Wallenberg syndrome (lateral medullary syndrome)

Case contributed by Mehmet Yağtu
Diagnosis almost certain

Presentation

Sudden onset dysphagia, decreased gag reflex, muscle weakness of right side lower extremites

Patient Data

Age: 40 years
Gender: Male

There is an area consistent with infarct in the right lateral medulla. It demonstrates restricted diffusion on ADC. Subtle high signal is appreciated on FLAIR and T2 W images. 

Case Discussion

Wallenberg syndrome is the most prevalent posterior ischemic stroke syndrome.  Twenty percent of the ischemic strokes occur in the posterior circulation. If clinicians assume that about half of these suffer from Wallenberg syndrome. There was a predominance of middle aged men. Large artery atherothrombotic causes account for about 75% of the cases followed by cardioembolism in 17% and vertebral dissection in 8% 1.

The primary pathology of Wallenberg syndrome is occlusion of the posterior inferior cerebellar artery (PICA) or one of its branches 2. The syndrome can also be due to occlusion of the vertebral artery, or the inferior, middle, or superior medullary vessels. Anatomically the infarcted area in Wallenberg syndrome is supplied by the posterior inferior cerebellar artery (PICA). It turns out occlusion of the PICA accounts for only a small number of cases. The majority (80%) of cases are caused by occlusion of the vertebral artery, which gives rise to the PICA and the anterior spinal artery before it joins with the opposite vertebral artery to form the basilar artery. The most common mechanism of occlusion of the vertebral artery or PICA is atherothrombosis 3.

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