Bilateral Medial Medullary Infarction in a Patient with Basilar Artery Fenestration – Cause or Coincidence? Raja Godasi MBBS1, Rashid Ahmed MD1, Hesham Masoud MD1

SUNY Upstate Medical University Department of Neurology

Introduction

Case presentation

Conclusion

Fenestration refers to localized duplication of avessel. Basilar artery fenestration is a congenitalvariant with an incidence of 5%. Medial medullaryinfarction (MMI) is a rare stroke syndromeaccounting for 0.5-1.5% of all strokes and bilateralinvolvement is uncommon. The most commonpresentation of bilateral MMI is the sudden onset of avariable constellation of findings which can includequadriparesis/quadriplegia, dysarthria, nystagmus,sensory disturbances, hypoglossal palsy and bulbardysfunction.

A 56-year-old female with no significant

cerebrovascular risk factors except for a remote

history of breast cancer in remission, presented within

5 hours of sudden onset, whole body paresthesia

sparing the face, oscillopsia, nausea and vomiting.

Initially neurological examination was remarkable

only for bilateral vertical nystagmus. MRI brain

disclosed a “V” shaped diffusion restriction in the

medial medulla with ADC correlation. CT

angiography of the head revealed proximal basilar

artery fenestration at the level of medulla. The next

day, patient developed asymmetric quadriparesis,

dysarthria, hypophonia and dysphagia. Repeat MRI

demonstrated evolution of medial medullary

infarction with FLAIR hyperintensity. An extensive

stroke work-up was unremarkable, except for a patent

foramen ovale without evidence of venous

thrombosis.

Our case, as well as several others, show association

between basilar artery fenestration and strokes in the

brainstem. Knowledge of this rare entity is important to

consider when pursing workup for medullary lacunar

strokes.

Discussion

Pontine and lateral medullary infarctions have been

reported in patients with basilar artery fenestrations.

However, to our knowledge, this is the first reported case

of bilateral medial medullary infarction. Hemodynamic

alterations and turbulence are thought to make

fenestrated artery a more common site for thrombosis

compared to a normal artery. It is also noted that partial

endothelium-lined intraluminal septa appearing as spurs

are seen in fenestrated arteries. These are hypothesized to

cause turbulent blood flow leading to thrombosis and

possible embolization from the fenestrated artery.

Paradoxical embolic etiology, though a possibility in our

case was thought to be unlikely in the absence of venous

thrombosis or cortical infarction on DWI.

A B C

A- Initial MRI DWI showing “V” shaped heart sign in medulla, B- Initial MRI ADC sequence, C- Repeat MRI with subtle FLAIR hyperintensity

References

D E F

D- CT Angiography of the head showing proximal basilar fenestration, E- 3D reconstruction of the fenestration, F- Magnified view of the fenestration

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