Medical Image of the Week: Traumatic Aortic Dissection

Figure 1. Chest x-ray demonstrating widened mediastinum with prominence of the aortic arch.

Figure 2. Contrast enhanced CT axial (A, left) and coronal (B, right) views demonstrate descending thoracic aortic dissection with mediastinal hematoma and intimal flap (arrow).

A 21-year-old gentleman with no significant past medical history presented to the emergency department following a highway speed motor vehicle collision. The patient was a restrained passenger in the back seat of the vehicle. On initial evaluation the patient was in stable condition and complaining of acute onset back pain. Physical exam was remarkable for facial contusions, tenderness to palpation about the thoracic and lumbar spine, and a normal neurologic exam.

Imaging with chest x-ray (CXR) revealed widening of the mediastinum with prominence of the aortic arch (Figure 1). Further investigation with contrast enhanced computed tomography (CT) of the chest, abdomen and pelvis showed descending thoracic aortic dissection with mediastinal hematoma (Figure 2). The patient underwent successful endovascular repair and was discharged in stable condition.

Acute traumatic aortic injury is a potentially life-threatening condition requiring prompt evaluation. Initial investigation in the trauma setting often includes CXR imaging (1). CXR findings which should raise suspicion for aortic injury in the appropriate clinical scenario include mediastinal widening, abnormality of the aortic silhouette, and right side tracheal deviation.

CT angiography (CTA) is considered the definitive diagnostic modality in most cases, with high sensitivity and specificity. Mediastinal, periaortic and retrocrural hematoma are findings suggestive of traumatic aortic injury. Definitive findings include contrast extravasation, irregularity of the aortic contour, contained rupture, intramural thrombus, and aortic dissection.

Justin S. Caskey, BS

University of Arizona

College of Medicine

Tucson, Arizona, USA

Reference

1. Nagpal P, Mullan BF, Sen I, Saboo SS, Khandelwal A. Advances in imaging and management trends of traumatic aortic injuries. Cardiovasc Intervent Radiol. 2017 May;40(5):643-54. [CrossRef] [PubMed]

Cite as: Caskey JS. Medical image of the week: traumatic aortic dissection. Southwest J Pulm Crit Care. 2018;16(2):94-5. doi: https://doi.org/10.13175/swjpcc016-18 PDF

Medical Image of the Week: Subarachnoid Hemorrhage

Figure 1. Axial CT of the head without contrast demonstrates a large subarachnoid hemorrhage in the basal cisterns and adjacent to the insular cortices (blue arrows).

Figure 2. Coronal CT angiogram of the head demonstrates a saccular outpouching of the anterior communicating artery (blue arrow) consistent with an aneurysm.

A 70-year-old lady with a past medical history of hypertension and dyslipidemia was brought in by her family members for evaluation of confusion and headache for 1 week. There was no history of recent trauma or falls. There was no known family history of aneurysm or sudden death. On examination, her blood pressure was 139/99 mmHg, heart rate 92 bpm, afebrile and respiratory rate was 13 breaths per minute. She was alert but only oriented to self. Pupils were symmetric and reactive to light. She was able to follow commands and power was symmetric in all limbs.

CT of the head without contrast showed diffuse subarachnoid and intraventricular hemorrhage with signs of raised intracranial pressure (Figure 1). Neurosurgery was consulted and she underwent emergent insertion of an external ventricular drain. Head CT post-ventriculostomy showed improvement in her ventricular dilatation. CT angiography was performed later and showed an anterior communicating artery aneurysm (Figure 2), thought to be culprit of her subarachnoid hemorrhage. Craniotomy with surgical clipping was performed. This was followed by improvement in her mental status.

The common presenting symptom of patients with subarachnoid hemorrhage is headache. They will classically describe it as "worst headache of my life". This can be accompanied by altered mental status, nausea, vomiting, or meningeal signs. Head CT without contrast should be obtained immediately if there is suspicion of subarachnoid hemorrhage. Studies have shown that head CT is extremely sensitive if obtained within 6 hours of clinical presentation but its sensitivity declines over time (1). Lumbar puncture should be performed if head CT is negative but there is strong suspicion of subarachnoid hemorrhage. A combination of negative head CT and lumbar puncture is sufficient to rule out subarachnoid hemorrhage in a patient presented with headache (2).

Kai Rou Tey¹, MD; Tammer Elaini², MD

¹Department of Internal Medicine, University of Arizona College of Medicine- South Campus and ²Department of Pulmonary, Critical Care, Allergy and Sleep University of Arizona College of Medicine

Tucson, AZ USA

References

1. Perry JJ, Stiell IG, Sivilotti ML, et al. Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study. BMJ. 2011;343:d4277. [CrossRef] [PubMed]
2. Perry JJ, Spacek A, Forbes M, et al. Is the combination of negative computed tomography result and negative lumbar puncture result sufficient to rule out subarachnoid hemorrhage? Ann Emerg Med. 2008 Jun;51(6):707-13. [CrossRef] [PubMed] 

Cite as: Tey KR, Elaini T. Medical image of the week: subarachnoid hemorrhage. Southwest J Pulm Crit Care. 2016;13(2):88-9. doi: http://dx.doi.org/10.13175/swjpcc063-16 PDF