Disclosures: Saumya G. Aujla, MD: Nothing to disclose

Case Description: A patient with a history of chronic left sciatica and Klippel-Feil Syndrome, presented with 5 months of worsening left lower extremity (LLE) and gluteal pain. Gabapentin, cyclobenzaprine, and physical therapy failed to improve his neuropathic and musculoskeletal pain. He exhibited bilateral ankle dorsiflexion weakness and positive straight leg raise test. MRI revealed left L5-S1 neuroforaminal stenosis. The patient was diagnosed with idiopathic lumbosacral plexitis. He underwent an L5 selective nerve root block with symptomatic improvement. He spent the next 9 months teaching abroad during which time his leg weakness progressed necessitating wheelchair use. Upon return, he presented to ER with severe LLE pain. Physical exam was notable for wasting of bilateral quadriceps, LE anterior compartments, and intrinsic foot muscles. Fasciculations were noted in the right quadriceps and deep tendon reflexes were reduced throughout.

Setting: Outpatient Clinic

Patient: 51-year-old male with chief complaint of painful foot drop.

Assessment/Results: Lumbosacral spine MRI showed prominent left L5 foraminal narrowing and bilateral diffuse abnormal muscle signals. Electromyography revealed active and chronic partial denervation in three myotomal regions, consistent with lower motor neuronopathy. He was diagnosed with ALS and started on riluzole. He underwent an elective hemi-laminectomy with significant LLE pain relief.

Discussion: The initial presentation of painful foot drop secondary to idiopathic lumbosacral plexitis (LSP) with concomitant refractory left sciatica was later determined to be lower motor neuronopathy due to the 14-month span of symptoms and electrodiagnostic studies. This patient’s diagnosis of ALS was delayed due to an uncommon, superimposed condition, LSP. Diagnosing ALS when it coexists with other spinal pathologies remains a challenge, and to our knowledge, there is no known association between LSP and ALS.

Conclusion: This patient has progressive muscular atrophy, a variant of ALS, that was masked by LSP. A wide differential should be maintained when lower motor neuron symptoms present with concurrent spinal pathologies.

Level of Evidence: Level V

« Back to AAPM&R Annual Assembly 2019

PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/painful-foot-drop-as-the-presenting-symptom-in-a-man-with-amyotrophic-lateral-sclerosis-a-case-report/