(Kiosk 1) Acute Motor Axonopathy Associated with Lyme Disease: A Case Report

Case Diagnosis: Motor Axonopathy Associated with Lyme Disease

Case Description or Program Description: A 63-year-old right-handed female presented with bilateral progressive asymmetric lower extremity pain and weakness, with less intense distal upper extremity symptoms. These started 1 week after an otherwise uncomplicated surgery for carpal tunnel syndrome 9 months prior, and were associated with fatigue, malaise, headache and 35 pounds of unintended weight loss. Examination showed normal sensation and distance-dependent weakness and atrophy in the lower, and less so upper extremities. Electrodiagnostic studies showed severe lower extremity motor axonopathy with acute and chronic denervation in all tested muscles, and normal sensory nerve responses. Broad workup including laboratory for infectious, inflammatory, toxic and other causes, pelvic and spine MRI, and cancer screening were all normal, except for positive Borrelia Burgdorferi IgG. She had no history of known tick exposure or rash, and lived in an urban environment. She was treated with oral Doxycycline with significant improvement in systemic symptoms, and slow improvement in leg pain and weakness over the next months.

Setting: Outpatient Musculoskeletal Clinic

Assessment/Results: At 1 year follow-up, there was normalization of strength, except for persistent weakness in the toe flexors and plantarflexors. Electrodiagnostic study showed significant improvement in the previously seen motor axonal process, with normalization of CMAP amplitudes and nearly normal interference pattern.

Discussion (relevance): The acute presentation with systemic symptoms suggested an infectious, inflammatory, toxic or possible paraneoplastic process. The negative workup for other causes and immediate response to treatment with Doxycycline in this patient confirmed Lyme etiology. 6 prior cases of Lyme-related motor-only axonopathy have been reported in literature, most with improvement in symptoms and neurological function after treatment.

Conclusions: Lyme related motor-only neuropathy and polyradiculopathy are rare, but previously reported. As symptoms can be reversed with adequate antibiotic treatment, early recognition and treatment are necessary to limit axonal loss and disability.