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]

Definition

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.

• Pulmonary embolism
• Congestive heart failure
• Esophageal rupture

Common Causes

Transudate

• Cirrhosis
• Hypoalbuminemia
• Hypothyroidism
• Left ventricular failure
• Nephrotic syndrome
• Pulmonary embolism

Exudate

• Autoimmune diseases
• Malignancy
• Pancreatitis
• Parapneumonic effusion
• Pulmonary embolism
• Tuberculosis

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.

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

> 10 mm

< 10 mm

If no cause is suspected clinically: ❑ Perform diagnostic thoracentesis If dyspnoea is present at rest: ❑ Perform therapeutic thoracentesis ❑ Remove up to 1500 ml of fluid ❑ Rule out pulmonary embolism

{{{ I02 }}}

If any cause is suspected clinically ❑ Treat the cause If no cause is suspected clinically ❑ Observe

Pleural fluid aspiration ❑ Approach to thoracentesis is described below. ❑ Analyze the appearance of pleural fluid. Order tests ❑ Serum total protein ❑ Serum LDH Pleural fluid tests ❑ Protein ❑ LDH ❑ Glucose ❑ Gram stain ❑ Differential cell count ❑ Cytology ❑ pH

Apply Light's criteria

Exudate?

Transudate?

Pleural fluid analysis revealed the cause?

Treat the cause

Yes

No

Treat the cause

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

Diagnosed?

No

Yes

Contrast enhanced CT

Treat the cause

Treat the cause if diagnosed

No diagnosis found?

❑ Imaging guided pleural biopsy ❑ Thoracoscopy

No diagnosis found?

❑ Bronchoscopy (if bronchial obstruction is suspected clinically)

Treat the cause if diagnosed

No diagnosis found?

Diagnose as non specific pleuritis

Reconsider following causes ❑ Tuberculosis ❑ Pulmonary embolism ❑ Lymphoma ❑ Heart failure

Treat the cause ifdiagnosed?

Observation if no cause found

CT: Computerized Tomography

Approach to Thoracocentesis

Shown below is an algorithm summarizing the approach to thoracocentesis, according to the 2010 guidelines issued by British Thoracic Society.

Assess the clinical significance of pleural effusion

> 10 mm thickness of effusion on USG

Shortness of breath at rest

No known cause

❑ Rule out pulmonary embolism ❑ Therapeutic thoracocentesis

Proceed with thoracocentesis

CHF suspected?

Remove up to 15oo ml of fluid

❑ Bilateral effusion ❑ Afebrile ❑ No chest pain

❑ Unilateral effusion

❑ Trial of diuretics

❑ Proceed with Thoracocentesis

CHF: Congestive Heart Failure; USG: Ultrasonography

Pleural Fluid Analysis

Shown below are the algorithms for pleural fluid analysis after thoracocentesis, according to the 2010 guidelines issued by British Thoracic Society.

Appearance

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

Blood stained pleural effusion

❑ Perform haematocrit on pleural effusion

>50% of peripheral haematocrit

< 50% peripheral haematocrit

Haemothorax

Consider alternative diagnosis

Light's Criteria

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

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

Differential Cell Count

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

Pleural Fluid pH

Pleural fluid pH

< 7.30

< 7.20

Consider following causes ❑ Malignancy ❑ Rheumatoid arthritis ❑ Esophageal rupture ❑ Tuberculosis

❑ Perform tube drainage

Cytology

Interpretation of Cytology Results

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

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 spirate 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

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.