April 13, 2026
Feline Constipation / Megacolon
Straining, inappetence, and a colon full of concrete on rads.
Manage early or lose the colon later.
9yo MN DSH 6.8kg, straining in box x3 days, not eating well. Rads show massive colon packed w stool. Palpably distended abdomen. Previous episode 6 mo ago. Megacolon or just constipation? Tx plan?
💊OBSTIPATION — DEOBSTIPATE THEN PREVENT — Recurrent obstipation in middle-aged cat = megacolon developing. Deobstipate now, aggressive prevention long-term.
Acute Deobstipation
- IV fluid rehydration first — most constipated cats are dehydrated; LRS 40–60 mL/kg/day
- Warm water enema — 5–10 mL/kg warm saline or lactulose; NEVER use Fleet (phosphate) enemas in cats (fatal hyperphosphatemia)
- Manual extraction under GA — if enemas fail; gentle digital breakup with water-soluble lube
- Post-deobstipation rads — confirm adequate evacuation
Long-Term Prevention
- Miralax (PEG 3350) 1/8–1/4 tsp PO q12–24h — osmotic laxative; titrate to soft stool
- Lactulose 0.5 mL/kg PO q8–12h — alternative osmotic; some cats refuse the taste
- Cisapride 2.5–5 mg PO q8–12h — prokinetic; compounded (not commercially available)
- High-fiber or high-moisture diet — canned food preferred; psyllium 1–2 tsp/day if tolerated
- Hydration: Water fountains, SQ fluids 100–150 mL every 1–3 days if needed
⚠️ When to Consider Subtotal Colectomy
- Refractory to maximal medical management (>3 deobstipation procedures)
- Dilated, atonic colon on rads with no response to prokinetics
- Surgery has good outcomes — 85–90% success; expect soft stool for 4–6 weeks post-op, then normalizes
Your cat's colon is very backed up — we need to clear it under sedation. Then we'll start daily medication to prevent this from happening again. If it keeps recurring despite treatment, surgery to remove the enlarged colon has very good results.
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