Military Post-Traumatic Headache: Vicious Blasts and Vicious Cycles
Anne Calhoun, MD
Key Points:
- Migraine-like headaches frequently develop after combat related head injuries
- Factors beyond the injury itself play a key role in the development and resolution of these headaches
- Underlying factors in chronic headaches often include sleep problems, medication overuse, anxiety and posttraumatic stress disorder (PTSD)
Background
Roughly 20% of US soldiers returning from Operation Iraqi Freedom/Enduring Freedom sustained a concussion during their deployment. And among those suffering a concussion, 37% had post-traumatic headache, defined as headaches beginning within one week following the concussion. Providers classified the majority of these post-traumatic headaches as migraine. These headaches have occurred more frequently than non post-traumatic headaches.
To understand the migraine-like features of these headaches, one needs to know that the brain responds to trauma using pathways similar to those in migraine. Research reveals that migraine can be a consequence of mild traumatic brain injury (TBI). A link between migraine and TBI can be post-traumatic stress disorder (PTSD). This article looks at how these conditions can interact in a vicious cycle to produce chronic pain.
Traumatic Brain Injury Facts
Today, almost a third of the injuries from the battlefields of Iraq and Afghanistan are to the head and neck. This pattern is significantly higher—50% to 100% higher—than in World War II, Korea or Vietnam. Along with this, more of our wounded are surviving and returning home with their injuries, thanks to the rapid transport of casualties to definitive care stations.
It is well known that the signature injury of this war is the blast, accounting for almost 80% of injuries. In fact, the majority of our wounded suffer some degree of TBI. Mild TBIs—meaning that loss of consciousness was less than one hour—are the injuries most associated with chronic post-traumatic headache.
Paralleling this surge of blasts and TBIs is an epidemic of PTSD. Between 2003 and 2007, newly diagnosed cases grew almost 9-fold, with the burden of the disorder borne by the troops on the ground—the Army and the Marines. Better reporting of PTSD following the introduction of the electronic medical records in 2004 and greater awareness of the condition likely explains the surge in cases. Unquestionably, there is also the key factor of increased combat exposure of our troops on the ground, due to multiple deployments and extended tour lengths.
What Post-traumatic Headache Means
Before any meaningful discussion of “post-traumatic headache” (PTH), it is necessary to ask what “post-traumatic” means in this context. If post-traumatic is taken to imply causation—that the headache is due to the trauma, then we would have to focus on the physics of the blast and the mechanisms of tissue injury to understand or discuss PTH. (And when dealing with an individual patient and his injuries, this can be appropriate.) But there are problems with this approach when we consider PTH as a headache disorder. First, each injury is unique. Second, although PTH develops in the vast majority of mild TBI cases, most studies show an inverse relationship between the severity of the injury and subsequent development of headache. These studies imply that there are factors at work beyond the physical injury that are at least partly responsible for the generation or maintenance of these headaches.
If post-traumatic is understood to describe a temporal relationship—that these headaches follow a brain injury, then instead, we look for clues in the associated factors and evaluate their respective contributions to the overall clinical picture. With this definition, we can discuss important generalities that are common to the development of chronic PTH following combat trauma—even where individual injuries may be quite diverse.
Prevalence of Migraine in the Theatre
We do know that there is something about the battlefield that increases susceptibility to migraine. A brigade of soldiers—93% male, with an average age of 27—was screened with a validated headache questionnaire immediately following a one-year tour in Iraq. The screener asked detailed questions about headache symptoms during the last three months of their deployment. Researchers applied formalized criteria to the answers provided and classified the headaches as migraine, probable migraine, or non-migraine headaches. Surprisingly, an astounding 19% of the troops were judged to have migraine; 17.5% had probable migraine and 11.4% had non-migraine headaches. Only 5% had been diagnosed with migraine prior to their deployment. This is much higher than would be predicted for a young, mostly male population. The reported general population prevalence of migraine in men is about 6% and 18% in women.
To explain this high prevalence of migraine in theatre, we know that these headaches have both a genetic predisposition and a threshold for expression. Certain factors appear to lower that threshold, making attacks more likely. These include chronic exposure to migraine triggers, such as lack of sleep, stress, heat, exertion, strong smells, hunger, weather fronts, and glare—factors that are prevalent on the battlefield. Our troops often rely on caffeine and sleeping pills as they work with heavy packs and body armor in the desert heat.
