A probable case of oral bisphosphonate-associated osteonecrosis of the jaw and recovery with parathyroid hormone treatment.

INTRODUCTION: Bisphosphonates are effective for treating osteoporosis, Paget's disease of bone, and malignancy-associated bone diseases. Bisphosphonate-associated osteonecrosis of the jaw (ONJ) is a rare but serious adverse effect of bisphosphonate therapy. Due to inhibitory actions on bone turnover, bisphosphonate therapy may result in the accumulation of microdamage.

CASE SUMMARY: A 74-year-old Korean woman (height, 150 cm; weight, 51 kg) was referred to the Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, South Korea, for evaluation of pain and persistent abnormal exposure of jaw bone after extraction of teeth. She had been receiving weekly oral alendronate treatment for osteoporosis for ~5 years. The patient had the clinical features of bisphosphonate-associated osteonecrosis of the mandible, which was precipitated by teeth extraction ~14 months prior to the outpatient referral visit. At her clinical baseline visit, serum hormone concentrations and bone turnover markers were as follows: thyroid-stimulating hormone, 0.88 μIU/mL (reference range, 0.25-5.00 μIU/mL); 25-hydroxyvitamin D3, 20.9 (9.0-37.6) ng/mL; parathyroid hormone (PTH), 57 (11-62) pg/mL; serum osteocalcin, 8.7 (12.9-55.9) ng/mL; and urine N-telopeptide 21 (26-124) nM/mM creatinine. She had multiple systemic risk factors for ONJ, including older age, type 2 diabetes mellitus, and long duration of bisphosphonate therapy. There was no mandibular lesion improvement despite repeated surgical procedures performed within a 14-month period. Bisphosphonate therapy was discontinued and PTH therapy was started. After 2 months, exposed oral mucosa had healed. After 4 months of treatment, the pain had completely subsided, and after 6 months the patient's eating and drinking habits returned. The serum concentration of osteocalcin, a bone formation marker, which was initially suppressed (8.7 ng/mL), increased 174% (15.1 ng/mL) from baseline after 6 months of treatment with PTH.

CONCLUSIONS: Here we report a probable case of oral bisphosphonate-associated ONJ featuring suppressed bone turnover. Treatment with the bone formation-stimulating agent PTH was beneficial.