Hyperphosphatemia

Background

Major Causes

• Increased phosphate intake (Vitamin D, laxative abuse)
• Increased renal reabsorption (Hypoparathyroidism)
• Decreased excretion (Renal failure)
• Transcellular shifts (Tumor lysis syndrome, Rhabdomyolysis)

Clinical Features

• Fatigue
• Shortness of breath
• Anorexia
• Nausea
• Vomiting
• Insomnia

Differential Diagnosis

• Calciphylaxis
• Vitamin D intoxication
• Tumor lysis syndrome
• Laxative (Phospho-soda) abuse
• Rhabdomyolysis
• Hypoparathyroidism
• Pseudohypoparathyroidism
• Multiple myeloma

Evaluation

• >4.5mg/dL

Labs

Symptoms usually related to associated renal failure, hypocalcemia or hypomagnesemia

• Metabolic Panel (with calcium, Magnesium, and Phosphorus)

Management

Hyperphosphatemia treatment

• Treat the underlying cause
• Restrict calcium phosphate intake
• IV Normal Saline (if normal renal fx)
• Acetazolamide (500mg IV q6hr) - if normal renal function
• Phosphate Binder - Aluminum hydroxide (50-150mg/kg PO q4-6h) - limited effect
• Dialysis if refractory

See Also

• Electrolyte Abnormalities (Main)