PLEURAL EFFUSION Flashcards
Define pleural effusion.
Excess fluid that accumulates in the pleural cavity. It is a complication not a diagnosis.
What are the two types of fluid that can collect in the pleural cavity?
Transudate
Exudate
What process causes a transudative pleural effusion?
Pressure filtration in the absence of capillary injury
What process causes a exudative pleural effusion?
Fluid leaking between cells as a result of inflammatory injury.
What does Light’s criteria distinguish?
Whether the fluid is transudative or exudative.
According to Light’s criteria, when is the fluid likely to be exudative? (Name 3 criteria)
Ratio of pleural fluid protein to serum protein is greater than 0.5
Ratio of pleural fluid LDH to serum LDH is greater than 0.6
Pleural fluid LDH is more than 0.6 times the normal upper limit for serum.
What is the usual upper limit for LDH in the serum?
Lab dependent but 200-300 IU/I
Without knowing serum protein and LDH levels, how might you distinguish between an exudate and a transudate?
Protein content of fluid
Above 2.9 is likely to be an exudate
Below 2.5 is likely to a transudate
Between the two you will need to use Light’s criteria.
What are the causes of a transudative pleural effusion? (Name at least 5)
Congestive heart failure (left side) Hepatic cirrhosis Hypoproteinemia Nephrotic syndrome Acute atelectasis (collapsed lung or lobe) Hypothyroidism Graves' disease Meig's syndrome - benign ovarian tumour causing ascites
What are the causes of an exudative pleural effusion? (Name at least 5)
Infection Malignancy Pulmonary Embolism Autoimmune disorders especially Rheumatoid arthritis TB Pancreatitis Boerhaave's syndrome Drug induced Lupus
How might someone with a moderate to severe pleural effusion present?
Dyspnea
What signs might you expect to find in someone with a pleural effusion?
Reduced expansion of the affected lung Dull to percussipn Reduced vocal resonance In very severe cases, there may be tracheal deviation Oedema in peripheries is often present
Purely based on the signs that you might find with a patient with pleural effusion, how might you tell whether effusion is exudative or transudative?
Transudative effusions will most often present bilaterally.
Exudative effusions often affect only one lung or lobe.
What investigations would you order to diagnose the pleural effusion?
Chest x-ray
Aspiration
What might be seen on the x-ray of someone with a pleural effusion?
White shadowing
Meniscus
Blunting of costophrenic and cardiophrenic angles.
