Pure motor unilateral leg paresis caused by a spinal cord infarction

Excerpt

An 85-year-old woman presented to the emergency department with acute onset weakness of the left leg since the day before. She did neither notice any speech difficulties, nor weakness of the left arm. She denied any pain or sensory symptoms in the limbs. Her past medical history was remarkable for arterial hypertension, COPD and she was an ex-smoker. On clinical examination the Mingazzini sign was positive on the left side. There was a global paresis of 4/5 (MRC-scale) in the left leg. Sensation to vibration and light touch was normal in the legs. Patellar reflex was increased and the plantar response was extensor (Babinski sign), both on the left. A minor stroke was suspected but a brain MRI with diffusion-weighted images failed to show any acute ischemic lesion. Motor-evoked potentials showed a marked prolongation of central motor conduction time (CMCT) to the left leg and a normal CMCT to the right leg. Subsequently, a small spinal cord infarction was suspected and this was confirmed on a spinal cord MRI which revealed a small T2-hyperintense lesion in the lateral spinal cord of segment T7 on the left side (Fig. 1). This lesion involved the lateral corticospinal (pyramidal) tract. The patient was already on aspirin and antihypertensive medication and these were continued. Her paresis and gait gradually improved.

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