A 43-year-old man comes to the office due to malaise, night sweats, and cough for the past several weeks. He also has chronic constipation with bowel movements once every two to three days. He has not had fevers, night sweats, or weight loss. Pulmonary examination shows normal air exchange with scattered crackles and no wheezes. The patient also has nontender cervical lymphadenopathy. Serum chemistry shows a calcium level of 12.0 mg/dL. Chest x-ray demonstrates scattered nodules and parenchymal infiltrates, as shown in the image below. Lymph node biopsy reveals noncaseating granulomas. Which of the following is the most likely cause of the elevated calcium level in this patient?

Question

A 43-year-old man comes to the office due to malaise, night sweats, and cough for the past several weeks. He also has chronic constipation with bowel movements once every two to three days. He has not had fevers, night sweats, or weight loss. Pulmonary examination shows normal air exchange with scattered crackles and no wheezes.  The patient also has nontender cervical lymphadenopathy.  Serum chemistry shows a calcium level of 12.0 mg/dL.  Chest x-ray demonstrates scattered nodules and parenchymal infiltrates, as shown in the image below.  Lymph node biopsy reveals noncaseating granulomas.  Which of the following is the most likely cause of the elevated calcium level in this patient?

Quizplus · Accepted Answer

Eductional Objective: Hypercalcemia in sarcoidosis is caused by parathyroid hormone-independent formation of 1,25-dihydroxyvitamin D by activated macrophages.  This leads to increased intestinal absorption of calcium.

A 43-Year-Old Man Comes to the Office Due to Malaise