Osteonekrose efter behandling med lavdosis bisfosfonat
Baggrund
Bisfosfonater hæmmer osteoklastaktiviteten og knogleomsætningen og anvendes i lave doser til behandling af osteoporose. Risiko for udvikling af osteonekroser efter behandling med lavdosis bisfosfonater er minimal og mindre end risikoen ved højdosis behandling. Desuden synes der at være en forøget risiko ved samtidig, systemisk glukokortikoidbehandling. Lavdosis bisfosfonat gives i tabletform eller intravenøst i modsætning til højdosis bisfosfonat, der altid gives intravenøst med ugers mellemrum.
Patienttilfælde
En 67-årig kvinde henvises til Tand-, Mund- og Kæbekirurgisk Afdeling, Aarhus Universitetshospital, på grund af dunkende smerter og blottet, nekrotisk knogle efter ekstraktion af –2 samt cystefjernelse. Patienten var pga. lupus erythematosus i langvarig behandling med systemisk glukokortikoid og pga. osteoporose i behandling med lavdosis bisfosfonat (Alendronat 70 mg/uge) gennem fire år. Patienten blev symptomfri efter rodbehandling af –3 samt konserverende behandling af den bisfosfonatinducerede osteonekrose med antibiotikum og klorhexidin, mens den nekrotiske, blottede knogle persisterede.
Konklusion
Risikoen for udviklingen af osteonekroser efter eksponering for lavdosis bisfosfonater og oralkirurgiske indgreb eller tandekstraktioner er lav, men forøges ved samtidig systemisk glukokortikoidbehandling. Såfremt patienten er i lavdosis bisfosfonater samt i systemisk glukokortikoidbehandling, anbefales forud for oralkirurgiske indgreb og tandekstraktioner en tre måneders ”drug holiday” , hvor bisfosfonatbehandling efter samråd med ordinerende læge seponeres og først genoptages, når der er slimhindedække.
Klinisk relevans:
Osteonecrosis following low doses bisphosphonate therapy
Background
Treatment with low doses bisphosphonates decreases the osteoclastic activity and bone turn over. It is used in the treatment of osteoporosis. The risk for developing osteonecrosis after treatment with low doses bisphosphonates is minimal and smaller than the risk for developing osteonecrosis after treatment with high doses bisphosphonates. Concomitant, systemic glucocorticoid therapy may increase the risk. Low doses bisphosphonates are administered perorally or intravenously while high doses bisphosphonates are always administered intravenously every other week.
Case study
A 67-year-old woman was referred to the Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Denmark, because of pain and exposed, necrotic bone following extraction of 32 and removal of a cyst. The patient suffered from lupus erythematosus and had received long-term treatment with systemic glucocorticoids and because of osteoporosis, was also treated with low doses bisphosphonates (Alendronat) for the last 4 years. After root canal treatment of necrotic 33 and conservative treatment of the exposed, necrotic bone with antibiotics and chlorhexidine gluconate the patient was symptom free but the exposed and necrotic bone persisted.
Conclusion
The risk for developing osteonecrosis after treatment with low doses bisphosphonates and oral surgery or tooth extractions is low but increases with concomitant, systemic glucocorticoid therapy. Discontinuation of oral bisphosphonates for a period of three months before oral surgery or toothextractions and until healing is observed is recommended in patients treated with low doses bisphosphonates and systemic, concomitant glucocorticoid therapy in consultation with the treating physician.
