Central Nervous System

The increased survival of those with blast-related head injuries in the military (due to Kevlar body armor) and the increased recognition of milder presentations through screening have prompted extensive research in this area. Much of this has been performed at the Walter Reed Army Hospital in Washington, DC, which receives returning injured troops from the Iraq and Afghanistan conflicts. Following screening, approximately 59% are diagnosed with traumatic brain injury (TBI), the majority of which are mild cases.Reference Okie ³ The extensive published military data permits comparisons between their injuries and those suffered by civilians in a similar blast, particularly terrorist bombings. ⁴

Mechanisms of acute TBI include:

• • Primary pressure wave transmitted through the skull, causing shear between the various different density tissues. Contusions, hemorrhages, edema and diffuse axonal injury may result;

• • Air embolism;

• • Acceleration/deceleration forces on the head similar to a motor vehicle accident.Reference Warden ^{5 ,} Reference Ford and Rosenfeld ⁶

Mild TBI may manifest as physical, cognitive, behavioral or emotional problems. Common symptoms include headaches, altered sleep pattern, and hypersensitivity to light, noise and distractions.Reference Martin, Lu, Helmick, French and Warden ⁷ Signs are often subtle and easily missed. There is considerable overlap with features of post-traumatic stress disorder, major depression and acute stress disorder. This association may deter some from reporting symptoms due to the stigma attached, further delaying diagnosis and interventions to help reduce the long-term sequelae.

Ear, Nose and Throat (ENT)

The ear is, by its nature, designed to be hyper-responsive to pressure changes, thus it is particularly susceptible to blast injury.Reference Darley and Kellman ⁸ Of all the long-term health impacts of blast injury, audio-vestibular problems are among the longest-lasting effects, and appropriate management is crucial to minimize associated morbidity.Reference Catchpole and Morgan ^{9 ,} Reference Nageris, Attias and Shemesh ¹⁰ Data from OklahomaReference Van Campen, Dennis, Hanlin, King and Velderman ¹¹ show no correlation between patient location and symptoms reported, suggesting that even those far from the blast should be questioned regarding symptomatology.

Hearing loss is common and long-lasting post blast exposure.Reference Catchpole and Morgan ^{9 ,} Reference Radford, Patel, Hamilton, Collins and Dryden ¹² Follow-up months and years post blast-related injury reveals a high prevalence of ongoing morbidity.Reference Van Campen, Dennis, Hanlin, King and Velderman ^{11 ,} Reference Mallonee, Shariat, Stennies, Waxweiler, Hogan and Jordan ^{13 -} Reference Van Campen, Dennis, King, Hanlin and Velderman ¹⁵ The typical 4 kHz “notch” normally associated with acoustic trauma is not always seen on the audiogram.Reference Van Campen, Dennis, Hanlin, King and Velderman ¹¹

Inner ear problems, such as tinnitus and vestibular damage, also cause longer-term damage.Reference Radford, Patel, Hamilton, Collins and Dryden ¹² Progress is slow, and the effects long-lasting; only seven percent of patients with tinnitus post-blast exposure in Israel showed any improvement at one year.Reference Nageris, Attias and Shemesh ¹⁰ Dizziness and balance problems are among the main complaints of service personnel returning from Iraq after blast exposure.Reference Scherer and Schubert ¹⁶

Tympanic membrane rupture is commonly observed.Reference Turegano-Fuentes, Caba-Doussoux and Jover-Navalón ¹⁷ Poor healing rates have been noted, possibly secondary to the severity of the explosion.Reference Miller, McGahey and Law ¹⁴ Long-term complications can ensue: cholesteatoma,Reference Roth, Kronenberg, Lotem and Leventon ¹⁸ otitis,Reference Roth, Kronenberg, Lotem and Leventon ^{18 ,} Reference Lucic ¹⁹ and facial nerve palsy.Reference Lucic ¹⁹

Importantly, there appears to be no correlation between the tympanic membrane injury and later complications of blast injury in other systems such as the lung.Reference Lebovici, Gofrit and Shapira ²⁰

Ophthalmology

Explosions often inflict severe eye injuries, mostly due to secondary blast effect (fragments).Reference Ari ²¹ There is a wide range of injuries seen following terrorist bombings, ranging from minor corneal abrasions to penetrating injuries of the globe requiring enucleation.Reference Thach ²² Ocular injuries also may be grossly contaminated from materials packed around the explosive device, leading to continued ooze despite washouts. There is only one documented case in the literature of injury to the eye from pure primary blast wave. ⁴

Despite the eyes’ accounting for <0.1% of the body's frontal body surface area, ocular injury has been shown to be 20-50 times greater than expected by surface area alone in combat situations.Reference Thach ²² This may be explained by the essential sensitivity of the eye compared with other epithelial structures such as the skin.

