LAUSR

BACKGROUND Chronic diarrhea is defined as more than three bowel movements per day, or loose stools, or stool weight > 200 g/d for at least 4 weeks. Accompanying symptoms may include urgency, abdominal pain or cramps. SUMMARY A number of causes have to be considered, including inflammatory, neoplastic, malabsorptive, infective, vascular and functional gastrointestinal diseases. Other causes include food intolerances, side effects of drugs, or postsurgical conditions. Diarrhea may also be symptom of a systemic disease, like diabetes or hyperthyroidism. Special patient groups, like the very elderly and immunocompromised patients, pose special challenges. This review follows a question-answer style and addresses questions raised on the intersection of primary and secondary care. What do you mean by diarrhea? Why is it important to distinguish between acute or chronic diarrhea? How shall the patient with chronic diarrhea be approached? How can history and physical exam help? How can routine laboratory tests help in categorizing diarrhea? Which additional laboratory tests may be helpful? How to proceed in undiagnosed or intractable diarrhea? What are the treatment options in patients with chronic diarrhea? Key messages: Acute diarrhea is usually of infectious origin with the main treatment goal of preventing water and electrolyte disturbances. Chronic diarrhea is usually not of infectious origin and may be the symptom of a large number of gastrointestinal and general diseases or drug side effects. In undiagnosed or intractable diarrhea the question shall be raised whether the appropriate tests have been performed and interpreted correctly.