Traumatic Brain Injury (TBI) Pain Phenomena
As a result of aggressive interventions and rehabilitation, traumatic brain injury (TBI) patients are living longer. The bad news is that TBI patients are living longer with pain. Patients and families may become frustrated due to the possibility of living with intractable pain. It is well established that pain is often left underappreciated and undertreated in cognitively-impaired patients. Common neurological complications after traumatic brain injury include pain, spasticity, and late functional decline. Pain may be acute or chronic. Pain may be musculoskeletal, neuropathic (“nerve pain”), or secondary to medical complications.
A cookbook pain management approach, particularly for persons with traumatic brain injury, is inappropriate. Individualized pain management is required. Therefore the following article provides some caveats and is supplemented by patient care experiences.
More than 90 percent of wounded soldiers—the highest survival rate in American wars—have made it off the battlefield. The increased survival rates have increased for both military and civilian TBI victims.
Because of advances in evaluation and treatment of individuals after traumatic brain injury (TBI), the number of co-morbidities has risen. With the invention of Computed Tomogram (CT) in the 1970s, diagnosing life-threatening events resulted in many saved lives and a better understanding of TBI. Because many of the brain injuries involve motor vehicle accidents and falls, concurrent bodily injury frequently accompanies the event. Some researchers estimate that the rate of posttraumatic headaches approaches 90% early on1 or 44% within six months after injury.2 Unlike what is seen objectively on sophisticated scans, pain is never clearly understood because the suffering is subjective. Objectively, one can easily comprehend pain in the presence of fractures, but even the most horrendous changes of degenerative back or neck films are not necessarily objective indications of pain. Conversely, normal spine imaging studies do not conclusively negate a patient’s pain complaints. For example, chronic myofascial pain syndromes—a significant cause of disability—is not visible on imaging studies. Whereas a full understanding of the pathology and responses to trauma is suboptimal, it is optimized in the hands of the experienced clinician. Rehabilitation physicians’ expertise is ideal for determining residual impairments and disabilities—in addition to the medical diagnoses. This information is paramount to a complete assessment and successful rehabilitation.
Incidence and Prevalence Incidence and Prevalence
Because there are a variety of pain syndromes associated with brain injury, the reported incidence and prevalence varies. The time course of onset and duration varies from case to case. Pain can appear at anytime after TBI (either in the acute stage, during recovery, or in the stable phase). In the author’s opinion, the associated suffering of TBI pain is of greater significance than solely the incidence and prevalence of pain.
Risk Factors: Who is susceptible?
Traumatic brain injury is a leading cause of death and lifelong disability in the United States. The Centers for Disease Control and Prevention has estimated that each year, approximately 1.5 million Americans survive a TBI, among whom 230,000 are hospitalized. Each year in America approximately 50,000 people die and another 80,000 to 90,000 people are left with a permanent TBI-related disability. TBI is three times more common in men. Adolescents, young adults, and the elderly are at the highest risk. The most common mechanisms of injury are motor vehicular collisions, falls, and violence.
Pathophysiology: “Doctor, How Bad Is It?”
TBI can be categorized into primary and secondary injury. Primary injury is the damage that occurs at the time of impact. Secondary injury, influenced by medical interventions, occurs because of the body’s response to the primary injury. Both primary and secondary injury can be localized or diffuse. Local injury tends to be caused by contact forces, whereas diffuse injury is more likely caused by non-contact, acceleration-deceleration, and rotational forces.
There are numerous outcome measures used to categorize the severity of brain injury but are outside the scope of this article. The reader is encouraged to become familiar with the outcome tools. Unfortunately all have limitations, but it is important to know that they exist. There is not one diagnostic tool that specifically correlates injury severity into disability prognosis. Consequently, the rehabilitation prognosis is dependent on myriad factors, including the clinician’s rehabilitation experience and the individual’s pre-injury functional status. Brain injury severity is most commonly described by the degree of impaired consciousness as defined by the Glasgow Coma Scale. This scale designates brain injury as mild, moderate, or severe on the basis of eye opening, verbal responses and observed motor movement. The Rancho Los Amigos Levels is another tool used to characterize levels of cognitive recovery. The FIM instrument is the most widely used functional status measure in rehabilitation.
Duration of loss of consciousness (LOC) is another factor used to describe brain injury severity. Mild brain injury includes any change in mental status or LOC of 30 minutes or less, whereas moderate brain injury is a change in mental status or LOC that persists greater than 30 minutes but less than six hours. Persons who have LOC for more than six hours are considered to be severe brain injury patients.
Radiographic imaging can be helpful but remains limited in predicting functional or neuropsychological outcomes. For example, patients may have marked disability and a normal MRI. Abnormal CT or MRI findings with no neurological deficits are commonly referred to as mild TBI with complications or moderate TBI. Patients with normal scans and no neurological findings are commonly designated as mild TBI. Newer neuroimaging techniques are evolving.
Interestingly, the brain injury literature describes the “mild” or “minor” traumatic brain injury group as reporting the most pain complaints.3 The highest sites of pain listed were headache, followed by neck/shoulder, back, upper limb, and lower limb pain. It is hypothesized that the moderate and severe TBI groups are underrepresented due to their communication impairments.
The author notes many similarities in caring for brain injury and chronic pain patients. Anderson, et al3 concurs with this point of view. The investigators report a list of symptoms common between these two groups. The list includes reduced attention span, perserveration, egocentricity, depression, anxiety, impaired relationships, impaired vocational capabilities, frequent medical visits, dependence, and irritability.
Acute and Chronic Pain
It is important to distinguish acute and chronic pain for prognosis and treatment.