What could be causing my recurring stomach aches and diarrhea?

Evaluation and Management of Recurring Stomach Aches and Diarrhea

You need a medical evaluation with basic laboratory testing to rule out infectious, inflammatory, and malabsorptive causes before attributing your symptoms to a functional disorder like irritable bowel syndrome. 1, 2

Initial Assessment Priority

Your symptoms require evaluation because the differential diagnosis is broad and includes both benign functional disorders and serious conditions requiring specific treatment. 2, 3

Key Historical Features to Assess

Duration and Pattern:

• If symptoms have lasted more than 4 weeks, this is chronic diarrhea requiring a different diagnostic approach than acute infectious causes 2, 3
• Nocturnal diarrhea or continuous symptoms suggest organic disease rather than functional disorders 4

Alarm Features Requiring Urgent Evaluation:

• Visible blood in stool (suggests bacterial pathogens like Shigella, Salmonella, Campylobacter, or STEC) 1
• Fever (though not highly discriminatory, higher temperatures suggest bacterial etiology) 1
• Unintentional weight loss (suggests organic disease) 4
• Severe or persistent abdominal pain with minimal fever (may indicate STEC or other serious bacterial infections) 1

Critical History Elements:

• Recent antibiotic use within 8-12 weeks (raises concern for C. difficile) 1
• Recent travel (consider traveler's diarrhea if symptoms persist ≥14 days, test for parasites) 1
• Surgical history, particularly cholecystectomy, gastric/bariatric surgery, or bowel resection (predisposes to bile acid malabsorption) 5, 4
• Medication review including over-the-counter products and sugar-free items containing sorbitol (up to 4% of chronic diarrhea is medication-related) 5, 6
• Diabetes history (multiple mechanisms cause diarrhea including autonomic neuropathy and bile acid malabsorption) 5, 6

Initial Laboratory Testing

Basic screening should include: 5, 6, 2

• Complete blood count (CBC)
• C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)
• Comprehensive metabolic panel
• Albumin
• Anti-tissue transglutaminase IgA with total IgA (celiac screening)
• Thyroid function tests

These tests have high specificity for organic disease when abnormal. 5, 6

Stool Studies Indicated When:

You should have stool testing if: 1

• Fever is present
• Blood or mucus visible in stool
• Severe abdominal pain
• Symptoms persist despite initial management
• Immunocompromised state
• Recent hospitalization or antibiotic use (test for C. difficile)

Routine stool cultures are NOT recommended for uncomplicated cases without alarm features. 7

Most Likely Diagnoses Based on Symptom Patterns

Functional Disorders (Most Common in Chronic Cases)

Irritable Bowel Syndrome (IBS):

• Abdominal pain that peaks before defecation, is relieved by defecation, and is associated with changes in stool form or frequency 3, 8
• Requires at least 12 weeks of symptoms with 2 of 3 features: pain relieved with defecation, onset associated with change in stool frequency, or onset associated with change in stool appearance 1
• This is a diagnosis of exclusion after ruling out organic causes 1, 2

Malabsorptive Causes

Bile Acid Malabsorption:

• Diarrhea occurring hours after meals, typically responds to fasting 5
• Higher prevalence in diabetics 5
• Common after cholecystectomy (up to 10% develop chronic diarrhea) 5, 4
• First-line treatment is cholestyramine if confirmed 5

Celiac Disease:

• Most common small bowel enteropathy in Western populations 6
• Can present with pale, bulky stools and abdominal pain 6
• Diagnosed with celiac serology 6, 2

Infectious Causes (If Acute or Recent Onset)

Viral Gastroenteritis:

• Most common cause of acute diarrhea 7
• Norovirus causes vomiting and nonbloody diarrhea lasting 2-3 days 1
• Self-limited disease 7

Bacterial Pathogens:

• Consider if fever, bloody stools, or severe abdominal pain present 1
• Common organisms include Campylobacter, Salmonella, Shigella, and STEC 1

Treatment Approach

Supportive Care for All Patients:

• Oral rehydration with early refeeding is preferred for dehydration 7
• Avoid antimotility agents if bloody diarrhea is present 7
• Loperamide may improve symptoms in watery diarrhea without alarm features 9, 7

Specific Treatment Based on Diagnosis:

• IBS: Dietary modifications, symptom-targeted therapy, consider cognitive behavioral therapy for chronic pain 1, 8
• Bile acid malabsorption: Cholestyramine, avoid excessive fat intake 5
• Bacterial infections: Antibiotics when appropriately indicated (shigellosis, campylobacteriosis, traveler's diarrhea) 7
• Celiac disease: Gluten-free diet 2

Critical Pitfalls to Avoid

• Do not use opioids for chronic abdominal pain management 8
• Do not delay evaluation if alarm features are present (bloody stool, fever, weight loss, severe dehydration) 1, 7, 10
• Do not assume functional disorder without excluding organic causes first 1, 2
• Do not order routine stool cultures in uncomplicated acute diarrhea without risk factors 7