Abstract
Bone fractures occurred during treatment with long-term high-dose administration of etidronate (EHDP) in two hemodialysis patients, despite regression of giant ectopic soft tissue calcinosis. Case 1 : A 61-year-old woman with diabetes had undergone hemodialysis treatment since 1993. In 1997, she developed severe pain in the shoulders and pubic joint due to tumoral calcinosis. X-ray and computer tomography (CT) image showed extensive tumoral calcifications in the soft tissues around these joints. Oral administration of EHDP 300 mg/day was started in August 1998, and the dose was decreased to 200 mg every 2 days in 3 years. The pain was improved, and the size of calcinosis decreased. Because joint pain recurred with an increase of CRP in 2003, the dose of EHDP was increased to 400 mg/day for three months following a three-month off period, which was repeated. In 2004~2005, rib and metatarsal fractures occured in association with decreased bone density. Case 2 : A 60-year-old man suspected of chronic glomerulonephritis had been receiving hemodialysis therapy since 1991. In 1995, he developed severe shoulder and hip pain associated with tumoral calcinosis. Since oral therapy of EHDP 200 mg/day for 4~8 weeks followed by an off-period could not reduce the size of calcinosis, the duration of oral EHDP (200~400 mg) therapy was elongated to 9 months, followed by repeated cycles of 200 mg for three months with a three-month off-period. The pain and size of the calcification were improved. However, in 2002 asymptomatic rib fracture occurred due to decreased bone density. EHDP, which is supposed to be effective for reduction of ectopic calcinosis in soft tissue, not only has a suppressive effect on bone absorption but also has a strong suppressive effect on bone calcification. That might account for fractures following long-term treatment of EHDP in our cases.