Progression from Episodic to Chronic Headache
To illustrate the process of transitioning from occasional or episodic headaches to chronic headaches, let’s look at a model for the chronification process. With migraine, there is a genetic component—an inherited susceptibility. The susceptible individual then encounters an occasional migraine trigger and experiences occasional, or episodic migraine. These individuals are typically able to manage attacks with effective acute migraine medications. But when individuals get into trouble with increasing frequency of headaches, they enter into a vicious cycle of progression to chronicity. Chronic migraine is marked by some degree of headache discomfort on at least half the days of the month, and, if left untreated, 8 or more of these would become migraines.
How one enters the vicious cycle likely differs to some degree from individual to individual and is a matter of debate among headache specialists. This illustration shows entering the circle through non-restorative sleep, which can be attributed to any of a vast array of issues. Chronic poor sleep is a risk factor for progression to more frequent headaches. Then, if drugs are taken for each attack, medication overuse or “rebound” headaches can ensue, perpetuating the headaches. Medication overuse is present in 70% of patients with chronic migraine. This factor may then interact with anxiety—which is quite common in migraine sufferers. Anxiety is 5 times more likely with migraine and vice-versa. The migraineur may worry if enough pills are available to treat headaches; or be anxious over whether the pain will become worse. Anxiety, in turn, may interfere with sleep initiation or maintenance, continuing the vicious cycle. There are also brain pain processes which amplify the cycle. Side-effects of the medications taken (for headache pain or prevention, anxiety or sleep) can, in turn, make the sleep worse. Consequences of poorer sleep include an increase in anxiety, depression, eating disorders, fatigue and stress. The worse the progression, the more likely the patient is to overuse medications and experience anxiety, depression and or PTSD.
Progression from Acute to Chronic PTH
Similar factors may be involved in the transformation of acute PTH to chronic PTH. Certainly, the reported inverse relationship between severity of injury and headache chronicity is intriguing and argues for other, equally important factors. The next illustration shows how mild TBI may lead into a vicious cycle of headache chronification. The blast has two components: (1) the physical impact produces an acute PTH, experienced after about 80% of mild TBIs. This can lead to medication use—or overuse—particularly when the soldier is self-medicating without appropriate evaluation. And here, it is important to remember that caffeine is a drug that can readily perpetuate chronic headaches. There is also the psychological impact—what the soldier saw, what he heard, what he smelled, what he imagined. This can fuel the anxiety component of the vicious cycle and lead to non-restorative sleep.
Most cases of PTH resolve within the first 6 to 12 months, but with protracted cases, research suggests psychological factors play a role in etiology and headache maintenance. Addressing psychological factors is necessary for eventual relief. Among cases that don’t resolve within the first year, there are two key factors. A study of veterans with TBI showed high association of persistent neurologic or neuropsychological abnormalities with PTSD and disturbed sleep: 90% of these persistent cases had PTSD; over 80% had disturbed sleep. Only 11% of those with normal neurologic or neuropsychological exams had either PTSD or disturbed sleep.
Post-traumatic Stress Disorder
PTSD is a severe anxiety reaction to a traumatic event, in which individuals repeatedly relive that event, avoid stimuli associated with it, and experience symptoms such as difficulty sleeping and irritability. It is common in our combat veterans, particularly those who have sustained head injuries. After careful examination of a brigade of returning soldiers, a study reported PTSD in 44% of those who had experienced injuries with loss of consciousness, 27% of those with lesser concussions (no loss of consciousness), 16% of those with other (non-TBI) injuries, and 9% of those with no injury.
Solders with TBI were more likely than those with other injuries to report poor general health, missed workdays, medical visits and a host of physical symptoms. However, after adjustment for PTSD and depression, the head injury itself was no longer significantly associated with any of these outcomes, except for headache. In other words, headache appears related to the injury itself. PTSD and depression appear to explain the missed workdays, medical visits and host of other symptoms.
In the overall clinical picture, it can be hard to disentangle TBI and PTSD. Three factors appear to account for persistent symptoms following a mild TBI. These include the relative severity of the injury, multiple injury mechanisms….and PTSD. In turn, factors associated with development of PTSD include service in Iraq as opposed to Afghanistan, female gender, multiple injury mechanisms and….a TBI. This is reflective of what military history has taught us. Records from the US Civil War showed that the dual factors of individual vulnerability and magnitude of exposure were key factors in development of a syndrome that was similar to what we know as PTSD. The youngest soldiers were the hardest hit, as were members of units that sustained the most extensive battlefield losses.
