| Decreased intestinal absorption Starvation Parenteral alimentation with inadequate phosphate content Malabsorption syndrome, small bowel bypass Absorption blocked by oral antacids with aluminum or magnesium Vitamin D–deficient and vitamin D–resistant osteomalacia Increased urinary excretion Phosphaturic drugs: theophylline, diuretics, bronchodilators, corticosteroids Hyperparathyroidism (primary or secondary) Hyperthyroidism Renal tubular defects with excessive phosphaturia (congenital, Fanconi syndrome induced by monoclonal gammopathy, heavy metal poisoning), alcohol use disorder Hypokalemic nephropathy Inadequately controlled diabetes mellitus Hypophosphatemic rickets Phosphatonins of oncogenic osteomalacia (eg, FGF23 production) Transcellular shift of phosphorus Administration of glucose Anabolic steroids, estrogen, oral contraceptives, beta-adrenergic agonists, xanthine derivatives Hungry bone syndrome Acute respiratory alkalosis Salicylate poisoning Other Electrolyte abnormalities Hypercalcemia Hypomagnesemia Metabolic alkalosis Abnormal losses followed by inadequate repletion Diabetes mellitus with acidosis, particularly during aggressive therapy Recovery from starvation or prolonged catabolic state Chronic alcohol use disorder, particularly during restoration of nutrition; associated with hypomagnesemia Recovery from severe burns |