Immune suppression and isolated severe head injury: a significant clinical problem.

In the developed world, trauma is the principal cause of death under the age of 40 and is the third largest overall killer. In the UK, approximately 25,000 people die each year as a result of major injury, 25% as a result of head injuries alone. Despite improved diagnosis and management, infection remains the commonest complication in those patients surviving the initial injury. Some 5% are reported to die as a result of septic complications. Prolonged periods of intensive care and respiratory support predispose to infective respiratory complications. These patients in the absence of significant systemic injury and, as a result of severe head injury, are unable to mount an effective immune response. This literature review examines the changes that have been reported to occur in the immune system following isolated severe head injury and explores the relationship these changes may have to the increased development of infective complications.