OVERVIEW

What is pleural effusion?

The pleural cavity is a potential space located between the lungs and the chest wall. Under normal circumstances, there is a thin layer of fluid on the surfaces of the visceral pleura (the pleura close to the organs) and the parietal pleura (the pleura close to the chest wall), which acts as a lubricant during respiration. The pleural cavity and its fluid are not static; the shape and pressure of the pleural cavity change significantly with each respiratory cycle, causing continuous filtration and absorption of pleural fluid to maintain dynamic equilibrium. Any factor that causes excessive fluid formation or delayed absorption in the pleural cavity can lead to pleural effusion.

Is pleural effusion common among patients?

Pleural effusion is a common complication in cancer patients and has a relatively high incidence rate.

How is pleural effusion classified?

Based on etiology, it is generally divided into two main types: exudative pleural effusion and transudative pleural effusion.

• Pleural effusion caused by inflammatory exudation due to various factors leading to pleural inflammation is called exudate, which is often rich in protein.

• Non-inflammatory fluid in the pleural cavity resulting from other diseases (e.g., cardiac insufficiency, hypoalbuminemia) is called transudate, which is usually watery.

What are the characteristics of pleural effusion in children?

• The most common cause of pleural effusion in children is infection, primarily purulent infections. (Note: Purulent infections are general infections characterized by redness, swelling, heat, pain, and dysfunction at the infection site. In contrast, specific infections are caused by pathogens such as Mycobacterium tuberculosis, Clostridium tetani, or Bacillus anthracis, each with unique features and varying treatment approaches.)

• It is mainly associated with pneumonia-related pleural effusion, such as bacterial pneumonia, lung abscess, and bronchiectasis-related pleural effusion.

• Statistics show that approximately 40% of Chinese children with pneumonia may also develop pleural effusion to varying degrees.

• The most common pathogenic bacteria causing pleural effusion are Staphylococcus aureus and Streptococcus pneumoniae.

• Purulent pleuritis-induced pleural effusion is significantly more common in infants and young children than in preschool and school-aged children.

What is tuberculous pleural effusion? How does it differ from pulmonary tuberculosis?

Tuberculous pleural effusion is mostly caused by tuberculous pleurisy (a form of extrapulmonary tuberculosis), resulting from excessive exudation due to tuberculous pleurisy.

Statistics indicate that the average age of onset for tuberculous pleurisy is around 28 years, while pulmonary tuberculosis (involving the lung parenchyma) has an average onset age of around 50 years. Common symptoms include pleuritic pain (intermittent chest pain caused by friction between the visceral and parietal pleura during respiration; tuberculous pleural effusion often lacks this type of pain due to the lubricating effect of the fluid), cough, fever, etc.

SYMPTOMS

What are the clinical manifestations of pleural effusion?

Dyspnea is the most common symptom, often accompanied by chest pain and cough. Symptoms vary depending on the cause.

• Tuberculous pleurisy is more common in young people, often presenting with fever, dry cough, and chest pain. As the volume of pleural fluid increases, chest pain may alleviate, but chest tightness and shortness of breath may occur.

• Malignant pleural effusion is more common in middle-aged and elderly patients, usually without fever but with dull chest pain, accompanied by weight loss and symptoms related to respiratory or primary tumor sites.

• Inflammatory effusions are mostly exudative and often accompanied by cough, sputum production, chest pain, and fever.

• Pleural effusion caused by heart failure is transudative, with other manifestations of cardiac insufficiency.

What are the consequences of pleural effusion?

Further enlargement of the effusion can compress mediastinal organs, leading to significant palpitations and dyspnea. Severe cases complicated by bacterial infection may result in pleural adhesions, anemia, shock, pulmonary edema, and in extreme cases, heart or kidney failure.

CAUSES

What are the common causes of pleural effusion?

• Increased hydrostatic pressure in pleural capillaries: Such as congestive heart failure, constrictive pericarditis, increased blood volume, obstruction of the superior vena cava or azygos vein, leading to transudative pleural effusion.

• Increased pleural permeability: Such as pleural inflammation (tuberculosis, pneumonia), connective tissue diseases (systemic lupus erythematosus, rheumatoid arthritis), pleural tumors (malignant metastasis, mesothelioma), pulmonary infarction, subphrenic inflammation (subphrenic abscess, liver abscess, acute pancreatitis), etc., leading to exudative pleural effusion.

• Decreased colloid osmotic pressure in pleural capillaries: Such as hypoalbuminemia, liver cirrhosis, nephrotic syndrome, acute glomerulonephritis, myxedema, etc., leading to transudative pleural effusion.

