Shaken-baby Syndrome

Mechanism:

• Angular / rotational deceleration causing cerebral concussion & subdural hematoma. It is the sudden angular deceleration experienced by the brain & cerebral vessels, not the specific contact forces applied to the surface of the head, that results in teh intracranial injury.
• Trivial forces, eg. routine play, infant swings, fall from a low height are insufficient to cause the syndrome.
• Restricted to <3yo

Risk factors:

• Young parents, unstable family situations, low socioeconomic status
• disability or prematurity of the child

Perpetrators:

• father > BF > female babysitters > mother

Hx:

• Vague history that varies with time
• Mechanism of injury that is incompatible with the developmental capacity of the child
• Impaired LOC, lethargy, irritability
•  apnea, breathing abnormalities
• Vomiting, poor feeding
• Sz, increased/ decreased tone

PEx:

• Bruising, swelling, soft-tissue injuries and burns
• Cutaneous marks
• Scalp hemorrhage, full fontanelle, retina hemorrhage (65-95%)
  • dx of inflicted head injury can’t rest on the finding of retinal hemorrhage alone
• Lethargy, irritability, unresponsive
• Meningismus
• Opisthotonos / moribund

Ix

• CT 
• Plain skull x-ray – skull #
• Skeletal survey: multiple or complex # 
  • posterior or lateral rib # & metaphyseal # are characteristic, but not pathognomonic