Rehabilitation after Traumatic Brain Injury
Traumatic brain injury (TBI) is the most common central nervous system trauma in the US. It is ten times more common than spinal cord injuries. Each year, more than a million patients are seen in the emergency room in the US for some type of traumatic brain injury. More than 50,000 people die each year from traumatic brain injuries. About 23 percent of all persons brought to the hospital with traumatic brain injury die before or during the hospitalization. The most significant determinants of death are severity of injury and the age of the patient.
About 230,000 people with traumatic brain injury are admitted to the hospital and survive until discharge. About 90,000 of these are left with long term disability from these injuries every year.
Estimated Costs of Traumatic Brain Injury
There are three components to the costs associated with a traumatic brain injury. There are acute care costs that vary according to the severity of the injury. The average length of stay for a patient with a traumatic brain injury is about 7 days. The average cost of the hospital stay is in excess of $8000. People with severe traumatic brain injury have a length of stay of over 17 days and associated costs of more than $33,000 USD. Secondly, there are costs associated with being in a rehabilitation facility. The cost for this is about $46,000 USD for a stay that lasts an average of about 23 days. Lastly, there are the more indirect costs associated with loss of income and productivity of the patient and the person who must stay at home to care for the patient.
Causes of Injury
The highest incidence of traumatic brain injury occurs in males in the 15-24 year old age range. Hospitalization rates are the highest for young males, older adults, American Indians, Alaskan natives, and blacks.
The most common cause of injury is a motor vehicle accident. The second most common cause is falls followed by violent assaults. Sports injuries can also cause traumatic brain injuries. For the elderly, the most common cause of a traumatic brain injury are falls.
The primary mechanisms of injury is either a direct blow to the head or an acceleration-deceleration injury. Generally, direct blows to the skull will cause the classic coup-contrecoup injuries in which there is injury to the area the brain was struck at and to the opposite side of the injury due to sloshing around of the brain in the skull.
Injuries from motor vehicle accidents are usually of the acceleration-deceleration type. The lesions tend to be more in the frontal, inferior frontal, and temporal lobes. Rotational forces often coincide with these types of injuries, resulting in twisting of the cerebral hemispheres and damage to the core brain structures. This is called diffuse axonal injury.
After a severe traumatic brain injury, there are a number of changes at the organ and molecular level. Cerebral blood flow is often reduced and autoregulation of the pressure inside the brain is impaired. There is an increased permeability of the blood brain barrier so that inflammatory molecules and oxygen free radicals contributing to ongoing brain injury after the trauma has occurred.
Outcome after traumatic brain injury ranges from death to complete recovery. Time to maximal recovery may range from a few days to a few years, depending on the severity of the injury and the type of function in question.
There are several measures of diffuse brain injury. In the beginning, the Glasgow Coma Scale is used to define the extent of the injury. This scale assesses eye opening, verbal response, and motor response with scores ranging from 3 to 15. Severe injuries involve scores less than or equal to eight. Moderate traumatic brain injury is considered when the Glasgow Coma Scale is 9-12 and a mild traumatic brain injury occurs when the score is greater than 13.
Measures of the duration of impaired consciousness are better predictors of outcome than measures of depth of coma such as the Glasgow Coma Scale. These measures include the amount of posttraumatic amnesia can be determined after the fact or at the time of injury. Time to follow commands is the time from injury to the time when the patient is able to follow simple commands consistently.
Early somatosensory evoked potentials (SEPs) can be useful in predicting prognosis from a traumatic brain injury. Those patients with a TBI who have absent median nerve responses have only a five percent chance of awakening and those that do awaken will often have severe disability. On the other hand, normal median nerve SEPs suggest a 69 percent chance of awakening.
A number of measures have been used to assess functional outcome after a traumatic brain injury. There is an extended Glasgow Outcome Scale measurement that improves the reliability and sensitivity of the regular Glasgow Outcome Scale. The extended Glasgow Outcome Scale ranges from dead to upper good recovery. The Disability Rating Scale is another measure of outcome in traumatic brain injuries.
Physical and Medical Consequences
Because of the widespread nature of traumatic brain lesions, motor control can be affected at multiple levels, resulting in a mixed picture of movement disorders. Spasticity tends to present with a more mixed picture than that seen after more localized injuries of the spinal cord. The classic description of spasticity seen in brain injuries includes enhanced stretch reflexes, released flexor reflexes in the legs, a loss of dexterity and weakness.
The presence of high motor tone and other movement disorders is highly correlated to the severity of brain injury. For patients with a severe enough brain injury to require admission to an inpatient rehab unit, the prevalence of spasticity may be as high as 84 percent. Tremors may be seen in up to 10 percent of patients with severe traumatic brain injury. Other manifestations of movement disorders include balance difficulties, chorea, tics, and Parkinsonism.
Treatment for these disorders depends on the functional impact of the disorder and the point in time of recovery from the traumatic brain injury that treatment occurs. Spasticity and movement disorders that do not result in a functional impairment do not need to be treated. Physical therapy modalities such as serial casting and splints, ice, stretching, and functional mobilization are important as first line treatments. Medications can be given for spasticity, such as baclofen, diazepam, tizanidine, and dantrolene. They have side effects, however, that include sedation and cognitive impairment. Other treatments for spasticity include injections of alcohol and phenol, as well as botulinum toxin injections and the use of intrathecal baclofen pumps.
