The arterial dissection at the level of the posterior vascular system is a recognized cause of stroke. This can happen at the extra or intracranial level. The PICA has an intracranial origin in 95% of the patients. In the remaining cases, it arises below the foramen magnum, with close relation to bone and muscular structures. Here, the artery can be exposed to direct trauma. We present two patients where this association was suspected.
21-year-old man, with no relevant medical history. He suffered direct trauma and sudden whiplash during a rugby match. He presented instability and falls. In the neurological exam we found left horizontal nystagmus, right dysmetria, trunk ataxia, and instability in gait with right lateropulsion. Magnetic resonance imaging (MRI) showed diffusion restriction in the right lateral region of the medulla, compatible with acute stroke. No vascular lesions were evident in MRI angiography. EKG, transthoracic and transesophageal echocardiogram and carotid duplex ultrasonography were normal. Digital angiography showed a right PICA artery with caudal origin, below the inferior border of the occipital foramen, with a redundant descending loop, and ascending next to the lateral recess of the IV ventricle. There were no irregularities of the wall or obstructions. Treatment with aspirin, rosuvastatin and symptomatic management of vertigo was initiated. He evolved with a marked improvement in the neurological examination during follow-up. With this findings, we arrived to the diagnosis of probable traumatic dissection of extracranial PICA.
56-year-old woman with a history of dyslipidemia. She presented suddenly, while exerting intense physical effort lifting heavy boxes, with mild hemiparesis and thermoalgesic hypoesthesia in left arm and leg, dizziness and trunk ataxia, compatible with Wallemberg syndrome. Brain MRI showed diffusion restriction in the right lateral medulla and right paravermis. In the MRI-angiography a mural hematoma was evidenced at the right vertebral artery, with a half-moon shape. Extracranial origin of the right PICA artery and decrease of ipsilateral V4 caliber were also observed. There wew no other relevant findings. Treatment with aspirin, atorvastatin, and symptomatic management was initiated. The patient improved within a few days, with a diagnosis of probable traumatic dissection of extracranial PICA.
We think that the case of two probable traumatic dissection of PICA with extracranial origin is report worthy.. This is is a rare cause of brainstem stroke. In young patients with a history of direct or indirect trauma, vessel dissection seems the most likely cause. Individuals with extracranial origin and path of the artery may be more exposed to this mechanism.
We invite the members of this forum to participate in the case discussion, and we would like to apply for and invitation to submit to the Journal of Radiology Case Reports.
Thank you very much,
Matías J. Alet, MD
Buenos Aires - Argentina
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