There are four basic patterns of functioning after trauma: (1) severe disruption in psychological function beginning immediately after the trauma and persisting for years, (2) initial disruption in function, but improvement over time and recovery, (3) initial adjustment to the trauma with deterioration over time, and (4) resilience. Resilient patients recover after relatively mild short-term disruptions. One theory is that resilient individuals may be genetically different—among the quarter of the population with two long variants of the 5HT transporter gene. With poor psychological functioning comes increased likelihood of chronic headaches. Increased risk for poor psychological function can be related to traumatic events in earlier life, especially childhood. These events can then render an individual more vulnerable to later traumas including traumatic spectrum disorders, such as PTSD.
Treatment
Optimal treatment must address the issues involved. Typically these include a minimum of headache, psychological dysfunction, medication use/overuse, sleep disturbances, inactivity, and dietary issues.
For the headaches, treatment typically follows established guidelines for preventive and acute therapy of the type of primary headache that the condition most closely resembles—usually chronic migraine. This includes avoidance or resolution of medication overuse headache or caffeine-related headaches.
For the psychological component, especially PTSD, there is evidence supporting the effectiveness of several treatment modalities, including both individual and group trauma-focused cognitive behavioral therapy including somatic experiencing, guided imagery, stress management, and eye movement desensitization and reprocessing (EMDR). Two resources developed specifically for the military by Belleruth Naparstek can be found on healthjourneys.com entitled the Military Welcome Home Guided Imagery Pack and Healing Trauma (PTSD). James Gordon’s Center for Mind-Body Medicine is listed as a resource in the National Resource Directory (NRD), a federal government Web site for wounded, ill and injured Service Members, Veterans, their families, and those who support them. The Center for Mind Body Medicine also has a $400,000 research grant from the Defense Center of Excellence (DCOE) for Psychological Health to study the Center’s trauma healing model with veterans returning from Iraq & Afghanistan. Contact the NRD for specific military resources or the Center for more details.
Among treatment choices, there is evidence that trauma-focused treatment is more effective than non-trauma-focused. One example of individual trauma-focused somatic experiencing is “Virtual Iraq,” an immersion therapy that utilizes video gaming technology. These virtual reality experiences can be individualized to the setting of the trauma—for example, a roadside explosion, or an urban street-fight. Sights, sounds, tank rumbling and motion, and even smells have been used to reproduce the setting of the trauma. The intent is for the soldier to revisit the trauma in progressively greater detail as the he learns to “dial down” his response to it. “Dialing down” the emotional response seems to be a key component of resilience. Functional MRI studies in PTSD patients have shown that these techniques can be learned, with benefits demonstrated on brain scans.
Disrupted sleep specifically warrants targeted treatments. This may require assessment of sleep apnea, but more likely use of classic sleep hygiene techniques is more important. Disturbed sleep seems to be a core feature of PTSD, not just a common symptom. In fact, early onset of sleep disturbances following the trauma is predictive of PTSD one year later. Persistent sleep problems that remained years after the injury were also associated with greater neurobehavioral impairment and with unemployment. Guided imagery with the Healthful Sleep CD by Belleruth Naparstek and Emotional Freedom Technique (EFT) at eftuniverse.com are excellent resources for PTSD sleep specific problems.
Any inactivity due to pain, sleep deprivation or PTSD needs reversal beginning with increased activity as soon as possible. This should advance gradually from non-exercise activity to some degree of cardiovascular exercise. If maintaining a level of exercise, assess capability for possible advancement. Dietary treatment consists mainly of avoiding known headache triggers including headache-promoting substances such as caffeine, artificial sweeteners, nitrates, tobacco and possibly alcohol.
Summary
Proper diagnosis of PTH is essential. This includes not only proper headache diagnosis, but evaluation for psychological dysfunctions including sleep disturbance and PTSD. Effective treatment of chronic PTH after combat-related mild TBI may resemble the treatment plan of chronic migraine. This requires appropriate preventive and acute medications, elimination of analgesic overuse and/or caffeine rebound, effective treatment of anxiety disorder/PTSD and depression and improved sleep hygiene to restore sleep.
Anne Calhoun, MD, CAPT/MC/USNR-Ret, Partner, Co-Founder, Carolina Headache Institute
Chapel Hill, NC