Prognosis for TBI
Physicians look at several indicators to predict the level of a patient's recovery during the first few weeks and months after injury:
- Duration of coma
- Severity of coma in the first few hours after the injury (as measured by the Glasgow Coma Score)
- Duration of post-traumatic amnesia (PTA)
- Location and size of contusions and hemorrhages in the brain
- Severity of injuries to other body systems sustained at the time of the TBI
Precise predictions are difficult with TBI, but some generalizations can be made:
- The more severe the injury, the longer the recovery period, and the more impairment a survivor will have once recovery has plateaued.
- Recovery from diffuse axonal injury takes longer than recovery from focal contusions.
- Recovery from TBI with hypoxic injury is less complete than without significant hypoxic injury.
- The need for surgery does not necessarily indicate a worse outcome. For example, a patient requiring the removal of a blood clot may recover as completely as one who never needs surgery.
Cognitive and behavioral processes are controlled by specific areas of the brain, so the location of the injury determines the type of impairment. For example, patients who suffer a diffuse axonal injury and/or a diffuse hypoxic injury often have difficulty with concentration and long-term memory. They may have trouble dealing with more than one thing at a time, difficulty keeping track of appointments, and keeping organized. Those who suffer focal contusions or hemorrhages have problems associated with the particular brain areas affected. For example, a hemorrhage deep in the left side of the brain may cause weakness of the right side of the body. A patient with contusions of the frontal lobes may have trouble being organized or may have behavioral problems such as abnormal passivity, impulsiveness, or aggressiveness.
The length of time a patient spends in a coma correlates to both post-traumatic amnesia (PTA) and recovery times:
- Coma lasting seconds to minutes results in PTA that lasts hours to days; recovery plateau occurs over days to weeks.
- Coma that lasts hours to days results in PTA lasting days to weeks; recovery plateau occurs over months.
- Coma lasting weeks results in PTA that lasts months; recovery plateau occurs over months to years.
Physicians trained in the care of brain-injured patients can best determine how these generalizations apply to a particular TBI survivor.
There are several mechanisms of recovery after brain injury. Initial improvement may be due to the reduction of swelling (edema) of brain tissue occurring over days, weeks or months, depending on the severity of the injury. Next, damaged brain cells begin functioning again, usually over a period weeks to months. Finally, undamaged areas of the brain may, to a certain extent, take over the functions of areas that suffer permanent damage.