Endocrine Abstracts

Background

Primary hyperparathyroidism (PHPT) results from inappropriate overproduction of parathyroid hormone from one or more of parathyroid glands with consequent hypercalcemia. Medical therapy by bisphosphonates is indicated for patients contraindicated for surgical treatment or those with therapy failure. We report the observation of a patient receiving zoledronic acid for persistent PHPT and who developped bisphosphonate-related osteonecrosis of the jaws (BRONJ).

Case report

A 54-year-old man, who had diabetes mellitus presented with symptomatic PHPT manifested by joint pain with chondrocalcinosis, and elevation in serum PTH to 720.4 pg/ml and total calcium to 3.2 mmol/l levels. Neck ultrasonography, sestamibi scan, cervico-thoracic Magnetic Resonnance Image were negative. Exploratory cervicotomy was indicated and parathyroidectomy of 3 glands was released. The fourth parathyroid gland was not found. Histological findings revealed hyperplasia of three parathyroid glands. He was presented with reccurence after 3 years. Cervical computed tomography and sestamibi scan were negative and a second mediastinal operative procedure was planned, however, no ectopic parathyroid gland was found. Because of persistence of severe hypercalcemia associated to renal lithiasis, he was medically managed with intravenous zoledronic acid for 6 years. One day, he came with left gingival pain. He was referred to maxillofacial surgeon who noted gingival redness and swelling with pus discharge and necrotic bone exposure. Finally, he was diagnosed with BRONJ. A review of the dental history indicated that he extracted one tooth 2 months ago. Subsequent treatment consisted of antibiotic and recurretage of the extraction socket without improvement. Bisphosphonates were discontinued immediately after the diagnosis and sequestrectomy was performed. A histological reported sclerotic and necrotic bone. The patient maintained on palliative treatment consisting of local wound dressings, antibiotics, and antimicrobial rinses. Although surgery appeared to give some initial relief painful symptoms returned and the patient was proposed to hyperbaric oxygen.

Conclusion

BRONJ has been well documented in a patient with persistent primary hyperparathyroidism who received 6 years of bisphosphonates. It presents a serious adverse effect and often related to a site of previous dental treatment. Therefore, patients should be informed of an increased potential risk for osteonecrosis and the importance of conservative therapy.