Clinical and pathophysiological characteristics of valproate-induced pleural effusion

Abstract

Introduction

Valproic acid is a carboxylic acid derivative commonly prescribed for several types of seizure disorders or for acute manic episodes in patients with bipolar disorder. Several cases of valproate-induced pleural effusion have been reported, although the precise pathophysiological mechanism remains unknown.

Objective

To describe the presentation of pleural effusion associated with valproate use and to categorize published case reports according to clinical, immunological, and pleural effusion cell type.

Methods

PubMed/MEDLINE and Embase databases were systematically searched from January 1970 until November 2020 using the following search terms: “valproic acid” OR “valproate” OR “pleural fluid” OR “exudative effusion” OR “transudative effusion” OR “valproic lung adverse events”. These searches yielded 171 references of which 135 articles were considered irrelevant, leaving 36 potentially relevant references which were carefully scrutinized. Twenty-eight cases of valproate-induced pleural effusion were identified after excluding two articles reporting five patients with lung parenchymal adverse reactions to treatment with valproic acid; two articles reporting three patients in whom the pleural effusion could not be attributed to valproic acid alone; one case discussing valproate therapy and fungal pleural effusion; and one describing a patient who suffered from severe cardiac failure. There were also two cases, in an abstract form, with pericardial and pleural effusion, but without any further informative details, and, thus, they were also excluded from this survey.

Exudative eosinophilic pleural effusion

This was the most common type of valproate-induced pleural effusion reported in 17 out of 28 cases (60.7%), with concurrent peripheral eosinophilia in ten. Acute hypersensitivity reaction, inflammation of the pleural cavity induced by the drug, drug toxicity, and damage to mesothelial cells due to oxidants, comprise the possible pivotal mechanisms.

Exudative lymphocytic pleural effusion

This was reported in two cases, with concurrent pericardial effusion in one. Discontinuation of valproate led to resolution of the effusion, although the underlying pathophysiological mechanisms remain abstruse. Interestingly, a patient presented with recurrent pleural effusion characterized by transition from eosinophilic to lymphocytic predominance after readministration of valproate.

Transudative pleural effusion

Three out of 28 cases (10.7%) were characterized by neutrophilic transudative pleural effusion after long-term therapy with valproate, while concurrent pericardial effusion was also noted in two.

Valproate-induced lupus erythematosus with pleural effusion

Five patients receiving valproate therapy (17.9% out of the 28 cases) developed drug-induced lupus erythematosus with concurrent pleural effusion that was eosinophilic in three. All patients had positive antinuclear antibodies; anti-histone antibodies were positive in two.

Conclusions

Valproate-induced pleural effusion is rare, but patients receiving treatment with valproic acid who develop respiratory symptoms should be examined for valproate-induced pleural effusion.

Keywords:

• Valproic acid
• pleural effusion
• drug-induced lupus erythematosus (DILE)
• adverse effects

Acknowledgement

We would like to thank Professor Allister Vale for his valuable suggestions and guidance towards a thorough revision of this review.

Statement of ethics

Research involving human participants: There are no records about human involvement according to GDPR (General Data Protection Regulation − 2016/679).

Author contributions

S. Tryfon and E. Serasli were responsible for the conceptualization and supervision of this investigation. E. Papadopoulou carried out the analytical procedures and was involved in the drafting of the methodology of the manuscript. M. Saroglou, D. Vlachopoulos, and A. Georgopoulou carried out the protocol and collected all the data. S.Tryfon contributed to the design of the protocol, performed the statistical analysis, and, along with G. Ismailos and E. Papadopoulou, was involved in the drafting of the manuscript and carried out the revisions of the final version.

All authors read and approved the final manuscript.

Disclosure statement

All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.