Hyperphosphatemia






				Hyperphosphatemia in Critical Care

				Hyperphosphatemia is caused by increased absorption, decreased loss (renal failure) or increased production (cell destruction). Hyperphosphatemia causes hypocalcemia and ectopic calcification The treatment is phosphate binding agents Hyperphosphatemia is caused by increased absorption, decreased loss or increased production. Increased intake can occur as a result of excessive intravenous administration or oral supplementation or Vitamin-D intoxication. Occasionally hyperphosphatemia results from recurrent administration of phosphate-containing enemas. There is reduced excretion in renal failure, hypoparathyroidism and magnesium deficiency. Increased production is secondary to increased cell destruction – tumour lysis syndrome, rhabdomyolysis, bowel ischemia, hemolysis, acute acidosis and malignant hyperthermia. Pseudohyperphosphatemia (rather like pseudohyponatremia) may occur due to hypertriglyceridemia. Causes of Hyperphosphataemia Increased intake Intravenous infusion Oral supplementation Vitamin D intoxication Phosphate-containing enemas Acute phosphorus poisoning Increased Production Tumour-lysis syndrome Rhabdomyolysis Bowel infarction Malignant hyperthermia Hemolysis Acid-base disorders (lactic acidosis, diabetic ketoacidosis, respiratory acidosis) Reduced Loss Renal failure Hypoparathyroidism Acromegaly Tumoral calcinosis Vitamin D intoxication Bisphosphonate therapy Magnesium deficiency Pseudohyperphosphataemia Multiple myeloma Haemolysis in vitro Hypertriglyceridaemia Acute hyperphosphatemia causes few sudden problems (unlike, for example hyperkalemia and hypermagnesemia). The major effect is to cause hypocalcemia and tetany, if serum phosphate rises rapidly. Calcium can be deposited in the tissues (ectopic/metastatic calcification) in severe hyperphosphatemia, as can occur in renal failure. The treatment for acute hyperphosphatemia is administration of phosphate binding salts – calcium, magnesium and aluminum. The latter is avoided in renal failure, as aluminum can accumulate (calcium is preferred).



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