Findings of metabolic bone disease in infants with unexplained fractures in contested child abuse investigations: a case series of 75 infants.

Background Infants who present with multiple unexplained fractures (MUF) are often diagnosed as victims of child abuse when parents deny wrongdoing and cannot provide a plausible alternative explanation. Herein we describe evidence of specific and commonly overlooked radiographic abnormalities and risk factors that suggest a medical explanation in such cases. Methods We evaluated such infants in which we reviewed the radiographs for signs of poor bone mineralization. We reviewed medical, pregnancy and family histories. Results Seventy-five of 78 cases showed poor bone mineralization with findings of healing rickets indicating susceptibility to fragility fractures that could result from a wide variety of causes other than child abuse. We found risk factors that could explain the poor bone mineralization: maternal and infant vitamin D deficiency (VDD), decreased fetal bone loading, prematurity and others. Most infants had more than one risk factor indicating that this bone disorder is a multifactorial disorder that we term metabolic bone disease of infancy (MBDI). Maternal and infant VDD were common. When tested, 1,25-dihydroxyvitamin D levels were often elevated, indicating metabolic bone disease. Conclusions Child abuse is sometimes incorrectly diagnosed in infants with MUF. Appreciation of the radiographic signs of MBDI (healing rickets), risk factors for MBDI and appropriate laboratory testing will improve diagnostic accuracy in these cases.