From the Guidelines
The most common cause of pleural effusion is heart failure (HF), accounting for approximately 29% of all cases, followed by malignancy (26%), pneumonia (16%), and other conditions. When the heart fails to pump efficiently, increased pressure in the blood vessels causes fluid to leak into the pleural space between the lungs and chest wall 1. This condition is often characterized by the accumulation of a transudative fluid (low protein content) due to increased hydrostatic pressure rather than inflammation or tissue damage.
Common Causes of Pleural Effusion
- Heart failure (HF): 29% of all cases
- Malignancy: 26% of all cases
- Pneumonia: 16% of all cases
- Tuberculosis: 6% of all cases
- Post-surgery: 4% of all cases
- Pericardial diseases: 4% of all cases
- Cirrhosis: 3% of all cases
The aetiology of pleural effusion can vary depending on whether the effusion is unilateral or bilateral, with heart failure and malignancy being the most common causes of bilateral effusions 1. Patients with pleural effusion commonly experience symptoms such as shortness of breath, chest pain, and dry cough. Diagnosis typically involves chest imaging (X-ray or ultrasound) followed by thoracentesis if needed for fluid analysis to determine the underlying cause.
Diagnosis and Treatment
- Chest imaging (X-ray or ultrasound)
- Thoracentesis for fluid analysis
- Treatment of the underlying cause, such as heart failure with diuretics like furosemide, ACE inhibitors, and other heart failure medications.
It is essential to note that the categorization of a pleural effusion as transudate or exudate is not always indicative of a particular aetiology or group of aetiologies, and misclassification can occur 1. Therefore, a thorough diagnostic approach is necessary to determine the underlying cause of the pleural effusion and provide appropriate treatment.
From the Research
Causes of Pleural Effusion
The most common causes of pleural effusion are:
- Heart failure
- Infection
- Malignancy
- Pulmonary embolism 2 Other causes include:
- Congestive heart failure
- Pneumonia
- Cancer 3
- Lung cancer
- Breast cancer
- Lymphoma
- Ovarian carcinoma
- Stomach cancer 4
Types of Pleural Effusion
Pleural effusions can be classified into two main types:
- Transudative effusions: often caused by heart failure, cirrhosis, or kidney failure 2
- Exudative effusions: often caused by infection, malignancy, or pulmonary embolism 2 Parapneumonic effusions are the most common cause of exudates 2
Diagnosis and Treatment
Diagnosis of pleural effusion involves: