Penetrating trauma to chest: what does a radiologist need to know?
Penetrating trauma to chest with pulmonary contusion and laceration, hemopneumothorax, rib fracture and subcutaneous chest wall emphysema
A 27 year old male was stabbed in his left chest by a knife. He was brought to the emergency department by his friend. On examination, the patient was conscious and was well oriented to time, place and person. His blood pressure was 130/80 mm Hg and his pulse rate was 110 beats per minute. There was a puncture wound noted in his left chest.
Patient underwent chest X-ray followed by a non contrast CT chest. Frontal chest radiograph demonstrated spectrum of findings related to the penetrating injury to chest. Chest X-ray posteroanterior view demonstrated left 4th rib fracture with subcutaneous emphysema. Pulmonary contusion and laceration was noted in the left parahilar region. Apical pneumothorax was also noted in the chest X-ray. CT chest was done for further evaluation and it correlated with the findings in the chest X-ray. Patient was managed conservatively.
General epidemiology and clinical presentation: Stab injuries are a form of penetrating trauma that may be self-inflicted or inflicted by another person. Either accidental or intentional, they may be caused by a variety of objects and may occur anywhere in the body. Young male patients are more likely to be involved in these kind of injuries and the presenting features depend upon the site and the extent of the injury. Imaging findings: In penetrating trauma to the chest, injury can be in the chest wall, pleural cavity, lung parenchyma or can extend all the way to the mediastinum. CT is the imaging modality of choice for the evaluation of these patients. In cases with clinical suspicion of vascular injury or mediastinal injury, contrast CT chest should be done. Imaging feature depends upon the site and the depth of the penetration. Chest wall findings can be wall hematoma (hyperdense collection in chest wall), subcutaneous emphysema (air foci in the chest wall) or rib fracture (discontinuity in one or more ribs). Findings in the pleural cavity can be in the form of pneumothorax (air in the pleural cavity), hemothorax (hyperdense collection in the pleural cavity) or both (with air fluid level on X-ray or CT). Lung parenchymal injury can present with lung contusion (non-segmental, focal areas of parenchymal opacification) or laceration (disruption of lung parenchymal architecture with pneumatocele formation) with or without bronchial communication. Similarly, injury to the trachea and esophagus may show gross pneumomediastium with features of mediastinitis. In patients with cardiac and large vessel injuries, there might be active extravasation of contrast with hematoma/ pseudoaneurysm formation. Treatment and Prognosis: Treatment of the stab injury to the chest depends upon the extent of the injury. Chest wall injuries including the subcutaneous emphysema and rib fracture can be treated non surgically. Pneumothorax and hemothorax, if significant, may require chest tube drainage. Non complicated pulmonary contusion and laceration are also managed conservatively. Injury to the mediastinal structures and large vessels may require surgical exploration and treatment. Superficial injuries show good recovery with conservative treatments only. Involvement of significant lung parenchyma and the mediastinal structures, on the other hand, is a bad prognostic factor and can lead to significant mortality and morbidity.
Penetrating trauma to chest is a common encounter in radiology practice in the emergency departments. Radiologists should be familiar with the spectrum of imaging findings associated with these kind of injuries. Early diagnosis and treatment can be life saving for the patients.