Role of Common Investigations in Aetiological Evaluation of Exudative Pleural Effusions

Background: Pleural effusion is a common problem encountered in daily practice. To Establish aetiology of exudative effusions is a diagnostic challenge to general practitioners and even to pulmonologists especially in resource poor government hospitals with lack of investigations like thoracoscopy. Some recent studies had shown that around 2% of patients remained undiagnosed even after these investigations.

Aims And Objective: To evaluate the role of the commonly available investigations such as pleural fluid study, blind pleural biopsy, sputum examination, CT scan thorax, bronchoscopy in the aetiological evaluation of exudative effusions and to ascertain the proportion of cases which remain undiagnosed after all the above investigations.

Material And Methods: This was a prospective single-centred cross-sectional study carried out at the NRS Medical College, Kolkata, India from February 2008 to February 2013 which included 568 patients of exudative pleural effusions. We performed commonly available procedures like pleural fluid study, blind pleural biopsy, sputum examination, CT scan thorax, bronchoscopic procedures to the diagnosis.

Results: Total number of patients studied were 568. Tuberculosis was the most common cause (54.57%) followed by malignancy (28.17%), empyema (10.56%), parapneumonic effusion (5.28%) and others. Carcinoma of the lung was the commonest cause of malignant effusions and bronchoscopic biopsy was given the highest yield of histological diagnosis (84.6%) followed by CT guided FNAC (77.6%) and pleural fluid cytology (55%). Highest yield to diagnose tubercular effusion was found in lymph node FNAC (81.5%) followed by pleural biopsy (62%). Sputum smear for AFB was positive in only 27.4% cases. Bleeding followed by pneumothorax were the most common complications. Complications are very less (1.3% and 0.9% respectively). 2 patients (0.34%) remained undiagnosed even after these all above said investigations.

Conclusion: Above mentioned commonly available investigations can ascertain diagnosis in most of the cases in the aetiological evaluation of exudative effusions and they are relatively safe procedures.