Pleural effusion

Question 1

What is a pleural effusion and what are the different types of pleural effusions?

Answer 1

A pleural effusion is a build up of fluid in the pleural space. There are different types of pleural effusions depending on the type of fluid. 
Hydrothorax = Serous fluid
Haemothorax = Blood
Urinothorax = Urine
Chylothorax = Chyle
Pyothorax = Pus

Question 2

How do pleural effusions arise?

Answer 2

The normal pleural space contains approx 10mL of fluid. This represents that balance between:

1. Hydrostatic and oncotic pressure in the parietal and visceral capillaries
2. The persistent sulcal lymphatic drainage.

Pleural effusions herald an underlying disease process - pulmonary/non-pulmonary origin (acute/chronic)

Altered permeability of the pleural membrane
- E.g. inflammation, malignancy, PE

Reduction in intravascular oncotic pressure
- E.g . Hypoalbuminaeamia (nephrotic syndrome)

Increased capillary permeability or vascular disruption
- E.g. trauma, malignancy, inflammation, pancreatitis

Increased capillary hydrostatic pressure
- E.g. congestive heart failure, SVC syndrome

Reduction of pressure in the pleural space
- E.g. trapped lung

Decreased lymphatic drainage /complete lymphatic vessel blockage

Increased peritoneal fluid with micro-perforated extravascation across the diaphragm via lymph system

Movement of fluid from pulmonary oedema across the visceral pleura

Question 3

What are the consequence of a pleural effusion?

Answer 3

1. Flattening/inversion of the diaphragm
2. Mechanical dissociation between the visceral and parietal pleura
3. Eventual restrictive ventilatory defect

Question 4

Symptoms?

Answer 4

Common symptoms associated with pleural effusion may include the following:
• Chest pain
• Difficulty breathing
• Painful breathing (Pleurisy)
• Cough (dry or productive)
• Deep breathing typically increases the pain.
• Symptoms of fever, chills, and loss of appetite often accompany pleural effusions caused by infectious agents.

Question 5

Diagnosis?

Answer 5

Medical History
o A history of congestive heart failure or cirrhosis
o Symptoms of cough, difficulty breathing, pleuritic chest pain etc.

Inspection
o Obvious dyspnoea – use of accessory muscles, hyperventilation, increased resp. rate
o Visible asymmetrical chest expansion

Palpation
o Asymmetrical chest expansion
oDeviated trachea
o Deviated apex beat - mediastinal shift

Percussion
o Stony dullness of the lung area
o Decreased vibration/tactile fremitus

Auscultation
o Reduced or inaudible breath sounds on the affected side
o Egophony (patient voices the letter “e,” but when auscultating it sounds like “a”)
o Friction rub (if there is fluid in the pleural area, the heart will rub against the inflamed or fluid filled space).

Question 6

How does a CXR appear for a pleural effusion?

Answer 6

Pleural effusions appear as whitish areas at the lung base (unilaterally or bilaterally). If a person lies on their side for a few minutes, most pleural effusions will move and layer out along that side of the chest cavity which is positioned downward. This movement of the pleural effusion can be seen on an X-ray taken with the person lying on their side (a lateral decubitus X-ray).
Straight line rather than curvature = hydro-pneumothorax (not pleural effusion) as there is air above the fluid and the two are exerting pressure against each other

Question 7

How do you remove the fluid?

Answer 7

The removal of fluid from the pleural space, followed by laboratory analysis of the fluid can differentiate between transudate and exudate. Additional testing of the pleural fluid may also include a cell count, cytology, and cultures

Question 8

Risk factors for a pleural effusion

Answer 8

Pleural effusions are caused by an underlying medical problem (cardiac failure, cirrhosis, malignancy, tuberculosis, pneumonia, pulmonary embolism, hypo-albuminemia, trauma) and therefore the presence of any of these medical problems are risk factors for the development of pleural effusions. It is important to note, however, that not all individuals with these medical problems will develop pleural effusions.

Question 9

Describe the transudate pleural effusions

Answer 9

ransudates result from an imbalance of oncotic and hydrostatic pressures, without changes in endothelial permeability.

Non-inflammatory oedema

Clear, pale yellow fluid

Low protein count (<3gm/dL)

No tendency to coagulate as it is mainly albumin not fibrinogen

Same glucose content as serum (>40mg/dL)

Specif gravity: low

pH = >7.23

Low LDH content

Effusion LDH: Serum LDH ratio = <0.6

Effusion protein/serum protein ratio: <0.5

Microscopy: <1000 lymphocytes

Question 10

Causes of a transudative pleural effusion?

Answer 10

Cardiac failure

Cirrhosis

Question 11

Describe exudative pleural effusion?

Answer 11

Exudates are the result of inflammatory processes of the pleura and/or decreased lymphatic drainage, associated with increased vascular permeability.

Inflammatory oedema

Cloudy, yellow or bloody fluid

High protein count (>3gm/dL)

Coagulates due to high content of fibrinogen

Low glucose content (<40mg/dL)

High specific gravity

pH: <7.23

High LDH content

Effusion LDH: serum LDH ratio = >0.6

Effusion protein : serum protein ratio = >0.5

Microscopy = >1000 lymphocytes

Question 12

Causes of an exudative pleural effusion?

Answer 12

Pneumonia
Cancer
Tuberculosis
Pulmonary embolism
Hypoalbuminemia
Trauma

Question 13

How can you quickly tell if a pleural effusion is exudative or transudative?

Answer 13

If the protein is > 35 then it is definitely exudate and you don’t need to do further tests. If the protein is <25 then it’s definitely transudate.

Question 14

How do you treat a pleural effusion?

Answer 14

Small transudative pleural effusions may require no treatment, while larger ones and most exudative pleural effusions require treatment.

1. Thoracentesis
   The initial treatment of choice is drainage of the pleural fluid. Thoracentesis is where a tube is inserted into the effusion, and the effusion is drained out. This procedure needs monitoring, and in some instances, the tube may need to remain in the pleural space for a longer period of time for continued drainage. The need for repeated thoracentesis varies from patient to patient depending on the underlying cause, the amount of effusion fluid, the type of effusion (thick, thin, malignant, or infectious, for example) and if there is recurrence of the pleural effusion.
2. Surgery to break up adhesions
3. Pleurodesis (pleural sclerosis)
   Pleurodesis is a procedure whereby different irritant substances or medications are inserted into the pleural space in order to fibrose and scar the visceral and pleural surfaces together. This procedure seals the pleural space so that pleural effusions have difficulty reaccumulating.
4. Medications
   The use of medications for pleural effusions depends on the underlying cause.
   Antibiotics are used when there is an infectious cause
   Diuretics (e.g. furosemide) may be used to slowly help reduce the size of the pleural effusion.

Question 15

What are the potential complications of a pleural effusion?

Answer 15

The potential complications associated with pleural effusion are:
o lung scarring,
o pneumothorax (collapse of the lung) as a complication of thoracentesis,
o empyema (a collection of pus within the pleural space)
o sepsis (blood infection) sometimes leading to death.