Posterior circulation infarcts

Case contributed by Dr Karina Dorfman

Presentation

Background of hypertension, dyslipidemia, and COPD. Presented with sudden onset of headache, vertigo, and vomiting. The symptoms started two hours before his admission to the emergency room. Blood pressure measurement was 180/100 mmHg. Neurologic examination showed ataxia, broad-based walking, and positive Babinski sign on the left side.

Patient Data

Age: 60 years
Gender: Male
CT

At admission

Noncontrast CT shows old lacunar infarcts in the right lentiform nucleus and right thalamus, without evidence of bleeding or signs of acute infarction.

Both noncontrast CT, CT angiography, and post-contrast CT show extremely prominent bilateral dolichoectasia of vertebral arteries, cavernous ICA segments, and M1 segments of MCA. Additionally, fusiform aneurysmal dilatations of the basilar tip and left P1 segment are shown.

CT angiography excluded arterial thrombosis or dissection.

On the following day, the patient's clinical condition rapidly deteriorated with loss of consciousness. The patient was intubated and urgent noncontrast head CT was performed.

CT

Follow-up non contrast CT, performed on the next day

Compared with the previous noncontrast head CT, a new well-demarcated hypodense area appeared in the right superior surface of the cerebellum hemisphere and vermis, corresponding to superior cerebellar artery territory acute infarct. Loss of gray-white matter differentiation in the right occipital and medial temporal lobe areas is also noted, representing early acute infarct in PCA territory. 

Additionally, new circumferential hyperdensity appeared inside the fusiform aneurysm of the basilar tip, representing a basilar artery thrombosis (dense basilar sign).  

CT

Two days after the initial presentation

Follow up noncontrast head CT shows the evolution of infarcts in right PCA and superior cerebellar artery territories (superior surface of the right cerebellum hemisphere and vermis, right occipital and medial temporal lobes, right thalamus) and acute infarcts in left PCA territory (left thalamus and occipital lobe hypodense areas ) with new hyperdensity inside left P1 fusiform aneurysm.

The hyperdensity in basilar tip aneurysm is more prominent in this examination compared with the previous.

CT angiography confirms the presence of thrombus inside basilar tip fusiform aneurysm with extension to the left P1 segment-most clearly demonstrated on coronal reconstruction.

Case Discussion

In this case, a severe form of intracranial dolichoectasia is shown, complicated by basilar artery fusiform aneurysm thrombosis with resultant extensive posterior circulation infractions. 

Dolichoectasia and fusiform aneurysms are well-known complications of hypertension, appearing more commonly in men. Fusiform aneurysms are prone to both bleeding and thrombosis, and therefore are difficult for treatment. In contrast to saccular aneurysms, endovascular interventions are usually not applied to fusiform aneurysms due to the procedural complexity related to long segments of pathological thin-walled arteries with advanced atherosclerosis. By-pass grafting may be attempted. Recently, the development of flow diverting stents created an opportunity for endovascular treatment for these aneurysms. However, the vast majority of patients are treated conservatively.

Basilar aneurysm thrombosis is one of the disastrous complications of fusiform aneurysms with a mortality rate of approximately 70%. Unfortunately, this patient died shortly after his presentation.

Courtesy of Dr. Nina Borissovsky and Dr. Maxim Pougatchev.

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Case information

rID: 78198
Published: 7th Jun 2020
Last edited: 2nd Jul 2020
Inclusion in quiz mode: Included
Institution: Bnai Zion Medical Center

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