• Impaired lymphatic drainage of the parietal pleura: Such as lymphatic obstruction due to cancer, developmental lymphatic drainage abnormalities, etc., leading to exudative pleural effusion.

• Trauma: Such as ruptured aortic aneurysm, esophageal rupture, thoracic duct rupture, etc., leading to hemothorax, empyema, or chylothorax.

• Iatrogenic causes: Such as medications, radiation therapy, gastrointestinal endoscopy and treatment, bronchial artery embolization, ovarian hyperstimulation syndrome, excessive fluid overload, coronary artery bypass surgery, bone marrow transplantation, central venous catheter perforation, and peritoneal dialysis, which can cause exudative or transudative pleural effusion.

Who is more prone to pleural effusion?

Pleural effusion is more common in people over 40 years old, especially the elderly.

Under what circumstances is pleural effusion more likely to occur?

For those prone to pleural effusion, factors such as catching a cold, respiratory infections, fatigue, or poor rest may trigger it.

What conditions commonly lead to non-inflammatory exudative pleural effusion?

Non-inflammatory exudative effusion, also known as transudative effusion, is often seen in conditions such as heart failure, liver cirrhosis, kidney disease, and malnutrition.

It is usually accompanied by symptoms in other parts of the body. For example, patients with liver cirrhosis often have lower limb edema and jaundice, kidney disease patients may experience morning eyelid edema, and malnourished individuals often exhibit generalized edema.

Does tuberculosis infection always lead to tuberculous pleural effusion?

Not necessarily.

People of any age can contract tuberculosis, but tuberculous pleuritis often occurs when the body is in a hypersensitive state (heightened sensitivity to pathogens), which is more common in young people.

In such cases, Mycobacterium tuberculosis and its metabolites enter the pleural cavity, causing tuberculous pleuritis. Early symptoms may include high fever and chest pain, with no abnormalities on X-ray. Later, exudation develops into pleural effusion.

Are patients with tuberculous pleural effusion contagious?

They may have some degree of contagiousness.

Patients with tuberculous pleural effusion differ from those with pulmonary tuberculosis. Active pulmonary tuberculosis patients, especially before or in the early stages of anti-tuberculosis treatment (the first 2–4 weeks), may carry Mycobacterium tuberculosis in their sputum, which can spread through the air.

Traditionally, tuberculous pleural effusion was considered non-contagious, meaning patients without pulmonary tuberculosis lesions would not have infectious sputum. However, some studies have confirmed that a small number of such patients may still test positive for Mycobacterium tuberculosis in their sputum.

DIAGNOSIS

What tests are generally performed for patients with pleural effusion after admission?

Patients with pleural effusion typically present with symptoms such as cough, chest pain, fever, night sweats, chest tightness, and weight loss. To address these symptoms, doctors will first conduct imaging tests like chest X-rays or CT scans. If pleural effusion is detected, the next step involves an ultrasound of the pleural fluid, followed by thoracentesis or closed thoracic drainage, along with routine pleural fluid analysis to determine the underlying cause.

If the cause remains unclear after these tests, further procedures such as medical thoracoscopy for pleural biopsy or exploratory thoracotomy may be performed. At this stage, additional preoperative tests are required, including complete blood count, coagulation tests, viral screening (HIV, syphilis, hepatitis B, etc.), electrocardiogram, and pulmonary function tests.

Is the T-SPOT test, a new method for diagnosing tuberculous pleural effusion, reliable?

Tuberculous pleural effusion is a form of tuberculosis (TB), which remains a serious global health challenge. Approximately 2 billion people worldwide are infected with Mycobacterium tuberculosis. Traditional diagnostic methods for TB include the PPD skin test, serum TB antibody tests, TB DNA detection, and pathological examinations. A major diagnostic challenge is that many TB patients (including those with tuberculous pleural effusion) test negative using conventional methods, falsely indicating no TB infection (a phenomenon known as false negatives), which delays treatment.

The T-SPOT test was officially introduced in China in August 2010 (after being approved in Canada in 2005 and the U.S. in 2008). In clinical practice for tuberculous pleural effusion, traditional methods are first used to detect TB infection. If results are negative (suggesting no TB infection), doctors in hospitals offering T-SPOT testing may recommend this additional test, which requires only a blood sample. A positive result (indicating TB infection) leads to strict anti-TB treatment tailored to the patient's condition. After complete drainage of the effusion (e.g., via closed thoracic drainage), patients can continue anti-TB treatment at home.

