Midtown Morning Report: What is the differential for foot drop?

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The Bottom Line:     Differential Diagnosis of foot drop

  • Upper motor neuron involvement – CVA can cause weakness of the whole extremity. Due to spasticity, the limb is artificially long. To ambulate, the person rotates the leg in a semicircular fashion, also referred to as circumduction. Dysphagia, aphasia, or upper limb weakness are also evident.
  • Cerebellar gait – The cerebellum is responsible for the smoothness and balance of gait. Cerebellar gait deficits are seen as ataxia and failure to walk in tandem.
  • Ataxic gait – Presentation is bilateral. Due to the involvement of long tracks of the spinal cord, position and vibration senses are lost. This leads to high steppage and side to side sway, as can be seen in alcohol use disorder.
  • Severe L5 lumbar radiculopathy
  • Parkinsonian gait – Involvement of substantia nigra causes failure of the smooth transition of the gait cycle leading to initiation problems coupled with short and fast steps called festinate gait.
  • Lumbar plexus involvement such as autoimmune, compressive-tumor,
  • Diabetic amyotrophy
  • Conversion reaction, somatization disorder, and malingering should be considered if the workup is unremarkable, and there is potential for substantial secondary gain, depression, anxiety, or other suspected psychological issues. (Nori)
Carolus

Assessment of Steppage Gait (Foot Drop)

History
    ask about possible causes of compression at fibular neck, which may lead to peroneal neuropathy
        confinement to bed
        habitual leg crossing
        habitual or prolonged squatting or kneeling
        use of leg brace or recent plaster cast below the knee
        use of leg positioning or leg supports during recent surgery
    also ask about other precipitating factors for peroneal neuropathy
        recent weight loss
        ankle strain or prolonged leg stretching
        masses in the popliteal space (Baker cysts)
    ask about recent medical history
        possible causes of neuropathies – diabetes, alcohol use disorder, vitamin B12 deficiency, or chemotherapy
        trauma such as fibula neck fracture
        hip arthroplasty, which can injure sciatic nerve and mimic peroneal neuropathy (foot drop may appear within days)
    ask about pain
        painful foot drop may indicate L5 radiculopathy, trauma, lumbar plexopathy, or mononeuritis multiplex
        painless foot drop without other neurologic symptoms suggests peroneal neuropathy
    ask about other weakness or sensory problems in legs, lower back, and/or arms (DynaMed)

Nori, S. L., & Stretanski, M. F. (2022). Foot Drop. In StatPearls. StatPearls Publishing. Free Full Text

DynaMed Gait Disorders in Adults EBSCO Information Services. Accessed April 29, 2024.

Carolus AE, et al . The Interdisciplinary Management of Foot Drop. Dtsch Arztebl Int. 2019 May 17;116(20):347-354. Free Full Text