Unilateral pleural effusion

Question 1

How common is pleural effusion?

Answer 1

The estimated prevalence of pleural effusion is 320 cases per 100,000 people.

Question 2

Who is affected by pleural effusion?

Answer 2

Anyone?

Question 3

What causes pleural effusion?

Answer 3

Transudate (usually bilateral): Due to hydrostatic pressure changes as in CHF, cirrhosis and hypoalbuminemia (+ nephrotic syndrome).

Exudate: Due to inflammation of pleura as in malignancy, rheumatoid arthritis, etc.

Pus: Empyema from infections.

Blood: Trauma.

Chyle: From rupture of thoracic duct.

Urine: Urinothorax in hydronephrosis.

Unique etiologies for left sided effusions:
- pericarditis
- dissecting aneurysm
- rupture esophagus
- acute pancreatitis
Unique etiologies for right sided effusions:
- Liver abscess

Question 4

What signs may the patient have on examination?

Answer 4

• Dullness to percussion, decreased tactile fremitus, and asymmetrical chest expansion, with diminished or delayed expansion on the side of the effusion.
• Mediastinal shift away from the effusion: This finding is observed with effusions greater than 1000 mL.
• Diminished or inaudible breath sounds
• Egophony (known as “E-to-A” changes) at the most superior aspect of the pleural effusion
• Pleural friction rub

Question 5

Which other conditions might present similarly?

Answer 5

Congestive heart failure and pulmonary edema
Diaphragmatic injuries
Esophageal rupture and tears
Hypothyroidism and myxedema coma
Lung neoplasms
Pancreatitis
Q fever
Rheumatoid arthritis

Question 6

How would you investigate this patient?

Answer 6

Plain chest X-ray

Thoracentesis should be performed for new and unexplained pleural effusions when sufficient fluid is present to allow a safe procedure.
Observation of pleural effusion is reasonable when benign etiologies are likely, as in the setting of overt congestive heart failure, viral pleurisy, or recent thoracic or abdominal surgery.

Biopsy should be considered if TB or malignancy is suspected.

Question 7

What would you tell the patient and how would you explain the condition to them?

Answer 7

Explain cause (if known)

Fluid has accumulated in the space between the lungs and the chest wall (use diagram?). Either needs draining through a needle (or chest drain?) or will resolve with treatment of the underlying cause.

Question 8

How do you think the patient and/or family might be affected by the diagnosis? Will it affect their
ability to work/care for themselves?

Answer 8

Depends on the underlying cause!

Question 9

What symptoms might the patient experience?

Answer 9

The clinical manifestations of pleural effusion are variable and often are related to the underlying disease process. The most commonly associated symptoms are progressive dyspnea, cough, and pleuritic chest pain.

Question 10

What is a transudate?

Answer 10

Transudates are caused by disturbances of hydrostatic or colloid osmotic pressure, not by inflammation. They have a low protein content (<2.5g/dL) in comparison to exudates and thus appear clearer.

LDH <0.6

Question 11

What is an exudate?

Answer 11

Extravascular fluid due to vessel alteration during inflammation (increased permeability, vascular constriction then dilation). This results in an extracellular fluid of high protein content (> 2.9 g/dL) , with cell debris present and high specific gravity (>1.020).

LDH >0.6

Cloudy

Question 12

What questions are they likely to have?

Answer 12

Where did the fluid come from?
Will it happen again?
When will I be better?

Question 13

How would you manage this patient?

Answer 13

Treat the underlying cause.

Drainage of the fluid only for diagnostic purposes or if the fluid is purulent.