[EEG-slowing after high-dose Methotrexate with citrovorumfactor-rescue. A spectralanalytic study (author's transl)]

In 23 treatment courses of high-dose Methotrexate (MTX) with Leukovorin-rescue for osteogenic sarcoma serial EEG-examinations before and after MTX-infusion were done. In 11 course Vincristine had been administered additionally. Frequency-analysis of EEG-background activity was performed by computer-based FFT. At the end of the MTX-infusion EEGs were unchanged, compared with the findings before start of treatment. At 24 and 48 hours after start of infusion, there was a slight but statistically significant slowing, recognizable from an increase of the theta/alpha-ratio (median + 48%, range -7% to + 373%) and a drop of dominant frequency (median-8%, range +12% to -53%). There was a stronger trend towards normalisation in patients, not having received Vincristine. The greatest changes were found in a patient, whose serum-MTX-concentration at 24 hours exceeded the upper therapeutic limit. The EEG-findings are discussed as an equivalent of a subclinical MTX-encephalopathy. Acute encephalopathies with severe EEG-changes and morphological changes on CT have been observed in MTX-intoxications.