Pleural Effusion Flashcards
What is pleural effusion?
A pleural effusion results when fluid collects between the parietal and visceral pleural surfaces of the thorax.
What are the 2 different types of pleural effusions?
Tranudate and exudate.
Briefly differentiate between exudate and transudate pleural effusions
Exudative meaning there is a high protein count (>3g/dL). Exudative causes are related to inflammation. The inflammation results in protein leaking out of the tissues in to the pleural space (ex- meaning moving out of)
Transudative meaning there is a relatively lower protein count (<3g/dL). Transudative causes relate to fluid moving across into the pleural space (trans- meaning moving across).
Give examples of causes of exudative pleural effusion
- Lung cancer
- Pneumonia
- Rheumatoid arthritis
- Tuberculosis
Give examples of transudative causes of pleural effusion
- Congestive cardiac failure
- Hypoalbuminaemia
- Hypothroidism
- Meig’s syndrome (right sided pleural effusion with ovarian malignancy)
What are the signs of pleural effusion?
- Decreased expansion
- Stony dull percussion note
- Diminshed breath sounds
- Decreased or absent tactile fremitus
If there is a large effusion, which way does the trachea deviate?
Deviates away from the effusion.
What are the symptoms of pleural effusion?
- Dyspnoea
- Pleuritic chest pain
- Cough
What investigations should be ordered for pleural effusion?
- CXR
- Pleural ultrasound
- Diagnostic thoracocentesis of pleural fluid
- Protein count, cell count, pH, glucose, LDH and microbiology testing
- Pleural biopsy
Why investigate using CXR?
Indicated in any patient with dyspnoea. A postero-anterior chest x-ray and lateral view (now less commonly done) is the first test for this condition. It may confirm the clinical suspicion of, or incidentally reveal, a pleural effusion, but should usually prompt pleural ultrasound.
Shows blunting at the costophrenic angles.
What is shown on a CXR with pleural effusion?
- Blunting of the costophrenic angle
- Fluid in the lung fissures
- Larger effusions will have a meniscus
- Tracheal and mediastinal deviation if it is a massive effusion
Why investigate using ultrasound?
Useful in locating an area of fluid collection for thoracentesis, especially if the effusion is loculated or small.
Shows collection of fluid in pleural space and can detect septations within a pleural collection.
Why investigate using diagnostic thoracocentesis?
Laboratory investigation for:
- Clinical chemistry (protein, glucose, pH, LDH and amylase)
- Bacteriology (microscopy and culture, TB stain)
- Cytology
- Immunology (Rh factor, ANA and complement)
Establish whether the effusion is a transudate or an exudate and underlying cause.
Briefly describe Light’s criteria
Light’s criteria is used to determine if pleural effusion is exudative:
- Effusion protein/ serum protein >0.5
- Effusion LDH/ serum LDH >0.6
- Effusion LDH level greater than two-thirds the upper limit of the laboratory’s reference range of serum LDH
When is pleural biobsy indicated in investigating pleural effusion?
If plerual fluid analysis is inconclusive, consider parietal pleural biopsy. Thoracoscopic or CT-guided pleural biopsy increases diagnostic yield (by enabling direct visualisation of the pleural cavity and biopsy of suspicious areas).
Briefly describe the gross appearance of pleural fluid analysis
Note: clear/ straw coloured, turbid/ yellow and haemorrhagic
Briefly describe the cytology of pleural fluid analysis
Note: neutrophils, lymphocytes, mesothelial cells, abnormal mesothelial cells, multinucleated giant cells, lupus erythematous cells and malignant cells
Briefly describe the clinical chemistry of pleural fluid analysis
Note: protein, glucose, pH, LDH and amylase
Briefly describe the immunology of pleural fluid analysis
Note: Rh factor, ANA and complement levels
