Prolonged Hungry Bone Syndrome: Treatment with a Parathyroid Analog

Presentation Number: SUN 323
Date of Presentation: April 2nd, 2017

Chantal Lewis*1, Sushela S Chaidarun2 and Richard J Comi2
1Dartmouth Hitchcock Medical Center, Lebanon, NH, 2Dartmouth-Hitchcock Medical Center, Lebanon, NH

Abstract

Prolonged hungry bone syndrome: treatment with a parathyroid analog

 

 

Introduction

X-linked hypophosphatemia (XLH) is a rare genetic disorder which has a prevalence of one case per 20,000 live births. Complications of this condition includes both secondary and tertiary hyperparathyroidism which may necessitate surgical intervention. There is very little published about these patients after parathyroidectomy and the severe hungry bone syndrome that ensues 1. Terapartide is a PTH analog that is US FDA approved for treatment of osteoporosis at high risk of fracture. However to date there has not been a reported case of the treatment of hypoparathyroidism with teraparatide post parathyroidectomy in XLH.

Clinical Case

39 year old male with a history of chronic kidney disease stage 4, s/p 3-gland parathyroidectomy 10 years prior and X-linked hypophosphatemic rickets complicated by tertiary hyperparathyroidism (PTH 2081 range 15-65pg/ml) was admitted to ICU after an elective re-exploration and parathyroidectomy with autotransplantation. Immediately post operatively the patient was noted to have severe hypocalcemia as low as corrected calcium 6.6 mg/dL with ionized calcium range 0.70-0.86 (1.15-1.33 mmol/L), PTH 13 (range 15-65pg/ml), ALP 559 (40-120 units/L). He was started on calcium gluconate drip at a rate of 2g/hour which was then titrated up to 5g/hour until post-op day 6 when he was transitioned to the following oral regimen: calcitriol 2mcg q4hrly and calcium citrate 2850mg q4hrly. He required these high doses of replacement therapy with intermittent intravenous calcium to maintain his corrected Calcium level >6.5mg/dL where he was asymptomatic.

He had a prolonged hospital course (25days) and by day 21 of hospitalization serum PTH levels remained low at 13 and corrected calcium level ranged from 5.7-7.8 (normal range 8.5-10.5mg/dL) despite aggressive supplementation. As he continued to experience symptoms of hypocalcemia, off label use of Teriparatide (forteo which was on hospital formulary) was initiated for treatment of hypoparathyroidism 2. He was initially started at a dose of 20mcg sc daily which was then titrated to 20mcg BID. Within three days of therapy the calcium levels increased and stabilized at 8.5mg/dL. This allowed for a safe decrease in the frequency of dosing of calcitriol and calcium citrate to q6hourly before discharge.

Conclusion

This case demonstrates the use of Teriparatide (forteo) in a unique patient population as an effective treatment for post-operative hypoparathyroidism resulting in decreasing requirements of supplemental calctriol and calcium and improved quality of life.

 

Nothing to Disclose: CL, SSC, RJC