Dissection of internal carotid artery after injury: a case report.

Clinical History

A 42-year-old male was transported to the emergency room with vomiting and confusion as his prevalent symptoms. His relatives reported walloping 7 hours before. His medical history was free. The patient underwent a non-enhanced brain CT, CTA of the cervix, brain MRI - MRA and DSA.

Imaging Findings

The patient was referred to the emergency department by his GP with a recent history of confusion and vomiting. He was afebrile and no symptoms of nausea were present. The patient was not on any medication and had no allergies. A CT scan was performed and demonstrated a hyper density imaging of the left MCA and low density imaging at the territory of the left basal ganglia (fig1a,b). Because of the back round of the walloping there was a mighty suspicion of thrombosis of the left MCA. A CT angiography (CTA) of the cervix revealed dissection of the left internal carotid artery (ICA) and thrombus in the medial cerebral artery (MCA) (fig 2). The study continued with MRI and MRA exams witch demonstrated absence of imaging of the left MCA, tapered stenosis of the left ICA and recent ischemic infarct at the territory of the left basal ganglia (fig 3,4,5,6,7). The DSA confirmed the dissection of extra-cranial part of left ICA and MCA (fig 8a). A stent was placed in ICA and following DSA demonstrated the reestablishment of blood flow in the territory of left ICA and MCA (fig 8b).

Discussion

Carotid artery dissection is a significant cause of ischemic stroke in all age groups. Dissection of the internal carotid artery can occur intracranially or extracranially, with the latter being more frequent. Internal carotid artery dissection can be caused by major or minor trauma, or it can be spontaneous in which case genetic, familial, and/or heritable disorders are likely etiologies. Patients can present in a variety of settings, such as a trauma bay with multiple traumatic injuries; their physician's office with nonspecific head, neck, or face pain; or to the emergency department with a partial Horner syndrome. A high index of suspicion is required to make this difficult diagnosis. Sophisticated imaging techniques, which have improved over the last 2 decades, are required to confirm the presence of dissection. Early institution of antithrombotic treatment provides the best outcome. When the suspicion of internal carotid artery arises, non contrast CT scan is not an adequate screening test. Dissection of the internal carotid artery may be inferred from indirect findings, which include soft-tissue swelling, hematoma adjacent to the internal carotid artery, and infiltration of perivascular fat planes. Also, fracture or fracture/dislocation of the cervical bones should raise suspicion for internal carotid artery injury. CTA may be the first and possibly the only modality used for screening purposes for trauma patients who fit general screening criteria (based on signs, symptoms, and mechanism) for carotid artery dissection and who will already be undergoing CT scan for another indication. Magnetic resonance angiography (MRA) may soon replace conventional angiography for the diagnosis of internal carotid artery dissection. Improved resolution, speed, non-invasiveness, and good negative predictive value make MRA an excellent screening tool and in some cases superior to angiography. Furthermore, MRA does not require the use of an iodinated contrast dye, which can increase morbidity and mortality, although minimally. Conventional angiography is the criterion standard for the diagnosis of internal carotid artery dissection. Conventional angiography has a 1% overall risk of complications; it is invasive, resource-intensive, and costly; and should be reserved for patients in whom internal carotid artery dissection is suspected. Conventional angiography currently has the highest sensitivity and specificity compared with other imaging modalities. Despite the difficulty one faces trying to diagnose the dissection of the internal carotid artery, the combination of the modern imaging studies can definitely lead to an accurate diagnosis concluding to a proper and timely treatment of the patient.

Differential Diagnosis List

Final Diagnosis

Dissection of internal carotid artery after injury.

URL:	https://eurorad.org/case/6092
DOI:	10.1594/EURORAD/CASE.6092
ISSN:	1563-4086