Advantages of T-SPOT: Unaffected by BCG vaccination or the patient's immune status; can detect active pulmonary TB, extrapulmonary TB, tuberculous pleural effusion, and cases with immunosuppression (e.g., HIV patients or long-term corticosteroid users); provides results within 24 hours.

What diseases should be suspected if pleural effusion occurs in elderly patients without an obvious cause?

Malignant pleural effusion caused by tumors should be considered first. In elderly patients presenting with pleural effusion accompanied by weight loss and chest pain—but without signs of infection like leukocytosis or high fever—malignant pleural effusion is a primary concern. Prompt testing for tumor markers and chest CT scans are necessary to rule out malignancies such as lung cancer or metastatic chest tumors.

What does the presence of malignant pleural effusion indicate?

Malignant pleural effusion refers to fluid accumulation caused by lung cancer or other malignancies involving the pleura or primary pleural tumors. It is a complication of advanced cancer. Reports indicate that nearly all cancers can invade the pleura, with lung cancer accounting for one-third of cases.

The appearance of malignant pleural effusion in cancer patients signifies that the disease has reached an advanced stage.

What precautions should be taken during tests for pleural effusion?

• Pleural biopsy is not suitable for patients with empyema or hemothorax.

• During fluid drainage, monitor the patient closely. If symptoms like dizziness, cold sweats, palpitations, pallor, weak pulse, cold extremities, pulmonary edema, or coughing occur—indicating a pleural reaction or re-expansion pulmonary edema—stop drainage immediately. Lay the patient flat, administer oxygen, monitor closely, and provide symptomatic treatment to prevent shock.

Which diseases can pleural effusion be easily confused with?

Tuberculous pleuritis must be differentiated from bacterial pneumonia, pleuritis, pulmonary embolism, and malignant pleural effusion.

TREATMENT

Which department should I visit for pleural effusion?

Respiratory Medicine Department. In severe cases, go directly to the Cardiothoracic Surgery Department.

How to self-rescue during an acute pleural effusion episode?

Stay calm, rest in bed, and reduce oxygen consumption. Have someone call 120 immediately.

How should family members of pleural effusion patients provide first aid?

First, stay calm and avoid panic. Help the patient lie down slowly. Family members can also assist with oxygen administration and call 120 immediately, accurately describing the patient’s condition.

How is pleural effusion treated?

Pleural effusion is often part of a chest or systemic disease, so treating the underlying cause is crucial.

• Tuberculous pleurisy: Rest, nutritional support, symptomatic treatment, thoracentesis, and anti-tuberculosis therapy.

• Parapneumonic effusion: Antibiotic treatment; thoracentesis if excessive fluid accumulates.

• Empyema: Infection control, drainage of pleural effusion, and lung re-expansion to restore pulmonary function. Chronic empyema requires general treatment, including high-energy, high-protein, vitamin-rich foods, correction of electrolyte imbalances, and acid-base balance. Surgical intervention may be necessary.

• Malignant pleural effusion: Repeated thoracentesis, systemic chemotherapy, localized radiotherapy for mediastinal lymph node metastasis, and anti-tumor therapy.

What types of medications are used to treat pleural effusion?

• Corticosteroids: Prednisone
• Chemotherapy drugs: Mitomycin, bleomycin, etc.
• Biological agents: Picibanil
• Immunomodulators: Corynebacterium parvum vaccine, interleukin-2, interferon

What are the benefits of early closed thoracic drainage for pleural effusion?

• Obtain pleural fluid for tests (routine, biochemical, tumor cell detection) to facilitate early diagnosis.

• Monitor disease progression by observing drainage volume.

• Promote lung re-expansion and restore respiratory function.

• Prevent further compartmentalization of pleural effusion (where fibrous septa divide the pleural cavity, complicating later drainage) and reduce infection risks.

• Enable therapeutic procedures via the drainage tube, such as pleural lavage or intrapleural drug injections (e.g., azithromycin for pleurodesis or platinum-based chemotherapy for malignant effusions).

What should pleural effusion patients pay attention to after closed thoracic drainage?

• Record daily drainage volume; avoid excessive fluid removal within 24 hours to prevent pleural reactions or dyspnea. Clamp the tube temporarily if output is too high.

• Notify the doctor immediately if drainage suddenly decreases, as this may indicate tube blockage.

• Monitor the puncture site for fluid leakage, redness, or swelling, and report abnormalities promptly.

Does worsening chest pain during pleural effusion treatment indicate poor efficacy?

Not necessarily.

