Decreased intake or absorption Malabsorption Small bowel bypass, short bowel Vitamin D deficit (decreased absorption, decreased production of 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D) Increased loss Alcoholism Chronic kidney disease Diuretic therapy Endocrine disease Hypoparathyroidism (genetic, acquired; including hypomagnesemia and hypermagnesemia) Post-parathyroidectomy (hungry bone syndrome) Pseudohypoparathyroidism Calcitonin secretion with medullary carcinoma of the thyroid Familial hypocalcemia Associated diseases Pancreatitis Rhabdomyolysis Septic shock Physiologic causes Decreased serum albumin1 Decreased end-organ response to vitamin D Hyperphosphatemia Aminoglycoside antibiotics, plicamycin, loop diuretics, foscarnet |