Recognize
- Mild 2.0–2.5 · Mod 1.0–2.0 · Severe < 1.0 mg/dL
- Symptoms (severe): muscle weakness, rhabdo, respiratory failure, hemolysis, AMS, seizure, cardiomyopathy
- Causes: refeeding syndrome, DKA recovery, alcoholism, sepsis, burns, post-parathyroidectomy, antacids, diuretics, dialysis
IV repletion (severe / symptomatic)
- Phos < 1.0: K-Phos or Na-Phos 0.5 mmol/kg IV over 4–6 h
- Phos 1.0–2.0: 0.25 mmol/kg IV over 4–6 h
- Use K-Phos if K < 4 · Na-Phos if K ≥ 4 or hyperkalemic
- Max rate ~7 mmol/h · monitor Ca (Ca-Phos precipitation), K, Mg
- Recheck Phos q6h during infusion
PO repletion (mild)
- Neutra-Phos / K-Phos 250–500 mg PO BID–QID
- Diarrhea common — limits dose
- Skim milk = ~1 g phos / quart
Refeeding syndrome
- High risk: malnutrition, alcoholism, anorexia, prolonged NPO
- Prophylaxis: thiamine 100 mg before glucose · check Phos/K/Mg q12h × 3 d
- Slow caloric reintroduction
Disposition
- Admit: Phos < 1.0, symptomatic, requiring IV, refeeding-risk patient