Osteopathy due to methotrexate.
Two children with ALL receiving long-term therapy with methotrexate (50 mg/week i.v.) developed severe osteoporosis accompanied by swelling of the joints, gait disturbances and fractures after minimal trauma. Bone scans 85Sr disclosed a decreased input and increased turnover of calcium especially in the most used bones. The data of the calcium phosphorus metabolism are within the normal range. The minimal changes in the biopsy material of the iliac crest may be due to little mechanical use so that this part of the skeleton is not much affected by the osteoporosis. Since the controls receiving the same therapy did not have signs of such severe osteoporosis it is assumed that an additional, till unknown factor may play an additional role in this kind of methotrexate side effect.