Most blows to the head cause no loss of consciousness and no brain injury. If someone is knocked out for a minute or two, there has been a brief disturbance of the brain cells (concussion); usually there are no after-effects. Most patients so affected leave hospital within 1–3 days, have no organic signs, and recover and return quickly to work without further complaints.
cause unconsciousness for hours or many days, followed by loss of memory before and after that period of unconsciousness. The skull may be fractured; there may be fits in the first week; and there may develop a blood clot in the brain (intracerebral haematoma) or within the membranes covering the brain (extradural and subdural haematomata). These clots compress the brain, and the pressure inside the skull – intracranial pressure – rises with urgent, life-threatening consequences. These are identified by neurologists and neurosurgeons, confirmed by brain scans (see COMPUTED TOMOGRAPHY; MRI), and require urgent surgical removal. Recovery may be complete, or in very severe cases can be marred by physical disabilities, EPILEPSY, and by changes in intelligence, rational judgement and behaviour. Symptoms generally improve in the first two years.
A minority of those with minor head injuries have complaints and disabilities which seem disproportionate to the injury sustained. Referred to as the post-traumatic syndrome, this is not a diagnostic entity. The complaints are headaches, forgetfulness, irritability, slowness, poor concentration, fatigue, dizziness, intolerance of alcohol, light and noise, loss of interests and initiative, DEPRESSION, ANXIETY, and impaired LIBIDO. Reassurance and return to light work help these symptoms to disappear, in most cases within three months. Psychological illness and unresolved compensation-claims feature in many with implacable complaints.