1219 - Mitigating Functional Loss in Methotrexate Neurotoxicity: a Case on Intrathecal Methotrexate Induced Non-Traumatic Spinal Cord Injury.

Case Diagnosis: Intrathecal Methotrexate Induced Subacute Combined Degeneration

Case Description: 36-year-old female with Philadelphia chromosome-positive B cell acute lymphoblastic leukemia involving cerebrospinal fluid status post intrathecal methotrexate presented with 2 weeks of progressive lower extremity paresthesias, weakness, and incomplete saddle anesthesia. MRI evidenced subacute combined degeneration of the spinal cord secondary to methotrexate neurotoxicity. She received steroids, B vitamin supplementation, and N-methyl-D-aspartate(NMDA) antagonists. The patient presented with T4 incomplete flaccid paraplegia and urinary retention with intact urge sensation upon admission to inpatient rehab. On exam, bilateral knee extension and plantar flexion were ⅕ on manual muscle testing with ¼ tone to the bilateral hip extensors, adductors, and knee flexors on Modified Ashworth Scale. During her 27-day hospitalization, her weakness progressed with further loss of bladder function. At discharge, she was modified independent at a wheelchair level for mobility and ADLs. Continuing outpatient therapy and medical management she recovered ⅗ strength to her quadriceps enabling her to rise from sitting.

Discussions: Methotrexate neurotoxicity can vary in presentation from seizures, stroke-like symptoms, encephalopathy, and rarely spinal cord injury (SCI). Mainly described in pediatric oncologic literature given its use in childhood cancers, proposed mechanisms of susceptibility include polymorphisms in genes related to neurogenesis and insufficient rescue therapy with folate. While patients can recover from cortical white matter lesions, there is little to no literature supporting recovery from spinal cord lesions. This is the first reported case of recovery. From a rehabilitation standpoint it is important to continue neurologic evaluation as the initial injury may progress or improve requiring updated medical management.

Conclusions: This case raises awareness of intrathecal methotrexate as a unique cause of non-traumatic SCI with possible improvement or injury progression. Patients with this condition will likely require frequent physiatric assessment and ongoing rehabilitation throughout their initial injury and recovery to address their evolution.