Review Question - QID 218748

This patient who presents with an acute stroke to the lateral medulla (as seen in Figure A) most likely has Wallenberg syndrome, which would feature dysphagia as 1 of its symptoms.

Wallenberg syndrome is caused by a stroke to the lateral medulla. This syndrome is caused by occlusion of the posterior inferior cerebellar artery (PICA). The PICA supplies the lateral medulla involving the nucleus ambiguus, vestibular nuclei, lateral spinothalamic tract, spinal trigeminal nucleus, and sympathetic fibers. It also partially supplies the inferior cerebellar peduncle. Patients with lateral medullary syndrome will present with dysphagia, hoarseness, and a decreased gag reflex due to damage to the trigeminal nucleus. Patients will also have vertigo and ataxia due to damage to the vestibular nucleus. Damage to the sympathetic fibers will result in an ipsilateral Horner syndrome with a small pupil (miosis) and a drooping eyelid (ptosis). Finally, patients will have decreased pain and temperature sensation of the ipsilateral face and contralateral body (due to crossing of the fibers of the lateral spinothalamic tract from the body).

Frederick et al. presented a summary of Wallenberg syndrome for emergency department providers. They found that dysphagia is rarely the presenting symptom for this syndrome but providers should have a high index of suspicion for stroke due to its high morbidity. They recommended obtaining an MRI if Wallenberg syndrome is suspected due to low sensitivity of CT scans.

Figure/Illustration A is an axial MRI cut showing an increased signal in the lateral medulla (yellow arrow), which is consistent with a lesion that causes Wallenberg syndrome.

Incorrect Answers:
Answer 1: Blindness of the contralateral side would be seen in patients with a stroke caused by posterior cerebral artery occlusion. This primarily affects the occipital lobe and would present with macular sparing contralateral hemianopsia. The macula has partial supply bilaterally and therefore remains relatively preserved in these patients.

Answer 2: Deviation of the tongue would be seen in patients with medial medullary (Dejerine) syndrome. This syndrome is caused by a stroke to the medial medulla and presents with ipsilateral hypoglossal palsy, contralateral hemiparesis, and contralateral lemniscal sensory loss.

Answer 4: Loss of taste would be seen in patients with lateral pontine syndrome caused by a stroke in this region. This syndrome would present with facial paralysis, decreased salivation, loss of taste from the anterior tongue, vertigo, and decreased pain and temperature sensation of the ipsilateral face and contralateral body.

Answer 5: Quadriplegia would be seen in patients with locked-in syndrome caused by a stroke to the basilar artery. These patients have damage to the ventral pons and midbrain resulting in quadriplegia and inability to breathe or swallow. Of note, they have preserved consciousness and preserved vertical eye movements.

Bullet Summary:
Wallenberg syndrome is caused by a lateral medullary stroke and presents with dysphagia, hoarseness, ataxia, ipsilateral Horner syndrome, and decreased pain and temperature sensation of the ipsilateral face and contralateral body.