Intrathecal Methotrexate-Induced Lumbosacral Polyradiculopathy: A Case Report

Area of Science:

• Neuro-oncology
• Chemotherapy complications
• Neurology

Background:

• Intrathecal methotrexate (IT MTX) is a chemotherapy agent used for certain cancers.
• Polyradiculopathy is a rare but serious complication associated with IT MTX administration.
• Pathophysiology may involve drug-induced folate deficiency and local immune responses in the spinal cord.

Observation:

• A 68-year-old woman with breast cancer and lymphoma developed low back pain post-IT MTX.
• MRI revealed cauda equina nerve root thickening and leptomeningeal enhancement.
• Electromyography/nerve conduction studies showed severe axonal and motor polyneuropathy.

Findings:

• The patient's symptoms and imaging findings were consistent with IT MTX-induced polyradiculopathy.
• This condition presents as a severe axonal and motor polyneuropathy.
• Diagnosis relies on clinical presentation, MRI, and electrophysiological studies.

Implications:

• Polyradiculopathy from IT MTX is a treatable condition.
• Conservative management is the primary approach.
• Immunotherapy (IVIg, IV methylprednisolone) may be considered.
• Further research is needed to establish definitive treatment protocols for IT MTX adverse effects.