Sensory symptoms in ipsilateral limbs/body due to lateral medullary infarction

To characterize the incidence, topography, and radiologic and pathophysiologic findings of ipsilateral sensory symptoms in the limbs/body in patients with lateral medullary infarction.

Between 1994 and 2001, the author identified 12 patients with lateral medullary infarction (6.7% of all lateral medullary infarction patients) who presented with ipsilateral sensory symptoms in the limbs/body in addition to typical lateral medullary syndrome. Brain MRI, nerve conduction velocity, and electromyographic studies were performed. Twenty-four patients without ipsilateral sensory symptoms were included as a control group. Clinical and radiologic findings were compared between the two groups.

The ipsilateral sensory symptoms were generally described as numbness or tightness, predominantly affecting the upper extremities, especially distal fingers. Vibration and proprioceptive sensation were occasionally impaired. None showed evidence of peripheral neuropathy or radiculopathy. The patients with ipsilateral sensory symptoms significantly more often had vertigo, nausea/vomiting, severe gait ataxia, hiccup, ipsilateral hemiparesis, and caudally located lesions than those without. The caudal lesions producing ipsilateral sensory symptoms tended to extend dorsomedially.

Lateral medullary infarction associated with ipsilateral sensory symptoms in the limbs/body is an uncommon but distinct variant caused by caudal lesions extending dorsomedially that probably involve the ipsilateral dorsal column or decussating lemniscal fibers.