A Case of Peripheral Neuropathy Combined with Leukoencephalopathy after Injection with Intrathecal Methotrexate and Vincristine.

Vincristine and methotrexate are the anchor drugs in the treatment of acute lymphocytic leukemia. The neurological complications caused by either vincristine or methotrexate have been well documented. A 10 year-old girl diagnosed acute lymphocytic leukemia without central nervous involvement and treated with CCG 1882 based therapy. She suffered from ascending paralysis from lower extremities without seizure or mental change three days after the fifth dose of vincristine and the fifth dose of intrathecal methotrexate during consolidation chemotherapy composed of 3-drug(vincristine, methotrexate, and L-asparaginase). Two days later, she developed dysarthria and respiratory discomfort. Her neurological examination showed a symmetric, flaccid, quadriparesis with loss of deep tendon reflex. But, she did not have sensory loss. We thought Guillain-Barre syndrome as first impression and carried out diagnostic evaluation. Viral study revealed no abnormality and cerebrospinal fluid study was not consistent with Guillain-Barre syndrome or infectious disease. Diffusion weighted magnetic resonance imaging showed a well-demarcated area of moderately high signal intensity in the white mater of the both parietal lobes. Neuromuscular conduction test revealed severe amplitude reduction in motor nerve action potential meaning on peripheral polyneuropathy. These findings were corresponded with drug-induced peripheral neuropathy and chemotherapy-related leukoencephalopathy that was detected incidentally. She did not receive further doses of vincristine and intrathecal methotrexate during the consolidation phase. There was gradual improvement of the weakness in the both lower and upper limbs for 3 months. She was recovery to walk with minimal support. We report peripheral neuropathy combined with subclinical leukoencephalopahty after injection with intrathecal methotrexate and vincristine.