Hippocampal Involvement in Valproate-Induced Acute Hyperammonemic Encephalopathy

Soares-Fernandes, João; Machado, Álvaro; Ribeiro, Manuel; Ferreira, Carla; Figueiredo, José Ricardo de; Rocha, Jaime

doi:10.1001/archneur.63.8.1202

Cited by 9 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other encephalopathies, such as hyperammonemic encephalopathy [62] and intoxications with glufosinate, a herbicide [63], or methanol [64], are rarely accompanied by changes in DWI signal in the hippocampus.…”

Section: Anoxic Encephalopathy and Encephalopathies Of Other Etiologymentioning

confidence: 99%

Diffusion-Weighted Imaging for the Differential Diagnosis of Disorders Affecting the Hippocampus

et al. 2011

View full text Add to dashboard Cite

Background: The human hippocampus can be affected in a large variety of very different neurological diseases, of which acute ischemic stroke, transient global amnesia, epilepsy, and limbic encephalitis are the most common. Less frequent etiologies include various infections and encephalopathy of different origins. Clinical presentation notably comprises confusional state, altered vigilance, memory deficits of various extent and seizures. While in hypoxic or hypoglycemic encephalopathy, clinical presentation and surrounding circumstances provide some clues to reach the correct diagnosis, in the above-listed more common disorders, signs and symptoms might overlap, making the differential diagnosis difficult. This review presents recent studies using the diffusion-weighted imaging (DWI) technique in diseases involving the hippocampus. Methods: References for the review were identified through searches of PubMed from 1965 to January 2011. Only papers published in English were reviewed. Full articles were obtained and references were checked for additional material where appropriate. Results: All pathologies affecting the hippocampus are associated with distinct lesion patterns on magnetic resonance imaging, and especially DWI has the ability to demonstrate even minute and transient hippocampal lesions. In acute ischemic stroke in the posterior cerebral artery territory, involvement of the hippocampal formation occurs in four distinct patterns on DWI that can be easily differentiated and correspond to the known vascular anatomy of the hippocampus. In the subacute phase after transient global amnesia (TGA), dot-like hyperintense lesions are regularly found in the lateral aspect of the hippocampus on DWI. The DWI lesions described after prolonged seizures or status epilepticus include unilateral or bilateral hippocampal, thalamic, and cortical lesions of various extent, not restricted to vascular territories. In limbic encephalitis, DWI lesions are only infrequently found and usually affect the hippocampus, uncus and amygdala. Furthermore, in some rare cases DWI lesions of different etiology may coexist. Conclusion: In patients with diseases affecting the hippocampus, DWI appears to be useful in differentiating between underlying pathologies and may facilitate a definite diagnosis conducive to an optimal treatment. With a careful clinical examination, experience with the interpretation of DWI findings and knowledge of associated phenomena, it is indeed possible to differentiate between ischemic, ictal, metabolic, and TGA-associated findings.

show abstract

Section: Anoxic Encephalopathy and Encephalopathies Of Other Etiologymentioning

confidence: 99%

Diffusion-Weighted Imaging for the Differential Diagnosis of Disorders Affecting the Hippocampus

et al. 2011

View full text Add to dashboard Cite

show abstract

“…[2][3][4][5]7,13 One interesting observation in our cases was that all five patients with FLE developed prominent gait instability symptoms that led to disability, while having only mild encephalopathy, and in the presence of serum VPA levels within the reference range and normal or slightly elevated liver enzymes. [2][3][4][5]7,13 One interesting observation in our cases was that all five patients with FLE developed prominent gait instability symptoms that led to disability, while having only mild encephalopathy, and in the presence of serum VPA levels within the reference range and normal or slightly elevated liver enzymes.…”

Section: Discussionmentioning

confidence: 57%

“…Mental status changes are the most common manifestations of VPA-induced encephalopathy. [2][3][4][5]7,13 One interesting observation in our cases was that all five patients with FLE developed prominent gait instability symptoms that led to disability, while having only mild encephalopathy, and in the presence of serum VPA levels within the reference range and normal or slightly elevated liver enzymes.…”

Section: Discussionmentioning

confidence: 57%

Gait instability in valproate-treated patients: Call to measure ammonia levels

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Manual search of reference lists and gray literature did not identify additional studies. After screening and assessing for eligibility, 240 studies were included with the remaining articles being excluded for meeting the exclusion criteria 6,7,12–245 . Among the excluded 350 articles, 37 were literature reviews, 5 were pharmacokinetically related, 41 were VPA overdose related, and 267 articles were unable to clearly answer our objectives listed.…”

Section: Resultsmentioning

confidence: 99%

Valproic Acid–Associated Hyperammonemia

Wong

Fan

Wan

et al. 2023

J Clin Psychopharmacol

View full text Add to dashboard Cite

BackgroundHyperammonemia is an adverse effect that poses clinical uncertainty around valproic acid (VPA) use. The prevalence of symptomatic and asymptomatic hyperammonemia and its relationship to VPA concentration is not well established. There is also no clear guidance regarding its management. This results in variability in the monitoring and treatment of VPA–induced hyperammonemia. To inform clinical practice, this systematic review aims to summarize evidence available around VPA-associated hyperammonemia and its prevalence, clinical outcomes, and management.MethodsAn electronic search was performed through Ovid MEDLINE, Ovid Embase, Web of Science, and PsycINFO using search terms that identified hyperammonemia in patients receiving VPA. Two reviewers independently performed primary title and abstract screening with a third reviewer resolving conflicting screening results. This process was repeated during the full-text review process.ResultsA total of 240 articles were included. Prevalence of asymptomatic hyperammonemia (5%–73%) was higher than symptomatic hyperammonemia (0.7%–22.2%) and occurred within the therapeutic range of VPA serum concentration. Various risk factors were identified, including concomitant medications, liver injury, and defects in carnitine metabolism. With VPA discontinued, most symptomatic patients returned to baseline mental status with normalized ammonia level. There was insufficient data to support routine monitoring of ammonia level for VPA-associated hyperammonemia.ConclusionsValproic acid–associated hyperammonemia is a common adverse effect that may occur within therapeutic range of VPA. Further studies are required to determine the benefit of routine ammonia level monitoring and to guide the management of VPA-associated hyperammonemia.

show abstract

Hippocampal Involvement in Valproate-Induced Acute Hyperammonemic Encephalopathy

Cited by 9 publications

References 3 publications

Diffusion-Weighted Imaging for the Differential Diagnosis of Disorders Affecting the Hippocampus

Diffusion-Weighted Imaging for the Differential Diagnosis of Disorders Affecting the Hippocampus

Gait instability in valproate-treated patients: Call to measure ammonia levels

Valproic Acid–Associated Hyperammonemia

Contact Info

Product

Resources

About