Hyperphosphatemia

An abnormally elevated concentration of inorganic phosphate in the blood (>1.45 mmol/L or >4.5 mg/dL), often associated with secondary hypocalcemia due to calcium-phosphate precipitation and reduced free calcium availability.

Causes

• Kidney failure --> impaired renal phosphate excretion

• Hypoparathyroidism

• Pseudohypoparathyroidism

• Phosphate-containing laxatives

• Vitamin D toxicity --> increased intestinal phosphate absorption

• Diabetic ketoacidosis --> phosphate redistribution

• Cellular breakdown causes

  • Rhabdomyolysis

  • Tumor lysis syndrome

  • Massive tissue injury

  • Severe hemolysis