Pleural Effusion

1. Overview

Pleural effusion is an abnormal accumulation of fluid in the pleural space between the visceral and parietal pleura. It may present with breathlessness, pleuritic chest pain, cough, reduced exercise tolerance, fever, weight loss or may be found incidentally on chest imaging.

Pleural effusions are broadly classified as transudates or exudates. Transudates are usually due to systemic fluid imbalance, such as heart failure, cirrhosis or nephrotic syndrome. Exudates are usually due to local pleural or lung disease, such as pneumonia, malignancy, tuberculosis, pulmonary embolism or inflammatory disease.

Key OSCE priorities

• Assess severity of breathlessness and oxygenation.
• Ask about cough, fever, pleuritic chest pain and sputum.
• Ask about weight loss, night sweats, haemoptysis and smoking.
• Screen for malignancy, tuberculosis, pneumonia, pulmonary embolism and heart failure.
• Ask about liver disease, renal disease and nephrotic syndrome.
• Ask about asbestos exposure because of mesothelioma risk.
• Perform a structured respiratory examination.
• Look for signs of pleural effusion: reduced expansion, stony dull percussion and reduced breath sounds.
• State that unexplained unilateral effusion needs imaging and pleural fluid analysis.
• Escalate urgently if the patient is hypoxic, septic or severely breathless.

Important causes

• Heart failure.
• Pneumonia with parapneumonic effusion.
• Empyema.
• Lung cancer.
• Pleural metastases.
• Mesothelioma.
• Tuberculosis.
• Pulmonary embolism.
• Cirrhosis with hepatic hydrothorax.
• Nephrotic syndrome.
• Chronic kidney disease.
• Pancreatitis.
• Systemic lupus erythematosus.
• Rheumatoid disease.
• Trauma or haemothorax.
• Chylothorax.

Red flag features

• Severe breathlessness.
• Low oxygen saturation.
• Fever with sepsis features.
• Pleuritic chest pain.
• Haemoptysis.
• Unexplained weight loss.
• Night sweats.
• Persistent cough.
• Unilateral pleural effusion.
• Smoking history.
• Asbestos exposure.
• Known cancer.
• Recent surgery or immobility.
• Immunosuppression.

2. History Taking

Opening

• Wash hands.
• Introduce yourself.
• Confirm patient identity.
• Explain that you would like to ask about their breathing and chest symptoms.
• Gain consent.
• Check whether the patient is currently severely breathless, has chest pain, haemoptysis or feels faint.
• If acutely unwell, state that you would assess using ABCDE and call for senior help.

Presenting complaint

• Ask what symptoms brought the patient in.
• Ask when the symptoms started.
• Ask whether onset was sudden or gradual.
• Ask whether symptoms are improving, worsening or stable.
• Ask about shortness of breath.
• Ask about pleuritic chest pain.
• Ask about cough and sputum.
• Ask about fever or rigors.
• Ask whether this has happened before.

Breathlessness assessment

• Ask whether the patient is breathless at rest.
• Ask whether they can speak in full sentences.
• Ask how far they can walk now compared with baseline.
• Ask whether they are breathless lying flat.
• Ask about paroxysmal nocturnal dyspnoea.
• Ask whether symptoms affect washing, dressing, eating or sleeping.
• Ask whether breathlessness is progressive.
• Ask whether symptoms improved after previous fluid drainage if recurrent.

Pleuritic chest pain assessment

• Ask where the pain is located.
• Ask whether it is sharp or stabbing.
• Ask whether it is worse with deep inspiration.
• Ask whether it is worse with coughing or movement.
• Ask about radiation to shoulder, back, arm, jaw or neck.
• Ask about pain severity out of 10.
• Ask what relieves the pain.

Respiratory symptoms

• Cough.
• Sputum production.
• Purulent sputum.
• Haemoptysis.
• Wheeze.
• Fever.
• Rigors.
• Night sweats.
• Weight loss.
• Hoarseness.
• Recurrent chest infections.

Pneumonia and empyema screen

• Fever.
• Rigors.
• Productive cough.
• Purulent sputum.
• Pleuritic chest pain.
• Shortness of breath.
• Malaise.
• Confusion in older patients.
• Recent pneumonia.
• Failure to improve despite antibiotics.
• Persistent fever despite treatment.
• Immunosuppression.

