Model Answer
0 min readIntroduction
Chronic diarrhoea, defined as diarrhoea lasting for more than four weeks, represents a significant clinical challenge due to its diverse etiology and potential for substantial morbidity. It differs from acute diarrhoea in its persistence and often requires a more extensive diagnostic workup to identify the underlying cause. The causes are multifactorial, ranging from infections and inflammatory conditions to malabsorption syndromes and endocrine disorders. Accurate diagnosis is crucial for effective management and improved patient outcomes.
Common Causes of Chronic Diarrhoea
Chronic diarrhoea can be broadly categorized into several groups. Below is an enumeration of common causes within each category:
1. Infectious Causes
- Parasitic Infections: Giardia lamblia, Entamoeba histolytica, Cryptosporidium are common culprits, particularly in travellers or individuals with compromised immunity.
- Bacterial Overgrowth: Clostridium difficile (often following antibiotic use), Yersinia enterocolitica, and Campylobacter jejuni can cause persistent diarrhoea.
- Viral Infections: While less common for chronic diarrhoea, persistent viral infections like cytomegalovirus (CMV) can occur in immunocompromised individuals.
2. Inflammatory Bowel Disease (IBD)
- Crohn’s Disease: Characterized by transmural inflammation, often affecting the ileum and colon, leading to diarrhoea, abdominal pain, and weight loss.
- Ulcerative Colitis: Involves inflammation limited to the colonic mucosa, causing bloody diarrhoea, urgency, and tenesmus.
- Microscopic Colitis: Includes collagenous and lymphocytic colitis, presenting with chronic watery diarrhoea, often in older adults.
3. Malabsorption Syndromes
- Celiac Disease: An autoimmune reaction to gluten, causing damage to the small intestinal mucosa and leading to malabsorption of nutrients and chronic diarrhoea.
- Lactose Intolerance: Inability to digest lactose, resulting in osmotic diarrhoea.
- Pancreatic Insufficiency: Reduced production of pancreatic enzymes, impairing digestion of fats, proteins, and carbohydrates, leading to steatorrhea (fatty stools) and diarrhoea.
- Bile Salt Malabsorption: Can occur after ileal resection or disease, leading to diarrhoea due to unabsorbed bile salts stimulating colonic secretion.
4. Endocrine/Metabolic Disorders
- Hyperthyroidism: Increased thyroid hormone levels can accelerate intestinal motility, causing diarrhoea.
- Diabetes Mellitus: Diabetic neuropathy can affect gastrointestinal motility, leading to diarrhoea or constipation.
- Addison’s Disease: Adrenal insufficiency can cause electrolyte imbalances and diarrhoea.
5. Medication-Induced Diarrhoea
- Antibiotics: Disrupt the gut microbiome, leading to antibiotic-associated diarrhoea.
- Nonsteroidal Anti-inflammatory Drugs (NSAIDs): Can cause intestinal inflammation and ulceration.
- Laxatives: Chronic overuse can lead to dependence and diarrhoea.
- Chemotherapeutic Agents: Many chemotherapy drugs have diarrhoea as a side effect.
- Metformin: Commonly causes diarrhoea in diabetic patients.
6. Other Causes
- Irritable Bowel Syndrome (IBS): A functional gastrointestinal disorder characterized by abdominal pain and altered bowel habits, including diarrhoea.
- Post-Surgical Changes: Following gastric or intestinal surgery, altered anatomy can lead to malabsorption and diarrhoea.
- Microscopic colitis: Collagenous and lymphocytic colitis
The diagnostic approach to chronic diarrhoea involves a detailed history, physical examination, stool studies (for infection, fat content, and inflammatory markers), blood tests (to assess for endocrine disorders and nutritional deficiencies), and potentially endoscopic procedures (colonoscopy, ileoscopy) with biopsies.
Conclusion
Chronic diarrhoea is a complex symptom with a wide range of potential causes. A thorough evaluation, categorizing the possible etiologies – infectious, inflammatory, malabsorptive, endocrine, and medication-induced – is essential for accurate diagnosis and targeted treatment. Emerging research into the gut microbiome and its role in chronic diarrhoea is continually refining our understanding and opening new avenues for therapeutic intervention. Early diagnosis and management are crucial to prevent complications like dehydration, malnutrition, and reduced quality of life.
Answer Length
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