Why are blast injuries such an important issue right now? At this very moment, our country’s armed forces are facing the constant threat of encountering explosives, whether in the form of rocket-propelled grenades, improvised explosive devices (IEDs), or land mines. Civilian workers and military personnel working in these combat zones are at increased risk of blast-related trauma, particularly blast-related traumatic brain injury (TBI). Some of the TBI and concussive injuries associated with explosions aren’t diagnosed accurately due to several confounding factors. For one thing, injuries caused by explosions cause a multitude of separate problems, and blast-induced TBI or concussion is often the least visibly apparent. The focus of medical care providers must be on the most life threatening injuries, and often a concussion or mild TBI would leave no outward marks to diagnose. Another confounding factor is that service members might cover up their symptoms because they won’t want to abandon their unit. Because blast exposure is so common in the combat zones and almost everyone has had some of the acute symptoms of concussion, it may not be identified as problematic until the service member returns home from the deployment.
A TBI is caused by a blow or jolt to the head, or a penetrating head injury that disrupts the normal function of the brain. Exposure to a blast event can affect the body in a number of ways, depending on the details of the specific event. The complex collection of injuries and their various competing symptoms makes diagnosis and treatment much more difficult. Primary blast waves can cause concussions or mild traumatic brain injury (MTBI) without a direct blow to the head. Consider the proximity of the victim to the blast particularly when given complaints of headache, fatigue, poor concentration, depression, anxiety, and insomnia. The symptoms of concussion and posttraumatic stress disorder (PTSD) can be similar and confound diagnosis.
Explosions have the capability to cause multisystem, life-threatening injuries, which result in complicated triage, diagnostic, and treatment challenges. Explosions can produce classic injury patterns from blunt and penetrating mechanisms to several organ systems, but they can also result in unique injury patterns to specific organs including the lungs and the central nervous system. Understanding these crucial differences is critical to managing the symptoms.
The extent and pattern of injuries produced by an explosion are a direct result of several factors including the amount and composition of the explosive material, the surrounding environment, the distance between the victim and the blast, the delivery method if a bomb is involved, and any other environmental hazards. No two events are identical, and the spectrum and extent of injuries produced varies widely.
Blast injuries are divided into four classes: primary, secondary, tertiary, and quaternary. Primary injuries are due to the initial shock wave as it moves through the body, targeting gas-containing organs like the ears, lungs, and gastrointestinal tract. Secondary injuries are due to bomb fragments and other shrapnel. Tertiary injuries are caused when the body becomes airborne and impacts with other objects. Quaternary injuries include burns, crushing injuries and respiratory injuries.
Blast injuries can cause hidden brain damage and neurological deficits based on the complex pattern of damage. Blast injuries usually manifest in trauma involving multiple organ systems. For example, bleeding from injured organs like the lungs or bowels can trigger a lack of oxygen in other vital organs, including the brain. Tissue destruction initiates the synthesis and release of hormones into the bloodstream which, when delivered to the brain, change its function. Irritation of the nerve endings in injured peripheral tissue and organs also significantly contributes to blast-induced neurotrauma.
Individuals exposed to blasts frequently manifest loss of memory for events before and after explosion, confusion, headache, impaired sense of reality, and reduced decision-making ability. Patients with brain injuries acquired in explosions often develop sudden, unexpected brain edema and cerebral vasospasm despite continuous monitoring; however, the first symptoms of blast-induced neurotrauma (BINT) are latent, occurring months or sometimes years after the initial event. The broad variety of symptoms includes weight loss, hormonal imbalance, chronic fatigue, headache, and problems in memory, speech and balance. These changes are often debilitating, interfering with daily activities. Because BINT in blast victims is underestimated, valuable time is often lost for both preventive therapy and timely rehabilitation.