Post-concussion syndrome, also known as postconcussive syndrome or PCS, and historically called shell shock, is a set of symptoms that a person may experience for weeks, months, or occasionally up to a year or more after a concussion – a mild form of traumatic brain injury

Traumatic brain injury

Traumatic brain injury , also known as intracranial injury, occurs when an external force traumatically injures the brain. TBI can be classified based on severity, mechanism , or other features...

 (abbreviated TBI). PCS may also occur in moderate and severe cases of traumatic brain injury. Symptoms of PCS, which is the most common entity to be diagnosed in people who have suffered TBI, may occur in 38–80% of mild head injuries.