Isolated Painless Foot Drop due to Cerebral Infarction Mimicking Lumbar Radiculopathy: A Case Report

Abstract

Although they usually originate from peripheral problems, foot drop is caused by lesions affecting the neural pathway related to dorsiflexor muscles, whether of central or peripheral origin. We present a patient with sudden isolated foot drop caused by a small infarct in the primary motor cortex mimicking a peripheral origin. This report indicates that patients presenting isolated foot drop should be managed carefully and the possibility of both central and peripheral causes should be considered. To our knowledge, this is the first report of sudden isolated foot drop caused by a cortical infarction mimicking lumbar radiculopathy.

Etiology of spastic foot drop among 16 patients undergoing electrodiagnostic studies: patient series

“…These authors encouraged awareness of patients who have both a peripheral lesion in the lumbar spine and a central lesion in the primary motor cortex, as the UMN lesion was masked by the LMN lesion. 8 These previous cases are similar to our case 3 with the concurrent lumbar spinal pathology and a UMN lesion. All of these cases underwent unnecessary spinal surgical procedures (lumbar in 2 cases and cervical facet biopsy in 1 case) before the definitive cause of the SFD was diagnosed, that is, a meningioma in 2 cases and cerebral infarction in the other.…”

“… 4 They stressed that the diagnosis of the central cause of foot drop may be delayed and that patients may undergo needless surgeries. Kim et al 8 reported a case of a patient with complaints of weakness of the left foot with a normal physical examination. Lumbar MRI showed a ruptured disc with compression of the left L4–5 nerve root.…”

“…These authors encouraged awareness of patients who have both a peripheral lesion in the lumbar spine and a central lesion in the primary motor cortex, as the UMN lesion was masked by the LMN lesion. 8 …”

“…1,9 Differentiating between UMN and LMN pathology may prove challenging when patients present with signs and symptoms of peripheral neuropathy and SFD. 4,7,8 Narenthiran et al 4 reported the case of a patient with a 5-year history of progressive right-sided foot drop who had previously undergone biopsy of an abnormality relating to the right C7-T1 facet, which was benign. Physical examination revealed UMN signs in the ipsilateral foot.…”

“…[2][3][4] Several conditions have been reported to cause SFD, including brain tumors (meningioma, glioma), metastases, cerebrovascular accidents (CVAs), cervical disc herniations, demyelinating plaques due to multiple sclerosis (MS), traumatic brain injury, cerebral abscess/contusion, spinal cord compression, and neurocysticercosis. [2][3][4][5][6][7][8][9][10] Cerebral cases may arise in the parasagittal area because of either direct damage or local mass effect because the medial homunculus of the primary motor cortex at the mesial surface and top of the lateral surface of the precentral gyrus are responsible for ankle and toe movements. 3,4 SFD has been reported to occur in 52%-67% of patients with spinal upper motor neuron (UMN) pathology.…”