Pleural effusion resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Twinkle Singh, M.B.B.S. [2]

Overview

Pleural effusion is defined as the presence of excessive fluid in the pleural cavity resulting from transudation or exudation from the pleural surfaces.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

Common Causes

Transudate

Exudate

Initial Diagnosis

Shown below is an algorithm for diagnosing pleural effusion clinically according to an article published by Richard W. Light in New England Journal of Medicine.^[1]

Characterize the symptoms:

❑ Shortness of breath
❑ Chest pain

❑ Cough

Examine the patient:

❑ Asymmetrical chest expansion
❑ Dullness to percussion
❑ Decreased tactile fremitus
❑ Mediastinal shift

❑ Shift away from the effusion side in massive effusion

❑ Shift towards the effusion side in lobar bronchial obstruction

❑ Decreased breath sounds

❑ Look for signs suggestive of specific etiology

Suspected cause	Suggestive signs
Congestive heart failure	Distended neck veins S3 heart sound Peripheral edema
Pulmonary embolism	Thrombophlebitis Right ventricular heave Hyperventilation
Hepatic cause	Signs of liver failure Ascites
Malignancy	Lymphadenopathy Weight loss Hepatosplenomegaly

❑ Perform chest X-ray

If chest X-ray is equivocal, perform the following:

❑ Chest ultrasonography OR
❑ Lateral decubitus chest radiograph

❑ Assess thickness of pleural effusion on USG or lateral decubitus chest X-ray

> 10 mm

< 10 mm

❑ Perform diagnostic thoracentesis if

❑ No cause is known

❑ Pleural infection is suspected

❑ Malignant effusion is suspected clinically

If dyspnoea is present at rest:

❑ Perform therapeutic thoracentesis

❑ Remove up to 1500 ml of fluid

❑ Rule out pulmonary embolism

If CHF is suspected clinically

If any cause is suspected clinically

❑ Treat the cause

If no cause is suspected clinically

❑ Observe

❑ Bilateral effusion
❑ Afebrile
❑ No chest pain

❑ Unilateral effusion OR
❑ Fever present OR
❑ Chest pain

❑ Trial of diuretics

❑ Perform thoracocentesis

Pleural Fluid Analysis

Shown below are the algorithms for diagnosing pleural effusion after thoracocentesis is done. Algorithm is adapted from the 2010 guidelines issued by British Thoracic Society.^[2]

Pleural fluid aspiration

❑ Analyze the appearance of pleural fluid.

Fluid appearance	Suspected cause
Putrid odour	Anaerobic empyema
Food particles	Esophageal rupture
Bile stained	Billiary fistula
Milky	Chylothorax or pseudochylothorax
Anchovy sauce like appearance	Amoebic abscess
Grossly bloody	Malignancy Pulmonary embolism with infarction Trauma Asbestosis

Order tests

❑ Serum total protein
❑ Serum LDH
Pleural fluid tests
❑ Protein
❑ LDH
❑ Glucose
❑ Gram stain
❑ Differential cell count
❑ Cytology
❑ pH

❑ Apply Light’s criteria

Pleural fluid protein divided by serum protein	> 0.5
Pleural fluid LDH divided by serum LDH	> 0.6
Pleural fluid LDH	> 2/3 of upper limit of normal serum LDH

Pleural fluid is classified as an exudate if one or more of the above criteria are met.

Exudate

Transudate

Did pleural fluid tests reveal the cause?

❑ Treat the cause:

❑ Heart failure

❑ Cirrhosis

❑ Hypoalbuminemia

Yes

No

❑ Treat accordingly

❑ Order additional tests

Tests	Suspected cause
Culture and sensitivity	Infection
Amylase	Esophageal rupture Pancreatitis
ADA	Tuberculosis (measured if pleural fluid lymphocytosis is present)
Cholesterol crystals Chylomicrons Triglycerides	Chylothorax or pseudochylothorax
Haematocrit	Hemothorax

If additional tests did not reveal any cause:

❑ Perform contrast enhanced CT

If additional tests diagnosed the effusion:
❑ Treat accordingly

❑ Treat the cause if diagnosed

If no diagnosis found:
❑ Proceed with imaging guided pleural biopsy OR
❑ Thoracoscopy

No diagnosis found?

❑ Proceed with bronchoscopy (if bronchial obstruction is suspected clinically)

❑ Treat accordingly if diagnosed

No diagnosis found?

