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

Physical examination ❑ 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

Signs suggestive of specific etiology

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

❑ Chest radiograph

Chest radiograph equivocal?

❑ Chest ultrasonography OR ❑ Lateral decubitus chest radiograph OR ❑ CT chest

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

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

Approach to Diagnosis and Management of Pleural Effusion

Pleural fluid analysis ❑ Protien ❑ LDH ❑ Gram stain ❑ Cytology ❑ Culture ❑ Pleural fluid pH (if infection is suspected)

Apply Light's criteria ❑ Measure both serum and pleural fluid protein and LDH

Transudate?

Exudate?

Treat the cause

Diagnosed?

No

Yes

Contrast enhanced CT

Diagnosed?

Treat the cause

No diagnosis found?

❑ Imaging guided pleural biopsy ❑ Thoracoscopy

Diagnosed?

No diagnosis found?

❑ Bronchoscopy (if bronchial obstruction is suspected clinically) ❑ Mycobacterial culture ❑ Adenosine deaminase (to rule out tuberculosis) ❑ If chylothorax is suspected clinically ❑ Measure pleural fluid cholesterol crystals ❑ Chylomicrons ❑ Triglycerides ❑ Cholesterol levels

Diagnosed?

No diagnosis found?

Diagnose as non specific pleuritis

Treat the cause

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

Diagnosed?

Waitful watch if no cause found