Top Causes of Recurrent Diarrhoea in young adults and Key Investigations to Diagnose it

🚨 Common Causes of Recurrent Diarrhoea

Recurrent diarrhoea can be categorized based on its underlying mechanism: watery, fatty, or inflammatory. Each type points to different causes:

1. Irritable Bowel Syndrome (IBS)

• A functional gastrointestinal disorder with no identifiable structural cause.

• Often triggered by stress, diet, or hormonal changes.

• Diarrhoea-predominant IBS (IBS-D) is a common subtype.

2. Inflammatory Bowel Disease (IBD)

• Includes Crohn’s disease and ulcerative colitis.

• Characterized by chronic inflammation of the gastrointestinal tract.

• Symptoms include bloody stools, abdominal pain, and weight loss2.

3. Celiac Disease

• An autoimmune reaction to gluten that damages the small intestine.

• Leads to malabsorption and fatty diarrhoea.

• Associated with bloating, fatigue, and nutrient deficiencies.

4. Microscopic Colitis

• Inflammation of the colon visible only under a microscope.

• Common in older adults and presents with chronic watery diarrhoea.

• Colonoscopy may appear normal, requiring biopsy for diagnosis.

5. Bile Acid Malabsorption

• Occurs when bile acids are not properly reabsorbed in the intestine.

• Can result from Crohn’s disease, cholecystectomy, or ileal resection.

• Causes secretory diarrhoea that persists even during fasting.

6. Pancreatic Insufficiency

• Inadequate production of digestive enzymes by the pancreas.

• Leads to maldigestion and fatty stools.

• Seen in conditions like chronic pancreatitis and cystic fibrosis.

7. Small Intestinal Bacterial Overgrowth (SIBO)

• Excessive bacteria in the small intestine disrupt digestion.

• Causes bloating, gas, and diarrhoea.

• Often secondary to motility disorders or anatomical abnormalities.

8. Laxative Abuse or Medication Side Effects

• Chronic use of stimulant laxatives can lead to dependency and diarrhoea.

• Other culprits include antibiotics, metformin, and proton pump inhibitors.

🔬 Key Investigations for Recurrent Diarrhoea

A structured diagnostic approach is essential to identify the root cause. Investigations typically include:

🧪 Blood Tests

• Complete Blood Count (CBC): Detects anemia or infection.

• C-reactive Protein (CRP): Indicates inflammation.

• Anti-tissue Transglutaminase IgA: Screens for celiac disease.

• Thyroid Function Tests: Rules out hyperthyroidism.

💩 Stool Studies

• Stool Culture: Identifies bacterial, viral, or parasitic infections.

• Fecal Calprotectin: Marker for intestinal inflammation (IBD).

• Fat Staining: Detects steatorrhea (fatty diarrhoea).

• Osmotic Gap: Differentiates osmotic vs. secretory diarrhoea.

📸 Imaging and Endoscopy

• Colonoscopy with Biopsy: Essential for diagnosing IBD and microscopic colitis.

• Upper GI Endoscopy: Used when celiac disease or other upper GI pathology is suspected.

• Abdominal Ultrasound or CT Scan: Evaluates structural abnormalities.

🧫 Breath Tests

• Hydrogen/Methane Breath Test: Diagnoses SIBO or carbohydrate malabsorption.

📝 Final Thoughts

Recurrent diarrhoea is more than just a nuisance—it’s a symptom that deserves attention. Whether it’s a functional disorder like IBS or a more serious condition like IBD or celiac disease, early diagnosis and targeted treatment can dramatically improve outcomes. If you’re experiencing persistent diarrhoea, consult a healthcare provider for a personalized evaluation.