Vitamin D-related progressive renal insufficiency in an elderly patient with postsurgical hypoparathyroidism associated with extensive brain calcification

We present a 76-year-old female patient with dementia who has postsurgical hypoparathyroidism associated with extensive brain calcification and progressive renal insufficiency. She had been treated with vitamin D combined with calcium or vitamin D alone due to hypoparathyroidism for 8 years. However, intermittent hypercalcemia including hypercalcemic crisis (serum Ca 15.2 mg/dL) and progressive renal dysfunction had developed. This patient was transferred to our long-term care hospital because of worsening dementia. Since laboratory data at admission revealed hypercalcemia and azotemia, alfacalcidol (1 microg/day) was discontinued. However, severe hypocalcemia (3.9 mg/dL) occurred later, while her azotemia was improved. With a low dose of alfacalcidol(0.25 microg/day), the serum calcium level is now below normal (approximately 7.0 mg/dL). There is neither hypocalcemic symptom nor exacerbation of renal insufficiency. From the clinical history of recurrent hypercalcemic episodes and renal calculi observed on computed tomography, the progression of renal insufficiency was considered to be related to persistent hypercalciuria caused by vitamin D and calcium, especially vitamin D therapy.