Blast injuries from Madrid terrorist bombing attacks on March 11, 2004
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- Martí, M., Parrón, M., Baudraxler, F. et al. Emerg Radiol (2006) 13: 113. doi:10.1007/s10140-006-0534-4
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Blast injuries after terrorist attacks are seen with increasing frequency worldwide. Thousands of victims were attended in the hospitals of Madrid, Spain, on March 11, 2004 after the bombing attacks against the commuter trains. Thirty-six patients were attended in our institution. Seventeen of them suffered from severe or life-threatening injuries, and 19 had mild injuries. The most common lesions were thoracic trauma and blast lung injury, acoustic trauma, and orbital and paranasal sinus fractures. Other findings were hepatic and splenic lacerations, and vertebral and limb fractures. Emergency radiology had an important role in the correct management of the victims. Prompt radiological diagnoses of these complex lesions are crucial to efficient treatment. Therefore, radiologists have to become familiar with the injury patterns and specific lesions caused by blast wave.
KeywordsTerrorismBlast injuriesBlunt injuriesDiagnostic imagingComputed tomographyRadiography
There are various scenarios that lead to injury from blast, sometimes referred to as blast overpressure injury. However, the number and extent of worldwide terrorist attacks has risen sharply in recent years [1, 2].
Terrorism has been defined as all kinds of criminal acts directed against a state and intended or calculated to create a state of terror in the minds of particular persons or a group of persons or the general public .
Primary blast injuries are caused solely by the direct effect of blast overpressure on tissue. Unlike water, air is easily compressible. As a result, primary blast injuries usually affect air-filled organs and air–fluid interfaces such as the lungs, the middle ear, and the gastrointestinal tract. Rupture of tympanic membranes, pulmonary damage, and air embolization, as well as rupture of hollow viscera, are the most important primary forms of blast injury.
Secondary blast injuries, like penetrating trauma and fragmentation injuries, are caused by bomb fragments and other displaced objects.
Tertiary blast injuries are caused by the effects of structural collapse and of persons being thrown by the blast wind (penetrating or blunt trauma, fractures, and traumatic amputations).
Quaternary blast injuries refer to burns, toxic inhalation, exposure to radiation, asphyxiation, and inhalation of dust and include exacerbations or complications of persisting conditions (e.g., patients receiving anticoagulants, pregnant women, etc.).
Body part affected
Types of injuries
Caused by the impact of the over-pressurization wave with body surfaces
Air containing structures are most vulnerable (ear, lungs, gastrointestinal tract)
Blast lung, bowel perforation and hemorrhage, mesenteric shear injuries, solid organ lacerations, eye perforation, tympanic membrane rupture, ossicular disruption, cochlear damage, brain contusions without physical signs of head injury
Caused by bomb fragments and other displaced objects
Any body part may be affected
Penetrating ballistic (fragmentation) or blunt injuries
Caused by individuals being thrown by the blast wind
Any body part may be affected
Penetrating or blunt trauma, fractures and traumatic amputations, closed and open brain injury
All explosion-related injuries, illnesses, or diseases not due to primary, secondary, or tertiary mechanisms. Includes exacerbation or complications of existing conditions
Any body part may be affected
Burns, breathing problems from toxic fumes
The injuries suffered by survivors of these attacks combine the lethal effects of penetrating trauma, blast injury, and burns [2, 7, 8]. However, bombing incidents are prone to be highly variable concerning scene settings, victim populations, and explosive charge properties including weight and chemical structure . In general, damage decreases exponentially with distance from the point source of the blast . When explosions take place inside buildings, trains, and busses, standing waves and enhanced differences in pressure occur because of the additive effects of reflections or reverberations from walls and rigid objects [6, 9]. Reflection from surfaces such as walls can increase the blast effect by a factor to two to eight .
This article provides a description of radiological findings of blast injuries among victims admitted to the University Hospital La Paz on March 11, 2004, emphasizing specific lesions like blast lung injury. It is our intention to review the injury patterns resulting from explosions in a semi-confined space.
Materials and methods
Within the short period of 30 min, 36 patients were brought to the emergency department. Twenty patients were men and 16 were women, including one pregnant woman.
Each severely injured patient (yellow and red) was surveyed by a physician team (intensivist, orthopedic, and general surgeon).
