Orthopaedic Sports Medicine
The case patient is a victim of second-impact syndrome (SIS), which occurs when a patient receives a head injury, usually a concussion or cerebral contusion, and then receives a second head injury before the symptoms of the first injury have subsided. Usually an athlete suffering from SIS will collapse suddenly within seconds to minutes of impact. Preliminary signs include fixed, dilated pupils and evidence of respiratory failure. SIS is believed to result from a loss of autoregulation of the brains blood supply following the first concussion. The second impact therefore causes severe vascular engorgement within the cranium and an increase in intracranial pressure. A thorough head CT scan would reveal massive widespread edema and uncal herniation of the temporal lobe(s) through the foramen magnum. Brainstem compromise results from compression by this uncal hernia, causing respiratory failure, ocular involvement, and coma.4
- Widespread edema with uncal herniation.
4. Cantu RC. Second-impact syndrome. Clin Sports Med 1998;17:37-44.
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