Malignancy screen

• Unexplained weight loss.
• Loss of appetite.
• Persistent cough.
• Haemoptysis.
• Chest pain.
• Hoarseness.
• Recurrent pneumonia.
• Smoking history.
• Previous cancer.
• Occupational asbestos exposure.
• Fatigue.
• Night sweats.

Mesothelioma and asbestos exposure screen

• Previous asbestos exposure.
• Construction, shipyard, insulation, plumbing, roofing or demolition work.
• Living with someone who worked with asbestos.
• Long latency between exposure and symptoms.
• Progressive breathlessness.
• Chest wall pain.
• Weight loss.
• Known pleural plaques or previous abnormal chest imaging.

Tuberculosis screen

• Persistent cough.
• Fever.
• Night sweats.
• Weight loss.
• Loss of appetite.
• Fatigue.
• Previous TB.
• Close contact with TB.
• Travel or residence in a high TB prevalence area.
• Crowded living conditions.
• HIV risk or immunosuppression.

Heart failure screen

• Orthopnoea.
• Paroxysmal nocturnal dyspnoea.
• Ankle swelling.
• Rapid weight gain.
• Nocturnal cough.
• Reduced exercise tolerance.
• Known ischaemic heart disease.
• Hypertension.
• Valvular heart disease.
• Previous heart failure.
• Diuretic use and adherence.

Pulmonary embolism screen

• Sudden breathlessness.
• Pleuritic chest pain.
• Haemoptysis.
• Syncope or collapse.
• Unilateral leg swelling or calf pain.
• Recent surgery.
• Recent immobility or long-haul travel.
• Active cancer.
• Previous DVT or PE.
• Pregnancy or postpartum period.
• Combined oral contraceptive pill or oestrogen therapy.
• Known thrombophilia.

Liver, renal and systemic disease screen

• Known cirrhosis or chronic liver disease.
• Abdominal distension or ascites.
• Jaundice.
• Alcohol excess.
• Known kidney disease.
• Reduced urine output.
• Frothy urine.
• Facial or leg swelling.
• Known nephrotic syndrome.
• Joint pains, rash or mouth ulcers suggesting autoimmune disease.

Pancreatic and abdominal screen

• Upper abdominal pain.
• Pain radiating to the back.
• Nausea or vomiting.
• History of pancreatitis.
• Heavy alcohol use.
• Gallstone disease.
• Recent abdominal surgery or trauma.

Past medical history

• Previous pleural effusion.
• Heart failure.
• Ischaemic heart disease.
• Valvular heart disease.
• Pneumonia.
• Tuberculosis.
• Lung cancer or other malignancy.
• COPD.
• Pulmonary embolism or DVT.
• Cirrhosis.
• Chronic kidney disease.
• Nephrotic syndrome.
• Pancreatitis.
• Autoimmune disease.
• Recent surgery or trauma.

Drug history and allergies

• Current regular medications.
• Diuretics.
• Antibiotics.
• Anticoagulants.
• Antiplatelets.
• Immunosuppressants.
• Chemotherapy.
• Methotrexate or other drugs associated with lung disease.
• Recent medication changes.
• Drug allergies and reaction.
• Antibiotic allergies specifically.

Family history

• Lung cancer.
• Other malignancy.
• Tuberculosis exposure.
• Venous thromboembolism or thrombophilia.
• Autoimmune disease.
• Heart failure or cardiomyopathy.
• Renal disease.

Social history

• Smoking status and pack-year history.
• Vaping.
• Alcohol intake.
• Recreational drug use.
• Occupation and asbestos exposure.
• Dust, chemical or silica exposure.
• Recent travel.
• TB contacts.
• Living conditions.
• Baseline mobility and exercise tolerance.
• Functional impact of breathlessness.
• Living situation and support.

Ideas, concerns and expectations

• Ask what the patient thinks is causing the fluid or symptoms.
• Ask what they are most worried about.
• Ask whether they are worried about cancer, infection, TB, heart failure or blood clots.
• Ask what they were hoping would happen today.
• Acknowledge that finding fluid around the lung can be worrying.

