Encefalopatía inducida por ácido valproico: serie de siete casos

introduction: valproic acid (va) induced encephalopathy is an unusual complication characterized by decreasing level of consciousness, focal neurological deficits, cognitive slowing, vomiting, drowsiness, and lethargy, with or without hyperammonemia. electroencephalography (eeg) is characterized by continuous generalized slowing. the eeg findings, as well as clinical manifestations and hyperammonemia, tend to normalize after va withdrawal. patients and methods: we present a series of seven patients who developed va-induced encephalopathy at the neurology department of hospital salvador between 2003 and 2010. we report two illustrative cases in extenso. results: our series is composed by five women and two men. five patients developed hyperammonemia (ammonemia above 50 μg/dl). 55years was the average of patients (range: 37 to 82 years). va dose was between 375 and 2.000 mg (average 903 mg). latency between start or important change in va dose was 3 days to 16 years and a month. all patients had brain damage. polytherapy with phenobarbital, phenytoin and carbamazepine was significant. the most frequent eeg pattern was diffuse slowing. a 82-year-old female developed a seudo-periodic activity suggesting a non-convulsive status epilepticus. the clinical manifestations, eeg findings and laboratory normalized after va withdrawal. conclusions: acid valproic-induced encephalopathy is a reversible but potentially fatal adverse reaction that requires a high index of suspicion. brain damage and polytherapy seem to be important risk factors.