Vertebral Histomorphometry in a Child with Glucocorticoid-Induced Osteoporosis

Abstract

Vertebral fractures are an under-recognized problem in children with glucocorticoid-induced osteoporosis (GIO). They cause severe back pain and spinal column deformity with a decrease of quality of life. For evaluating the bone mass, bone mineral density measurements have been widely carried out using dual energy X-ray absorptiometry. However, bone histomorphometric analyses of GIO in children are scarce. Bone histomorphometric analyses of vertebral bodies have not been reported. Our aim is to report the first bone histomorphometric data for vertebrae from an autopsied child with GIO. A 15-year-old girl with systemic lupus erythematosus was started on a daily oral dose of 10 mg of prednisolone at 6 years of age. She presented with back pain from 12 years of age. Magnetic resonance imaging at 14 years of age showed a compression fracture of the first lumbar (L1) vertebral body. At 15 years of age, she died of heart failure owing to pulmonary hypertension. Collapsed (L1) and non-collapsed (seventh thoracic vertebrae; T7) vertebral bodies were autopsied for bone histomorphometry and compared. T7 showed severe osteoporosis (bone volume, 4.99%; trabecular thickness, 59 µm; trabecular separation, 1,134 µm). Compared with T7, L1 showed increased bone volume (33.9%) and trabecular thickness (77 µm), and decreased trabecular separation (156 µm) owing to the impact of the vertebral fracture. The bone formation and bone resorption parameters were comparable between the two vertebrae. These histological findings suggest that severe osteoporosis developed after long-term glucocorticoid administration, and that the remodeling activities were similar in the fractured and non-fractured vertebrae.