CASE 6300 Published on 15.10.2007

Traumatic injury of the thoracic aorta in a 14-year-old

Section

Cardiovascular

Case Type

Clinical Cases

Authors

Christie-Large M, Phillips CA, Wellings RM

Patient

14 years, male

Clinical History
A 14-year-old male was brought to a major trauma centre following a road traffic accident - he was an unrestrained rear seat passenger. Chest X-ray was suggestive of an aortic injury. This was confirmed at CT. His aorta was stented and he made a complete recovery.
Imaging Findings
The patient was rushed to a major trauma hospital with the rest of his family, following a head on collision with another car at 40 mph. He had been unrestrained, sitting in the back seat behind the front seat passenger. On arrival he was tachycardic and tachyapnoeic with a GCS of 15/15. Immediate resuscitative procedures were performed and he soon became haemodynamically stable. A trauma series of films [chest and pelvis] was arranged. The chest X-ray showed a widened mediastinum, left haemothorax and blunting of the aortic contour. A chest drain was inserted and a CT arranged. A multi-row detector helical CT of the brain, cervical spine and contrasted arterial phase chest and porto-venous phase abdomen and pelvis was performed with a 2.5mm slice thickness [our standard trauma protocol]. Reconstructions were performed on a workstation. This found a mediastinal haematoma in direct contact with the aorta and a contained rupture of the aorta extending from the isthmus inferiorly for 4.2cm. His other injuries included bilateral lung contusions, grade 1 splenic, liver and right kidney lacerations, a small anterior mesenteric haematoma and a fractured right femoral shaft. He remained haemodynamically stable and was transferred to a paediatric cardiothoracic unit where his aorta was stented. He made a full, uneventful recovery.
Discussion
Traumatic aortic rupture is rarely seen in hospital as the majority of patients will die at the scene of massive exsanguination - in fact only 10%- 20% will survive to hospital. Those that do present have an incomplete tear or dissection with a contained haematoma or a pseudoaneurysm. Even then 30% will die in the first 6 hours. There are very few reported cases in the paediatric population [1]. The key to diagnosis is a high index of suspicion because of the mechanism of injury - usually a rapid deceleration either from a fall or high speed road traffic accident [RTA]. Those cases resulting from a RTA will usually not have been wearing a seatbelt. In one small series of traumatic paediatric aortic ruptures - 4 out of 5 were unrestrained passengers [1]. Symptoms are variable and non specific and often other injuries will distract clinical attention away from the aorta. This is probably even more the case in a paediatric trauma as this injury is very rarely seen in this population [1,4]. An abnormal chest X-ray is often the first clue to diagnosis. The classic film is described as having a left apical pleural cap, loss of the normal aortic contour, depression of the left hilum and elevation of the right, a left haemothorax and deviation of a nasogastric tube to the right if inserted [2,3]. Not all of these signs are always present but our patient certainly demonstrated the loss of aortic contour! The gold standard for investigation was previously direct aortography but helical multi-slice CT is now well established as the preliminary diagnostic tool of choice[2]. Other methods of diagnosis include transoesophageal echocardiography. On CT a mediastinal haematoma in direct contact with the aorta is highly suspicious of aortic injury.The aortic isthmus is the most commonly involved site [90%] followed by the ascending aorta [10-15%] and the descending aorta near the diaphragmatic hiatus [1%-3%]. Signs seen include an abrupt change in aortic calibre, pseudoaneurysm formation, intimal flap and intramural haematoma [2,3]. Previously these were treated by open operative repair on bypass with a very high associated mortality. Nowadays there is increasingly good evidence to support endovascular stenting as the treatment of choice as the outcome is generally far superior. This appears to also be true for the paediatric population [4,5]. In conclusion - traumatic aortic rupture is uncommon in children and teenagers but does occur. The mechanism of injury is invariably a sudden deceleration and often they are unrestrained passengers in an RTA. A high index of suspicion is required by all clinicians, including the radiologist, to make the diagnosis.
Differential Diagnosis List
Traumatic thoracic aortic injury in a 14-year-old
Final Diagnosis
Traumatic thoracic aortic injury in a 14-year-old
Case information
URL: https://www.eurorad.org/case/6300
DOI: 10.1594/EURORAD/CASE.6300
ISSN: 1563-4086