Non-malignant pleural effusion

Muhammad Redzwan S. Rashid Ali
KPJ Johor Specialist Hospital, Johor Bahru, Johor, Malaysia

Non-malignant pleural effusion refers to the accumulation of excess fluid in the pleural space due to causes other than cancer. It is a common clinical condition with diverse etiologies and may present with symptoms such as dyspnea, chest pain, and cough. The effusion traditionally can be classified as transudative or exudative based on Light’s criteria, which assess pleural fluid protein and lactate dehydrogenase (LDH) levels relative to serum. 

NMPE are assumed to be benign but the trajectory can become chronic and difficult to treat, hence it may not be so “benign” as often we think. 

Transudative effusions are the most common cause of pleural effusions and typically result from systemic factors such as congestive heart failure, liver cirrhosis (hepatic hydrothorax), or nephrotic syndrome. These conditions cause an imbalance in hydrostatic and oncotic pressures without direct pleural involvement.

Exudative effusions arise from local pleural or pulmonary conditions, including infections (e.g., tuberculosis, pneumonia-related parapneumonic effusions), abdominal cause, renal cause, pulmonary embolism, autoimmune diseases (e.g., rheumatoid arthritis, lupus), and pancreatitis. These effusions indicate increased pleural membrane permeability or lymphatic obstruction.

The talk will discuss common selected causes of NMPE via case vignettes and ways to diagnose, differentiate and to treat it via medical therapy and pleural interventions. Treating the underlying disease often resolves the effusion. In some cases, therapeutic thoracentesis is performed to relieve symptoms. Recurrent or complicated effusions may require chest tube drainage, pleurodesis, or long-term indwelling pleural catheters.