Blast injuries are categorized as primary to quaternary, and sometimes quinary [1]. High-order explosives (HE) such as trinitrotoluene (TNT) engender high-pressure shock waves, which are the source of primary blast injuries (PBIs). HEs can cause the full spectrum of injuries, while low-order (LE) explosives such as petrol bombs, do not cause primary blast injuries (PBIs).

PBIs are mainly found in air-filled cavities in the body, the most frequently affected organs being the ears, lungs, and intestines. Ear damage is often presented as perforation of the tympanic membrane, middle ear damage, hearing loss, tinnitus, ear pain, and otorrhea [2]. Blast injury to the lung is a potentially fatal injury. It typically manifests as apnea, bradycardia, and hypotension, and other symptoms and signs include chest pain, tachypnea, dyspnea, cough, and hemoptysis. These signs arise from the lung injury itself, in addition to a cardiovascular response to the injury, manifesting as decreased cardiac output and a fall in blood pressure. Further consequences of blast lung injury are air embolism, lung contusion, acute respiratory distress syndrome (ARDS), and disseminated intravascular coagulation (DIC).

Abdominal PBIs, demonstrated by perforation of a hollow viscus, hemorrhage, and lacerations of solid organs, clinically emerge as oligemia, acute abdomen, vomiting with or without blood, and significant abdominal pain. Nevertheless, some display no outward signs initially [3]. PBIs may also cause brain injury by impairing blood flow and perfusion [4] [5]. Brain damage results from secondary and tertiary blast injuries as well.

Secondary blast injuries constitute the greater number of injuries and are the result of bomb fragmentation and airborne debris culminating in body penetration and blunt trauma [6] [7]. Tertiary blast injuries occur due to the impact against other objects when an individual is thrown by the force of the explosion. Those near the center of the blast and children are most vulnerable, so they frequently sustain fractures and may lose limbs. Quaternary blast injuries result from added effects of an explosion not mentioned above, namely burns, crush injuries, falls, subjection to radiation and toxic substances. Quinary injuries include the injurious action of post-explosion environmental contaminants, such as radiation or bacteria.

• Unconsciousness

  Internal wounds may cause dizziness, unconsciousness, laboured breathing, and bleeding. Blast waves frequently cause rupture of the fragile eardrum membrane. Usually this is manifested by pain, difficulty in hearing, and traces of blood. [britannica.com]

  These pathological findings of brain injury can result in a spectrum of acute clinical presentations ranging from mild concussion, to focal neurological findings, to unconsciousness, coma and death. [brainline.org]

  The severity of a TBI may range from mild, a brief change in mental status or consciousness, to severe, an extended period of unconsciousness or amnesia after the injury. [sandiegouniontribune.com]

  Due to unconsciousness and more immediate concerns such as massive haemorrhage, damage control surgery and rapid strategic aeromedical evacuation, neurological investigation is often assigned a lower priority and may not occur until the rehabilitation [jmvh.org]

• Painful Cough

  Patients may present with a variety of symptoms, including dyspnea, chest pain, cough, andhemoptysis. Physical examination may reveal tachypnea, hypoxia, cyanosis, anddecreased breath sounds. [doi.org]

  Some blast lung victims have obvious respiratory distress (tagged red – or black if hospital care delayed), but others just have symptoms, including shortness of breath, chest pain, cough, or bloody sputum. [disasterdoc.net]

• Tinnitus

  Case study and literature review The patient presented to a level 1 trauma and burn center with a ruptured tympanic membrane, otalgia, mixed hearing loss, dizziness, and tinnitus. [ncbi.nlm.nih.gov]

• Otalgia

  Case study and literature review The patient presented to a level 1 trauma and burn center with a ruptured tympanic membrane, otalgia, mixed hearing loss, dizziness, and tinnitus. [ncbi.nlm.nih.gov]

  […] blindness, deafness, spinal cord injury, claudication High flow O2; place supine Consider hyperbaric O2 therapy Ear Injury Tympanic membrane most common primary blast injury Signs of ear injury usually evident on presentation (hearing loss, tinnitus, otalgia [resusreview.com]

