Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (730 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Presence of fluid in the pleural cavity resulting from excessive transudation or exudation from the pleural surfaces. It is a sign of disease and not a diagnosis in itself.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Effusion, Pleural; Effusions, Pleural; Pleural Effusions.
Where it fits in the MeSH classification
- Broader topics
- Pleural Diseases
- Narrower topics
- Pleural Effusion, Malignant
- See also
- Yellow Nail Syndrome; Thoracentesis
Research landscape
PubMed indexes 22,753 records tagged with the MeSH heading “Pleural Effusion” (counts retrieved 2026-11-04). 3,102 of them (13.6%) were published from 2020 onward, and the busiest period so far is through 1999 with 10,045 records.
Reviews account for 2,145 records (9.4%) and meta-analyses for 164. Randomized controlled trials number 286 (1.3%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 10,045 |
| 2000-2009 | 4,369 |
| 2010-2019 | 5,237 |
| 2020 onward | 3,102 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 2,145 | 9.4% |
| Meta-analyses | 164 | 0.7% |
| Randomized controlled trials | 286 | 1.3% |
Method: PubMed query "Pleural Effusion"[MeSH Terms] with publication-type and date filters, retrieved 2026-11-04.
Reading the evidence in respiratory medicine
Research on airway and lung disease mixes lung-function tests, symptom diaries, imaging and hospital records, so what was measured and in whom matters as much as the result. Many conditions here, such as asthma and COPD, vary between people and over time, and exposure studies (smoking, pollution, workplace dust) show association rather than proof of cause. Nothing on this page is advice about treatment or inhalers; anyone with breathing difficulty should seek care from a qualified clinician. Check how the condition was defined, the severity of the people studied and whether outcomes were symptoms, lung function or hospital admissions.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Malignant pleural effusion: current understanding and therapeutic approach | 2024 | Review article Design not recorded in structured metadata | 79 | cc by PMID 38243259 · DOI · PMC10797757 |
| A new dynamic nomogram for predicting the risk of severe Mycoplasma pneumoniae pneumonia in children | 2024 | Research article Design not recorded in structured metadata | 34 | cc by PMID 38589453 · DOI · PMC11002011 |
| Epidemiology and Management of Pediatric Group A Streptococcal Pneumonia With Parapneumonic Effusion: An Observational Study | 2024 | Research article Design not recorded in structured metadata | 21 | cc by PMID 38900036 · DOI · PMC11319078 |
| Pathobiology and clinical significance of malignant pleural effusions | 2026 | Review article Design not recorded in structured metadata | 3 | cc by PMID 41514125 · DOI · PMC12905272 |
Malignant pleural effusion: current understanding and therapeutic approach [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Malignant pleural effusion (MPE) is a common complication of thoracic and extrathoracic malignancies and is associated with high mortality and elevated costs to healthcare systems.
- Closing excerpt
- This article provides a review of the current advances, new discoveries and future directions in the pathophysiology, diagnosis and management of MPE.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (151 words)
Malignant pleural effusion (MPE) is a common complication of thoracic and extrathoracic malignancies and is associated with high mortality and elevated costs to healthcare systems. Over the last decades the understanding of pathophysiology mechanisms, diagnostic techniques and optimal treatment intervention in MPE have been greatly advanced by recent high-quality research, leading to an ever less invasive diagnostic approach and more personalized management. Despite a number of management options, including talc pleurodesis, indwelling pleural catheters and combinations of the two, treatment for MPE remains symptom directed and centered around drainage strategy. In the next future, because of a better understanding of underlying tumor biology together with more sensitive molecular diagnostic techniques, it is likely that combined diagnostic and therapeutic procedures allowing near total outpatient management of MPE will become popular. This article provides a review of the current advances, new discoveries and future directions in the pathophysiology, diagnosis and management of MPE.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 38243259 · DOI · PMC10797757
A new dynamic nomogram for predicting the risk of severe Mycoplasma pneumoniae pneumonia in children [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Mycoplasma pneumoniae pneumonia (MPP) is usually mild and self-limiting, but still about 12% of them will progress to severe Mycoplasma pneumoniae pneumonia (SMPP), which have poor survival rates and often require intensive medical resource utilization.
