Primary hyperparathyroidism is the most frequent cause of hypercalcemia in adults. Hypercalcemia due to primary hyperparathyroidism is generally mild-moderate. Severe hypercalcemia in these cases is rare. Coexistence of severe hypercalcemia and hypercalcemic encephalopathy is very unusual with a very limited number of reported cases.
A 50-year-old female presented to the Emergency Department with symptoms of nausea and severe abdominal pain. Her serum calcium level was 19.4 mg/dl (8.810.2 mg/dl) and PTH level was 73.4 (1565 ng/dl) on presentation. Her serum amylase levels were also elevated. After her hospitalization she was treated with saline infusions and furosemide however her calcium level increased to 22.4 mg/dl. The calcium level was also refractory to s.c. calcitonin 200 mg twice a day for 3 days and zoledronic acid 4 mg. Ultrasonography of the neck revealed a 3.2×2.7×4.6 cm mass suspicious for a pathological parathyroid gland or a thyroid nodule adjacent to the left thyroid lobe. Considering her general situation getting worse despite maximum medical treatment, she underwent an emergency parathyroidectomy and left thyroid lobectomy. Early after the operation, the patients general condition deteriorated reaching a pre coma state. The cranial computed tomography at this point revealed periventricular ischemia compatible with metabolic encephalopathy.
During the follow-up, the calcium levels normalized eventually requiring oral active vitamin D and calcium supplementation. She no longer presented symptoms of encephalopathy. The pathology specimen was reported as being compatible with an atypical parathyroid adenoma.
Although mild-moderate hypercalcemia is frequent in primary hyperparathyroidism it should be noted that it can be severe and refractory to maximum medical treatment requiring emergency surgical intervention. In addition, not being one of the most frequent reasons, severe hypercalcemia due to primary hyperparathyroidism should be considered as an important cause of metabolic encephalopathy.