Red flags

• Severe breathlessness.
• Oxygen desaturation.
• Fever with sepsis features.
• Haemoptysis.
• Weight loss.
• Night sweats.
• Persistent cough.
• Pleuritic chest pain.
• Known cancer.
• Smoking history.
• Asbestos exposure.
• Unilateral leg swelling.
• Immunosuppression.

Closing the history

• Summarise the key points back to the patient.
• Ask if they would like to add anything else.
• Thank the patient.
• State that you would check observations, oxygen saturation, perform respiratory and cardiovascular examination, and arrange imaging and pleural fluid investigations if indicated.

3. Physical Examination

The examination should assess severity, oxygenation, signs of pleural effusion, and clues to the underlying cause such as heart failure, infection, malignancy, liver disease, renal disease or pulmonary embolism.

Before starting the examination

• Wash hands or use alcohol gel.
• Introduce yourself with name and role.
• Confirm the patient's identity.
• Explain the examination clearly.
• Gain consent.
• Ask whether the patient is comfortable to proceed.
• Position the patient sitting upright or at 45 degrees.
• Expose the chest appropriately while maintaining dignity.
• Ask for a chaperone if appropriate.

Initial assessment

• Look from the end of the bed.
• Assess whether the patient is comfortable, breathless, cyanosed, pale, cachectic or sweaty.
• Assess whether the patient can speak in full sentences.
• Look for oxygen therapy, monitoring, chest drain, pleural catheter or drainage bottle.
• Look for use of accessory muscles.
• Look for asymmetrical chest movement.
• Look for surgical scars or signs of previous pleural procedures.
• If acutely unwell, perform ABCDE assessment and call for senior help.

Vital signs

• Respiratory rate.
• Oxygen saturation.
• Heart rate.
• Blood pressure.
• Temperature.
• Level of consciousness.
• Pain score if pleuritic chest pain is present.
• Daily weight if fluid overload is suspected.

Hands

• Look for peripheral cyanosis.
• Check capillary refill time.
• Look for finger clubbing.
• Look for nicotine staining.
• Look for palmar pallor.
• Look for peripheral oedema.
• Look for tremor or asterixis if liver disease or CO2 retention is suspected.
• Look for signs of rheumatoid disease if autoimmune cause is suspected.

Pulse and blood pressure

• Assess pulse rate.
• Assess pulse rhythm.
• Tachycardia may suggest hypoxia, infection, PE, pain or malignancy.
• Irregularly irregular pulse may suggest atrial fibrillation.
• Measure blood pressure.
• Hypotension may suggest sepsis, massive PE or severe systemic illness.

Face, mouth and neck

• Look for central cyanosis.
• Look for conjunctival pallor.
• Look for cachexia or weight loss.
• Look for jaundice.
• Assess cervical and supraclavicular lymph nodes.
• Check tracheal position.
• Assess jugular venous pressure.
• Raised JVP may suggest heart failure or malignancy-related obstruction.

Chest inspection

• Inspect chest shape.
• Look for reduced movement on one side.
• Look for respiratory distress.
• Look for scars from thoracentesis, chest drain or thoracic surgery.
• Look for chest wall masses.
• Look for radiotherapy marks.
• Observe respiratory pattern.

Palpation

• Assess chest expansion.
• Compare expansion bilaterally.
• Reduced expansion may occur on the side of the effusion.
• Assess tactile vocal fremitus.
• Tactile vocal fremitus is usually reduced over a pleural effusion.
• Palpate for chest wall tenderness.
• Confirm tracheal position.
• Large effusions may push the trachea away from the affected side.

Percussion

• Percuss symmetrical areas of the chest.
• A pleural effusion classically gives stony dullness to percussion.
• Map the upper level of dullness if possible.
• Compare side to side.
• Dullness can also occur with consolidation or collapse, so auscultation and imaging are needed.

Auscultation

• Auscultate symmetrical areas of the chest.
• Breath sounds are usually reduced over a pleural effusion.
• Vocal resonance is usually reduced over a pleural effusion.
• Bronchial breathing may be heard just above the upper level of an effusion.
• Listen for crackles suggesting pneumonia or heart failure.
• Listen for wheeze suggesting asthma, COPD or airway obstruction.
• Listen for pleural rub if pleurisy is present.

