To Study the Common Etiologies of Pleural Effusion and Their Clinical Profile in Patients Attending in A Tertiary Care Hospital in Delhi

To Study the Common Etiologies of Pleural Effusion and Their Clinical Profile in Patients Attending in A Tertiary Care Hospital in Delhi

Dr. MD Shams ^*, Dr khushnuma parween¹

1. Junior resident (academic), Department of Pathology, Narayana medical College and Hospital, Jamuhar, sasaram, Bihar-821305

Correspondence to: Dr. MD Shams, Department of Respiratory Diseases & TB Rajan Babu Institute of Pulmonary Medicine and Tuberculosis, Municipal Corporation of Delhi, GTB Nagar, Kingsway Camp, New Delhi-110009.

Copyright

© 2026 Dr. MD Shams. This is an open access article distributed under the Creative Commons Attribution  License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: 17 July 2026

Published: 28 July 2026

DOI: https://doi.org/10.5281/zenodo.21637885

Introduction

Pleural effusion is an abnormal excess accumulation of fluid in the pleural space. The pleural space is space between the lung and chest wall and normally contains a small amount of fluid about 10 to 20 mL, with a low protein concentration (less than 1.5 g/dL), which serves as a coupling system [1]. Excess fluid accumulation occurs due to disruption of the equilibrium that exists across pleural membranes. Pleural effusion indicates an acute or chronic pathologic process that may be of primary pulmonary origin or of secondary origin related to another organ system.

Pleural effusion is not a diagnosis in itself but it aids in diagnosis of underlying pathological process with evaluation of its cause and further management. Light’s criteria which include serum and pleural fluid biochemical analyses is most commonly used to distinguish between the exudative and transudative pleural effusion (PE) in routine clinical practice [2]. Light’s criteria have high sensitivity for diagnosing exudative pleural effusion but it is also found that occasionally it cannot differentiate the underlying causes such as infections and malignancies. With the advent of various diagnostic aids like pleural fluid cytology, pleural biopsy, ultrasonography, bronchoscopy, thoracoscopy, CT thorax, serological tests like ANA, ADA, Rheumatoid factor, microbiological culture helps the physician to diagnose at an earlier course of the disease. Although most tests have their drawbacks viz thoracoscopy is invasive procedure and leaves 7% of cases undiagnosed; microbiological culture test has high turn-around-time (TAT), CT thorax has high radiation exposure etc. Recently with further advancement, some pleural fluid and serum markers have shown increased specificity and diagnostic accuracy in patients with pleural effusion (PE). For instance, patients with tuberculous PE have high interleukin-27(IL-27), interferon-gamma (IFN-γ), adenosine deaminase (ADA) pleural fluid levels while serum N-terminal pro-brain natriuretic peptide (NT-proBNP) for congestive heart failure (CHF) patients [3]. However, the diagnostic accuracy of other available markers such as tumour markers, procalcitonin (PCT) and C reactive protein (CRP) for malignant and infectious diseases remains unsatisfactory. Therefore, further researches are required to identify novel markers in PE with increased diagnostic accuracy and faster TAT to aid earliest diagnosis and timely management to increase outcome among patients.

Need of the study

Pleural effusion is a common clinical problem with a wide range of potential underlying causes, including infections, malignancies, heart failure, and more. Understanding the common etiologies and clinical characteristics specific to the population in Delhi can help healthcare providers make accurate diagnoses and initiate appropriate treatment early. The prevalence of different causes of pleural effusion can vary by region and population. What may be common in one area might not be as prevalent in another. This study will provide valuable data specific to Delhi, aiding in tailored patient care and resource allocation. Identifying the underlying cause of pleural effusion is crucial for timely and effective management. Some causes, like infections or malignancies, may require specific treatments. A study of this nature can help healthcare professionals in Delhi expedite the diagnostic process. By understanding the common etiologies, healthcare facilities can optimize resources, including diagnostic tests and treatments. This can help in managing patient care efficiently, particularly in a tertiary care hospital where resources may be limited.

