Review: Does Concussion in Deployed Settings Occur in isolation?

The presence of multiple co-morbidities appears to influence clinical course and overall recovery. 

A study published in the March 2020 issue of Headache examines the clinical presentation and early clinical course of U.S. military service members following concussion with the goal of underscoring the impact of pre-existing migraine and other co-occurring conditions.

After conducting a retrospective neurology chart review of 40 service members after their concussions in the deployed environment, headaches were found to be the most frequently reported acute symptom following concussion. This symptom was followed by insomnia, tinnitus, impaired concentration, nausea, dizziness, anxiety, impaired balance, depression and hearing loss.

“This study looks at deployment-related concussion and how it ties into the status of these people’s headaches,” says Thomas Berk, MD, a neurology professor at NYU Langone Health, an expert in the field who provided commentary. “In general, people who have a predisposition for migraine tend to have a more prolonged recovery period from concussion.” The authors of the Headache paper, he says, wanted to look specifically at early outcomes, examining how the headache itself was treated, the kinds of medications used to treat it, and how the soldiers were evaluated in regard to their return to duty.

Methods and results

Examining the service members’ charts, Dr. Berk says, “The authors specifically wanted to look at what the service members were like before and during the injury as well as what happened to them afterward—what their outcomes were, how likely it was for them to need to be sent back home or whether they would be able to return to duty.”

The authors made a distinction between co-occurring and comorbid conditions. “Many of the soldiers experienced injuries like musculoskeletal problems or acute stress reactions at the same time that they had their concussion,” says Dr. Berk. Comorbidities present prior to the injury included conditions like headaches, anxiety and depression, insomnia and post-traumatic stress disorder.

The authors found that 63% of the soldiers had some kind of headache before deployment. Of those, 12.5% reported a known prior history of migraine. In service members who experienced post-concussion headache, 68% experienced it daily. “And of those soldiers, almost all of them had some migraine symptom associated with it,” says Dr. Berk. Furthermore, the soldiers that required evacuation from the field were most likely to have three or more comorbidities or co-injuries before their concussion.

Tailoring treatments

Dr. Berk says that it’s noteworthy that about 75% of the headaches subjects experienced responded to migraine-specific treatments. “If you understand what the comorbidities were— whether this is somebody with a tendency towards migraine or if the headaches that they’re now experiencing are more like migraine—we can tailor the treatments better to what the soldiers have, and theoretically improve their recovery period.”

Migraine treatments could be effective in soldiers already predisposed to migraine symptoms. For others, Dr. Berk says, their headaches may be more related to musculoskeletal tension. “It could be related to whiplash injury or what we would call cervicogenic headache, which is more related to neck issues. Headache after concussion can present in a number of ways.” When clinicians get patients’ specific health history, they can better tailor their therapy, whether that means they prescribe treatments that cater to migraine-like symptoms or, in the case of cervicogenic headache, opt for physiotherapy and other treatments that cater to neck issues.

Practical applications

Dr. Berk says the takeaway is that when clinicians assess for concussion, it’s essential to find out what the pre-concussion headaches were like. “Compare the two and see if there are any similarities. When we ask them what the headaches are like specifically, it means asking them what the quality of pain is.” Clinicians should make note of where in the head or neck the pain is located, how long it lasts, and whether it’s continuous or daily. They should also consider what non-pain symptoms they experience when the pain exacerbates (like sensitivity to light, noise, and smells).

According to Dr. Berk, it can also be enlightening to find out what medications have already been tried. “One of the things that we know from prior studies is that people who are predisposed to migraine will respond very well, even in their less migraine-like headaches, to migraine-type medicines, and people who are not won’t really respond at all to medicines like triptans.”

Dr. Berk believes that if researchers break post-traumatic headache down into its subtypes and compare which medications people respond to within the subtypes, researchers will learn a great deal about how the brain reacts. “Migraine means that your brain is wired a little differently, and likely that’s why, in concussion, the kinds of symptoms that you start to experience if you have migraine are more migraine-like.”

Headache®: The Journal of Head and Face Pain is the official journal of the American Headache Society. AHS frequently reviews published research and provides commentary on the work being done to help advance the understanding of headache and face pain. For more analysis on studies published in Headache®, visit the AHS News page.