Sarcoidosis can give rise to abnormal calcium metabolism — manifesting as elevated serum calcium or excessive urinary calcium excretion — despite a normal parathyroid hormone level. This pattern is a recognised complication of sarcoidosis and calls for a distinct clinical approach.
Clinical scenario: A patient with sarcoidosis is found to have hypercalcemia or hypercalciuria, with parathyroid hormone within the normal range. This combination points away from primary hyperparathyroidism and toward a sarcoidosis-related mechanism.
Management in this setting may begin with dietary and environmental measures. In cases where those measures are not sufficient, a specific oral medication may be appropriate — which agent applies and under what clinical conditions is outlined in the full protocol.
An increase in 1,25-(OH)2-vitamin D3 production from pulmonary macrophages and granulomas may lead to increased absorption of calcium.
This can eventually result in hypercalcemia, seen in up to 5 percent of patients with sarcoidosis, and more commonly hypercalciuria.
In isolated hypercalciuria, treatment may begin with a reduction in calcium intake, increased fluids and avoidance of sun.
Occasionally, hydroxychloroquine may be effective at 200-400 mg daily for more significant hypercalciuria.
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