Unilateral Pleural Effusion

Question 1

What is a pleural effusion?

Answer 1

Excessive accumulation of fluid in the pleural space between parietal and visceral pleura.

Question 2

Pleural effusion can be divided by their protein concentration into transudates and exudates.

What is the difference between transudates and exudates?

Answer 2

Transudate: lower protein content <30g/L ; LDH <200IU/L ; fluid to serum LDH ratio <0.6

Exudate: higher protein content >35g/L ;
pleural fluid protein : serum protein >0.5
Pleural fluid LDH : serum LDH >0.6

Question 3

What are the causes of a transudate pleural effusion?

Answer 3

Transudate pleural effusion can be due to increase venous pressure i.e.

Cardiac failure

Constrictive pericarditis

Fluid overload

Hypoproteinaemia e.g. nephrotic syndrome

Hypothyroidism

Meigs’ syndrome - ovarian tumours producing right-sided pleural effusions

Question 4

What are the causes of exudate pleural effusion?

Answer 4

Exudate pleural effusion mostly due to increased leakiness of pleural capillaries secondary to infection, inflammation or malignancy i.e.

Bacterial pneumonia

Carcinoma of the bronchus

Pulmonary infarction

Tuberculosis

Mesothelioma

Autoimmune rheumatic disease

Lymphoma

Question 5

What are the causes of unilateral pleural effusion?

Answer 5

Tumour:
Bronchogenic carcinoma
Mesothelioma
Pleural metastases

Lymphoma:
Pleural lymphoma
Primary effusion lymphoma

Infection: Para-pneumonic effusion; Empyema ; extension from subdiaphragmatic primary infection

Chylothorax:
Ruptured / injured thoracic duct
Tumour infiltration e.g. lymphoma

Haemorrhage:
Trauma
Iatrogenic trauma

Question 6

What are the signs and symptoms of pleural effusion?

Answer 6

Usually asymptomatic.
May present with dyspnoea, pleuritic chest pain, cough

*Past medical Hx important to find the underlying cause

Signs:
Decreased expansion

Stony dull percussion

Diminished breath sounds on the affected side

Reduced tactile vocal remits and vocal resonance

Bronchial breathing above the effusion where lung is compressed

Look for assoc. disease i.e. malignancy (cachexia, clubbing, lymphadenopathy, mastectomy scar) ;

stigmata of chronic liver disease ;

Hypothyroidism ;

Rheumatoid arthritis ;

Butterfly rash SLE

Question 7

What are the risk factors for pleural effusion?

Answer 7

Strong risk factors:
Congestive Heart Failure - most common cause of pleural effusion

Pneumonia (effusions forming from pneumonia = parapneumonic effusions) - 2nd most common cause of pleural effusion and occurs in up to 40% of patients hospitalised with pneumonia

Malignancy - 3rd most common cause of pleural effusion

Recent CABG surgery

Weak risk factors:
Pulmonary embolism
Recent MI 
Occupational lung disease i.e. beryllium, asbestos, silica exposure
Rheumatoid arthritis
SLE
Renal failure 
Uraemia 
Drug induced i.e. nitrofurantoin, dantrolene, ergot alkaloids (e.g., severalanti-migraine drugs), valproate, isotretinoin, and tyrosine kinase inhibitors.

Question 8

What investigations are carried out for suspecting pleural effusion - what do they show?

Answer 8

1. Bloods: FBC, CRP, blood culture
2. Chest X-ray: blunt costrophrenic angles
3. Pleural ultrasound: confirms fluid presence + guides diagnostic and therapeutic aspiration
4. Diagnostic aspiration
5. Pleural biopsy: if pleural fluid analysis is inconclusive

Question 9

Explain the procedure of diagnostic aspiration.

Why is the needed inserted just above the ribs?

Answer 9

Percuss the upper border of the pleural effusion and chose 1/2 intercostal spaces below it.

Draw 10-30ml fluid and send to lab for analysis.

Analysis includes protein, glucose, pH, LDH, amylase;

bacteriology (microscopy & culture, stain, TB culture);

cytology and immunology (rheumatoid factor, ANA) if needed.

ii. Inserting the needle just above the ribs avoids the neuromuscular bundles.

Question 10

What is the management generally?

What is the management if pleural effusion is symptomatic?

Answer 10

Treat the underlying cause i.e.

Chronic heart failure: loop diuretics + therapeutic thoracocentesis

Infective: IV antibiotics + therapeutic thoracocentesis

If pleural effusion symptomatic:

i. Drain it: aspirated in the same way as diagnostic tap or via an intercostal drain
ii. Pleurodesis: for malignant effusions with Talc or tetracycline (sclerosing agent to seal the pleural cavity gap to prevent fluid or air from building up)
iii. Surgery: persistent effusion and increasing thickness of pleura needs surgery
* fluid should be removed slowly to prevent pain/shock

Question 11

What is chylothroax and how is it caused?

Answer 11

Chylothorax is accumulation of lymph in pleural space due to leakage from the thoracic duct following a trauma or infiltration by carcinoma.

Question 12

What is empyema?

Answer 12

Pus in pleural space - can be a complication of pneumonia.

It requires urgent drainage!

Question 13

What is malignant pleural effusion?

How do you treat it?

Answer 13

Symptomatic re-accumulation of fluid in pleural space

Treat by therapeutic aspiration of the fluid and performing pleurodesis under thoracoscopy if necessary - only temporary relief.

Question 14

What are the complications of pleural effusions?

Answer 14

Atelectasis / lobar collapse

Pneumothorax following thoracocentesis

Pleural fibrosis

Trapped lung