A 78-year-old woman with a history of hypertension, chronic atrial fibrillation, monoclonal gammopathy of uncertain significance, treated for 10 months with valproate 1 g/day for tonic-clonic seizures.
The patient presented three hospitalizations in four months due to brief episodes of sensory deterioration with spontaneous reversal.
During the last hospitalization, he had normal vital parameters and a Glasgow 11/15 (confusing verbal response and ocular opening to painful stimulus, locating pain), nystagmus to lateral view.
Laboratory tests showed complete blood count, coagulogram, urea, creatininemia, sodium, potassium, magnesium, calcium, phosphorus, hepatogram, glucose, thyroid hormones, folates, vitamin B12, anti-pe-nuclear antibodies.
Lumbar puncture, toxicological, hemocultive, uro-culture and orotic acid urine tests were negative.
A reassessment of her gammapathy with bone marrow puncture was normal.
Brain CT showed left occipital sequel image and chest X-ray was normal.
EEG showed a slow and generalized continuous activity compatible with metabolic encephalopathy.
Valproate dosages: 67 μg/ml (normal: 50-100) and acetaminophen: 123 μg/dl.
The clinical picture was interpreted as suspending valproate and lamoctulose 10 mi c/8 h and L-carnitine g iv/day; anticonvulsant was induced.
There was complete recovery 48 h after medication discontinuation with normalization of ammemia.
Five months later the patient had no further episodes.
