Comparison of clinical, magnetic resonance and evoked potentials data in a case of valproic-acid-related hyperammonemic coma.
Magnetic resonance (MR) multimodality evoked potentials (MEPs) and clinical findings were correlated in a 47-year-old epileptic man in whom parenteral valproic acid (VPA) therapy induced severe comatose hyperammonemic encephalopathy without biological signs of hepatotoxicity (or hepatocytic dysfunction). Although the plasma VPA level remained within a normal therapeutic range, the ammoniemia increased to a toxic peak level at 411 micromol/l 24 h after symptom onset, requiring VPA therapy discontinuation. Brain MR monitoring demonstrated early cytotoxic edema evolving into delayed vasogenic edema and final brain atrophy. Concomitantly to abnormalities within the brainstem on MR images, an increase in brainstem conduction at MEPs and clinical disturbance of brainstem reflexes were observed at the initial phase of the disease course. Later, the resolution of the MR and MEPs abnormalities paralleled the clinical recovery of the reflexes.
Hantson
Philippe
P
Department of Intensive Care, Cliniques Saint-Luc, Université catholique de Louvain, Avenue Hippocrate, 10, 1200 Brussels, Belgium. hantson@rean.ucl.ac.be
Grandin
Cécile
C
Duprez
Thierry
T
Nassogne
Marie-Cécile
MC
Guérit
Jean-Michel
JM
D001284:Atrophy; D003128:Coma / Q000097:blood / Q000139:chemically induced* / Q000175:diagnosis; D005071:Evoked Potentials; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015518:Rett Syndrome / Q000139:chemically induced* / Q000175:diagnosis*; D014635:Valproic Acid / Q000009:adverse effects* / Q000627:therapeutic use
D014635:Valproic Acid