Dependent on diagnosis, see:
Post-concussive syndrome
Intracranial hemorrhage
Moderate-to-severe traumatic brain injury
Elevated intracranial pressure
Mild traumatic brain injury
Elevated intracranial pressure
Head trauma 
Traumatic brain injury
Blast injury
Intracranial hemorrhage
Traumatic asphyxia
Moderate-to-severe traumatic brain injury
Trauma 
Elevated intracranial pressure