SAT-747 - Identifying and Managing Hungry Bone Syndrome after A Total Parathyroidectomy

Introduction:
In patients with end stage renal disease (ESRD) and with either secondary or tertiary hyperparathyroidism, postoperative hypocalcemia after a parathyroidectomy can be prolonged. This condition is called hungry bone syndrome (HBS). We present a remarkable case of HBS in a patient who underwent bilateral parathyroidectomy three weeks prior to showing symptoms.

Case report:
A 39-year-old male with a past medical history of ESRD secondary to hypertension, on hemodialysis, congestive heart failure, hyperlipidemia, obesity, and right chest brown tumor presented to the hospital with one day of generalized weakness and diffuse body numbness and tingling. He had a bilateral parathyroidectomy three weeks prior for tertiary hyperparathyroidism. Laboratory values on admission showed a potassium of 6.8 mmol/L, creatinine of 9.15 mg/dL, calcium of < 5 mg/dL and alkaline phosphatase of 814 U/L. Electrocardiogram showed normal sinus rhythm with first degree atrioventricular block, bifascicular block, and a corrected QT interval (QTc) of 601ms. Computed Tomography (CT) of the head showed mildly expansile ground glass appearance to the calvarium and facial bones, indicative of fibrous dysplasia and a partially calcified pineal gland cyst. He received calcium gluconate intravenously, dextrose, regular insulin, sodium bicarbonate, and sodium zirconium cyclosilicate. Nephrology and endocrinology were consulted, and the patient received urgent hemodialysis. Intact parathyroid hormone (PTH) was 44 pg/mL. He received multiple rounds of hemodialysis while in the hospital and was started on oral calcium tablets and epoetin alpha. Upon discharge, the patient’s calcium was 8.4 mg/dL. He was discharged with medications including calcitriol, calcium acetate, and calcium carbonate. The patient was scheduled to follow up with his outpatient hemodialysis center and his outpatient nephrologist.

Discussion:
Our case presentation displays severe, symptomatic hypocalcemia after a total parathyroidectomy in a patient with ESRD and a history of tertiary hyperparathyroidism. The on-admission calcium level of < 5 mg/dL, accompanied by significant QTc prolongation and neurological symptoms, underscores the consequences of abrupt PTH decline, leading to an imbalance of osteoclastic and osteoblastic activity. This imbalance leads to an increase in osteoblastic activity, causing increased calcium influx into the bones, leading to signs and symptoms of hypocalcemia as seen in this patient. The complexity of skeletal remodeling due to decreasing circulating PTH levels causing changes in calcium influx and efflux, severe hyperkalemia requiring urgent dialysis, and the challenge of calcium repletion in the setting of ESRD make this case noteworthy. This case highlights the crucial need for vigilant monitoring and aggressive supplementation of electrolytes after a parathyroidectomy.

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