A 63-year-old male presented several days after acute onset right hemibody paresis and vertigo which was preceded by 3 episodes of alternating hemiparesis. Examination revealed dysarthria with right hemibody paresis, leftward tongue deviation (Figure 1E), and right sided vibration sensation loss (Dejerine triad). Initial computed tomography angiography of the head and neck demonstrated absent flow related enhancement beyond the right V2 and left V4 segments with preserved basilar flow (Figure 1A). Magnetic resonance imaging of the head revealed restricted diffusion in the left medial medulla, indicating ischemic infarction (Figure 1B and C). The abnormal susceptibility effect involving bilateral V4 segments was suggestive of thrombus (Figure 1D).
Figure 1.
Leftward tongue deviation, brain MRI and multiphase CT angiography of the head and neck. (A) Absent flow related enhancement past right V2 segment (arrowhead) and left V4 segment (arrowhead) with opacification of distal to mid basilar artery (arrow). (B) Axial diffusion-weighted imaging showing restricted diffusion in the left medullary pyramid and paramedian distribution with (C) coronal FLAIR view demonstrating high T2 signal intensity in the rostral medulla indicating acute to subacute ischemic infarction. (D) Hypointensity on axial susceptibility-weighted imaging in the distal left V4 segment suggestive of thrombus (arrow). (E) Leftward tongue deviation.
A minority of patients with medial medullary infarction present with the full Dejerine triad due to absent ipsilateral tongue weakness.1,2 The most common mechanism is large artery atherosclerosis from vertebral artery disease with the rostral medial medulla preferentially involved.2 Nearly one third of patients with Dejerine syndrome have negative diffusion weighted imaging within 24 hours from symptom onset, often requiring repeat imaging for diagnostic confirmation.1,3 The proposed stroke mechanism for our patient is atheromatous branch occlusion from an acute left V4 segment thrombus that occluded the orifice of a paramedian perforator—a rarely reported large artery mechanism for Dejerine syndrome. In our patient, retrograde flow from the anterior spinal artery into the basilar artery is a rare but plausible mechanism for collateral flow depending on vertebrobasilar junction patency, while the distal basilar artery was likely filled by the posterior communicating arteries.4
Footnotes
Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article.
ORCID iD: Ario Mirian, MD, MSc 
https://orcid.org/0000-0002-1477-9196
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