Impact of Pre-Existing Migraine and Other Co-Morbid or Co-Occurring Conditions on Presentation and Clinical Course Following Deployment-Related Concussion

Objective To describe the clinical presentation and early clinical course of a sample of deployed U.S. military service members following concussion, underscoring the impact of pre-existing migraine and other co-occurring conditions. It is important to obtain a comprehensive clinical history to identify evidence of underlying migraine and other health conditions which may contribute to an individual's presenting symptoms influencing early management and outcomes following concussion. Early outcome measures assessed include headache treatment response and fitness for return to duty. Background Acute concussion is reported to result in an array of somatic, cognitive, and behavioral symptoms. It is well established that these symptoms are not specific for concussion and may result from exacerbation of pre-existing or underlying medical conditions and factors. Although most symptoms attributable to concussion resolve within days to weeks, there is evidence that persistent symptoms beyond that specific recovery time may be attributable to factors other than concussion. Military populations are at risk for a number of recognized co-morbid and co-occurring conditions, as well as special situational and psychosocial factors which may influence symptoms and clinical course following concussion. In addition, combat-related concussion frequently occurs in the setting of a blast or military vehicle accidents thus causing concurrent injuries where musculoskeletal injuries may contribute to the clinical presentation. The resultant acute stress reaction, secondary to the traumatic experience associated with concussion, may also cause or aggravate underlying psychological co-morbidities that may influence presenting symptoms. Prior studies identified co-morbidities associated with chronic post-concussive syndrome, which we find are also present during the early phase following deployment-related concussion, thereby influencing presentation and impacting recovery. This retrospective chart review was intended to demonstrate the presence and potential impact of co-morbid and co-occurring conditions contributing to symptoms following concussion, especially migraine due to its high prevalence among post-traumatic headaches. Methods Retrospective chart review was performed by the treating neurologist of 40 service members following concussion in the deployed environment. Clinical symptoms and co-morbid and co-occurring conditions including evidence of pre-existing migraine identified during comprehensive neurologic evaluations were collected. Both pre-deployment/pre-traumatic and post-traumatic headache features supporting migraine and early instituted headache management and treatment response are described. Rates of return to duty in this sample were also tabulated. Results Headaches were the most frequently reported acute symptom following concussion in this deployed service member population (38/40 patients [98%]), followed by insomnia, tinnitus, impaired concentration, nausea, dizziness, anxiety, impaired balance, depression, and hearing loss. Co-occurring acute injuries, acute stress reaction, and recent onset medication overuse were the most frequent co-occurring conditions identified by the treating neurologist as potentially contributing to the service member's presentation. Chronic co-morbidities identified included chronic headache, anxiety/depression, insomnia, and post-traumatic stress disorder. Service members with 3 or more identified co-morbidities or co-occurring conditions were more likely to require evacuation from theater. Pre-deployment headaches were reported by 25/40 [63%] service members, with 5/40 [12.5%] reporting known prior personal history of migraine. Of those reporting pre-deployment headaches, 21/25 [84%] described migraine features and/or triggers, though most [(15/25) 60%] reported as infrequent. Daily post-traumatic headaches were frequent (26/38 [68%]) and associated with typical migraine features and/or triggers. Of those treated with triptans (16/40 patient [42%]), most (12/16 patient [75%]) showed positive treatment response. Conclusions Concussion in the deployed settings does not occur in isolation, with co-morbid and co-occurring conditions being common. Presence of multiple co-morbidities appears to influence clinical course and overall recovery. Post-traumatic headaches are often phenotypically fully consistent with migraine, and appear related to pre-existing migraine if supported by detailed pre-deployment headache history suggesting same. Careful and comprehensive history taking and evaluation is invaluable in identifying associated conditions including migraine, potentially helping clinicians with more accurate symptom attribution, diagnoses, and improved clinical management following acute concussion.