Admission after mild head injury: benefits and costs.

Large numbers of patients are admitted to hospital in Britain after mild head injury in the hope of anticipating complications. Investigation of 1442 consecutive admissions with head injury to the Edinburgh Royal Infirmary yielded 56 intracranial haematomas. Of 865 patients who were alert and orientated in the accident and emergency department after having been briefly knocked out but who had no skull fracture, no focal neurological signs, and no history of headache or vomiting, only one developed an intracranial haematoma. In deciding which patients should be admitted a skull fracture is a much more important risk factor than is a history of brief unconsciousness. If criteria for admission took account of this fewer patients would be admitted and the saving would be considerable.