Concussion is a temporary disorder in brain function caused by a sudden forceful blow to the head. Its essential feature is a loss of consciousness lasting a few seconds or minutes with no residual neurological damage. It is not yet understood why unconsciousness occurs. It may be due to an interruption of the normal activity of the nerve cells in both the superficial and deep regions of the brain. It may also be due to a momentary separation of the connections between the nerve cells as the wave of pressure transverses the brain.
The major danger of a concussion lies in the more ominous and lasting forms of injury that may accompany it and at first may not be obvious. Such injuries include a contusion (bruise) or a laceration (tearing) of the brain or bleeding from a tear in one of the small veins or arteries lying between the brain and the skull.
The symptoms of a simple concussion are temporary, usually clearing up within a few hours, if the concussion is more severe, they may last several days. The most common symptoms are intermittent headache, occuring mostly when the person is active; brief giddiness when getting up from a recumbent position; and a slight difficulty in concentrating. A transient loss of memory is common.
The treatment of a concussion consists of rest for at least a few hours, combined with close observation of the patient for any neurological symptoms or signs that denote brain injury. To ease the headache pain, simple nonnarcotic drugs may be administered.