Systemic Lupus Erythematosus as a Rare Cause of Hypercalcemia: A Case Report

A 35-year-old woman with a history of systemic lupus erythematosus (SLE) presented with symptoms of an SLE flare, including joint pain, hair loss, photosensitivity, elevated calcium and creatinine levels, and lymphadenopathy. She also had an intracranial hemorrhage detected via brain MRI. Her hypercalcemia was unusual for SLE patients and was determined to be caused by an autoantibody stimulating the parathyroid hormone receptor, given her high serum calcium and phosphorus levels, low parathyroid hormone, and normal vitamin D levels. This case suggests that SLE should be considered as a rare but potential cause of severe hypercalcemia.