Mild Head Trauma and Chronic Headaches in Returning US Soldiers

Abstract

Objective.-To determine the incidence and types of head or neck trauma and headache characteristics among US Army soldiers evaluated for chronic headaches at a military neurology clinic following a combat tour in Iraq.Background.-Head or neck trauma and headaches are common in US soldiers deployed to Iraq. The temporal association between mild head trauma and headaches, as well as the clinical characteristics of headaches associated with mild head trauma, has not been systematically studied in US soldiers returning from Iraq.Methods.-A retrospective cohort study was conducted with 81 US Army soldiers from the same brigade who were evaluated at a single military neurology clinic for recurrent headaches after a 1-year combat tour in Iraq. All subjects underwent a standardized interview and evaluation to determine the occurrence of head or neck trauma during deployment, mechanism and type of trauma, headache type, and headache characteristics.Results.-In total, 33 of 81 (41%) soldiers evaluated for headaches reported a history of head or neck trauma while deployed to Iraq. A total of 18 (22%) subjects had concussion without loss of consciousness and 15 (19%) had concussion with loss of consciousness. Ten subjects also had an accompanying traumatic neck injury. No subjects had moderate or severe traumatic brain injury. Exposure to blasts was the most common cause of trauma, accounting for 67% of head and neck injuries. Headaches began within one week after trauma in 12 of 33 (36%) soldiers with head or neck injury. Another 12 (36%) reported worsening of pre-existing headaches after trauma. Headaches were classified as migraine type in 78% of soldiers with head or neck trauma. Headache types, frequency, severity, duration, and disability were similar for soldiers with and without a history of head or neck trauma.Conclusion.-A history of mild head trauma, usually caused by exposure to blasts, is found in almost half of returning US combat troops who receive specialized care for headaches. In many cases, head trauma was temporally associated with either the onset of headaches or the worsening of pre-existing headaches, implicating trauma as a precipitating or exacerbating factor, respectively. Headaches in head trauma-exposed soldiers are usually migraine type and are similar to nontraumatic headaches encountered at a military specialty clinic.

Natural History of Headache after Traumatic Brain Injury

“…Even the authors of the ICHD diagnostic criteria acknowledge the difficulty in distinguishing a high general population prevalence tensiontype headache from PTH occurring weeks or months after trauma (The International Classification of Headache Disorders, 2004). Our results are similar to those found by Theeler and Erickson (2009), who examined the temporal association of headaches following mild head or neck trauma in a military population, and found that only 27% of headaches developed within a week post-trauma. Whether such classification, or misclassification, of headache after TBI is important is under debate.…”

“…Classification is primarily based on time of onset after injury or regaining consciousness (within 7 days), and chronicity of headache based on duration of headache lasting less than or greater than 3 months (acute versus chronic). However, several studies have reported a longer latency between injury and PTH and a higher incidence of chronic PTH than one would expect based on the ICHD definition (Martins et al, 2009;Theeler and Erickson, 2009).…”

Combat exposure and migraine headache: Evidence from exogenous deployment assignment

“…In alternate specifications, we also include controls for predeployment migraine status, a neuroticism scale, and health, which should not affect our estimates of the effect of combat exposure if deployment assignment is exogenous. 9 A similar pattern of results is observed when we restrict the sample to only those who were serving in the Army. These findings are shown in Appendix Table 2. 18 firefight.…”

“…3). Migraines have been found to account for nearly 75 percent of post-traumatic headaches observed in soldiers (Theeler et al, 2008;Vargas, 2009) and have been linked to blast-or explosion-induced mild TBI (Vargas, 2009;Seifert and Evans, 2010;Theeler and Erickson, 2009). …”

“…We view this evidence as at least suggestive that deployment assignment is exogenous to health. 9 Under the assumption that, conditional on occupation, rank and branch, overseas deployment assignment is exogenous, δ 1 -δ 2 can be interpreted as the effect of deployment to a combat zone with firefight relative to a non-combat zone, while δ 1 can be interpreted as the marginal effect of deployment to a combat zone with firefight relative to a combat zone without For our main identification approach, we pool active-duty personnel (excluding those who served exclusively in the Reserves or National Guard) and estimate the following equation:…”