Aims and Objectives

Aim

To identify the common etiologies causing pleural effusion and their clinical profile in a tertiary care hospital.

Objectives

1. To study the risk factors associated with pleural effusion.
2. To study socioeconomic status associated with common etiologies

Materials and Methods

Study Design:

It is a prospective observational study.

Study Setting:

Department of Respiratory Diseases & Tuberculosis, Rajan Babu Institute for Pulmonary Medicine and Tuberculosis (RBIPMT), Delhi Municipal Corporation, GTB Nagar, Kingsway Camp, Delhi-110009.

Study period

Period.of 01-05-2023 to 31-10-2023

Study Population

It will be a hospital-based (OPD and IPD) study. All consecutive registered patients who presented with pleural fluid effusion on diagnostic aspiration of pleural fluid at RBIPMT and got admitted in the indoor wards of RBIPMT. It will be volunteer enrollment of IPD patient admitted in wards.

Consent and Ethical Considerations

The study will be carried out after obtaining approval from the Institutional Human Ethics Committee. An informed, written consent will be obtained from all the patients. Patients who volunteer for their inclusion in the study will only be enrolled in study. All patients can opt out of the study at any point of time during the study period.

Patient Inclusion Criteria

1. All patients who give informed consent for their inclusion in the study and who underwent diagnostic pleural fluid aspiration with evaluation will be included in the study.
2. All patients aged >18 years who are presented with pleural fluid effusion on clinical examination, radiological evaluation followed by diagnostic pleural fluid aspiration at RBIPMT.

Patient Exclusion Criteria

1. All patients who are aged <18 years.
2. All patients who will not give consent and does not wish to be part of the study.
3. Recurrent pleural effusion with established etiology will be part of the study for once only.

Sample Size and techniques:

KCC OPD in Rajan Babu Institute of Pulmonary Medicine and Tuberculosis has approximately 8 lakhs population visits every year and patients with pleural effusion admitted to wards accounts to about 8%.

Statistical Software

Sample size has been calculated with help of Epi Info (TM) 3.5.3. EPI INFO which is a trademark of the Centers for Disease Control and Prevention (CDC). For statistical analysis data were entered into a Microsoft excel spreadsheet and then analyzed by SPSS 27.0. and Graph Pad Prism version 5. Data had been summarized as mean and standard deviation for numerical variables and count and percentages for categorical variables.

Sample Size Justification

At 95% confidence level and considering most common presentation of exudates among the patients as 71.2% (Ranjan Agarwal et al [5]) and with an absolute error of 10%, the sample size estimated was 87 using the formula

n          =          zα2pq / (d2) Wherein;

Zα = 1.96 value of the standard normal variate corresponding to level of significanceAlpha 5%

n= required sample size

p= 0.712 (percentage of patients with most common presentation of exudates)

q = 1 - p

d= Loss % (Loss of information) Calculation:

Here p= 0.712

q=1-p = 1-0.712 =0.288

d2 = .01

n =zα2pq / (d2) = 78.8 i.e., 79

Considering 10% Non-conclusive a sample size of 79 + 7.9 ≈ 87 subjects will be included in the study.

Study group: No. of patients 87

Methodology

After taking informed consent from each patient presenting with pleural effusion, following test will be done.

Pleural Effusion Algorithm.

Statistical Analysis

Descriptive data will be analyzed with SPSS version 27.0 software. Categorical variables will be expressed as percentage and nominal categorical data between the groups will be compared using Chi-squared test or Fisher’s exact test as appropriate. Continuous variables will be presented as mean (SD) or median if the data is skewed and will be analyzed using analysis of variance (ANOVA) and student t- test as appropriate. For all statistical tests, a P value less than 0.05 will be taken to indicate a significant difference.

Observation & Results