FieldDxRefeeding SyndromeClinical signs, differential diagnosis, treatment and prevention in dogs, cats and horses.
Overview
A potentially fatal metabolic complication of reintroducing food too quickly after prolonged starvation. A sudden insulin-driven shift of phosphorus, potassium and magnesium into cells when carbohydrate feeding resumes after prolonged starvation.
Clinical signs
- Severe hypophosphatemia, hypokalemia, and hypomagnesemia; hyperglycemia; fluid retention; muscle weakness; hemolytic anemia; cardiac arrhythmias; seizures; coma; and death.
Predisposing factors
- Starvation or fasting for an extended period.
- Rapid reintroduction of concentrated carbohydrates triggers insulin release, causing rapid intracellular shifting of electrolytes.
Look-alikes to rule out
Hepatic Encephalopathy (HE) Hepatic Encephalopathy (HE) Diabetes Mellitus
Treatment
- Vigorously slow introduction of nutrition.
- For the first 12 to 24 hours, calculate diets to provide only 25% to 33% of the daily caloric requirements, using a highly digestible veterinary liquid diet diluted with water (e.g., 1 part diet to 2 parts water).
- Administer via constant-rate infusion (CRI) or divide into small boluses every 2 to 4 hours.
- Check blood glucose and electrolytes every 6 to 8 hours.
- Suction feeding tubes before each bolus to check for residual volume.
- If tolerated, increase caloric intake slowly over 3 to 4 days.
Prevention
Never feed starved animals at maintenance energy levels initially; calculate rations carefully based on current body weight.
Source
The Merck Veterinary Manual 11th Edition (Passage 305); (Passage 368)
MSD Veterinary Manual — Refeeding Syndrome (accessed 2026-08-11)
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