IM16.{13-14,16-17} | Diarrheal Disorder Treatment — Summary & Reflection

KEY TAKEAWAYS

Universal first step: rehydration — WHO Plan A (ORS at home), Plan B (75 mL/kg ORS supervised × 4 hr), Plan C (IV Ringer's Lactate 100 mL/kg: 30+70 mL/kg). Zinc in children under 5: 20 mg/day × 10–14 days. Continue feeding throughout.

Antibiotic use — selection by cause:
- Viral gastroenteritis: NO antibiotics
- Cholera: doxycycline 300 mg single dose (or azithromycin) after rehydration — never before
- Shigella: ciprofloxacin 500 mg BD × 3–5 days (avoid ampicillin/co-trimoxazole: high resistance)
- ETEC (traveller's diarrhoea): azithromycin 500 mg OD × 3 days
- C. diff: stop precipitating antibiotic + metronidazole (mild-moderate) or vancomycin (severe)

Parasitic treatment:
- Amoebiasis: metronidazole 400–800 mg TDS × 5–10 days THEN diloxanide furoate 500 mg TDS × 10 days (MANDATORY — never metronidazole alone)
- Giardiasis: metronidazole 400 mg TDS × 5–7 days OR tinidazole 2 g single dose
- Hookworm: albendazole 400 mg single dose; Strongyloides: ivermectin 200 µg/kg × 2 days

IBD treatment (step-up): UC: 5-ASA (mesalamine) → steroids (active flare only) → azathioprine/6-MP (maintenance) → anti-TNF/vedolizumab/ustekinumab (refractory). CD: similar but 5-ASA has limited efficacy; metronidazole + ciprofloxacin for perianal disease; anti-TNF (infliximab) for fistulising CD. TB screening mandatory before biologics.

Surgery in IBD: UC — potentially curative (total proctocolectomy + IPAA). Emergency: toxic megacolon failing 48–72 hr medical therapy, perforation, massive haemorrhage. Elective: refractory disease, steroid dependence, high-grade dysplasia. CD — NOT curative; surgery for complications: stricture, fistula, abscess, perforation. Stricturoplasty preserves bowel length.

Contraindications: Loperamide/antimotility agents CONTRAINDICATED in dysentery, fever, bloody stools, IBD flare. Antibiotics NOT indicated in uncomplicated viral gastroenteritis or most non-typhoidal Salmonella cases.

REFLECT

Think back to the two patients from the opening hook — the young man with severe cholera and the woman requesting metronidazole for watery non-bloody diarrhoea after a meal. The diagnostic and treatment reasoning is now fully within your grasp: the cholera patient needs IV Ringer's Lactate immediately (he cannot drink due to vomiting), then ORS as soon as he can tolerate oral intake, then a single dose of doxycycline — in that order. The woman with viral gastroenteritis needs reassurance, ORS, and no antibiotic. The capacity to make these two calls at the bedside, confidently and correctly, without reflexively prescribing antibiotics, is a clinical skill that directly reduces antibiotic overuse, resistance, and patient harm. Reflect on the IBD spectrum: both UC and CD require lifelong treatment relationships. When you encounter a patient with IBD, what elements of their social history, access to medications, and comfort with injectable biologics will shape the treatment choice most? The pharmacological knowledge in this module is the foundation; the clinical art lies in applying it to the whole patient.