Progression of methotrexate-induced leukoencephalopathy in children with leukemia

From 1972-1974, 228 children began treatment for acute lymphocytic leukemia and were prospectively assessed for neurologic complications. After CNS irradiation (2,400 rad) and intrathecal methotrexate (MTX), they received weekly intravenous maintenance therapy with MTX alone (40-60 mg/m2; 20 patients) or MTX (10-30 mg/m2) with other drugs (208 patients). Signs of leukoencephalopathy appeared in 11 children (nine without CNS leukemia) after 4-15 months of IV MTX alone, and included lethargy, seizures, spasticity, paresis, drooling, and dementia. Before or during the clinical onset, EEG frequencies slowed (all ten patients tested). Radionuclide scans showed periventricular accumulation of 99mTc (9/11 patients) and remained abnormal for greater than or equal to six months in eight patients. Cranial computed tomograms or neuropathology findings (five patients each) demonstrated leukoencephalopathy (nine patients) and radiation-related microangiopathy (ten patients). Severe neurologic and neuropsychologic dysfunctions were present in four long-term survivors.