Cardiovascular examination

• Assess JVP.
• Palpate the apex beat.
• Auscultate heart sounds.
• Listen for murmurs.
• Check for peripheral oedema.
• Look for signs of heart failure.
• Bilateral effusions with raised JVP and oedema suggest heart failure.

Abdominal examination

• Look for abdominal distension.
• Assess for ascites.
• Assess for hepatomegaly.
• Look for stigmata of chronic liver disease.
• Check for abdominal tenderness if pancreatitis is suspected.
• Assess for masses if malignancy is suspected.

Peripheral and systemic examination

• Check legs for pitting oedema.
• Check calves for unilateral swelling or tenderness if PE is suspected.
• Look for lymphadenopathy.
• Look for rash, joint swelling or deformity suggesting autoimmune disease.
• Assess hydration and nutritional status.
• Check temperature and signs of sepsis.

Classic signs of pleural effusion

• Reduced chest expansion on the affected side.
• Reduced tactile vocal fremitus.
• Stony dull percussion note.
• Reduced breath sounds.
• Reduced vocal resonance.
• Possible bronchial breathing above the effusion.
• Possible tracheal deviation away from a very large effusion.

To complete the examination

To complete my examination, I would review observations, check oxygen saturation, arrange chest X-ray and thoracic ultrasound, request blood tests, and consider diagnostic pleural aspiration under ultrasound guidance if the effusion is unexplained and safe to sample.

4. Differential Diagnosis

Transudative causes

• Heart failure.
• Cirrhosis with hepatic hydrothorax.
• Nephrotic syndrome.
• Chronic kidney disease.
• Hypoalbuminaemia.
• Peritoneal dialysis-related pleural leak.

Exudative causes

• Pneumonia with parapneumonic effusion.
• Empyema.
• Malignancy.
• Mesothelioma.
• Tuberculosis.
• Pulmonary embolism.
• Rheumatoid pleuritis.
• Systemic lupus erythematosus.
• Pancreatitis.
• Haemothorax.
• Chylothorax.

Malignant causes

• Primary lung cancer.
• Metastatic breast cancer.
• Metastatic ovarian cancer.
• Lymphoma.
• Mesothelioma.
• Other metastatic pleural disease.

Infective causes

• Bacterial pneumonia.
• Complicated parapneumonic effusion.
• Empyema.
• Tuberculosis.
• Viral pleuritis.
• Fungal infection in immunosuppressed patients.

Important mimics

• Lung collapse.
• Consolidation.
• Raised hemidiaphragm.
• Pleural thickening.
• Diaphragmatic hernia.
• Large lung mass.

5. Investigations

Bedside tests

• Full observations.
• Oxygen saturation.
• Capillary blood glucose if acutely unwell.
• Urine dip for protein if nephrotic syndrome is suspected.
• Pregnancy test in women of reproductive age when relevant.
• ECG if heart failure, PE, arrhythmia or chest pain is suspected.

Blood tests

• Full blood count.
• Urea and electrolytes.
• Creatinine and estimated GFR.
• CRP.
• Liver function tests.
• Albumin.
• Coagulation profile before pleural procedure if indicated.
• Blood cultures if sepsis or pleural infection is suspected.
• BNP or NT-proBNP if heart failure is suspected.
• D-dimer only if PE is possible and clinical probability supports testing.
• Autoimmune screen if connective tissue disease is suspected.

Imaging

• Chest X-ray to identify pleural effusion and look for pneumonia, malignancy or heart failure.
• Lateral decubitus chest X-ray is less commonly used but may show free-flowing fluid.
• Thoracic ultrasound to confirm fluid, estimate size, identify septations and guide pleural aspiration.
• CT chest if malignancy, complex pleural disease, empyema, PE or unclear cause is suspected.
• CT pulmonary angiography if PE is suspected and imaging is indicated.
• Echocardiography if heart failure, valvular disease or pulmonary hypertension is suspected.

Diagnostic pleural aspiration

• Consider diagnostic aspiration for unexplained unilateral pleural effusion.
• Use ultrasound guidance to reduce procedure risk.
• Assess whether there is enough fluid to sample safely.
• Check bleeding risk and anticoagulant use.
• Obtain informed consent.
• Send pleural fluid for protein, LDH, glucose, pH, Gram stain, culture and cytology as appropriate.
• Send additional tests such as AFB culture, TB PCR, ADA, triglycerides, cholesterol or amylase depending on suspected cause.

