Friday, March 9, 2012

Fractures believed to be child abuse may be metabolic bone disease

Endocrine Today June 2011

Fractures believed to be child abuse may be metabolic bone disease

Pediatric Academic Societies’ Annual Meeting 2011
New data suggest that metabolic bone disease, not child abuse, may be the cause of multiple unexplained fractures in some infants.

“Classic metaphyseal lesions, posterior rib fractures and fractures in different stages of healing are thought to be pathognomonic for child abuse,” researchers wrote. “However, we believe these findings can also be seen in metabolic bone disease of infancy.”
To investigate this theory, a radiologist reviewed X-rays of 63 infants with multiple unexplained fractures for features of metabolic bone disease; their fractures were originally considered child abuse. The researchers also searched the patients’ medical charts for the following factors that predispose children to metabolic bone disease: vitamin D deficiency in pregnancy and infancy; decreased fetal bone loading, including intrauterine confinement, malpresentation and maternal use of drugs that cause fetal immobilization; gestational diabetes; and use of drugs that decrease calcium absorption, such as acid-lowering drugs.
Results revealed that, on average, infants presented with fractures at 12.5 weeks of age, with each infant experiencing an average of nine fractures. The researchers identified 171 classical metaphyseal lesions in 42 infants and multiple rib fractures (≥4) in 29 infants. Although the researchers suspected epiphyseal separations in 6% of classical metaphyseal lesions, the majority were clinically silent and healed without callus or periosteal reaction.
X-ray images revealed that features of metabolic bone disease were present in all infants, the researchers said. Seventy-three percent of the pregnancies had evidence of fetal immobilization. Data showed that 52% of the infants tested and 87% of their mothers had abnormally low 25-hydroxyvitamin D levels. Thirteen percent of mothers also had gestational diabetes. The researchers noted that acid-lowering drugs were used by 14% of mothers during pregnancy and in 18% of the infants. Decreased fetal bone loading also occurred during 43% of pregnancies.
These results suggest that physicians should consider metabolic bone disease when encountering infants with multiple fractures, according to the researchers.
“Careful review of the X-rays with attention to the predisposing factors that can impair fetal and infant bone mineralization is critical to avoid an erroneous diagnosis of child abuse,” they wrote. “We do not believe that most [classical metaphyseal lesions] are fractures, but rather are regions of non-mineralized osteoid in healing [metabolic bone disease in infancy].”
For more information:
  • Miller ME. Poster 1403.31. Poster session: Endocrinology & diabetes. Presented at: Pediatric Academic Societies 2011; April 30-May 3, 2011; Denver.