Diarrhea for 2 Weeks: Most Likely Medical Explanations

Experiencing diarrhea for 2 weeks—often called persistent diarrhea—warrants a careful look at underlying causes. Most bouts of acute diarrhea resolve within a few days, but when loose or watery stools last longer than 14 days, they may signal a more complex issue. Below is an overview of the most common medical explanations, how providers approach evaluation, and when to seek further care.

1. Understanding Diarrhea Duration

• Acute diarrhea: <14 days
• Persistent diarrhea: 14–30 days
• Chronic diarrhea: >30 days

Diarrhea for 2 weeks falls into the “persistent” category. According to Foxx-Orenstein & McFarland (Mayo Clin Proc, 2010), persistent diarrhea often bridges the gap between simple infections and longer-term conditions.

2. Common Causes of Diarrhea for 2 Weeks

1. Infectious Causes
   • Parasitic infections (e.g., Giardia lamblia)
   • Clostridioides difficile (especially after antibiotics)
   • Persistent viral infections (rare)

2. Post-Infectious Diarrhea
   • After an acute gastroenteritis attack, gut motility or flora may remain altered for weeks.

3. Inflammatory Bowel Disease (IBD)
   • Crohn’s disease or ulcerative colitis can present with chronic, often bloody diarrhea.
   • Usually accompanied by abdominal pain, weight loss, fatigue.

4. Irritable Bowel Syndrome (IBS-D)
   • Recurrent loose stools with abdominal discomfort relieved by defecation.
   • Diagnosis of exclusion; no tissue inflammation on testing.

5. Malabsorption Syndromes
   • Celiac disease (gluten sensitivity): look for bloating, weight loss.
   • Lactose intolerance or other carbohydrate malabsorption.

6. Medication-Induced
   • Antibiotics, metformin, magnesium-containing antacids, SSRIs, laxatives.
   • Often improves on stopping or switching the drug.

7. Bile Acid Diarrhea
   • Excess bile acids in colon due to ileal resection or dysfunction.
   • Responds to bile acid sequestrants.

8. Endocrine Disorders
   • Hyperthyroidism: speeds up gut transit.
   • Diabetes with autonomic neuropathy.

9. Microscopic Colitis
   • Lymphocytic or collagenous colitis: chronic, non-bloody watery diarrhea.
   • Normal colonoscopy; diagnosis via biopsy.

10. Less Common Causes
    • Pancreatic insufficiency, small-intestinal bacterial overgrowth (SIBO)
    • Ischemic colitis, neoplasms (rare in 2-week timeframe)

3. Key Evaluation Steps

A systematic approach helps identify the underlying cause and rule out emergencies:

1. History & Physical Exam
   • Onset, stool characteristics (blood, mucus, fat)
   • Associated symptoms: fever, weight loss, abdominal pain, urgency
   • Medication review, recent travel, antibiotic use

2. Basic Laboratory Tests
   • Stool studies: culture, ova & parasites, C. difficile toxin
   • Blood counts, electrolytes (look for dehydration, hyponatremia)
   • Thyroid function, celiac serologies if indicated

3. Endoscopy & Imaging
   • Colonoscopy with biopsy for IBD or microscopic colitis
   • Abdominal ultrasound/CT if obstruction, masses, or organ disease suspected

4. Special Tests
   • Breath tests for SIBO or lactose intolerance
   • 72-hour fecal fat collection for steatorrhea

4. Potential Complications

Persistent diarrhea for 2 weeks can lead to:

• Dehydration: risk increases with ongoing fluid loss
• Electrolyte Imbalances: especially low sodium (hyponatremia) and potassium
  • Biggins & Kim (N Engl J Med, 2009) highlight that hyponatremia contributes to higher mortality in patients with advanced liver disease.
• Nutritional Deficiencies: loss of vitamins, minerals, protein
• Worsening of Chronic Conditions: e.g., liver-disease patients may see higher MELD scores (Kamath & Wiesner, Hepatology, 2001) if dehydration or electrolyte shifts occur.

5. Initial Management Strategies

While you pursue diagnosis, these measures can help:

• Hydration & Electrolytes
  • Oral rehydration solutions or clear broths
  • Avoid excess simple sugars, caffeine, alcohol

• Diet Adjustments
  • BRAT diet (bananas, rice, applesauce, toast) initially
  • Low-fat, low-fiber meals until improvement
  • Reintroduce lactose-containing or high-fiber foods slowly

• Medications
  • Loperamide or bismuth subsalicylate for symptom control (not if infection suspected)
  • Bile acid binders if bile-acid diarrhea confirmed

• Probiotics
  • May restore healthy gut flora, especially after antibiotics

6. When to Seek Further Care

Consider consulting a healthcare provider if you have diarrhea for 2 weeks plus:

• High fever (>38.5 °C/101.3 °F)
• Severe abdominal pain or bloody stools
• Signs of dehydration (dizziness, low urine output, dry mouth)
• Unintentional weight loss (>5% body weight)
• New neurological symptoms in diabetic patients

You might also try a free, online symptom check to help decide if immediate care is needed.

7. Closing Advice

Diarrhea for 2 weeks is more than just an inconvenience—it can signal persistent infection, chronic disease, or other medical issues. A structured evaluation helps pinpoint the cause and prevent complications such as dehydration and electrolyte imbalances. If your symptoms persist, worsen, or you develop red-flag signs (fever, blood in stool, severe pain), please speak to a doctor promptly. Early diagnosis and treatment can make all the difference.