Normally, a small amount of pleural fluid lubricates the pleural cavity. Inflammatory effusions initially cause fibrinous exudation, leading to chest pain during breathing, which lessens with reduced respiratory movement.

As the disease progresses, large effusions compress lung tissue, causing dull pain and dyspnea instead of sharp pain.

Later, as treatment reduces fluid volume, friction-related chest pain may recur during breathing.

What is the primary goal of malignant pleural effusion treatment? How is it treated?

• Effectively control fluid accumulation, relieve dyspnea, improve quality of life, and prolong survival.

• Perform closed thoracic drainage for gradual fluid removal, combined with intrapleural drug injections (chemotherapy, sclerosing agents, or biologics) to kill tumor cells and prevent recurrence.

What are the treatment characteristics for pediatric pleural effusion patients?

• A minority of severe cases with bacterial infections and moderate-to-large effusions (>200 mL) require closed thoracic drainage and antibiotics.

• Most children respond well to full-course antibiotic therapy, achieving full recovery.

What are the newer treatments for pleural effusion? What are the pros and cons of thoracoscopy?

• Traditional methods include thoracentesis or closed drainage, followed by fluid analysis and cause-specific treatment (e.g., anti-TB drugs, anti-inflammatory therapy, or intrapleural chemotherapy for malignancies).

• Thoracoscopy is increasingly important due to its advantages:

• High diagnostic accuracy via pleural biopsy.

• Shortens hospital stays.

• Fewer complications and lower recurrence rates.

• Minimally invasive pleural decortication, complete fluid removal, and simultaneous lesion excision for pathological diagnosis.

Both medical and surgical thoracoscopy have specific indications and contraindications.

• Risks/Disadvantages:
• Requires anesthesia, posing cardiopulmonary risks.
• Potential complications (e.g., pulmonary edema, atelectasis).
• Higher cost than conventional treatments.

DIET & LIFESTYLE

What should patients with pleural effusion pay attention to during hospitalization?

• Patients with large pleural effusions should adopt a comfortable position. A semi-recumbent or sitting position can relieve symptoms of dyspnea. Oxygen therapy may be administered if chest tightness is severe.

• If pleural effusion irritates the chest wall and causes unbearable pain, wide adhesive tape or a chest strap can be used to stabilize the chest wall, reducing thoracic movement and alleviating pain.

• Cooperate with medical staff to record closed thoracic drainage volume for better monitoring of disease progression.

What should patients with tuberculous pleural effusion pay attention to after discharge?

• Have blood tests and liver/kidney function checked every 2 weeks. Seek medical attention promptly if abnormalities occur (anti-tuberculosis drugs may damage the liver, kidneys, and peripheral nervous system).

• Strictly follow the doctor's instructions to take the prescribed dosage within the specified treatment period to ensure efficacy.

• Tuberculosis is not an incurable disease in the traditional sense. Building confidence, adhering to medication, and regular follow-ups are key to recovery.

What should pleural effusion patients pay attention to after discharge?

• Rest adequately in the short term and avoid overexertion. Activity levels should not cause fatigue.

• Minimize visits to public places to prevent upper respiratory infections (colds) due to weakened immunity.

• Take medications strictly according to the doctor's prescribed schedule and administration method.

What dietary considerations should pleural effusion patients follow?

• Consume high-protein and high-calorie foods. Most underlying diseases causing pleural effusion severely deplete protein and energy, so intake should exceed that of healthy individuals. Protein sources include dairy, eggs, animal organs, fish, and lean meat. Vegetable oils are preferred for fats.

• Vitamins and minerals enhance immune function. Eat leafy greens, fruits, and whole grains to supplement these nutrients.

Can pleural effusion patients exercise?

Avoid strenuous exercise while maintaining moderate rest.

How should family members care for pleural effusion patients?

Ensure regular medication and follow-ups; maintain cleanliness and comfort; provide nutritional support; offer psychological support to promote mental well-being.

PREVENTION

How to Prevent Pleural Effusion?

• Actively prevent and treat primary diseases: The key to preventing this condition.

• Strengthen physical fitness: Improve disease resistance by engaging in suitable physical exercise.

• Pay attention to lifestyle adjustments: Keep living areas dry, avoid raw or cold foods, refrain from overeating, and maintain normal spleen and stomach function.

• Enhance health education: Raise awareness of tuberculosis and cultivate good habits such as not spitting indiscriminately.

• Undergo regular health check-ups: Conduct routine physical examinations for adolescents to ensure early detection, isolation, and treatment.

• Administer BCG vaccines to infants and young children on schedule to develop immunity and reduce the incidence of tuberculosis.