Valproic Acid‐Induced Hyperammonemic Encephalopathy with Triphasic Waves

Abstract

Summary:Purpose: To examine a patient with valproic acid (VPA)-induced hyperammonemic encephalopathy accompanied by triphasic waves.Methods: A 61-year-old male patient with epilepsy experienced disturbance of consciousness after VPA dose was increased because of poor seizure control. The electroencephalogram (EEG) taken on admission revealed triphasic waves and high-amplitude &activity with frontal predominance. Although serum hepatic enzymes, such as AST and ALT, were normal, serum ammonium level was high at 96 pg/dl (normal range, 3-47 pg/dl). Serum amino acid analysis showed multiple minor abnormalities. Administration of VPA was discontinued immediately after admission, while other anticonvulsants were continued.Results: The patient's condition was improved on the fourth day of admission. An EEG, serum ammonium level, and amino acid profile were normal on the eighth day. Based on VPA administration, serum ammonium levels, and results of amino acid analysis, this patient had VPA-induced hyperammonemic encephalopathy .Conclusions: Our case indicates that caution is required if triphasic waves appear in VPA-induced hyperammonemic encephalopathy.

Acute encephalopathy after intravenous administration of valproate in non‐convulsive status epilepticus

“…At day two of IV VPA treatment the EEG showed a diffuse, highamplitude theta‐delta slowing over the fronto‐central regions which is in line with previous findings [6]. The diffuse slowing was not attributable to hepatic encephalopathy since signs of hepatic failure were absent.…”

Serum and CSF Glutamine Levels in Valproate‐related Hyperammonemic Encephalopathy

“…However, to our knowledge, this is the first report of elevated glutamine levels in a group of patients with VHE. One recent report describing triphasic waves in the EEG of a single patient with VHE mentioned an elevated glutamine level (7).…”

Pregabalin intoxication-induced encephalopathy with triphasic waves

“…Triphasic waves (TWs), originally described in hepatic encephalopathy, are a distinctive electroencephalographic pattern observed in many patients with a decreased level of consciousness [4]. Triphasic waves are also observed in toxic encephalopathies, such as valproateinduced hyperammonemic encephalopathy, serotonin syndrome, and intoxication by baclofen, lithium, levodopa, pentobarbital, cefepime, tiagabine, or ifospamide [5][6][7][8][9][10][11]. However, an association between PGB intoxication and TWs has not been reported.…”