The phosphate depletion syndrome occurs in profound hypophosphatemia. It can be fatal if left untreated. It may go unrecognized unless it is specifically looked for, since the patients at risk have underlying conditions which can cause similar findings.


Serum phosphorus level:

(1) Patients with the phosphorus depletion syndrome tend to have severe hypophosphatemia, with the serum phosphate < 1 mg/dL (0.323 mmol/L).

(2) A person may have intracellular phosphate depletion yet low or normal serum phosphate levels if there is a shift from intracellular to extracellular stores, as occurs in diabetic ketoacidosis.

(3) A person with a low serum phosphate level may have adequate intracellular stores if there has been an intracellular shift, as occurs with respiratory alkalosis or after a glucose load.



(1) depletion of ATP in muscle

(2) depletion of 2,3-diphosphoglycerate in erythrocytes, resulting in increased hemoglobin affinity for oxygen with tissue hypoxia


Patients at risk:

(1) chronic alcoholics

(2) severe malnourishment

(3) diabetes mellitus

(4) severe chronic renal wastage


Triggering events:

(1) feeding a severely malnourished person without phosphorus replacement

(2) ketoacidosis (alcoholic or diabetic)

(3) respiratory alkalosis (with intracellular phosphate shift)

(4) long term use of calcium or magnesium containing antacids



(1) hematologic: hemolytic anemia, impaired function of white blood cells and platelets

(2) myopathy: muscle weakness, heart failure, rhabdomyolysis

(3) neurologic: metabolic encephalopathy, ranging from confusion to coma

(4) respiratory failure: from diaphragmatic failure

(5) impaired bone mineralization


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