Battlefield brain

Mild traumatic brain injury in Afghanistan

Head injury is not uncommon among nondeployed military members and is more likely among deployed personnel. Soon after the start of the Afghanistan and Iraq wars in 2002, researchers found that MTBI episodes were self-reported by 12% to 20% of American military members returned from deployment to Iraq and Afghanistan; explosive ambush blast was recognized as a common mechanism of injury. Concern arose that blast-related MTBI could be occurring among combat troops. Military forces provided guidance on MTBI recognition and management.4,5

Blast injury

Blast is a rare mechanism of injury in civilian life, but it is common in combat. Blast weapons cause injury as a result of supersonic waves of intense air pressure and a variety of other mechanisms including blunt force.6 Severe blast energy exposure can cause multiple injuries, including ruptured tympanic membranes, transient cardiorespiratory effects such as apnea, and “blast lung.” Limited evidence from clinical experience, animal research, and case reports suggests that lower primary blast energy doses might cause isolated brain injury; however, controversy persists.7 The dose required to cause isolated MTBI is not known. Blast energy dissipates rapidly with distance, is highly variable, and is difficult to estimate. Until definitive research is available, it is prudent to consider the possibility that pure blast energy might cause isolated MTBI in some individuals.

Causes of persistent symptoms

Postconcussion symptoms can occur just as frequently among trauma patients with brain injury as among those without head injury8 and they are common in the general population. Considerable research effort is under way in Canada and around the world to resolve uncertainties about causes of PCSs.4

Brain injury does not necessarily cause lasting brain damage. There is consensus from several lines of evidence that cellular-level cascades lead to neuronal damage in moderate to severe head injury.9 The degree to which this pathophysiology accounts for PCSs remains unproven.2,4 Since World War I “shell shock,” controversy has persisted over whether brain injury, psychological reactions, or both account for persistent symptoms.2,4,10

Medically unexplained symptoms occur among Veterans of every war.11 Jones et al10 pointed out that societal belief can lead people to attribute symptoms to causes in spite of insufficient proof. They explained how “shell shock” was used popularly to explain as purely physical many symptoms experienced by Veterans who had been subjected to bombardment during World War I. Physicians of the day, however, were unable to distinguish between head injury and exceptionally stressful experiences as the cause of certain symptoms. Bryant12 recently warned about the consequences of inappropriately attributing PCSs to MTBI when they might be due to psychiatric conditions such as posttraumatic stress disorder or depression, or to other medical conditions.

Recognition and diagnosis

Ask about MTBI history in military Veterans with persistent, nonspecific symptoms. A thorough history and physical examination with attention to the neurological system is appropriate. When a Veteran gives a history of MTBI, inquire about all 3 symptom groups presented in Table 1.

No diagnostic test confirms MTBI. At present, the diagnosis relies on characteristic symptoms, neurocognitive findings, a credible timeline from the time of injury, and exclusion of alternatives. Imaging is not required in most cases. Promising tools allow researchers to look into the brain at the cellular or biochemical level where brain injury is thought to cause functional problems. Future prospects include biochemical markers of acute brain injury and functional magnetic resonance imaging.

It might not be possible to diagnose brain injury as the cause of symptoms many years after MTBI. The differential diagnosis includes many psychiatric and medical conditions, and the cause might be multifactorial. Early referral for mental health care is recommended for management of cognitive and psychological symptoms. Neurocognitive testing is appropriate when cognitive dysfunction is suspected and might be paid for by VAC, with preapproval for eligible clients.

Treatment

Despite weakness in the evidence base,1 experts believe that effective help is available for those suffering persistent symptoms after MTBI, whether or not the diagnosis is clear. Keys to successful outcome include a good collaborative relationship with a primary care provider, a team approach and attention to the military context of the Veteran’s concerns. Postconcussion symptoms such as depression, cognitive dysfunction, and headache respond to standard assessment and treatment. Early referral for mental health assessment and treatment is appropriate. When somatic symptoms fail to respond to standard treatments or there are specific indications, refer patients to neurology, ophthalmology, otolaryngology, or audiology.

Clients of VAC

Eligible clients of VAC, which can include serving members of the Regular and Reserve Canadian Forces, members of the Royal Canadian Mounted Police, and Veterans, might qualify for disability compensation and treatment. The 2006 New Veterans Charter introduced sweeping service changes for Canadian Forces members, Veterans, and their families. Rehabilitation programs assist eligible Veterans whose service-related health problems interfere with transition to civilian life. Depending on eligibility, these programs can include case management, rehabilitation, financial benefits, group health insurance, job placement assistance, support to families, access to lump-sum disability awards, and various health benefits.

Operational stress injury is defined as persistent psychological difficulty resulting from military service.13 Canada’s family physicians have long identified lack of access to mental health referral as a priority.14 Veterans Affairs Canada has been establishing multidisciplinary, military context–aware OSI clinics across Canada. A physician who feels that a Veteran would benefit from OSI clinic treatment may contact the nearest VAC district office, where client services teams assist eligible clients using case management to facilitate services when required.

Veterans Affairs Canada’s clients and staff depend on family physicians to complete paperwork supporting applications. Communication between VAC and family physicians ensures continuity of care for their shared Veteran clients and patients. The department’s client service teams welcome family physician collaboration.

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