On March 11, the radiologic team consisted of one coordinator radiologist, one emergency radiologist, two neuroradiologists, and three radiologists in training.
Plain radiograph (GE; two systems)
Portable plain radiograph (GE; two systems)
Ultrasonography, Power Vision (Toshiba)
Portable ultrasonography (Tosbee)
Dual multidetector helical Computed Tomography (CT), Asteion Dual (Toshiba)
In addition, there were other two helical CT systems (Somaton Plus, Siemens) available in the general radiology area.
CT examinations were performed in accordance with our routine departmental protocol. Sequential cranial CT was undergone first. Then, thoracic and abdominal scans were obtained from the apex of the lungs to the inferior edge of ischia after intravenous contrast injection. One hundred and thirty milliliters of contrast material was administered by bolus injection with a scan delay of 50 s. No oral contrast medium was given before the examinations. Approximately, the total scan time was 25 s. In some patients, cervical or facial CT was also performed. Oral and handwritten reports were immediately elaborated.
During the first 3 h after the admittance of the patients in the emergency area, there were 17 cranial CT performed, 16 body CT, 2 cervical spine CT, 4 facial CT, 6 focused abdominal sonogram for trauma (FAST), 3 abdominal sonograms, 24 plain chest radiographs, 16 lower limb radiographs, and 24 radiographs of other anatomic regions.
Distribution of injuries
Distribution of injuries in green patients
Number of patients (%)
Unilateral rupture of tympanic membrane
Bilateral rupture of tympanic membrane
Minor thoracic trauma
All of the 19 green patients were discharged from the emergency department throughout March 11.
Severely injured (yellow and red) patients
Main injured body region in yellow and red patients
Number of patients (%)
Head, face, and neck
Skin (severe burns)
Head and neck, thoracic, and abdominal lesions in severely injured patients diagnosed in the first imaging approach
Head and neck
Paranasal sinus fracture
Hemorrhagic brain contusions
Blast lung injury
3 (1)/17 (18%)
Free peritoneal fluida
US + CT
Abdominal pain without imaging findings
2 US + CT
Head, neck, and spine
Body CT revealed two dorsal vertebral body fractures and lumbar transverse apophysis fractures in two patients (one of them developed a psoas hematoma).
The spectrum of associated thoracic lesions included pleural effusion (n = 7, 41%), rib fractures (n = 5, 29%), pneumothorax (n = 3, 18%, a tension pneumothorax in one patient, with contralateral deviation of mediastinal structures), mediastinal hematoma (n = 2, 12%), pneumomediastinum (n = 2, 12%), vertebral fracture (n = 2, 12%), and subcutaneous emphysema (n = 2, 12%; Figs. 9b, 12, and 13). No great mediastinal vessel injuries were detected.
Blunt abdominal trauma was observed in four patients (24%). Two patients suffered solid organ laceration, a hepatic laceration, and a splenic laceration. In another patient, the abdominal ultrasound and CT scan showed intraperitoneal free fluid. He underwent laparotomy to have the peritoneal cavity explored, but no lesions were found. The fourth patient had an important abdominal pain without findings on FAST, abdominal ultrasonogram, and CT. The symptoms improved with conservative treatment.
During the last years, Spain has experienced its share of death and injury including the casualties of the terrorist bombing attacks on March 11, 2004 in Madrid. Traumatic injury is a disease of the young, and the patients hospitalized at our center had a median age of 36 years, which is comparable to casualties of previously known trauma types, but higher than in other series . This is due to the fact that most of the victims were workers or students.
In-hospital fatality rates were significantly lower than in other terrorist acts or in the case of war fatalities [12, 13]. The remoteness of our hospital from the explosion scenario may explain this event. The bombing incidents occurred within a train coach that is a confined space. Previous studies have claimed that, compared to patterns of injury in the open air blasts, explosions in confined spaces imply an overall increased mortality, more severe injuries, and higher incidence of primary blast injuries. However, there is no difference regarding the incidence of penetrating trauma or traumatic amputations [8, 9, 14] between the two groups.
The distribution and pattern of injuries are fundamentally comparable to the epidemiology of other series [9, 12, 15–18]. Injuries occurred predominantly to the head, neck and limbs, followed by the chest and abdominal organs. The tympanic membrane is the structure most frequently injured by blast . Therefore, rupture of the tympanic membranes observed in otoscopy serves as a sensitive marker for blast injuries in the triage .
