoglobulin A) and stool testing for fecal calprotectin to evaluate for inflammatory bowel disease. Patients with gastrointestinal bleeding, unexplained weight loss, 45 years or older, nocturnal diarrhea, steatorrhea, and/or iron deficiency anemia should undergo colonoscopy to evaluate for colorectal cancer as well as upper endoscopy. During colonoscopy, random biopsies are recommended to evaluate for microscopic colitis, which affects 13% of patients with chronic diarrhea. If evaluation does not identify a cause of chronic diarrhea, likely diagnoses are IBS-D or functional diarrhea and the patient should be treated with lifestyle modification, such as regularly scheduled meals, exercise, intake of at least 8 cups of noncaffeinated fluids daily, limiting caffeine to 3 cups or fewer daily, and avoiding alcohol and carbonated beverages. For general treatment of chronic diarrhea, dietary modifications, such as consuming a diet low in fermentable oligosaccharides (legumes, wheat, onions, garlic), disaccharides (lactose), and monosaccharides (fructose), and polyols (sorbitol, mannitol), or medications, such as opiate agonists (loperamide), anticholinergics (hyoscyamine, dicyclomine), or 5-hydroxytryptamine 3 receptor (5-HT3) antagonists (ondansetron), can be prescribed. These therapies typically improve diarrhea in 50% to 80% of patients.

Conclusions and relevance: The most common causes of chronic, noninfectious diarrhea include IBS-D and functional diarrhea. Diagnostic testing should include consideration of celiac disease, inflammatory bowel disease, and microscopic colitis. Empiric therapies for chronic diarrhea include lifestyle and dietary modifications and medications, including opiate agonists, anticholinergics, and 5-HT3 antagonists.

Importance Hemorrhoidal disease, pathology of the tissue lining of the anal canal, affects approximately 10 million individuals in the US. Hemorrhoidal disease may impair quality of life due to bleeding, pain, anal irritation, and tissue prolapse.

Observations Hemorrhoids are classified as internal, external, or mixed (concurrent internal and external hemorrhoidal disease). Internal hemorrhoids originate above the dentate line, the boundary between the upper and lower anal canal, and may cause rectal bleeding, discomfort, and tissue prolapse from the anal canal. Internal hemorrhoid prolapse is classified as grade I (into anal canal), grade II (beyond the anus with spontaneous reduction), grade III (requiring manual reduction), and grade IV (irreducible). External hemorrhoids, arising below the dentate line, cause rectal pain when engorged or thrombosed. Initial treatment of all hemorrhoidal disease involves increasing intake of dietary fiber and water and avoiding straining during defecation. Phlebotonics (eg, flavonoids [thought to improve venous tone]) reduce bleeding, rectal pain, and swelling, although symptom recurrence reaches 80% within 3 to 6 months after treatment cessation. If dietary modification and phlebotonics are ineffective, grade I to grade III internal hemorrhoidal disease can be treated with office-based interventions. Rubber band ligation—placing a band around the base of hemorrhoid tissue during anoscopy to restrict blood flow—resolves symptoms in 89% of patients, but repeated banding is needed in up to 20%. Sclerotherapy, which induces fibrosis with a sclerosant injection, is efficacious in the short term (weeks to months) among 70% to 85% of patients, but long-term remission occurs in only one-third of patients. Infrared coagulation uses heat to coagulate hemorrhoidal tissue, yielding 70% to 80% success in reducing bleeding and prolapse. Excisional hemorrhoidectomy, for disease unresponsive to office-based therapy or for mixed hemorrhoidal disease, achieves low recurrence (2%-10%), although with longer recovery (9-14 days). External hemorrhoidal disease rarely requires surgery unless acutely thrombosed. Outpatient clot evacuation within 72 hours of onset of a thrombosed external hemorrhoid is associated with decreased pain and reduced risk of repeat thrombosis. Patients presenting more than 72 hours after external hemorrhoid acute thrombosis should receive medical treatment (eg, stool softeners, oral and topical analgesics such as 5% lidocaine).

Conclusions and Relevance Hemorrhoidal disease affects 10 million people in the US. First-line treatment is increased fiber intake, avoidance of straining during defecation, and phlebotonics. In-office rubber band ligation for grade I to III internal hemorrhoid disease is first-line procedural treatment for persistent symptoms despite conservative therapies. Excisional hemorrhoidectomy is recommended for grade III to IV prolapse, thrombosis, or mixed hemorrhoidal disease that does not improve with less invasive approaches.