Caution in imaging choice should be exercised in those who possibly have sustained an intra-ocular metallic fragment from a blast. Thin slice Computed Tomography (CT) should be performed prior to Magnetic Resonance Imaging (MRI) in order to detect potential magnetic implanted materials. Aeromedical evacuation over 1000 m may cause extrusion of globe contents through a laceration if intra-ocular air, present from penetrating injury, expands.

Injury to Soft Tissues

Soft tissue injuries in the form of burns, crush injuries, lacerations and contusionsReference Hogan, Waeckerle, Dire and Lillibridge ²³ are the predominant blast injuries, and can cause significant long-term health effects.Reference Bumbasirević, Lesic, Mitkovic and Bumbasirević ²⁴ Disruption to soft tissue from the blast wave can result in extensive injury deep under what may appear to be a superficial wound. Not only does this often necessitate deep debridement or observation for injury, but the resulting nociceptor stimulation can result in wounds which may produce pain disproportional to the apparent injury, and adequate analgesia is important.Reference Aldington, Mcquay and Moore ²⁵ The presence of foreign bodies in wounds, from shrapnel or even embedded bony fragmentsReference Wong, Marsh, Abu-Sitta, Lau, Mann, Nawabi and Patel ²⁶ from a suicide bomber or other casualties, creates management challenges in terms of debridement, infection control and long-term wound healing. The effect of heat is two-fold. Hot fragments may immediately cauterize wounds, resulting in less blood loss than expected,Reference Potter and Carter ²⁷ and burns from the blast can predominate, especially in thermobaric-style blasts as occurred in Bali in 2002.Reference Edgar and Goodwin-Walters ²⁸ Infection of burns, especially if dirty fragments have been embedded, can be particularly problematic.Reference Silla, Fong, Wright and Wood ²⁹

Abdominal Injury

As in the case of blast lung and tympanic membrane rupture, the air-filled abdominal viscera suffer most from primary blast injury. Although primary blast wave abdominal injuries are typically seen in underwater explosions, there is an increased incidence of this problem being associated with complex blast waves in confined spaces. ^{4 ,} Reference Owers, Morgan and Garner ³⁰

The primary blast wave of an explosion can cause rapid compression, then decompression, of hollow structures, constricting the bowel wall layers of different densities at different rates.Reference Crabtree ³¹ The ensuing separation of mucosal layers leads to varying degrees of hemorrhage and possible thrombosis. Transmural necrosis of the bowel wall may then occur due to hypoperfusion. This may happen hours or even several days later, leading to eventual perforation.Reference Crabtree ^{31 ,} Reference Katz, Ofek, Adler, Abramowitz and Krausz ³² This mandates a period of careful observation in patients at risk, serial examination, and often repeated imaging.

The ileocaecal region is the most frequent site of injury.Reference Crabtree ^{31 -} Reference Mayorga ³⁴ Solid organs, usually the liver or spleen, may be contused or lacerated with high-intensity blast waves.

Suicide bomb victims in Israel often undergo whole body x-ray or CT scanning to detect fragment injury. Such injury to the buttock region can result in trauma to the lower colon/rectum, and clinicians should be vigilant in detecting this.Reference Aharonson-Daniel, Klein and Peleg ³⁵

Lung Injury

Blast lung injury is the most common fatal primary blast injury, and is second only to tympanic membrane rupture as the most frequent injury. It typically presents with dyspnea, hemoptysis, cough, and chest pain, with signs similar to acute respiratory distress syndrome. Primary blast waves cause tearing within the alveoli or blood vessels, hemorrhage, contusions and edema.

There is a characteristic latent period before the development of features of blast lung injury, and that period may be as long as 48 hours. ⁴ Deteriorating patients with blast lung injury require intubation and careful titration of ventilator pressure settings to avoid further barotraumas, and intravenous fluids to avoid overload.

Other respiratory health effects include inhalational injury, from hot toxic gases and aerosolized microbes, and air emboli from the blast wave.

