Pain Management After Traumatic Brain Injury (Part 1)
Many people who experience traumatic brain injury (TBI) complain of pain soon after the initial injury. Common sources of pain after TBI include headache, neck or back pain, nerve pain, and pain from orthopedic injuries (such as fractures or from embedded debris). Research has shown that pain affects a higher percentage of people with mild TBI (75%) than those with moderate to severe TBI (32%). People with mild TBI patients are more likely to complain of pain soon after their injury, while people with more severe TBI tend to report pain that develops months following their injury.
Unfortunately, chronic pain has been found to impede recovery, societal reintegration and quality of life for people with TBI. Research has shown that inadequate pain management can cause poor sleep quality, increased anxiety, depression, irritability, and concentration problems. It is therefore important that chronic pain is acknowledged, diagnosed, and managed so that the person with TBI can have a better chance at a successful recovery and a high quality of life.
This article is Part 1 of Pain Management after TBI, and will review the causes and presentations of pain. This will help people who suffer from pain (and their family and friends) better understand how to communicate these issues with a doctor. Part 2 will review options for the treatment and management of pain.
Why does chronic pain occur after a TBI? The cause of pain can be complex. One must consider the personal experience and perception of pain by each individual. No single person with a TBI experiences the same injury, nor perceives pain the same way. Factors that can influence to an individual’s perception of pain can include differences in a person’s social, cultural, psychological, and cognitive experiences.
For instance, a person with a TBI commonly suffers from chronic fatigue. Having to deal with chronic fatigue on a daily basis can lower a person’s threshold for pain. Depression, another common issue after TBI, can also lower the threshold for pain. When people experience a traumatic event that results in a TBI, it is common to also experience chronic or post-traumatic stress. Research has shown that traumatic stress increases hypervigilance, a heightening of awareness for a person’s surrounding and experiences. This may not only highlight the perception of pain, but it can also decrease the quality and amount of sleep. Again, sleep deprivation will lower a person’s pain threshold.
In addition to understanding that each individual will have a unique experience and perception of pain, it is also important to understand the physiological causes of pain. The central nervous system (CNS) and peripheral nervous system (PNS) network disturbances that occur with TBI are also intimately involved with the development and perception of pain. Research has shown that several physiological factors are involved in pain after TBI, including the injured area of the brain, hyperexcitability of neurons, overproduction of glutamate and other excitatory mediators, hypothalamic dysregulation, and pain centralization (when a problem from one area, such as the spine, produces pain in another area, such as the leg). Pain transmission can be influenced through various anatomical sites, including the spinal cord, thalamus, brain stem, frontal and prefrontal cortex, and limbic system. Therefore, damage or other stimuli that affects any one of these areas will influence a patient’s pain perception.
How does a doctor assess pain after TBI? Not surprisingly, there are several factors a doctor should consider, including severity of the brain injury, type of injury, co-morbid conditions, psychological issues, and social or cultural issues. The type and severity of TBI may be the first issue to consider. People with mild TBI tend to develop pain within the first few days of their injury, while people with moderate to severe TBI tend to develop pain months after their injury. This difference may be explained by mechanical and psychological components of mild TBI patients and central pain mechanisms found in moderate to severe TBI patients.
The next consideration a doctor will make is the type of pain being experienced. The most common pain complaints in the first 3 months after TBI include headache and back pain. Some of the common types of headaches that occur after TBI include chronic tension-type headaches, medication overuse headaches, classic and atypical migraines, cervicogenic and post-traumatic headaches. The American Headache Society has developed diagnostic criteria for post-traumatic headaches that are based on the timing of the headache’s onset and the type of injury that preceded the headache, so it is important to note these details for the doctor’s visit.
Some people will experience symptoms from more than one type of headache. For example, they might have symptoms indicating intermittent migraines that occur in addition to a chronic daily tension headache. Another common problem after TBI problem is photosensitivity or photophobia (sensitivity to light), which can induce retro-orbital headaches or serve as a trigger for migraines. It is important to note all symptoms and triggers with the doctor.
Although people with mild TBI tend to report headaches sooner than people with moderate-severe TBI, they also tend to experience resolution within 6 to 12 months following their injury. People with moderate to severe TBI develop headaches months after their injury, but may continue to experience them for a longer period of time thereafter. This difference may involve the meninges (the membrane area surrounding the brain and the skull, which has been found to influence the development of chronic pain in severe TBI patients due to the sensitivity of these structures to nociception (the body’s ability to sense harm).
Pain may also generate from cervical or spinal injuries that occur with TBI. Coup-contrecoup forces on the neck induce cervical pain similar to whiplash as it occurs in motor vehicle collisions. This pain is usually more prevalent in the acute timeframe following a TBI, and may or may not be accompanied by symptoms of nerve or spinal cord irritation or damage. Some patients may experience paresthesias (prickling or tingling sensations) as a result of these whiplash-type injuries secondary to tissue swelling, inflammation and muscle spasms causing nerve compression.
A doctor may also assess pain resulting from spinal fractures, disc herniations or other spinal injuries, such as annular tears, which could result from severe cervical torsion and hyper-flexion and extension. Depending on the mechanism of injury, the thoracic or lumbar spine may also be involved. The doctor must consider the spine when evaluating patients with visceral (deeper in the body) or peripheral (closer to the skin, or muscles close to the skin) pain, especially when the pain occurs with muscular weakness that is otherwise not explained.
Orthopedic injuries can occur alongside a TBI, and include such injuries as fractures, traumatic amputations, shrapnel or other embedded debris and musculoskeletal strains or sprains. These injuries must be fully evaluated by the doctor in order to understand the person’s perception of the pain from the injury, in the context of their overall well-being.
It is important to note that, along with other TBI-related symptoms, people with mild TBI tend to emphasize their pain experience, whereas people with moderate to severe TBI do not. This can be a result of impaired self-awareness, memory, concentration, or communication common to more severe TBI, but does not mean that a person with mild TBI is exaggerating symptoms, or that a person with more severe TBI is not experiencing any pain.
The first step in adequately managing chronic pain is to understand its potential causes, and to have some familiarity with how a doctor will assess the pain. This will help better communicate important information to the doctor, so that treatment can be better targeted. In Part 2 of this article on pain management, various pain treatments and interventions will be reviewed.