Gastroenterology Chronic Diarrhea

Chronic Diarrhea in Children Chronic diarrhea (lasting more than ۱۴ days though often defined as ۴ weeks) warrants a systematic evaluation given its broad etiologies and potential to impair growth and development. Pathophysiological Classification & Clinical Clues Understanding underlying mechanisms -osmotic, secretory, inflammatory, or mixed- is essential. Stool characterization (watery, fatty, bloody) guides differential diagnosis and stratifies investigation pathways. Age-Dependent Etiologies Neonates/Infants: prioritize genetic/congenital causes, including congenital diarrheas and enteropathies (CODES)-e.g. microvillus inclusion disease, congenital chloride or sodium diarrhea- which often require parenteral nutrition or bowel transplantation. Older Children: dominant contributors include post-infectious conditions, food allergies or intolerances, immune-mediated disorders, IBD, IBS, malabsorption syndromes, and environmental enteropathy in low-resource settings. Diagnostic Strategy Begin with thorough history and physical exam; include nutritional assessment and stool details. Initiate first-line tests: blood work, stool studies (e.g. infection, fat), breath testing for lactose intolerance, imaging as needed. Escalate to endoscopy with biopsy when organic disease is suspected. Genetic testing plays a pivotal role in neonatal or refractory cases. Management Principles Supportive Care: Ensure hydration with oral or iv fluids; nutritional rehabilitation is fundamental to restore gut integrity and break the cycle of malnutrition-associated diarrhea. Targeted Interventions: Dietary elimination for intolerance/allergy; yogurt-based or lactose-free diet; zinc supplementation; empiric antibiotics for specific infections; probiotics for antibiotic-associated diarrhea. Advanced Therapies: immunomodulatory drugs for IBD or autoimmune enteropathy; TPN or bowel transplant in intractable neonatal enteropathies.