The lungs are particularly susceptible to damage due to the extensive air/lung tissue interfaces. In addition, blast energy has been associated to tissue hypoxia, antioxidant depletion, and subsequent oxidative damage [11, 20–22]. Furthermore, the development of pulmonary dysfunction and sepsis/systemic inflammatory response syndrome remains a major threat to survival [9, 11, 23].
There were radiological findings consistent with blast lung injury in 94% of our severely injured patients. However, primary blast lung injury was associated to injury due to blunt trauma, with rib fractures or chest wall injury. Radiological findings of primary blast lung injury are characterized by ground-glass opacities or consolidations. Perihilar lung consolidations have been previously described in blast-injured patients. Still, patchy, diffuse, and subpleural opacities, might be explained by “rib imprint” hemorrhages across the surface of the pleura. Early characteristic infiltrates on chest radiographs, accompanied by severe barotrauma without rib fractures, strongly support the hypothesis that the main lung injury was caused by the blast wave itself . These radiological findings show the diffuse alveolar over-distension characterized by alveolar ruptures; thinning of alveolar septae; and enlargement of alveolar spaces, subpleural, intra-alveolar, and perivascular interstitial hemorrhage around pulmonary vessels; venous air embolism; and bone marrow and fat embolism observed in the histopathologic specimen [4, 24, 25]. In addition, the delayed effects observed over the next 24 to 48 h bear similarities to acute respiratory distress syndrome , which is more evident in patients who underwent a surgical operation.
Most of the head and neck injuries are due to direct blast effect (primary blast injuries) over air-filled cavities (middle ear, paranasal sinuses, and mastoid cells). Maxillary sinuses were the most commonly injured ones. However, these fractures were associated with other injuries (zygomaticomaxillary complex, frontoethmoidal, orbital, and endocranial lesions) in most of patients. Orbital injuries were due to a combination of direct blast effect over the fluid-filled globe (primary blast injuries) and blunt trauma (secondary or tertiary injuries) in which fragments of glass, bomb casing, masonry, or any other unsecured items were propelled by the explosion . Despite the relatively small surface area of the eyes, ocular injuries are not an uncommon cause of morbidity in victims of terrorist blasts [27–29]. Brain and spine lesions are mainly due to blunt trauma, although primary blast waves can cause concussions or mild traumatic brain injury without a direct blow to the head.
Blunt abdominal trauma was only observed in four of the victims. Rupture of the hollow viscera did not occur in our patients, although the colon shows to be the most frequent abdominal visceral structure injured in other series [30, 31]. Aside from laceration and hemorrhage of solid organs such as the liver and spleen, mesenteric ischemia or infarct may occur. The primary blast injuries to the abdomen are associated to barotraumas caused by secondary or tertiary mechanism. Quaternary blast injuries include complications of preexisting conditions, e.g., pregnancy. The pregnant woman who fell victim of the terrorist bombing had a hepatic laceration causing a massive hemoperitoneum. Probably the gravid uterus blunted the liver and caused the hemoperitoneum and shock. Transmission blast and stress wave energy is higher in fluid environments. In this case, the fetal death could directly be due to the collision of the blast wave with the fetus surrounded by the amniotic fluid, although the most common cause of fetal death is maternal shock.
Traumatic limb injuries are a consequence of the blast effect and high-energy primary fragment (part of the weapon) and secondary fragment (those that result from the explosion) injuries. Approximately 60% of the patient had orthopedic injuries. These lesions spanned a broad spectrum including soft tissue injuries, fractures, or even comminute fractures. Lower extremity is more frequently involved than the upper extremities. The complex nature of the injuries implies a high risk of infection and the need of additional surgical treatments .
In summary, the injuries suffered by the victims of the bombing attacks to the commuter trains on March 11, 2004 in Madrid had been produced by different mechanisms of blast injury simultaneously, and they were multiple and severe. When dealing with blast-injured patients, a precise triage in the emergency room is mandatory for an adequate imaging approach. Based on our experience, the radiologist should be able to recognize the whole spectrum of injuries inflicted by blasts and explosions. Prompt radiological diagnosis of these complex lesions is crucial to the efficient management of the victims.