[Electroencephalographic changes in coma due to hepatic insufficiency with porto-caval shunt (author's transl)].

EEG studies were done in 19 patients comatose due to severe hepatic insufficiency associated with porto-caval shunting. The neurological deficits were graded in 5 stages and related to the abnormal EEG-pattern observed in 38 records. With deepening of coma, alpha-frequencies were gradually replaced by theta- and delta-activities. The frequency of theta- and delta-runs decreased with neurological deterioration. Triphasic waves (typical and/or atypical) were seen in 26% of the records. Typical triphasic waves were found to be limited to stage 3 of coma, whereas atypical forms appeared in earlier and later stages. After infusions of L-Valin, a transient improvement and disappearance of triphasic waves was observed, but no significant effect could be established on the final course of the disease. Sleep-like potentials and the reactivity to external stimuli decreased in deep stages of coma. Severe EEG abnormalities were correlated to low cholinesterase and high lactid acid blood level, but no correlation was found to the level of ammonia.