Bipolar disorder and valproate-induced hyperammonemic encephalopathy in an adolescent with diabetes

Levocarnitine for valproate-induced hyperammonemia in the psychiatric setting: A case series and literature review

Introduction

Hyperammonemia is a potential adverse effect of valproic acid (VPA) therapy, which is often asymptomatic but can lead to severe, life-threatening encephalopathy. Carnitine deficiency due to VPA is the proposed mechanism for hyperammonemia and the development of VPA-induced hyperammonemic encephalopathy (VHE). Levocarnitine, the active form of carnitine, has been suggested for treatment and prevention of VHE.

Methods

Data was collected by chart review of 3 patients who received oral levocarnitine supplementation in the psychiatric setting for VPA-induced hyperammonemia. Review of the literature was performed through June 2017 using the following PubMed search terms: valproate, valproic acid, hyperammonemia, altered mental status, encephalopathy, and levocarnitine. Articles were included if they described use of levocarnitine in VPA-treated patients with psychiatric disorders.

Results

One patient developed encephalopathy with resolution of symptoms after VPA discontinuation. Valproic acid was restarted with the addition of levocarnitine to prevent VHE reoccurrence. In the other 2 cases, levocarnitine was started prophylactically in patients who developed hyperammonemia without emergence of any clinical symptoms. Ammonia levels were reduced to normal in all cases, and no symptoms consistent with encephalopathy were reported. The literature search identified 6 additional cases with 5 of 6 reports supporting use of levocarnitine for decreased ammonia levels as well as an observational trial.

Discussion

This literature review and case series illustrates successful use of levocarnitine supplementation for reduction of ammonia levels in the setting of VPA-induced hyperammonemia among patients with psychiatric disorders. However, clinical significance of ammonia reduction in asymptomatic patients is difficult to determine.

Valproate-induced hyperammonemia in juvenile ceroid lipofuscinosis (Batten disease)

PURPOSE

Valproate-induced hyperammonemia (VHA) and hyperammonemic encephalopathy (VHE) are well-known complications of valproate (VPA) treatment. Currently recognised risk factors for VHE include a high VPA dosage, the need for polytherapy and long duration of treatment. Despite the severe nature of the epilepsy, presence of concomitant psychiatric manifestations, and frequent need for poly-pharmacy associated with juvenile ceroid lipofuscinosis (JNCL, Batten disease) neither this disorder nor other subtypes of neuronal ceroid lipofuscinosis have previously been identified as risk factors for VHA/VHE. The aim of the present publication is to describe four cases with VHE in a well-defined Danish population of JNCL.

METHOD

An examination of medical records of all 35 patients with JNCL in Denmark was conducted and revealed fourteen patients treated with VPA.

RESULTS

Four patients treated with VPA developed VHE. All patients were prescribed VPA in standard dosages, had normal plasma concentrations of VPA and received antiepileptic drug (AED) polytherapy. Symptoms occurred shortly after commencement or increase in dose of VPA, and were quickly reversible upon discontinuation of VPA. Carnitine supplement was administrated in two patients, which resulted in resolution of symptoms and normalized ammonium levels.

CONCLUSION

Patients with JNCL are in great risk of developing VHA and VHE due to a high rate of polytherapy. Furthermore, studies have shown that carnitine level can be depressed in JNCL, which may increase the risk of VHA and VHE. We recommend that increased attention should be given to these patients.

Valproate (VPA)-associated hyperammonemic encephalopathy independent of elevated serum VPA levels: 21 cases in China from May 2000 to May 2012

Valproate (VPA) is a medication that is widely used in the treatment of neurological and psychiatric disorders, such as epilepsy and bipolar disorder. Valproate-induced hyperammonemic encephalopathy (VHE) is a rare central nervous system adverse effect of this medication that is characterized by impaired consciousness, which can range from drowsiness to coma; increased seizure frequency; acute cognitive symptoms; and gastrointestinal symptoms. In this manuscript, we report a single case and also review previous cases of VHE (n=20) in Chinese patients to identify risk factors for VHE. Increasing clinicians' awareness of VHE during concomitant VPA therapy is of utmost importance. Serum ammonia level is a useful and important diagnostic test. The discontinuation of VPA is currently the mainstay of treatment for VHE.

Adverse drug reactions induced by valproic acid

Valproic acid is a widely-used first-generation antiepileptic drug, prescribed predominantly in epilepsy and psychiatric disorders. VPA has good efficacy and pharmacoeconomic profiles, as well as a relatively favorable safety profile. However, adverse drug reactions have been reported in relation with valproic acid use, either as monotherapy or polytherapy with other antiepileptic drugs or antipsychotic drugs. This systematic review discusses valproic acid adverse drug reactions, in terms of hepatotoxicity, mitochondrial toxicity, hyperammonemic encephalopathy, hypersensitivity syndrome reactions, neurological toxicity, metabolic and endocrine adverse events, and teratogenicity.

Valproate-induced hyperammonemic encephalopathy: an update on risk factors, clinical correlates and management

INTRODUCTION

Valproate (VPA)-induced hyperammonemic encephalopathy (VHE) is a serious drug-related adverse effect characterized by lethargy, vomiting, cognitive slowing, focal neurological deficits and decreased levels of consciousness ranging from drowsiness to coma.

METHODS

We present a case series (n=5) and also review previous cases of VHE (n=30) in psychiatric patients to provide an update on risk factors, clinical correlates and management of VHE.

RESULTS

To our knowledge, there are 30 (16 female, 14 male) previously reported VHE cases in psychiatric patients. Risk factors for VHE include VPA-drug interactions, mental retardation, carnitine deficiency and presence of urea cycle disorders. Length of VPA treatment, VPA dosage, serum VPA levels and serum ammonia levels do not appear to correlate with onset or severity of VHE.VPA discontinuation is the primary treatment of VHE, although, l-carnitine, lactulose and neomycin have been used adjunctively in some patients.

CONCLUSION

Clinicians should consider VHE in patients taking VPA who present with lethargy, gastrointestinal symptoms, confusion and decreased levels of drowsiness. VPA discontinuation is currently the mainstay of treatment for VHE, although more research is warranted to delineate the underlying risk factors for VHE and consolidate treatment modalities for this potentially life-threatening drug adverse effect.