Hyperparathyroidism

Abstract

A 35-year-old lady presented with pain and swelling in left knee for the last 10 months. On evaluation, she was found to have a lytic lesion in the upper part of left tibia and underwent bone curettage with implantation of fibular graft. Histopathology revealed giant cell tumor, for which localized radiation therapy was advised, and she received external beam radiotherapy (30 Gy in 10 fractions over 2 weeks). Subsequently, a bone scan was performed which showed multiple lytic lesions, and she was referred to endocrinology for opinion. On evaluation, she was found to have corrected serum calcium 15.1 mg/dl (8.6–10.2), phosphate 2.4 mg/dl (2.7–4.2), alkaline phosphatase (ALP) 943 IU/ml (40–129), iPTH 1,687 pg/ml (15–65), 25(OH)D 13.2 ng/ml (11–43), and serum creatinine 1.1 mg/dl (0.5–1.2). Her serum prolactin was 18 ng/ml (5–25). 24-h urinary calcium was 174 mg with urinary creatinine of 640 mg. Ultrasonography (USG) of abdomen revealed bilateral nephrolithiasis. She did not have gallstone disease or pancreatitis. Her T-score was −3.8 at lumbar spine and −4.7 at femoral neck. USG of neck and ^99mTc-sestamibi scan localized right inferior parathyroid adenoma (RIPA). Preoperatively, hypercalcemia was managed with saline diuresis and intravenous zoledronic acid (5 mg), after which serum calcium decreased to 9.7 mg/dl. She underwent successful resection of RIPA through unilateral neck exploration. Weight of the excised adenoma was 1.9 g, and histopathology was consistent with parathyroid adenoma. 24 h after surgery, she developed symptomatic hypocalcemia with serum calcium 6.7 mg/dl, phosphate 1.3 mg/dl, alkaline phosphatase 1,100 IU/ml, and iPTH 104.6 pg/ml. She was managed with intravenous calcium infusion, calcitriol, and cholecalciferol with frequent monitoring of serum calcium and phosphate. Her symptoms improved with increase in serum calcium to 8.0 mg/dl and phosphate to 2.2 mg/dl. She was discharged on oral calcium, calcitriol, and cholecalciferol. At 6 weeks of follow-up, she is asymptomatic and has serum calcium 8.2 mg/dl, phosphate 3.0 mg/dl, and ALP 800 IU/ml. She was continued on 2 g elemental calcium and 1.5 μg calcitriol per day along with 60,000 IU cholecalciferol once per month and was advised serial monitoring of calcium profile.