Abstract
Background and Objectives: Neuromuscular problems after the treatment of acute lymphoblast leukemia (ALL) have been reported in children and thought to be induced by vincristine. Peripheral neuropathy is its dose-related toxicity. Clinical signs of vincristine neuropathy are early loss of Achilles tendon reflexes, followed by loss of other deep tendon reflexes accompanied with sensory disturbances. This study aimed to evaluate the electrophysiological consequences of vincristine chemotherapy in children.
Methods & Materials: In a prospective cohort one year study, the electrophysiologic testing was performed in 42 children, 25 of them with ALL and 17 of them non-ALL malignancies. It was performed before and 5 weeks after chemotherapy in above patients. Changes in the electrodiagnostic parameters before and after administration of vincristine and its relation with the dosage were determined.
Results: Twenty five children had ALL, M/F 16/9 and 6.08±3.85 years and 17 children had other malignancies including: lymphoma, neuroblastoma, rhabdomyosarcoma, retinoblastoma and Willms' tumor, M/F 7/10 and 6.54±4.45 years. In the ALL group, there was no significant change of motor and sensory NCV and amplitude of SNAP after 5 weeks however, the amplitude of CMAP was significantly decreased in both upper and lower extremities and F-wave latency was increased in both lower and upper extremities after chemotherapy. Post chemotherapy decreased CMAP amplitude was detected in 96% of ALL cases, majority of them it was moderate (70.8%). Sixteen (66.7%) patients suffered from gait abnormality. In the non-ALL group five (29.4%) cases were treated with regimen similar to that employed in the ALL group (group B) and 12 (70.6%) patients were treated with other regimens (group C). Neuropathy was detected in nine (52.9%) patients, five (100%) cases in group B and four (33.3%) cases in group C. In group B, mild, moderate and severe neuropathies were detected in 1 (20%), 3 (60%) and 1 (20%) cases, respectively. Patients in group C were affected with mild neuropathy. There was a direct relation between the degree of CMAP amplitude decretion with higher dosage of vincristine (P=0.007).
Conclusion: This study showed that the electrophysiologic changes of vincristine chemotherapy are common in children and usually detected in the form of a motor-axonal neuropathy. Gait abnormality is also a common manifestation.