Diagnose as non specific pleuritis

Reconsider following causes

❑ Tuberculosis
❑ Pulmonary embolism
❑ Lymphoma

❑ Heart failure

❑ Treat accordingly ifdiagnosed

Observation if no cause found

CT: Computerized Tomography

Do’s

Do not aspirate bilateral pleural effusion in a clinical setting suggesting of a transudate, unless the effusion fails to respond to therapy.
Obtain detailed drug history, as some drugs can cause pleural effusion such as methotrexate, amiodarone, phenytoin, nitrofurantoin, beta-blockers.
Keep a high suspicion for pulmonary embolism in pleural effusion cases.
Aspirate pleural fluid with a fine bore (21 G) needle and a 50 ml syringe with ultrasound guidance.
Aspirate pleural fluid into a heparinised blood gas syringe if infection is suspected and pleural fluid pH is needed to be done.
Send some of the pleural fluid sample in blood culture bottles if infection is suspected, particularly for anaerobic organisms.
Centrifuge pleural fluid sample if aspiration is milky to distinguish between empyema and lipid effusions.
Interpretation of centrifuged sample:

Supernatant	Interpretation
Clear	Empyema (turbid fluid was due to cell debris)
Turbid	Chylothorax or pseudochylothorax

Suspect urinothorax if pleural fluid smells of ammonia.
Measure NT-proBNP in cases where Light’s criteria diagnose effusion as exudate, but there is a strong clinical suspicion of heart failure.
Suspect rheumatoid arthritis or empyema if pleural fluid glucose is very low ( < 1.6 mmol/L).
Send pleural fluid aspirate sample in fluoride oxalate tube if pleural fluid glucose is needed to be measured.
Measure pleural fluid amylase if following are suspected clinically:
- Acute pancreatitis
- Pancreatic pseudocyst
- Esophageal rupture
- Ruptured ectopic pregnancy
- Pleural adenocarcinoma
Perform haematocrit on blood stained pleural effusion. Pleural fluid haematocrit >50% of peripheral haematocrit indicates the presence of hemothorax.
Consider following causes of pleural effusion based on differential cell count results:

Differential cell counts

Neutrophil predominant

Lymphocyte predominant (>50% lymphocytes)

Eosinophil predominant (≥ 10% eosinophils)

❑ Parapneumonic effusion
❑ Pulmonary embolism
❑ Acute tuberculosis
❑ Asbestosis

❑ Malignancy
❑ Tuberculosis
❑ Cardiac failure
❑ Lymphoma
❑ Rheumatoid pleurisy
❑ Sarcoidosis
❑ CABG effusion

❑ Air or blood in the effusion fluid
❑ Parapneumonic effusion
❑ Benign asbestosis
❑ Churg-strauss syndrome
❑ Lymphoma
❑ Pulmonary infarction
❑ Parasitic infection

Consider following causes if pleural fluid pH is < 7.30:

* Malignancy

* Rheumatoid arthritis

* Esophageal rupture

* Tuberculosis

Interpret cytology report of pleural fluid as follows:

Result	Interpretation
Inadequate sample	No mesothelial cells detected
No malignant cells seen	Sample is adequate; no atypical cells seen;malignancy is not excluded
Atypical cells	Inflammatory or malignant cells; further investigation required
Suspicious malignancy	Cells with few malignant features present; no definitive malignant cells present
Malignant	Definite malignant cells detected; further immunocytochemistry required

Dont’s

Do not allow pleural aspirate to come in touch with local anesthetic or air if pleural fluid pH is needed to be measured.

References

↑ Light RW (2002). “Clinical practice. Pleural effusion”. N Engl J Med. 346 (25): 1971–7. doi:10.1056/NEJMcp010731. PMID 12075059.
↑ Maskell N, British Thoracic Society Pleural Disease Guideline Group (2010). “British Thoracic Society Pleural Disease Guidelines–2010 update”. Thorax. 65 (8): 667–9. doi:10.1136/thx.2010.140236. PMID 20685739.

[pmid12075059-1] Light RW (2002). “Clinical practice. Pleural effusion”. N Engl J Med. 346 (25): 1971–7. doi:10.1056/NEJMcp010731. PMID 12075059.

[pmid20685739-2] Maskell N, British Thoracic Society Pleural Disease Guideline Group (2010). “British Thoracic Society Pleural Disease Guidelines–2010 update”. Thorax. 65 (8): 667–9. doi:10.1136/thx.2010.140236. PMID 20685739.

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