  Hence, auditory injury, especially from blast, has emerged as one of the most common combat-related injuries among deployed service members and has demonstrated the propensity to produce symptoms of tinnitus, hearing loss, otalgia, and vertigo ( 6, 7 [academic.oup.com]

  After exposure to a blast, patients might complain of hyperacusis, hearing loss, tinnitus, otalgia, or vertigo. Differences in rates of auditory system injury between civilian and military blasts may be related to the use of ear protection. [ahcmedia.com]

• Hearing Problem

  In the case of blast injuries, the burn patient who experienced a high-pressure wave, for example, may not be screened for potential hearing, cognitive, psychiatric, visual, gas-filled organ, and/or soft tissue problems. [rehab.research.va.gov]

• Vertigo

  RESULTS: Among the 41 patients (82 ears), 36 of them reported tinnitus, 25 hearing loss, 14 earache and 8 vertigo. It was noted that 44% of the patients had tympanic membrane perforations and that this was bilateral in two-thirds of the cases. [ncbi.nlm.nih.gov]

  […] deafness, spinal cord injury, claudication High flow O2; place supine Consider hyperbaric O2 therapy Ear Injury Tympanic membrane most common primary blast injury Signs of ear injury usually evident on presentation (hearing loss, tinnitus, otalgia, vertigo [resusreview.com]

  The combination of these effects can lead to hearing loss, tinnitus, headache, vertigo (dizziness), and difficulty processing sound.In general, primary blast injuries are characterized by the absence of external injuries; thus internal injuries are frequently [en.wikipedia.org]

  In addition to these symptoms, other a blast injury patient may experience tinnitus (ringing in the ear), hyperacusis (auditory hypersensitivity), vertigo, and/or balance disturbances. [hear.com]

  Hence, auditory injury, especially from blast, has emerged as one of the most common combat-related injuries among deployed service members and has demonstrated the propensity to produce symptoms of tinnitus, hearing loss, otalgia, and vertigo ( 6, 7 [academic.oup.com]

• Dizziness

  His dizziness resolved, allowing him to return to full employment. [ncbi.nlm.nih.gov]

  Internal wounds may cause dizziness, unconsciousness, laboured breathing, and bleeding. Blast waves frequently cause rupture of the fragile eardrum membrane. Usually this is manifested by pain, difficulty in hearing, and traces of blood. [britannica.com]

  Clinical Presentation May or may not include history of loss of consciousness Headache, seizures, dizziness, memory problems Gait/balance problems, nausea/vomiting, difficulty concentrating Visual disturbances, tinnitus, slurred speech Disoriented, irritability [brainline.org]

  The combination of these effects can lead to hearing loss, tinnitus, headache, vertigo (dizziness), and difficulty processing sound.In general, primary blast injuries are characterized by the absence of external injuries; thus internal injuries are frequently [en.wikipedia.org]

If possible, information should be gathered about the type and location of the explosion. A triage system is important and should be geared to rapidly identify PBIs and crush injury.

Chest radiographs are routinely obtained for all casualties exposed to overpressure, particularly in the presence of respiratory symptoms. A butterfly-shaped radiologic finding could be observed with blast injury to the lungs. Computerized tomography scans are also very useful. Both techniques may be used to investigate intraabdominal injury if suspected. The focused abdominal sonography for trauma (FAST) may be used to rapidly discern internal lesions that may not be immediately apparent and to determine the requirement for surgical intervention [8].

Laboratory tests include:

• Complete blood count, crossmatch and coagulation studies, as blood transfusion may be needed.
• Urinalysis is important as myoglobinuria indicates rhabdomyolysis. Also, it serves for the detection of renal injury.
• Acid-base parameters should be monitored, and carboxyhemoglobin measured; more so if the explosion happened within an enclosed space [9].
• Electrolytes levels, including calcium and phosphate, which may be deranged due to explosive chemicals.

