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]

• Dysphagia

  However, dysphagia developed 4 years later because of severe reflux-induced stenosis at the junction of the cervical esophagus and the left pedicled colon segment. [ncbi.nlm.nih.gov]

• Thin Skin

  The thin skin paddle was used for soft tissue coverage of flexor tendon repair, median and ulnar nerve reconstruction, and metacarpal bone open reduction and internal fixation (ORIF). Recovery of motor function was satisfactory. [ncbi.nlm.nih.gov]

• 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

  Long-standing hearing problems and mood disturbance, for example, could have received more immediate attention. Importantly, the patient's perceptions and satisfaction with his care improved dramatically under the mechanism-of-injury approach. [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]

• Poor Coordination

  Results provide evidence for poor coordination of frontal neural function after blast injury that may be the consequence of damaged anterior white matter tracts. Published by Elsevier Inc. [ncbi.nlm.nih.gov]

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.

• Staphylococcus Aureus

  We found that the VAC Therapy system produced more late methicillin-resistant Staphylococcus aureus infections (30%), more unanticipated returns to the operating room for wound problems (4:12 vs 0:12), and required more surgeries overall until closure [ncbi.nlm.nih.gov]

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3. Wani I, Parray FQ, Sheikh T, et al. Spectrum of abdominal organ injury in a primary blast type. World J Emerg Surg. 2009;4:46.
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9. Kirkman E, Watts S, Cooper G. Blast injury research models. Philos Trans R Soc Lond B Biol Sci. 2011;366(1562):144-159.