Abnormalities in Bone Mineral Density Distribution and Bone Scintigraphy in Patients With Childhood Onset Hypopituitarism

Abstract

The aim of our study was to evaluate the effects of long-life severe growth hormone deficiency on bone mineral density (BMD) and bone scintigraphy in adult patients with childhood onset (CO) hypopituitarism never treated with growth hormone. Our studies included 22 adult patients with CO hypopituitarism never treated with growth hormone (13 males and 9 females, aged 25–66 yr). The patients received replacement therapy with thyroxine, sex steroid hormones, and patients with secondary adrenocortical deficiency, hydrocortisone, but none of the patients had ever received GH treatment. In 22 patients, the total body with regional distribution of BMD, the lumbar spine L2–L4, and radial (33% site) BMD were determined by dual energy X-ray absorptiometry (DXA). In addition, 12 patients had the femoral neck BMD examined. In 10 cases, bone scintigraphy using 99-technetium labeled methylene diphosphonate was performed. Our studies revealed abnormalities, not yet described, in the regional distribution of BMD and bone scintigraphy in adults with CO hypopituitarism never treated with GH. In all patients, the results obtained from the total body showed definite disproportion in the regional distribution of BMD with a significantly advanced bone mineral deficit in the legs and a moderate deficit in the arms and total body. Local BMD measured at the radial (33% site) and lumbar spine L2–L4 revealed also a more pronounced bone mineral deficit in the cortical bone (33% distal radius) than in the trabecular bone (spine L2–L4). Bone scintigraphy showed a decrease in tracer accumulation in the shafts of the long bones but normal uptake in the spine, ribs, sternum, skull, and periarticular areas, indicating suppressed skeletal metabolism of cortical bone. Our studies indicate that long-life growth hormone deficiency leads to deficient and abnormal distribution of bone mineralization, a more pronounced deficit of BMD at the cortical bone, mainly expressed in the shafts of the long bones of the legs and arms, and moderately reduced BMD at the trabecular bone. Bone scans displaying low diphosphonates uptake in the shafts of the long bones point to greatly suppressed skeletal metabolism of the cortical bone in the patients with CO hypopituitarism never treated with GH.