Pain

Pain levels from blast can often be higher than those experienced by other mechanisms of injury, possibly because of deeper soft tissue disruption and stimulation of nociceptors. There is a case for starting analgesia directed at neuropathic and chronic pain very early in the patient's management.Reference Aldington, Mcquay and Moore ²⁵ Blast-injured patients had increased use of opioid on discharge, and reduced improvement in pain intensity, compared with those injured via other means.Reference Clark, Walker, Gironda and Scholten ³⁶

Infection

Explosive events frequently result in a large amount of bloodshed at the scene, particularly when secondary fragments are produced. Victims, rescuers, emergency medical services personnel, and hospital staff are all at potential risk of bloodborne infection, most notably from hepatitis B or C and Human Immunodeficiency Virus (HIV). Particular care should be taken in this environment, where there are likely to be multiple sharp projectiles such as broken glass.

There have been no documented cases of infectious disease transmission in suicide bombings.Reference Siegel-Itzkovich ³⁷ However, implantation of infected biological material has been noted in one case report.Reference Braverman, Wexler and Oren ³⁸ Current HPA/Department of Health guidance is to give an accelerated hepatitis B vaccination course for those with penetrating wounds, and to assess the need individually for those splashed with blood. ³⁹ Recommendations worldwide will depend on the prevalence of these infections in the local population.

The risk of infected wounds increases if the explosive material was contaminated or buried, wounds are not washed or dressed expediently, and if there is delay in debriding eschar from resultant burns.Reference Silla, Fong, Wright and Wood ²⁹

Aerosolized microbes from the surrounding environment have the potential to become pathogenic following explosions, e.g., candidemia associated with inhalational injury from market place bombings.Reference Wolf, Polacheck and Block ⁴⁰

Cardiac

Acute coronary syndromes have commonly been linked to stressful events, and explosions and terrorist events are no exception. Emotional triggers lead to acute autonomic dysregulation, neuroendocrine activation, and hemostatic and inflammatory responses. If this is associated with plaque disruption, it can result in myocardial ischemia, cardiac dysrhythmias, and thrombosis formation,Reference Bhattacharyya and Steptoe ⁴¹ and rates of acute coronary syndrome have been shown to rise after blast exposure.Reference Ruidavets, Paterniti, Bongard, Giroux, Cassadou and Ferrières ⁴² Injury to the heart from a blast can be similar to that from blunt trauma; contusions and microscopic injuries predominate, predisposing to arrhythmias.Reference Crabtree ³¹ Cardiac monitoring and further investigation should be undertaken when cardiac injury is suspected.Reference Crabtree ³¹

Orthopedics

Immediately apparent orthopedic injuries related to blast, such as fractures, strains and dislocations, can result in immediate and prolonged disability. It is vital that less apparent injuries, which may present later, are not missed, especially thoracic and lumbar injuries.Reference Roth, Kronenberg, Lotem and Leventon ^{18 ,} Reference Helgeson, Lehman, Cooper, Frisch, Anderson and Bellabarba ⁴³ Late presentation of back pain in the blast victim should not be ignored. Orthopedic injuries can disable an otherwise economically productive population, leaving reduced ability to function and care for dependents, which puts added pressure on the surrounding community.Reference Museve ⁴⁴ Late complications of orthopedic injury, such as compartment syndrome, infection, malunion, deep vein thrombosis (DVT) and neuropathic pain, must also be anticipated. Late development of pseudoaneurysms has also been reported.Reference Freiman, Marom, Ofer, Hoffman and Calif ⁴⁵

Inflammatory Responses

Recent work highlights the inflammatory response as part of a “quinary” stage blast injury. A unique, “hyperinflammatory” state manifesting as hyperpyrexia, sweating, and low central venous pressure despite adequate fluid input, has been reported.Reference Kluger, Nimrod, Biderman, Mayo and Sorkin ⁴⁶ Similar results from Belgrade point to markedly raised levels of eicasonoids resulting from the physical stress of blast injury.Reference Cernak, Savic, Ignjatovic and Jevtic ⁴⁷ More research is required in this area to determine the long-term health effects.