Pleural fluid appearance

• Clear straw-coloured fluid may be transudative or exudative.
• Turbid or purulent fluid suggests empyema.
• Blood-stained fluid suggests malignancy, PE, trauma or haemothorax.
• Milky fluid suggests chylothorax.
• Food-like or brown fluid may suggest oesophageal rupture, although this is rare.

Light's criteria

• Pleural fluid is exudative if pleural fluid protein divided by serum protein is greater than 0.5.
• Pleural fluid is exudative if pleural fluid LDH divided by serum LDH is greater than 0.6.
• Pleural fluid is exudative if pleural fluid LDH is greater than two-thirds of the upper limit of normal serum LDH.
• If any one criterion is met, the effusion is classified as exudative.
• Clinical context remains important because diuretics can affect interpretation in heart failure.

Pleural infection markers

• Low pleural fluid pH supports complicated parapneumonic effusion or empyema.
• Low pleural fluid glucose may occur in empyema, rheumatoid disease, TB or malignancy.
• Positive Gram stain or culture supports pleural infection.
• Frank pus confirms empyema.
• Ultrasound septations may suggest complex pleural infection.

Malignancy investigations

• Pleural fluid cytology.
• CT chest, abdomen and pelvis if malignancy is suspected.
• Image-guided pleural biopsy if cytology is negative and suspicion remains.
• Thoracoscopy may be used for diagnosis and management in selected cases.
• Urgent respiratory or cancer pathway referral if malignancy is suspected.

Important investigation points

• Unexplained unilateral pleural effusion usually requires further investigation.
• Thoracic ultrasound is important before pleural procedures.
• Chest X-ray can show effusion but does not reliably identify the cause.
• CT is useful when malignancy, PE or complex pleural disease is suspected.
• Pleural fluid analysis helps distinguish transudate from exudate and guides diagnosis.
• Do not perform blind pleural aspiration when ultrasound guidance is available.

6. Management

Management depends on severity, size of effusion, underlying cause, oxygenation and whether the effusion is infected, malignant, recurrent or causing significant symptoms.

Immediate approach if acutely unwell

1. Assess using ABCDE.
2. Call for senior help if severe breathlessness, hypoxia, sepsis, hypotension or respiratory failure is present.
3. Sit the patient upright.
4. Give oxygen if hypoxaemic according to local oxygen target protocol.
5. Attach monitoring if unstable.
6. Obtain IV access if clinically indicated.
7. Request urgent chest X-ray and thoracic ultrasound.
8. Treat suspected sepsis, pneumonia, PE or heart failure according to local protocols.

General management principles

• Treat the underlying cause.
• Assess whether the effusion is causing symptoms.
• Assess whether diagnostic pleural aspiration is needed.
• Use ultrasound guidance for pleural procedures.
• Provide analgesia if pleuritic pain is present.
• Monitor oxygen saturation and respiratory status.
• Refer to respiratory team for unexplained, recurrent, large, infected or malignant effusions.

If heart failure is likely

• Assess fluid status.
• Treat heart failure according to local protocol.
• Use diuretics if clinically fluid overloaded and not contraindicated.
• Monitor renal function and electrolytes.
• Consider echocardiography if diagnosis is uncertain or new.
• Pleural aspiration may not be needed if bilateral effusions clearly fit heart failure and respond to treatment.
• Investigate further if effusion is unilateral, very large, atypical or does not respond to treatment.

If parapneumonic effusion or empyema is suspected

• Assess for sepsis.
• Start antibiotics according to local antimicrobial guideline.
• Send blood cultures if severe or septic.
• Arrange thoracic ultrasound.
• Perform diagnostic pleural aspiration if safe and indicated.
• Chest drain is usually required for frank pus, positive microbiology or complicated pleural fluid features.
• Escalate to respiratory, microbiology and thoracic surgery if poor response or complex pleural infection.

If malignant pleural effusion is suspected

• Refer to respiratory or urgent cancer pathway according to local protocol.
• Send pleural fluid cytology if sampled.
• Arrange CT imaging if appropriate.
• Offer therapeutic aspiration if symptomatic.
• Discuss recurrent effusion options such as indwelling pleural catheter or pleurodesis.
• Consider oncology and palliative care input depending on diagnosis, symptoms and patient preferences.
• Provide clear explanation and support.

