Secondary brain injury is what occurs after the damage caused by the initial impact to the skull, according to doctors. Medical professionals classify it into two types: extracranial and intracranial.
Extracranial secondary brain damage cause problems either by restricting the flow of oxygen to the brain or restricting the flow of blood. Both of these conditions can eventually cause the death of brain cells. This can be extremely dangerous, especially if undetected for a time.
The most extreme consequence of oxygen deprivation is the persistent vegetative state (PVS) or death. Secondary brain damage due to lack of oxygen or low blood pressure can even occure to those who have already been admitted to intensive care units, according to studiess. Some studies have shown this can occur in about a third of patients, even when such an injury was not detected earlier.