Recognize
- Often asymptomatic — symptoms from associated hypocalcemia (tetany, seizure, QT prolong)
- Causes: AKI / CKD, tumor lysis syndrome, rhabdo, DKA, lactic acidosis, Phos-containing enemas (Fleet), vitamin D toxicity
- Risk: metastatic Ca-Phos deposition (Ca × Phos > 55)
Acute symptomatic / TLS
- IV fluids — NS 200–300 mL/h to enhance excretion (if renal function preserved)
- Hemodialysis: AKI, severe symptoms, refractory, Ca × Phos > 70
- Treat hypocalcemia cautiously — IV Ca only if symptomatic (risk of Ca-Phos precipitation)
- Tumor lysis: rasburicase, allopurinol, aggressive IVF, monitor K/Ca/Phos/uric acid q4–6h
Phosphate binders (chronic / non-emergent)
- Calcium acetate (PhosLo) 1334 mg PO TID with meals — first-line if Ca low/normal
- Sevelamer 800–1600 mg PO TID with meals — preferred if Ca high or vascular calcification risk
- Lanthanum / sucroferric / ferric citrate — alternatives
- Avoid Al-based binders (Al toxicity)
Address cause
- Stop Phos-containing laxatives / enemas, vitamin D analogs
- Low-Phos diet (dairy, processed foods, cola)
Disposition
- Admit: TLS, AKI, symptomatic, Ca × Phos > 55, requiring HD