If tuberculosis is suspected

• Use appropriate infection-control precautions if pulmonary TB is possible.
• Send pleural fluid and sputum samples for TB testing where appropriate.
• Refer to TB or respiratory team.
• Assess HIV risk and offer testing where appropriate.
• Notify public health according to local policy if TB is confirmed.
• Start anti-TB treatment only after appropriate diagnostic workup and specialist input unless urgent treatment is required.

If pulmonary embolism is suspected

• Assess haemodynamic stability.
• Give oxygen if hypoxaemic.
• Use local PE probability pathway.
• Arrange D-dimer or CT pulmonary angiography according to clinical probability.
• Consider anticoagulation according to local protocol if PE is likely or imaging is delayed.
• Escalate urgently if hypotension, syncope, severe hypoxia or shock is present.

Therapeutic pleural aspiration

• Consider if the effusion is causing significant breathlessness.
• Use ultrasound guidance.
• Obtain informed consent.
• Check anticoagulants and bleeding risk.
• Drain gradually and monitor symptoms.
• Stop if the patient develops chest pain, persistent cough, vasovagal symptoms or worsening breathlessness.
• Consider post-procedure imaging if clinically indicated or if complications are suspected.

Chest drain and pleural procedures

• Chest drain may be needed for empyema, complicated pleural infection, haemothorax or selected large recurrent effusions.
• Use appropriate aseptic technique and local safety checklist.
• Confirm site with ultrasound when appropriate.
• Monitor for pneumothorax, bleeding, infection, pain and re-expansion pulmonary oedema.
• Senior or specialist input is needed for complex pleural procedures.

Safety-net advice

• Seek urgent help for worsening breathlessness.
• Seek urgent help for chest pain.
• Seek urgent help for fever, rigors or feeling very unwell.
• Seek urgent help for coughing blood.
• Seek urgent help for fainting, confusion or blue lips.
• Return if symptoms recur after drainage.
• Attend follow-up imaging and respiratory appointments.

7. Examiner Questions

1. What is a pleural effusion?
2. What are the common causes of pleural effusion?
3. What is the difference between transudate and exudate?
4. What are Light's criteria?
5. What symptoms suggest pleural effusion?
6. What are the examination signs of pleural effusion?
7. What features suggest malignant pleural effusion?
8. What features suggest pleural infection?
9. What investigations would you request?
10. What would you send pleural fluid for?
11. Why is ultrasound used before pleural aspiration?
12. How would you manage empyema?
13. How would you manage malignant pleural effusion?
14. When would you refer to respiratory specialists?
15. What complications can occur after pleural aspiration?

Suggested short answers

8. OSCE Pearls

• Pleural effusion gives stony dullness, not just ordinary dullness.
• Reduced vocal resonance helps separate effusion from consolidation.
• Consolidation usually increases vocal resonance; effusion usually reduces it.
• Always ask whether the effusion is unilateral or bilateral.
• Bilateral effusions with oedema and raised JVP suggest heart failure.
• Unilateral unexplained effusion needs investigation.
• Weight loss, haemoptysis, smoking and asbestos exposure suggest malignancy.
• Fever, pleuritic pain and persistent sepsis suggest parapneumonic effusion or empyema.
• TB can present with pleural effusion and systemic symptoms.
• Pulmonary embolism can cause a small pleural effusion with pleuritic pain.
• Ultrasound is important before aspiration.
• Pleural fluid pH is important in suspected pleural infection.
• Frank pus in the pleural space is empyema.
• Do not forget complications of aspiration: pneumothorax, bleeding, infection and re-expansion pulmonary oedema.
• Always treat the cause, not just the fluid.

9. Example Presentation to Examiner

10. References

• British Thoracic Society Guideline for pleural disease in adults.
• British Thoracic Society Clinical Statement on Pleural Procedures.
• NICE Clinical Knowledge Summary: Lung and pleural cancers - recognition and referral.
• NICE NG12: Suspected cancer recognition and referral.
• Local respiratory, pleural disease, antimicrobial, TB, anticoagulation and emergency medicine protocols.