Etiological causes of exudative pleural effusion in patients treated in a teaching hospital

The aim of this study was to find out the common etiological causes of exudative pleural effusion in patients before starting treatment. Fifty patients, diagnosed with pleural effusion on admission were randomly selected from Medicine and Paediatric wards of Khulna Medical College Hospital during the period from March 2016 to November 2016. Etiological diagnosis was established by sequential clinical history and findings on physical examination, laboratory tests, chest radiograph, CT scan of the chest and pleural fluid analysis. Patients who remained undiagnosed were subjected to fibro-optic bronchoscopy, thoracoscopic pleural biopsy, and histopathology. Among the patients having pleural effusion, there were tuberculosis, pneumonia, malignancy and systemic lupus erythematosus in 27 (54%), 11 (22%), 7 (14%) and 1 (2%), respectively. Despite all investigations, 4 (8%) were remained undiagnosed etiologically. Most of the pleural effusion cases were diagnosed as tuberculosis. Early and adequate treatment resulted in complete recovery of the patients.


Introduction
Pleural effusion is common in respiratory medicine.It is a serious local or systemic disease and calls for urgent investigations to determine its cause.The patho-physiological mechanisms underlying pleural effusion include an increased pulmonary capillary pressure, decreased plasma oncotic pressure, increased permeability of pleural membrane, mediastinal involvement with reduced pleural lymphatic drainage, bronchial obstruction with high negative intrapleural pressure, and imbalance between formation and absorption of fluid. 1,2The effusion occurring through pressure filtration without capillary injury is termed as transudate.2][3][4] It may be noted that a malignant disease and pulmonary embolism may produce either a transudative or an exudative effusion.Exudates and transudates are best differentiated by Light's three criteria: i) ratio of pleural fluid protein to serum protein >0.5, ii) ratio of pleural fluid to the serum lactate dehydrogenase (LDH) >0.6 and iii) Mediscope 2017;4(1):30-33 30 ISSN: 2307-7689 www.gmc.edu.bdabsolute value of pleural fluid LDH >twothirds of the upper normal limit for serum.While exudates meet one or more of the three criteria, transudates meet none. 1 Ninety percent cases of pleural effusion in the western countries have been reported to be the result from only five diseases: CCF, pneumonia, malignancy, pulmonary embolism, and viral infections.2][3][4][5] Pleural effusion is a significant respiratory problem that needs hospitalization.
The present study was done to evaluate the common causes of pleural effusion in a developing country and also to compare that of developed countries.The present study correlate with other studies that right sided pleural effusion is more common than left sided pleural effusion.Majority causes of exudative pleural effusions were tuberculosis, pneumonia, malignancy, which is almost similar to the findings of other studies in developing countries. 2But in developed country scenario is different where malignancy is in the 1 st position then parapnumonic effusion, systemic lupus erythematosus and other exudative causes but tuberculosis is almost nil.

Conclusion
In developed countries, the common cause of pleural effusion are pneumonia and malignancy but in developing country the common cause of pleural effusion is tuberculosis due to poverty, overcrowding Mediscope 2017;4(1):30-33 32 comprehensive clinical history, complete physical examination, a chest X-ray and diagnostic ultrasonography.Subjects of either sex over 10 years of age were included in this study.Subjects <10 years of age were excluded from this study.
Complete blood count (CBC) with ESR, chest radiograph and pleural fluid study for biochemical, cytological, gram staining and malignant cells, serum protein and sputum examinations for acid fast bacillus (AFB) were done in all cases.Ultrasonography of the whole abdomen and serological test (ANA test) were done in some cases.Thoracocentesis was done in all cases for pleural fluid analysis.Pleural fluid was examined for biochemical, bacteriological and cytological list.
Inconclusive cases were evaluated by following investigation: fiber-optic bronchoscopy, broncho-alveolar lavage, fine needle aspiration cytology (FNAC) and gene expert.Pleural biopsy, AFB culture and pleural fluid Adenosine Deaminase were not done due to non availability.

Results
Table 1 shows the age and gender distribution of study subjects.There were 36 male and 14 female patients participated in the study.Most of them (88%) were of the age range between 20 to 50 years.Fig. 1 depicts the etiology of exudative pleural effusion, where tuberculosis, pneumonia, malignancy, systemic lupus erythematosus and inconclusive cases were 27 (54%), 11 (22%), 7 (14%), 1 (2%) and 4 (8%), respectively.Among tuberculosis cases, 20 (40%) were sputum positive for AFB and 7 (14%) were diagnosed by gene expert for tuberculosis.The malignant pleural effusion cases, 7 (14%), were confirmed by FNAC of lymphnode, lung biopsy, fiber-optic broncoscopy for bronco-alveolar lavage examination and bronchial tissue biopsy for histopathological examination revealing 5 cases as adenocarcinoma of lung and 2 cases as squamous cell carcinoma.

Table 1 . Age and gender distribution of the patients with pleural effusion Physical color Number of patients (%)
This prospective observational study was conducted in medicine and paediatric wards of Khulna Medical College Hospital, Khulna over a period of nine months from March 2016 to November 2016.During this period 50 patients were admitted in medicine ward and diagnosed as pleural effusion based on