The fact sheets may be viewed and downloaded for use in the treatment of blast injury patients, in the training of clinical staff or to disseminate to others. [acep.org]

Consideration was given to specific descriptions of survivors of closed head injury and their treatment. [ncbi.nlm.nih.gov]

Prognosis for a blast injury The prognosis for a blast injury is generally very good. In most cases, a patient will notice improvements within 6 weeks of the incident – often to complete recovery. [hear.com]

F Turégano-Fuentes, D Pérez-Diaz, M Sanz-Sánchez, R Alfici and I Ashkenazi, Abdominal blast injuries: different patterns, severity, management, and prognosis according to the main mechanism of injury, European Journal of Trauma and Emergency Surgery, [dx.doi.org]

Prognosis Mortality rates vary widely. [patient.info]

[…] of up to 50% of those suffering a primary blast injury to the lung. 10-14 Furthermore, several studies show that isolated eardrum perforation in survivors of explosions does not appear to be a marker of concealed pulmonary blast injury nor of a poor prognosis [emdocs.net]

Takahashi H, Shoko T, Taketazu F, Kuriyama K, Yoshikawa K, Deguchi Y Acute medicine & surgery 5(1) 106-109 Jan 2018 [Refereed] Investigation and treatment of pulmonary embolism as a potential etiology may be important to improve post-resuscitation prognosis [researchmap.jp]

Injuries were classified by etiology of explosion and anatomical location. Eighty-nine cases of blast injury were identified in 57,392 patients (0.2%) treated over the study period. [ncbi.nlm.nih.gov]

In the current military conflict in Iraq and Afghanistan, blast injury overwhelmingly is the most common wound etiology, and the incidence of survivors with brain injury has increased. [brainline.org]

Takahashi H, Shoko T, Taketazu F, Kuriyama K, Yoshikawa K, Deguchi Y Acute medicine & surgery 5(1) 106-109 Jan 2018 [Refereed] Investigation and treatment of pulmonary embolism as a potential etiology may be important to improve post-resuscitation prognosis [researchmap.jp]

A second etiology of tertiary injuries is the collapse of buildings or structures. Head injuries, fractures, blunt trauma, crush injuries, compartment syndrome, and asphyxia are sustained as the result of tertiary blast injury. [epmonthly.com]

With contributions by experts from around the globe, the book covers topics such as the epidemiology of blast and explosion injury, pathology and pathophysiology, and the modeling and mechanism of injury. [books.google.com]

LEVEL OF EVIDENCE: Epidemiologic study, level III. [ncbi.nlm.nih.gov]

Background: Recent epidemiologic studies have reported an increased risk for respiratory conditions in service members deployed to Iraq or Afghanistan (1) since 2001 and an increasing prevalence of chronic lung disease in this population (2). [annals.org]

We reviewed the pathophysiology of blast-related injuries and their implications for management. There is much overlap in treatment of these wounds, and a detailed description is beyond the scope of this review. [ncbi.nlm.nih.gov]

With contributions by experts from around the globe, the book covers topics such as the epidemiology of blast and explosion injury, pathology and pathophysiology, and the modeling and mechanism of injury. [books.google.com]

Citing Literature Number of times cited according to CrossRef: 26 Jason E Smith and J Garner, Pathophysiology of primary blast injury, Journal of the Royal Army Medical Corps, 10.1136/jramc-2018-001058, 165, 1, (57-62), (2018). [dx.doi.org]

Centers for Disease Control and Prevention (CDC). [acep.org]

This paper describes the diagnosis, management, and relevant educational and preventive measures of the problem. [ncbi.nlm.nih.gov]

CEU: The Centers for Disease Control and Prevention is authorized by IACET to offer 0.6 CEU’s for this program. [georgiapoisoncenter.org]

From the Centers for Disease Control and Prevention, 2009. www.cdc.gov. [brainline.org]

To address this issue, Centers for Disease Control and Prevention (CDC), in collaboration with partners from the Terrorism Injuries Information, Dissemination and Exchange (TIIDE) Project, as well as other experts in the field, have developed fact sheets [web.archive.org]

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