In emergency medicine, a<unk>  is a temporary improvement in a patient's condition after a traumatic brain injury, after which the condition deteriorates.  A<unk>  is especially indicative of an epidural hematoma.  After the injury, the patient is momentarily dazed or knocked out, and then becomes relatively<unk>  for a period of time which can last minutes or hours. Thereafter there is rapid decline as the blood collects within the skull, causing a rise in intracranial pressure, which damages brain tissue. In addition, some patients may develop "pseudoaneurysms" after trauma which can eventually burst and bleed, a factor which might account for the delay in loss of consciousness.
Because a patient may have a<unk> , any head trauma should be regarded as a medical emergency and warrants emergency medical treatment even if the patient is conscious.
Delayed cerebral edema, a very serious and potentially fatal condition in which the brain swells dramatically, may follow a<unk>  that occurs after a minor head trauma.<unk> s may also occur in conditions other than traumatic brain injury, such as heat stroke and the postictal phase after a seizure in epileptic patients.
Lucid interval
Osborn wave
Hyperfocus
Bigeminal rhythm
Persistent juvenile T-wave pattern
Resting potential
Absence seizure
Incontinentia pigmenti achromians