Mild head trauma and chronic headaches in returning US soldiers.

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.