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

Isolated Foot Drop Due to a Cerebral Infarction Mimicking Lumbar Radiculopathy: A Case Report and Literature Review

Isolated foot drop is a neurological sign frequently linked to lower motor neuron (LMN) lesions, including peroneal nerve damage or L4-L5 radiculopathy. Nonetheless, upper motor neuron (UMN) lesions, such as strokes or tumors located in the parasagittal motor cortex, may sometimes manifest as isolated foot drops. The main causes of isolated foot drop secondary to central etiologies are uncommon, with few instances documented in the literature. An 83-year-old male presented with a four-day history of left isolated foot drop that started in the big toe and then spread to involve the whole foot. Clinical examination was negative for any other neurological deficit. Magnetic resonance imaging (MRI) of the cervical, thoracic, and lumbar spine showed only mild lumbar spinal stenosis at the L4/L5 level. Brain MRI revealed acute infarction foci in the right superior frontal gyrus. While uncommon, central causes of isolated foot drop should be taken into account when peripheral examinations yield inconclusive results. This case highlights the significance of a thorough diagnostic method, encompassing brain imaging, to detect lesions in the central nervous system. Timely identification and management of these cases are essential for enhancing patient outcomes and avoiding misdiagnosis.

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

BACKGROUND

Differentiating foot drop due to upper motor neuron (UMN) lesions from that due to lower motor neuron lesions is crucial to avoid unnecessary surgery or surgery at the wrong location. Electrodiagnostic (EDX) studies are useful in evaluating patients with spastic foot drop (SFD).

OBSERVATIONS

Among 16 patients with SFD, the cause was cervical myelopathy in 5 patients (31%), cerebrovascular accident in 3 (18%), hereditary spastic paraplegia in 2 (12%), multiple sclerosis in 2 (12%), chronic cerebral small vessel disease in 2 (12%), intracranial meningioma in 1 (6%), and diffuse brain injury in 1 (6%). Twelve patients (75%) had weakness of a single leg, whereas 2 others (12%) had bilateral weakness. Eleven patients (69%) had difficulty walking. The deep tendon reflexes of the legs were hyperactive in 15 patients (94%), with an extensor plantar response in 9 patients (56%). Twelve patients (75%) had normal motor and sensory conduction, 11 of whom had no denervation changes of the legs.

LESSONS

This study is intended to raise awareness among surgeons about the clinical features of SFD. EDX studies are valuable in ruling out peripheral causes of foot drop, which encourages diagnostic investigation into a UMN source for the foot drop.

A rare case of parasagittal meningioma causing isolated foot drop: case report and review of the literature

Foot drop represents a very common reason for a neurologist referral and is often first seen in emergency departments or by a general practitioner. This condition is defined as weakness of ankle dorsiflexion (mainly through tibialis anterior muscle weakness). The most common causes include lower motor neuron lesion, with L4-L5 radiculopathy and peroneal neuropathy being the most frequent ones. Classical diagnostic pathway includes a thorough medical history, detailed neurological examination, radiological studies (MRI of the lumbosacral spine), EMG and nerve conduction studies, and a battery of laboratory tests. The absence of abnormal radiological and neurophysiological findings when searching for the most common causes of foot drop, should raise a red flag and broaden the diagnostic yield for central nervous system pathology (upper motor neuron, UMN) as a possible cause of foot drop. Central causes of isolated foot drop are very rare, with less than 20 cases reported in literature so far, and seven of them being a meningioma. We present a case of a 79-year-old female patient with an isolated foot drop (with no UMN signs on the initial examination) and parasagittal meningioma. Central causes of foot drop should be suspected when foot drop is associated with UMN signs on examination (hyperreflexia of the patellar or ankle jerk and extensor plantar reflex) and when standard diagnostic work-up (MRI of the lumbar spine, EMG and NCS, standard laboratory screening for most common causes of foot drop) is negative or inconclusive. Although very rare, central lesions present a far more serious cause of foot drop and require a more urgent diagnostic work up and a potential neurosurgical referral and treatment. Keeping in mind the possible central causes of foot drop would eliminate unnecessary diagnostic work up and avoid delayed diagnosis and treatment.

Evaluation and Treatment of Foot Drop Using Nerve Transfer Techniques

Foot drop represents a complex pathologic condition, requiring a multidisciplinary approach for appropriate evaluation and treatment. Multiple etiologic factors require recognition before considering invasive/operative intervention. When considering surgical management for the treatment of foot drop, it is first and foremost imperative to establish the cause of the condition. Not all causes resulting in clinical foot drop have surgical options. Establishing a cause allows the provider to more appropriately curtail a multidisciplinary approach to working-up, and ultimately, treating the patient. The authors offer an algorithm for evaluating and treating foot drop conditions associated with lumbar spine radiculopathy and peripheral nerve lesions.