Apraxia is another complication of a traumatic brain injury. This is the inability to perform skilled and purposeful limb movements and is associated with damage to the left frontoparietal hemisphere in right-hand dominant persons.
Low sodium is common after an injury to the brain and can show up as altered mental status, seizures, or dehydration, requiring monitoring of the electrolytes after moderate to severe traumatic brain injury. There are three diagnoses to be considered: 1) syndrome of inappropriate antidiuretic hormone secretion (SIADH); 2) cerebral salt wasting syndrome; and 3) acute adrenocortical insufficiency. SIADH results from a primary dysregulation of water metabolism with increases in extracellular fluid osmolality that results in the release of antidiuretic hormone. Acute adrenal insufficiency can cause both deficits in epinephrine/norepinephrine and cortisol levels. These conditions tend to be temporary in patients with traumatic brain injury.
Pituitary dysfunction is probably more common than realized by most clinicians. The symptoms are nonspecific and include malaise, anorexia, weight loss, lethargy, nausea, seizures, hypotension, hypoglycemia, and hypothermia. Patients at risk for this problem are usually those who have had a skull fracture to the base of the brain. The incidence of pituitary gland dysfunction is probably between 57 and 59 percent.
Disorders of the Senses
There can be visual problems after a traumatic brain injury. About 59 percent of those admitted to a rehab facility had some kind of visual problem. Often, formal evaluation of the visual system is impossible early after the traumatic brain injury because the patient cannot cooperate with testing. The caregivers must look for clues such as inattention to parts of the environment, past-reaching, and odd head postures. Some of the visual problems can be corrected with prisms to partially correct for the problems. Surgery for cranial nerve palsy is sometimes used as well. There is also vision therapy that uses practice and training in visual tasks in order to improve visual processes.
Dizziness and impaired balance are common concerns after a traumatic brain injury. This can be due to benign positional paroxysmal vertigo that follows changes in head position. It results from free-floating debris in the inner ear and usually involves both ears.
Taste and smell can be affected. Olfactory dysfunction may be more common than is realized after a traumatic brain injury. Forty percent of those undergoing formal evaluation of their olfactory function had no awareness that they had disabilities in this area. The actual incidence of this problem is up to 56 percent. The severity of the trauma appears to be related to these disorders of smell. Few patients actually regain the normal ability to smell.
Seizures after a severe traumatic brain injury make up 20 percent of all cases of epilepsy. The incidence of seizure disorders after traumatic brain injury is about 5-19 percent after closed head injury and 32-50 percent after a penetrating injury. There are early seizures that occur early in the injury and seizures that occur later on. While early seizures are predictive of later seizures, they are not as predictive of post-traumatic epilepsy as is the occurrence of a late seizure. There is evidence that giving Dilantin in the first week after a traumatic brain injury protects against many early seizures. There appears to be no good reason, however, to give Dilantin after that period of time.
There are certain risk factors that predispose patients to getting posttraumatic epilepsy. These include penetrating injuries, bilateral bruising of the brain and a skull fracture with fracture fragments penetrating the lining of the brain. The higher severity of injury, older age, early seizures, and multiple neurosurgery procedures seem to predict the incidence of post-traumatic epilepsy.
When a patient has a severe traumatic brain injury, peripheral nerve and limb fractures may be diagnosed late because of the patient’s inability to communicate pain. About 10-34 percent of all traumatic brain injury patients have injuries to their peripheral nerves. Risk fractures include having a long bone fracture, improper positioning, casts, surgery, and spasticity.
Extra bone formation in the soft tissues is common after a traumatic brain injury. Risk factors include having a severe traumatic brain injury, spasticity or surgery near a joint. Areas commonly affected include the hips, elbows, shoulders, and knees. Signs of this occurring include local swelling, decreased range of motion around a joint, and systemic signs, such as a fever. A bone scan can identify if this condition has occurred. The only way to treat it is to remove the extra areas of bone once the bone matures.
Emotional and behavioral difficulties are common after a traumatic brain injury even when physical findings are not present. These are major barriers to social roles and responsibilities of the patient. Problems can include difficulties in awareness of deficit, impulsivity, lack of inhibition, and lack of empathy or concern for others. They may have a flat affect, make inappropriate comments, or have uncontrolled laughing or crying.
Apathy is common and includes a reduction in goal-directed behavior as a result of a lack of motivation. It usually follows a frontal lobe injury. There are various drugs that can be used to control these abnormal behaviors.
Depression is another sequela of traumatic brain injury. The incidence of depression in the first year is about 30 percent. Anxiety can also be a factor in this condition as can aggressive behavior or irritability. Depression can increase the risk of suicide but also can diminish the quality of life. Many respond to antidepressant therapy and counseling.
Other problems after traumatic brain injury include alcohol and drug abuse. These disorders typically are present before the injury and persist after it. Posttraumatic stress disorder is another common complication of TBI. The PTSD often occurs along with depression. Some traumatically brain injured patients can also develop psychosis.