In sarcoidosis with noncaseating granulomas and hypercalcemia, which serum alteration is typically increased due to granuloma macrophages?

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Multiple Choice

In sarcoidosis with noncaseating granulomas and hypercalcemia, which serum alteration is typically increased due to granuloma macrophages?

Explanation:
In sarcoidosis, granulomas contain activated macrophages that express 1-alpha-hydroxylase, the enzyme that converts 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D (calcitriol) outside the kidney. This extra-renal production of calcitriol raises the level of active vitamin D, which increases intestinal calcium absorption and contributes to hypercalcemia. Because calcium is elevated, the parathyroid hormone level would be suppressed, not increased. Thus, the serum alteration typically increased is 1,25-dihydroxyvitamin D.

In sarcoidosis, granulomas contain activated macrophages that express 1-alpha-hydroxylase, the enzyme that converts 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D (calcitriol) outside the kidney. This extra-renal production of calcitriol raises the level of active vitamin D, which increases intestinal calcium absorption and contributes to hypercalcemia. Because calcium is elevated, the parathyroid hormone level would be suppressed, not increased.

Thus, the serum alteration typically increased is 1,25-dihydroxyvitamin D.

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