Progressive diaphyseal dysplasia: evaluation of corticosteroid therapy.

Progressive diaphyseal dysplasia is characterized clinically by crippling leg pain, fatigue, headache, poor appetite, muscle weakness, and waddling gait. Twelve affected patients, aged 2 years 4 months to 40 years, were treated with intermittent courses of low doses of prednisone given in a single dose on alternate mornings for periods ranging from 6 months to 10 years. The average initial dose of prednisone was 0.6 mg/kg/d, and average maintenance dose was 0.3 mg/kg/d. Relief of all crippling symptoms was achieved in all patients. No untoward serious side effects have been observed, and the growth of children was not slowed. However, corticosteroid therapy should be restricted to patients suffering from crippling pain. The mechanism through which steroids act remains undefined.