Shaken baby syndrome: a common variant of non-accidental head injury in infants

Child abuse can take the form of physical cruelty, neglect, or emotional or sexual abuse (1). Abuse-related craniocerebral trauma or non-accidental head injury (NAHI) accounts for only a small proportion of all child abuse, but is conspicuously over-represented in the first year of life (2). NAHI is the most frequent non-natural cause of death in infancy (3), and the most common cause of death overall between the ages of 6 and 12 months (4). The clinical spectrum ranges from trivial bruising to severe trauma with fatal outcome. The shaken baby syndrome (SBS) is a common form of NAHI in which the victim is held by the torso or the extremities and violently shaken, causing abrupt uncontrolled head movements with a marked rotatory component. Clinically, SBS is characterized by signs of severe diffuse cerebral trauma, i.e., acute encephalopathy, subdural hemorrhage, and retinal hemorrhage, occasionally accompanied by various combinations of metaphyseal fractures or rib fractures. The explanation provided for the injuries is frequently inadequate or inconsistent (3, 5). Some basic aspects of SBS, e.g., with regard to the biomechanics and the cause of death, have not been fully clarified (e1– e3). Recent, sometimes emotionally tinged scientific controversy over the diagnostic value of subdural hemorrhage in infants has further increased the uncertainty (e3– e5). Against the backdrop of recent well-publicized cases of fatal child abuse, the aim of this article is to depict the current state of knowledge on SBS. The scientific literature is reviewed and the recommendations of national and international expert panels are summarized.