Psychiatric Complications

Psychiatric and psychological reactions and long-term health effects following any sudden adverse event are common. The sudden and devastating impact of an explosion on casualties, emergency responders, and the community as a wholeReference Crabtree ^{31 ,} Reference Birmes, Raynaud and Daubisse ⁴⁸ can have an effect on long-term mental health, particularly if it is related to a terrorist attack. One disaster health model cannot be used to describe all post-disaster scenarios—the event type and the population affected alter the psychiatric needs.Reference North ^{49 ,} Reference Pffefferbaum, North, Flynn, Norris and DeMartino ⁵⁰

Post-traumatic stress disorder is the most widely-reported psychiatric consequence of blast exposure.Reference Brewin, Fuchkan and Huntley ^{51 ,} Reference North, Pfefferbaum, Kawasaki, Lee and Spitznagel ⁵² There is evidence of early onset post-exposure, and therefore it can be detected by screening soon after the event.Reference North, Nixon and Shariat ⁵³ Early intervention is beneficial,Reference Whibley ⁵⁴ and cognitive behavioral therapy (CBT) has been found to be useful in treatment.Reference Brewin, Fuchkan and Huntley ^{51 ,} Reference Gillespie, Duffy, Hackmann and Clark ⁵⁵ There is a postulated link between traumatic brain injury and post-traumatic stress disorder.Reference Warden ⁵⁶

Psychological distress in emergency responders has been noted.Reference Sansone and Roman ^{57 -} Reference Collins and Long ⁶⁰ Other noted symptoms include anxiety,Reference Hoek, Braceridge and Oliver ⁶¹ depression,Reference Riviere, Albessard, Gardette, Lapierre-Duval, Schwoebel and Lang ⁶² increased substance misuse,Reference North, Tivis and McMillen ^{63 ,} Reference North, Tivis and McMillen ⁶⁴ and worsening of previous psychiatric disorders.

Pregnancy

There is very little literature relating specifically to long-term health effects of the pregnant blast casualty. The main risks that may be missed are placental abruption, amniotic fluid embolus, and possible increased risk of blast lung.Reference Matthews ⁶⁵ Fetal skull fractures co-existing with maternal pelvic fracture have been reported.Reference Matthews and Hammersley ⁶⁶ Rhesus status should be established, and Anti-D given as necessary.

Pediatrics

Sadly, the indiscriminate nature of bombings and explosions means that children are as likely to be injured as adults. Physiological and psychological characteristics of the pediatric patient are such that their long-term health management poses particular challenges. Much data comes from the Oklahoma bombing. The second floor of the Alfred P. Murrah building housed a nursery in which 19 children died and 66 were injured.Reference Quintana, Parker, Jordan, Tuggle, Mantor and Tunell ⁶⁷ Tympanic membrane rupture was found to be particularly prevalent in children.Reference Quintana, Parker, Jordan, Tuggle, Mantor and Tunell ⁶⁷ Head injury also predominated,Reference Quintana, Parker, Jordan, Tuggle, Mantor and Tunell ⁶⁷ highlighting the crucial importance of suitable investigation for those presenting with head injury and clear advice for those discharged home. The day of the Omagh bombing was a children's carnival day, and nine children were killed, the most severely injured showing evidence of abdominal injury and burns.Reference Lavery and Horan ⁶⁸ Data from Iraq highlights the importance of a pediatric trauma registry to ensure adequate patient follow-up.Reference McGuigan, Spinella and Beekley ⁶⁹

The possible lack of evident external injury in children despite significant internal injury should be emphasized, and the need for repeated examinations and periods of observation stressed.Reference Quintana, Parker, Jordan, Tuggle, Mantor and Tunell ⁶⁷ This relates predominantly to abdominal, chest and head injury. In one extreme case report, a 14 year-old girl with no evidence of external wounds was found to have a nail embedded in her brain, with an entry site inside her mouth.Reference Benjaminov, Sklair-Levy, Rivkind, Cohen, Bar-Tal and Stein ⁷⁰ Children are more prone to abdominal blast injury than adults, due to their thinner abdominal walls and proportionately larger solid organs. ⁴

The wider implications of pediatric injury must not be ignored. Psychological consequences, with anxiety and behavioral problems, are common after exposure to blast.Reference Pfefferbaum ⁷¹ It is important to acknowledge that such effects may be seen in children distant from the blast who have been exposed through media coverage or by word of mouth.Reference Pfefferbaum, Jeon-Slaughter, Pfefferbaum, Houston, Rainwater and Regens ⁷² Injury to loved ones may exacerbate problems. In the worst case, the primary caregiver may have been severely injured or killed, and ensuring ongoing care and safety of the child is paramount.