Images courtesy of Lennard A. Nadalo, MD
Images courtesy of Lennard A. Nadalo, MD
Author
Lennard A. Nadalo, MD
Clinical Professor, Department of Radiology
University of Texas Southwestern Medical School
Consulting Staff
Envision Imaging of Allen and Radiological Consultants Association
Dallas, Texas
Disclosure: Lennard A. Nadalo, MD, has disclosed no relevant financial relationships.
Editor
Lars Grimm, MD, MHS
House Staff
Department of Internal Medicine
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewer
Jose Varghese, MD
Associate Professor of Radiology
Boston University School of Medicine
Boston, Massachusetts
Disclosure: Jose Varghese, MD, has disclosed no relevant financial relationships.
Polytrauma represents the accumulation of multiple serious injuries that collectively greatly increases the risk for death. The understanding of the mechanisms of trauma including force and direction help guide patient treatment. By anticipating the risks patients face based upon the known history and the initial evaluation, lives can be saved. Rapid CT scanning represents an important tool in the evaluation of multisystem trauma. Life-threatening injuries include cervical spine injury (left image) and aortic disruption (right image).
Triaging the most lethal injuries allows life-saving therapy to be initiated first. The Injury Severity Score is an anatomical scoring system that provides an overall score for patients with multiple injuries. Each injury is assigned an Abbreviated Injury Scale score and is allocated to 1 of 6 body regions (head, face, chest, abdomen, extremities [including pelvis], and external). The 3 most severely injured body regions have their highest score squared and added together to produce the Injury Severity Score score. The polytrauma x-rays shown demonstrate disruption of the bony pelvis (left image) and a widened aorta consistent with aortic disruption or dissection (right image).
Although a large number of injuries may prove fatal, the most common lethal injury patterns include intracranial hemorrhage, unstable cervical spine fractures, aortic tear, liver/spleen laceration, and unstable pelvic fractures. The initial evaluation of polytrauma is often a collection of x-rays. One of the indicators for multisystem trauma is the wide separation of the pubic symphysis. The force required to divide the pubic symphysis is an indication of injury. The pelvis contains multiple vessels which when injured result in severe hemorrhage. Death is usually by exsanguination. Wide separation (diastasis) of the pubic symphysis is indicated by the double-headed arrow on this pelvic x-ray. There is a second injury (fracture of the right sacrum as shown by the arrow) present as would be expected with injury of a ring system such as the pelvis.
Emergent evaluation of a cervical spine begins with a lateral x-ray from the occiput down to T1. Depending on the clinical scenario, additional imaging with CT may be appropriate. This CT of the cervical spine shows complete subluxation of C6 over C7 in a patient with a normal lateral cervical spine x-ray that did not clearly depict the lower cervical spine. Although some unstable cervical spine injuries can be surgically managed on a delayed basis (if spinal cord compression is not present) other injuries, such as a bilateral facet dislocation, usually need to be managed acutely.
Complex spinal fracture-dislocation injuries are devastating injuries often associated with aortic injuries. They usually develop secondary to significant acceleration-deceleration injury. Patients will often have spinal cord injury with neurogenic shock and varying degrees of motor or sensory deficits. MRI is the best modality to evaluate ligamentous, soft tissue, and spinal cord injury. These sagittal MRI images demonstrate spinal fracture-dislocations with injury to the spinal cord in the thoracic (left, arrow) and cervical (right, arrow) regions.
Closed head injuries can be difficult to detect on early physical examination because neurologic change may only evolve over time. Serial CT examination provides the best chance for diagnosis of traumatic closed head injuries. Typical injury patterns include cerebral contusion (edema), epidural or subdural hematoma, midline or transtentorial shift, and sheer injury. The CT shown demonstrates a subdural hematoma with multiple layers of hyperdense blood (blue arrows) resulting in mass effect with midline shift (black double-headed arrow).
Complex facial bone fractures are often found in polytrauma and can complicate intubation efforts. A detailed evaluation of the extent of injury usually requires CT with multiplanar reformatting. This oblique coronal reformatted CT demonstrates bilateral mandibular condyle fractures (white arrows) with dislocation at the temporomandibular joints (yellow arrows).
Injury to the aorta may be the result of blunt or penetrating trauma. In blunt injuries, force directed toward the sternum passes through to the heart and great vessels. The aorta is tethered to the heart via the ligamentum arteriousum, which limits movement and provides the nidus for injury, including rupture, dissection, or pseudoaneurysm. The most common site for traumatic aortic rupture is the aortic isthmus. Classical findings on radiographs include widened mediastinum (shown), tracheal displacement to the right, depression of the left main bronchus, and loss or the normal aortic knob outline. The aortic injury demonstrated on this scout image confirmed with CT angiography of the aorta.
Traumatic aortic injuries are life-threatening and many patients do not survive to reach the hospital. The initial injury is usually a contained rupture, or pseudoaneurysm. The classic CT findings in patients with traumatic aortic injury include mediastinal bleeding, aortic tear (arrow), intimal tear, tracheal shift, and dissection. The pulmonary artery (PA) and aorta (A) have been labeled.
Angiography was the traditional modality used for evaluating patients with traumatic aortic injury and is now used mainly as a confirmatory tool in hemodynamically stable patients. A contained rupture will appear as an irregular outpouching with acute margins at the classical site at the junction of the arch of the aorta and descending thoracic aorta, just beyond the origin of the left subclavian artery (shown). In some cases, an intimal flap may be appreciated.
