Temporary brittle bone disease: Association with decreased fetal movement and osteopenia

Infants who present with multiple unexplained fractures pose a difficult di agnostic dilemma of child abuse versus intrinsic bone disease. Temporary br ittle bone disease is a recently described disease characterized by a trans ient bone weakness in the first year of life which presents with multiple, unexplained fractures that can be confused with child abuse. The purpose of this study was to determine if there are common, historical features in in fants with unexplained fractures that might suggest a basis for the fractur es, and to determine if bone density measurements might indicate that such infants have low bone density. Medical records were reviewed in 33 infants who were referred for consultation for multiple unexplained fractures in wh ich the parents and other caregivers denied wrongdoing. In 9 of the infants , radiographic absorptiometry and/or computed tomography bone density studi es were performed. In 26 of these infants the diagnosis of temporary brittl e bone disease was made. A normal collagen test was found in 17 of the 26 i nfants studied; 9 infants did not have a collagen test because the diagnosi s of osteogenesis imperfecta was considered highly unlikely. In 25 of them there was a history of decreased fetal movement and/or intrauterine confine ment. Bone density, as judged by plain X-ray films, was normal in all 26 ca ses, but when formally measured by radiographic absorptiometry or computed tomography, the bone density measurements were low in 8 of the 9 infants st udied. These findings implicate decreased fetal movement and intrauterine c onfinement as contributing factors to temporary brittle bone disease and su ggest that normal, unconstrained fetal movement during pregnancy is importa nt for normal fetal bone formation. These findings support the model that b one formation and strength are dependent on the mechanical load placed on t he bone. The results also demonstrate the usefulness of bone density measur ements in evaluating the infant with multiple unexplained fractures to help distinguish nonaccidental injury from intrinsic bone disease.