Pleural space pathology: Pleural Effusion Flashcards

1
Q

Definition

A

Abnormal excess fluid accumulation in the pleural space between the visceral and parental layers
Diseases which increase the filtration rate or decrease the absorption rate will result in the accumulation of pleural fluid

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2
Q

Physiology

A

Normal pleural fluid is filtered from the pulmonary microvasculature and absorbed by the lung lymphatics.

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3
Q

Types of fluid

A

Transudative effusion (protein < 30g/L): caused by increased hydrostatic pressure or low oncotic pressure.

Exudative effusion (protein > 30g/L): caused by inflammation, infection and malignancy.

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4
Q

Causes of transudative fluid

A
  • Heart failure (MC) : increased microvascular pressure → pulmonary oedema → increased fluid being filtered into the low-pressure pleural space
  • Cirrhosis: liver failure → hypoalbuminaemia → low plasma oncotic pressure → increased filtration of pleural fluid
  • NephrOtic syndrome
  • Hypothyroidism
  • Peritoneal dialysis
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5
Q

Causes of exudative fluid

A

Malignancy (MC) : tumour infiltration of pleural capillaries and cytokines increase capillary permeability → increased leakage of fluid into the pleural space
Pneumonia (MC) : acute lung injury → increased vascular permeability → movement of high protein lung interstitial fluid into the pleural space
Pulmonary embolism
Pancreatitis
Autoimmune and connective tissue disorders
Dressler’s syndrome

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6
Q

What colour is transudative fluid

A

Transparent

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7
Q

What colour is exudative fluid

A

Cloudy

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8
Q

Signs

A
  • Reduced chest expansion and breath sounds on the affected side
  • Decreased tactile or vocal fremitus
  • Dullness to percussion: the most accurate positive finding, classically ‘stony dull’
  • Pleural friction rub + bronchial breathing
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9
Q

Symptoms

A

SOB/ Dyspnoea
Cough
Pleuritic chest pain: usually exudative
Symptoms of underlying cause e.g.
- Peripheral oedema (HF)
- Ascites (liver cirrhosis)
- Productive cough and fever (pneumonia)

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10
Q

DDx

A

Pneumothorax

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11
Q

Diagnosis

A

FIRST LINE + GOLD STANDARD = CXR
- Decreased costophrenic angles (BLUNTING)
- Excess fluid appears WHITE +/- tracheal deviation
Thoracentesis = sample pleural fluid
- pH, lactate, WCC, microscopy
- transudate or exudate

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12
Q

Light’s criteria

A

If the protein level is 25-35 g/L, Light’s criteria should be applied.
Validated set of pleural fluid lab test findings used to distinguish between transudate and exudate effusions for borderline presentations.

Light’s criteria state that an exudate is likely if one or more of the following criteria are met:
- Pleural fluid protein divided by serum protein is > 0.5
- Pleural fluid LDH divided by serum LDH is > 0.6
- Pleural fluid LDH > 2/3 the upper limit of normal serum LDH

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13
Q

Treatment

A

Chest drainage (thoracentesis)
Pleurodesis: scarring of the pleural space by slurry injection/talc
Treat underlying cause:
- loop diuretics for CHF

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14
Q

Complications

A

Empyema
Pneumothorax

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