Dorsal column myelopathy following intrathecal chemotherapy for acute lymphoblastic leukemia

Abstract

OBJECTIVE/CONTEXT: To describe a distinctive clinical and radiographic pattern of myelopathy following intrathecal chemotherapy. Myelopathy is a rare complication of intrathecal chemotherapy used in the treatment of acute lymphoblastic leukemia (ALL). We present a 42-year-old female with T-cell ALL who developed a myelopathy primarily involving the dorsal columns.

Method: Case report and literature review.

Findings: Within 24 hours of an injection of intrathecal methotrexate, cytarabine, and hydrocortisone, the patient developed ascending lower limb numbness and balance difficulties progressing to the inability to ambulate. Clinical examination showed profound loss of lower limb proprioception and light touch sensation below T5, mild proximal limb weakness, but preserved pinprick and temperature sensation with intact bowel and bladder function. Initial thoracic and lumbar spine magnetic resonance imaging (MRI) at 1 week revealed no abnormalities. However, repeat imaging at 6 weeks showed abnormal signal in the posterior cord with sparing of the anterior and lateral columns, diffusely involving the lower cervical cord through the conus medullaris. Dermatomal somatosensory-evoked potential (DSEP) conduction abnormalities were consistent with thoracic myelopathy. An empiric trial of high-dose intravenous corticosteroids during inpatient rehabilitation more than 6 weeks later produced no significant clinical improvement.

Conclusion/clinical relevance: Preferential and persistent dorsal column myelopathy is a distinctive clinical and radiographic presentation of a rare complication of intrathecal chemotherapy. The MRI abnormalities were initially absent, but evolved to consist of multi-level spinal cord T2 and STIR hyperintensity with regional gadolinium enhancement. DSEPs more accurately reflected the clinical level of spinal cord dysfunction.

Keywords: Chemotherapy, Intrathecal injections, Leukemia, Myelopathy, Spinal cord injuries, Somatosensory-evoked potential.

Figure 1

Initial sagittal MR image of thoracic spine at 1 week post-symptom onset. No cord abnormality detected in both T2-weighted (A) and STIR imaging (B).

Figure 2

Sagittal T2-weighted (A) and STIR (B) MR images of the thoracic spine at 6 weeks after symptom onset. The arrows identify the intramedullary signal abnormality.

Figure 3

Sagittal MR image of the lumbar spine at 6 weeks after symptom onset. Arrows identify the intramedullary signal abnormality to the level of the conus in the T2-weighted (A) and STIR images (B).

Figure 4

MR axial STIR image of lumbar (A) and T2-weighted thoracic (B) spine 6 weeks after symptom onset. The arrow localizes the posterior spinal cord lesion.

Figure 5

Axial contrast-enhanced T1-weighted MR images of the thoracic (A) and lumbar (B) spine at 6 weeks after symptom onset. The arrows localize the posterior spinal cord lesion and contrast enhancement.