In addition to aortic injuries, other common thoracic injuries in polytrauma include pneumothorax, hemothorax, pulmonary contusion, and an unstable chest wall (flail chest). Plain x-rays will usually facilitate diagnosis in most cases. This image from a scout CT demonstrates a tension pneumothorax on the right. The mediastinum is shifted away to the left (double-headed arrow). The patient was successfully treated by emergency placement of a right chest tube.
Polytrauma patients are at increased risk of developing pulmonary emboli in the early and late post-traumatic state due to vessel injury and stasis. The images shown are from a patient with shortness of breath following a fall from more than 30 feet. The chest x-ray (left) demonstrates a pattern of bilateral diffuse increased lung densities with a normal heart size, findings that are concerning for acute respiratory distress syndrome. Pulmonary angiography of the same patient (right) confirms a large embolus (yellow arrow) to the right upper lobe pulmonary artery branch.
These images are obtained from a patient 1 week after a fall who underwent lower extremity orthopaedic injury repair. The pulmonary angiogram (left image) demonstrates multiple pulmonary emboli (a, b). A cold left arm subsequently developed and further angiography (right image) revealed emboli in the right subclavian artery (b), right common carotid artery (a), and within the left subclavian artery (f). Labels (c, d, and e) represent well-formed emboli that passed through a patent foramen in the heart: (c) a saddle embolus forms a Y-shaped filling defect in the right subclavian artery; (d) a clot is noted within the proximal left subclavian artery; and (e) a well-formed embolus extends cephalad in the left subclavian artery. The emboli were successfully removed and the patient remained neurologically intact. A cardiac catheterization demonstrated a patent foramen of ovale heart defect as the cause of his paradoxical emboli.
Injuries to the abdomen can involve any of the solid or hollow viscera as well as the vasculature. Common abdominal injury patterns include pneumoperitoneum, hemoperitoneum, organ laceration, subcapsular hematoma, organ infarction, and active hemorrhage. CT provides the best means of evaluating abdominal injury. Reviewing images on lung windows will best reveal pneumoperitoneum which, if found, denotes underlying bowel perforation. The CT scan shown with lung windows shows pneumoperitoneum (arrow) due to multiple bowel lacerations.
Free fluid, such as blood, will accumulate in the most dependent portions of the abdomen. This may be secondary to direct vascular injury or organ damage. This CT scan demonstrates a laceration of the superior mesenteric artery with subsequent hemoperitoneum (arrow). Immediate direct communication with a surgeon is indicated in these patients because they may become very unstable and decompensate rapidly.
Solid organ injury is a major cause of mortality in abdominal injury and is best evaluated with intravenous contrast-enhanced CT. The liver is prone to injury and is the most common cause of death after abdominal trauma. Injury patterns include subcapsular hematoma, parenchymal laceration (arrow), parenchymal hematoma, and devascularization. Most blunt liver trauma is treated conservatively because many hepatic injuries will stop bleeding spontaneously.
Duodenal rupture occurs when the anterior abdominal wall is compressed violently against the spine. Gas (white arrow) is noted in the wall of the duodenum, indicating a tear of the duodenal wall. Contrast material is seen leaking to the lower liver edge (yellow arrow). Free fluid is seen in the dependent hepatorenal pouch (blue arrow). The duodenal laceration was confirmed at the time of surgery.
Hematuria in polytrauma patients may be due to injury anywhere along the urinary system. Damage to the kidneys from contusion (left image, arrow) or laceration can lead to passage of blood. Pelvic fractures (right image, arrow) can lacerate the ureters or bladder, leading to hematuria. Contrast-enhanced CT scans with delayed imaging can best evaluate these urinary tract injuries.
Multiple osseous fractures are a hallmark of polytrauma. Although all fractures need to be identified, treatment for many fractures can be delayed until more serious injuries have been addressed. Key features to identify are vascular or spinal cord injury because these can be potentially life-threatening. The CT scans are from a patient with polytrauma and demonstrate multiple rib fracture (left arrows), fracture-dislocation of the sacroiliac joint (middle arrows), and transection of the lumbar spine (right arrows).
Pelvic fracture occurs during high-impact injury and can be rapidly fatal if not adequately treated. The complications of pelvic fracture include vascular injury with hemorrhage and bladder injury with extravasation of urine. The pelvis is a ring structure and, therefore, if 1 fracture is identified, then at least 1 additional fracture must be present. Given the complex anatomy of the pelvis, CT with multiplanar reformatting is usually indicated. This three-dimensional CT reformat demonstrates left acetabular (yellow arrow), sacral (red arrow), and pubic (blue arrow) fractures with displacement of the bladder to the right due to pelvic swelling and hematoma.
Pelvic fracture may lead to hemorrhage from arterial, venous, or osseous sources. On CT this may present as hematoma (left arrow) or hemoperitoneum. Initial stabilization of the pelvic fracture, usually with external fixation, is needed. Treatment of these vascular injuries can be attempted with surgical exploration but more commonly angiographic embolization (right arrow) is used.
Images courtesy of Lennard A. Nadalo, MD
Author
Lennard A. Nadalo, MD
Clinical Professor, Department of Radiology
University of Texas Southwestern Medical School
Consulting Staff
Envision Imaging of Allen and Radiological Consultants Association
Dallas, Texas
Disclosure: Lennard A. Nadalo, MD, has disclosed no relevant financial relationships.
Editor
Lars Grimm, MD, MHS
House Staff
Department of Internal Medicine
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewer
Jose Varghese, MD
Associate Professor of Radiology
Boston University School of Medicine
Boston, Massachusetts
Disclosure: Jose Varghese, MD, has disclosed no relevant financial relationships.
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