Mechanism: conversion of vitamin 25-(OH)-D3 to vitamin 1,25-(OH)2-D3
Clinical features:
(1) underlying granulomatous disease (sarcoid, tuberculosis, coccidioidomycosis or other deep fungal infection, leprosy)
(2) hypercalcemia and hypercalcuria
(3) normal plasma parathyroid hormone concentrations
(4) elevated serum vitamin 1,25-(OH)2-D3
(5) normocalcemia the steroid suppression test
Steroid suppression test (page 2.237, Thakker): Administration of hydrocortisone 40 mg tid for 10-14 days will result in normocalcemia in granulomatous hypercalcemia. Persistent hypercalcemia suggests a second or alternative cause.
Differential diagnosis:
(1) hypercalcemia in malignant lymphoma with a similar endogenous conversion of vitamin D
(2) vitamin D intoxication in food
