A 45-year old male has an acute attack of vertigo, vomiting and ataxia. The most likely diagnosis is Thrombosis of
Posterior inferior cerebellar artery
Superior cerebellar artery
Middle cerebral artery
Posterior cerebral artery
(A) Posterior inferior cerebellar artery > In unilateral infarcts there is always a sharp delineation in the midline because the superior vermian branches do not cross the midline, but have a sagittal course.> This sharp delineation may not be evident until the late phase of infarction.> In the early phase, edema may cross the midline and create diagnostic difficulties.> Infarctions at pontine level are usually paramedian and sharply defined because the branches of the basilar artery have a sagittal course and do not cross the midline.> Bilateral infarcts are rarely observed because these patients do not survive long enough to be studied, but sometimes small bilateral infarcts can be seen.# Embolic occlusion or thrombosis of a V4 segment causes ischemia of the lateral medulla.> Constellation of vertigo, numbness of the ipsilateral face and contralateral limbs, diplopia, hoarseness, dysarthria, dysphagia, and ipsilateral Horner's syndrome is called the Lateral medullary (or Wallenberg's) syndrome.> Most cases result from ipsilateral vertebral artery occlusion; in the remainder, PICA occlusion is responsible.> Occlusion of the medullary penetrating branches of the vertebral artery or PICA results in partial syndromes.> Hemiparesis is not a feature of vertebral artery occlusion.> Rarely, a medial medullary syndrome occurs with infarction of the pyramid and contralateral hemiparesis of the arm and leg, sparing the face.> If the medial lemniscus and emerging hypoglossal nerve fibers are involved, contralateral loss of joint position sense and ipsilateral tongue weakness occur.> Cerebellar infarction with edema can lead to sudden respiratory arrest due to raised ICP in the posterior fossa.> Drowsiness, Babinski signs, dysarthria, and bifacial weakness may be absent, or present only briefly, before respiratory arrest ensues.> Gait unsteadiness, headache, dizziness, nausea, and vomiting maybe the only early symptoms and signs and should arouse suspicion of this impending complication,which mayrequire neurosurgical decompression, often with an excellent outcome.> Separating these symptoms from those of viral labyrinthitis can be a challenge, but headache, neck stiffness, and unilateral dysmetria favor stroke.
Miscellaneous