Diaphragmatic Injury Management in the Emergency Department Workup

Updated: May 01, 2020
  • Author: Michelle Welsford, MD, FACEP, FRCPC(Canada); Chief Editor: Trevor John Mills, MD, MPH  more...
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Workup

Imaging Studies

Chest radiography is the single most important diagnostic study and may show elevation of the hemidiaphragm, a bowel pattern in the chest, or a nasogastric (NG) tube passing into the abdomen and then curling up into the chest. Additionally, a hemothorax, while not specific for diaphragmatic injuries, may be the only chest radiographic finding. The chest radiograph does not allow direct visualization of the diaphragmatic injury/defect but, rather, the associated herniation or other injuries. The initial chest radiograph is nondiagnostic in approximately 10-40% of patients. Repeated chest radiograph may be helpful. The chest radiographic findings may be masked if the patient is being positive-pressure ventilated (intubated), because this may reduce any herniation. Therefore, obtaining the chest radiograph before intubation or after extubation may be more helpful.

The liver often protects a right-sided rupture from visceral herniation; thus, these ruptures may appear only as an elevated hemidiaphragm from a partially herniated liver. Left-sided ruptures are more evident when the bowel is herniated into the chest.

Chest radiograph of a blunt left diaphragmatic injury often shows an abnormal or wide mediastinum, even when the aorta is normal. The mediastinum should be investigated because of the association with aortic injury discussed previously.

Ultrasonography is commonly used in trauma cases and may visualize large disruptions or herniation; however, it may miss small tears from penetrating injuries. According to the American College of Radiology (ACR) appropriateness criteria, the role of ultrasonography in trauma is primarily for triage, and a positive focused assessment with sonography in trauma (FAST) and signs of hemodynamic instability may lead to immediate surgical intervention. Its use for detection of pleural fluid and pneumothorax is increasing, but it has not gained acceptance for a comprehensive evaluation of blunt chest trauma because of its lack of sensitivity for pulmonary, aortic, cardiac, and musculoskeletal injury. [16]

New-generation helical CT scanning is helpful but not 100% sensitive because of its poor visualization of the diaphragm. A diagnosis can be made if herniation of abdominal contents is visualized. Multidector CT (MDCT) has shown improvement in identifying penetrating and blunt diaphragmatic injury with the use of thin sections and multiplanar formats. [17, 18, 19]  Features of right-sided diaphragmatic rupture seen on MDCT scan include thickened diaphragm, hump, and band signs from herniation of the liver. Segmental diaphragmatic defect, herniation through a defect, and Collar sign (waistlike constriction of the herniated structure at the site of the diaphragmatic rupture) are more useful features of left-sided diaphragmatic rupture. [20]   In a study of 64-slice MDCT for identifying traumatic diaphragmatic rupture, overall sensitivity was 66.7%, specificity 100%, positive predictive value 100%, and negative predictive value 88.4%. However, only 3 of 9 patients with penetrating injury received a correct diagnosis preoperatively. [21]

MRI may aid in the diagnosis because it can accurately visualize the diaphragm's anatomy. MRI may be used in a patient in stable condition who has an equivocal diagnosis and no need for laparotomy (some penetrating injuries) or for late diagnosis.

Thoracoscopy has been used to better visualize the diaphragm when the diagnosis is unconfirmed and laparotomy is not required.

When considering a delayed diagnosis, chest radiography and contrast studies (via NG or enema)  are often used. MRI typically is an ideal diagnostic test in this instance.

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Other Tests

Diagnostic peritoneal lavage

When diagnostic peritoneal lavage (DPL) is used to detect diaphragmatic injury, a false-negative result may occur. An isolated penetrating injury from the chest can cause bleeding into the lesser sac, which may not communicate with the rest of the peritoneal cavity. A DPL in this situation would show no evidence of bleeding.

Drainage of lavage fluid from the chest tube has been reported and is a positive result.

In blunt trauma, the DPL result is often positive because of the associated injuries and not specifically because of the diaphragmatic tear.

In penetrating chest injuries, most centers use 10,000 RBC/mm3, a more sensitive criterion than normally used, to limit the number of false-negative results.

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