- Closing excerpt
- Based on age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze, the first dynamic nomogram for accurately predicting SMPP was successfully established.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (193 words)
Mycoplasma pneumoniae pneumonia (MPP) is usually mild and self-limiting, but still about 12% of them will progress to severe Mycoplasma pneumoniae pneumonia (SMPP), which have poor survival rates and often require intensive medical resource utilization. We retrospectively collected clinical data from 526 children with MPP admitted to the Children's Hospital Affiliated to Zhengzhou University from June 2018 to February 2023 and randomly divided the data into a training cohort and a validation cohort at a ratio of 4:1. Univariate and multivariate logistic regressions were used to identify independent risk factors for SMPP. Age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze are independent risk factors for SMPP in children. Then, we built an online dynamic nomogram ( https://ertongyiyuanliexiantu.shinyapps.io/SMPP/ ) based on the 11 independent risk factors. The C-index, ROC curve, DCA curve and calibration curve were used to assess the performance of the nomogram, which all showed that the dynamic nomogram has excellent clinical value. Based on age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze, the first dynamic nomogram for accurately predicting SMPP was successfully established.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 38589453 · DOI · PMC11002011
Epidemiology and Management of Pediatric Group A Streptococcal Pneumonia With Parapneumonic Effusion: An Observational Study [3]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundDuring autumn/winter 2022, UK pediatricians reported an unseasonal increase in invasive group A streptococcal infections; a striking proportion presenting with pneumonia with parapneumonic effusion.
- Closing excerpt
- Range and duration of intravenous antibiotics administered demonstrated the need for research on the optimal duration of antimicrobials and improved stewardship.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (245 words)
BackgroundDuring autumn/winter 2022, UK pediatricians reported an unseasonal increase in invasive group A streptococcal infections; a striking proportion presenting with pneumonia with parapneumonic effusion.MethodsClinicians across the United Kingdom were requested to submit pseudonymized clinical data using a standardized report form for children (ResultsFrom 185 cases submitted, the median patient age was 4.4 years, and 163 (88.1%) were previously healthy. Respiratory viral coinfection was detected on admission for 101/153 (66.0%) children using extended respiratory pathogen polymerase chain reaction panel. Molecular testing was the primary method of detecting group A streptococcus on pleural fluid (86/171; 50.3% samples). Primary surgical management was undertaken in 171 (92.4%) children; 153/171 (89.4%) had pleural drain inserted (96 with fibrinolytic agent), 14/171 (8.2%) had video-assisted thoracoscopic surgery. Fever duration after admission was prolonged (median, 12 days; interquartile range, 9-16). Intravenous antibiotic courses varied in length (median, 14 days; interquartile range, 12-21), with many children receiving multiple broad-spectrum antibiotics, although evidence for additional bacterial infection was limited.ConclusionsMost cases occurred with viral coinfection, a previously well-recognized risk with influenza and varicella zoster, highlighting the need to ensure routine vaccination coverage and progress on vaccines for other common viruses (eg, respiratory syncytial virus, human metapneumovirus) and for group A streptococcus. Molecular testing is valuable to detect viral coinfection and confirm invasive group A streptococcal diagnosis, expediting the incorporation of cases into national reporting systems. Range and duration of intravenous antibiotics administered demonstrated the need for research on the optimal duration of antimicrobials and improved stewardship.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 38900036 · DOI · PMC11319078
Pathobiology and clinical significance of malignant pleural effusions [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Metastatic malignant pleural effusion (MPE) represents advanced-stage cancer and is defined by the establishment of metastatic tumor foci within the pleural space.
