Nonaccidental head trauma in infants.

BACKGROUND: Nonaccidental head trauma in infants is the leading cause of infant death from injury. RESULTS AND DISCUSSION: Clinical features that suggest inflicted head trauma include the triad of the so-called shaken baby syndrome, consisting of retinal hemorrhage, subdural, and/or subarachnoid hemorrhage in an infant with little signs of external trauma. Studies have shown that, in general, the average short fall in the home is extremely unlikely to produce either subdural or retinal hemorrhage, although focal injuries such as skull fractures and epidural hemorrhage may be seen. Acceleration/deceleration, especially of the rotational type, is believed to be the most probable mechanism of injury in cases of nonaccidental head trauma. Damage to the cervicomedullary junction and the respiratory centers, with subsequent hypoxia and intracerebral edema, has also been implicated. After the initial trauma and hemorrhage, loss of cerebral autoregulation, breakdown of the blood-brain barrier, and disruption of ionic homeostasis occur, leading to brain edema and cytotoxicity. Cellular damage can involve large volumes of tissue, without respecting vascular territories.
CONCLUSION: Overall, a satisfactory biomechanical model is lacking, and the criminal nature of abusive injury makes it difficult to perform systematic, controlled studies. Unfortunately, outcomes are poor, and the rate of repeated abusive episodes is high. Future research should focus on the development of a satisfactory research model and on prevention strategies.