Cause and clinical characteristics of rib fractures in infants.

OBJECTIVE: Rib fractures are uncommon in infancy and, when diagnosed, often raise the suspicion of child abuse. However, the prevalence of other causes of rib fractures has not been well defined. The purpose of this study was to determine the causes and clinical presentations of rib fractures in infants <12 months old.

METHODS: Retrospectively, we identified all infants with rib fractures under 12 months old over a 3-year period using computerized databases at the Children's Hospital Medical Center in Cincinnati, Ohio and at the Children's Hospital, Winnipeg, Manitoba, Canada. Data extracted from the individual patient charts included: age, sex, chief complaint, number and location of rib fractures, associated injuries, birth history, history of cardiopulmonary resuscitation, and any evidence of bone dysplasia. After the chart review and a review of the radiographs by a pediatric radiologist, all fractures were determined to be attributable to one of the following causes: child abuse, birth injury, bone fragility, or accidental trauma. A determination of abuse was made when there were other injuries indicative of abuse, there was no clinical or radiographic evidence of bone fragility, there was a confession of abuse, when no reasonable history of trauma was provided, or when the history was not plausible to explain the rib fractures. Standard practice at these hospitals involves obtaining skeletal surveys on all children <2 years old when abuse is suspected. The child abuse team, which consists of physicians, nurses, and social workers, conducts these investigations and works closely with police in evaluating these children.

RESULTS: Thirty-nine infants with rib fractures were identified. Thirty-two (82%) were caused by child abuse. Three (7. 7%) were attributable to accidental injuries, 1 (2.6%) was secondary to birth trauma, and 3 (7.7%) were attributable to bone fragility. All 3 infants with fractures from accidental injury had sustained notable trauma (a motor vehicle collision, a forceful direct blow, and a fall from a height). Of the 3 infants with fractures secondary to bone fragility, 1 infant had osteogenesis imperfecta, 1 infant had rickets, and 1 infant, who was born at 23 weeks' gestation, had fragile bones attributable to prematurity.

CONCLUSIONS: Most rib fractures in infants are caused by child abuse. Although much less common, rib fractures can also occur after serious accidental injuries, birth trauma, or secondary to bone fragility. A thorough clinical and imaging evaluation is mandatory.