- Closing excerpt
- Furthermore, we discuss the clinical opportunities of studying MPE and identify promising directions for MPE research that may lead to a deeper understanding of the disease, ultimately aiming to enhance clinical outcomes for patients with advanced cancer.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (141 words)
Metastatic malignant pleural effusion (MPE) represents advanced-stage cancer and is defined by the establishment of metastatic tumor foci within the pleural space. It is most commonly associated with high degrees of morbidity and mortality. Annually, over 150,000 cancer patients in the United States develop MPE, which is associated with a dismal median survival of 3-12 months. As such, efforts must be made to understand the complex biological factors driving MPE pathophysiology. In this review, we discuss what is currently known and identify knowledge gaps regarding the intrinsic MPE biology of cancer cells and the heterotypic interactions between tumor cells and the immunologic pleural ecosystem. Furthermore, we discuss the clinical opportunities of studying MPE and identify promising directions for MPE research that may lead to a deeper understanding of the disease, ultimately aiming to enhance clinical outcomes for patients with advanced cancer.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41514125 · DOI · PMC12905272
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Management of Malignant Pleural Effusions. An Official ATS/STS/STR Clinical Practice Guideline [5]
- Research article British Thoracic Society Guideline for pleural disease [6]
- Research article Pleural Effusion in Adults-Etiology, Diagnosis, and Treatment [7]
- Research article Tuberculous pleural effusion [8]
- Research article Adenosine deaminase for diagnosis of tuberculous pleural effusion: A systematic review and meta-analysis [9]
- Research article Research progress on complications of Brucellosis [10]
References
- Gonnelli F, Hassan W, Bonifazi M, Pinelli V, Bedawi EO, Porcel JM, et al.. Malignant pleural effusion: current understanding and therapeutic approach. . 2024. PMID 38243259 · DOI · PMC10797757
- Zhang X, Sun R, Jia W, Li P, Song C. A new dynamic nomogram for predicting the risk of severe Mycoplasma pneumoniae pneumonia in children. . 2024. PMID 38589453 · DOI · PMC11002011
- Lees EA, Williams TC, Marlow R, Fitzgerald F, Jones C, Lyall H, et al.. Epidemiology and Management of Pediatric Group A Streptococcal Pneumonia With Parapneumonic Effusion: An Observational Study. . 2024. PMID 38900036 · DOI · PMC11319078
- Woods AT, Murray AA, Vincent BG, Akulian J, Pecot CV. Pathobiology and clinical significance of malignant pleural effusions. . 2026. PMID 41514125 · DOI · PMC12905272
- Feller-Kopman DJ, Reddy CB, DeCamp MM, Diekemper RL, Gould MK, Henry T, et al.. Management of Malignant Pleural Effusions. An Official ATS/STS/STR Clinical Practice Guideline. Am J Respir Crit Care Med. 2018. PMID 30272503 · DOI
- Roberts ME, Rahman NM, Maskell NA, Bibby AC, Blyth KG, Corcoran JP, et al.. British Thoracic Society Guideline for pleural disease. Thorax. 2023. PMID 37553157 · DOI
- Jany B, Welte T. Pleural Effusion in Adults-Etiology, Diagnosis, and Treatment. Dtsch Arztebl Int. 2019. PMID 31315808 · DOI · PMC6647819
- Shaw JA, Diacon AH, Koegelenberg CFN. Tuberculous pleural effusion. Respirology. 2019. PMID 31418985 · DOI
- Aggarwal AN, Agarwal R, Sehgal IS, Dhooria S. Adenosine deaminase for diagnosis of tuberculous pleural effusion: A systematic review and meta-analysis. PLoS One. 2019. PMID 30913213 · DOI · PMC6435228
- Jin M, Fan Z, Gao R, Li X, Gao Z, Wang Z. Research progress on complications of Brucellosis. Front Cell Infect Microbiol. 2023. PMID 37065189 · DOI · PMC10102637
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-11-04; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-11-04.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.