It is commonly caused by a blow to the head which injures the brain. This can also occur with penetrating injuries or indirect injuries such as sudden acceleration/deceleration which can damage the brain.
There are different severities of TBI ranging from mild to severe.
Diagnosis of TBI is generally made with radiographic imaging with CT scans and possibly MRI's. Treatment options vary from supportive care to emergent surgery depending on the type and magnitude of the damage.