---

Complete GP Treatment Guideline: Chronic Diarrhea with Weakness

---

1. DEFINITION & RED FLAGS

🚨 Alarm Features — Refer/Investigate Urgently

---

2. DIAGNOSTIC FRAMEWORK (Management Algorithm)

Step 1 — Classify by Symptom Pattern

Step 2 — First-Line Investigations (GP Level)

• CBC (anemia → blood loss or nutritional deficiency; eosinophilia → parasites)
• CMP (electrolytes — hypokalemia in secretory diarrhea; albumin — protein loss)
• CRP/ESR (inflammation screen)
• IgA tissue transglutaminase (TTG-IgA) + total IgA → celiac disease
• Thyroid function (hyperthyroidism can cause diarrhea + weakness)
• Iron, folate, B12, vitamin D (malabsorption markers)
• Blood glucose (diabetic diarrhea/autonomic neuropathy)

• Fecal occult blood
• Fecal calprotectin or lactoferrin (sensitivity ~92%/specificity ~82% for inflammatory diarrhea)
• Stool culture, ova & parasites, Giardia and Cryptosporidium antigen (or multiplex PCR)
• Stool fat (Sudan stain — sensitivity 76–94% for steatorrhea)

---

3. CAUSES BY MECHANISM (Major Categories)

Secretory Diarrhea

• Stimulant laxatives, chronic ethanol, drugs (olmesartan, metformin, SSRIs, colchicine)
• Hormone-producing tumors (VIPoma, carcinoid, gastrinoma, medullary thyroid cancer)
• Addison's disease, bile acid diarrhea, congenital electrolyte defects

Osmotic Diarrhea

• Lactase deficiency, sorbitol/fructose/FODMAPs, osmotic laxatives (Mg²⁺, PO₄³⁻)

Steatorrheal / Malabsorptive Diarrhea (major cause of weakness)

• Celiac disease (most common in adults — screen all!)
• Pancreatic exocrine insufficiency (stool fat >20 g/day → pancreatic function test)
• Bacterial overgrowth (SIBO), Whipple's disease, Crohn's disease
• Stool fat 14–20 g/day → search for small bowel cause
• Stool fat >20 g/day → assess pancreatic function

Inflammatory Diarrhea (IBD)

• Crohn's disease, ulcerative colitis, microscopic colitis (lymphocytic/collagenous)
• Infectious: Giardia, Entamoeba, C. difficile, tuberculosis

Functional / IBS-D

• Pain aggravated before BM, relieved by BM, urgency, bloating
• Diagnosis of exclusion

---

4. TREATMENT BY CAUSE

A. Specific / Curative Treatments

---

B. Symptomatic / Empirical Treatments (When Cause Not Identified or as Adjunct)

Antidiarrheal / Antimotility Agents

Stool-Modifying / Adjunctive

• Psyllium (bulk-forming): improves stool consistency; useful with fecal incontinence
• Calcium 1–2 g/day: may reduce stool frequency via unknown mechanism
• Pectin: delays proximal transit; adjunctive
• Probiotics: modest evidence; may help antibiotic-associated and travelers' diarrhea

---

5. MANAGEMENT OF WEAKNESS (Complication of Chronic Diarrhea)

A. Fluid & Electrolyte Depletion

• Oral rehydration solution (ORS) — central to management; isotonic solutions preferred
• For sport drinks: adequate for mild cases; WHO-ORS or Pedialyte preferred for moderate
• Potassium replacement: low K⁺ is a hallmark of chronic secretory diarrhea → oral KCl supplements; dietary potassium (bananas, potatoes)
• IV fluids (Ringer's lactate or NS) if oral intake inadequate or severe dehydration

B. Nutritional Deficiencies (Malabsorption)

C. Underlying Disease Causing Weakness

• Celiac disease → GFD corrects all deficiencies
• IBD → treat inflammation; nutritional support
• Adrenal insufficiency → hydrocortisone dramatically reverses weakness
• Hyperthyroidism → antithyroid treatment restores weight and strength
• Malignancy → oncology referral

---

6. WHEN TO REFER (Red Line for GP)

• Any alarm feature present
• Diagnosis unclear after initial workup
• Positive fecal calprotectin (>200 µg/g) → IBD workup
• Suspected malabsorption (steatorrhea, weight loss, hypoalbuminemia)
• Persistent diarrhea >4–6 weeks despite empirical treatment
• Colonoscopy/small bowel imaging indicated

---

7. GP APPROACH — PRACTICAL FLOWCHART

CHRONIC DIARRHEA (>4 weeks) + WEAKNESS
             │
             ▼
  STEP 1: Alarm features? ──YES──► Urgent colonoscopy / refer GI
             │ NO
             ▼
  STEP 2: Drug review → Stop offending drugs
             │
             ▼
  STEP 3: Exclude infection → Stool cultures, O&P, Giardia Ag, PCR
             │
             ▼
  STEP 4: Blood screen → CBC, CMP, CRP, TTG-IgA, TFTs, B12/folate/Fe, Vit D
          Stool screen → Calprotectin, stool fat, FOBT
             │
             ▼
  STEP 5: Pattern-based diagnosis:
    - IBS-D criteria met, normal bloods → Dietary trial (low-FODMAP), loperamide, rifaximin
    - Celiac suspected → GFD + refer GI
    - Malabsorption signs → Small bowel workup + nutritional replacement
    - Inflammatory signs (high calprotectin/CRP) → Colonoscopy + biopsy
    - Infectious → Targeted antibiotic therapy
             │
             ▼
  STEP 6: Correct Weakness
    - ORS / electrolyte replacement
    - Treat nutritional deficiencies (Fe, B12, folate, Vit D, Mg, Zn)
    - High-protein, low-irritant diet
             │
             ▼
  STEP 7: Empirical antidiarrheal if no diagnosis
    - Loperamide first-line
    - Cholestyramine trial (bile acid diarrhea)
    - Rifaximin trial (SIBO/IBS)
    - Refer if no response in 4–6 weeks

---

8. DIETARY ADVICE FOR PATIENTS

• Avoid lactose (dairy) initially as a trial — if improvement, confirm lactase deficiency
• Trial low-FODMAP diet for IBS-D
• Avoid sorbitol (sugar-free gum, candies), fructose (excess fruit juice), alcohol, caffeine
• Gluten-free trial only after celiac serology — do NOT start before blood test
• Small, frequent meals; avoid high-fat meals if steatorrhea suspected
• Maintain adequate fluid intake (minimum 2 L/day); use ORS if significant ongoing losses

---

9. MONITORING

• Review in 2–4 weeks after initial treatment
• Repeat CBC, electrolytes, albumin at 6–8 weeks if malabsorption or significant weakness
• Track weight, stool frequency (Bristol Stool Scale), and energy levels
• If persistent: escalate investigations (colonoscopy, CT enterography, hydrogen breath test)

---