This one is more of a presentation of different diseases, rather than a disease itself.
Definition: fluid accumulation in the pleural space.
Blood in the pleural space = haemothorax
Pus in the pleural space = empyema
Chyle (lymph with fat) = chylothorax
A pleural effusion can be classified as either a transudate or exudate.
Transudate = low protein content ( <25g/L)
May be due to increased venous pressure or hypoproteinaemia (reduced oncotic pressure).
Causes: Remember the failures– heart failure, kidney failure, liver failure (cirrhosis)
Also- constrictive pericarditis, fluid overload states, malabsorption, nephrotic syndrome
– hypothyroidism and Meigs’ syndrome ( = right pleural effusion + ovarian fibroma)
-Transudates tend to be bilateral because it’s usually a systemic problem causing it.
Exudate = high protein content (> 35g/L)
Mostly due to increased leakiness of pleural capillaries secondary to infection, inflammation or malignancy.
Causes: pneumonia (termed parapneumonic effusion, unless it’s an empyema), TB, pulmonary infarction, rheumatoid arthritis (RA), SLE, sarcoidosis, acute pancreatitis, bronchogenic carcinoma, malignant metastasis, lymphoma, mesothelioma, lymphangitis carcinomatosis, oesophageal carcinoma, post-MI
-Exudates are often unilateral.
So, what about in between 25 and 35g/L?
or… Light’s Criteria.
The fluid is an exudate if any of the following applies:
-Pleural fluid protein/serum protein >0.5
-Pleural fluid LDH/ serum LDH >0.6
-Pleural fluid LDH > 2/3rds the upper limit of normal serum LDH
-can be asymptomatic OR
-pleuritic chest pain
-symptoms of cause
-decreased chest expansion
-over area of effusion:
-reduced breath sounds
-stony dull percussion note
(apparently some people have magic ears and can note a difference between dull and stony dull)
-reduced vocal resonance and tactile vocal fremitus
-above the effusion, where lung is compressed, there may be bronchial breathing
-with large effusions, there may be tracheal deviation away from the effusion
-may see aspiration marks (from previous aspiration)
-signs of associated disease:
e.g. malignancy- cachexia, clubbing, lymphadenopathy, radiation marks, mastectomy scar
stigmata of chronic liver disease- spider naevi, telangiectasia, palmar erythema, gynaecomastia
rheumatoid arthritis- joint deformities
-Chest x-ray: visualise effusion, seen as homogenous opacification
small effusions = blunting of costophrenic angles
large effusions = water-dense shadows with concave upper borders- meniscus
(a completely flat horizontal upper border implies that there is also a pneumothorax)
–Ultrasound– useful in identifying the presence of pleural fluid and in guiding diagnostic or therapeutic aspiration
Turbid, yellow fluid may be due to empyema or Para pneumonic effusion.
Haemorrhagic fluid may be due to trauma, malignancy or pulmonary infarction.
Send fluid off for: Clinical chemistry, Microbiology, Cytology, Immunology
Clinical chemistry =
Glucose– < 3.3 mmol/L in empyema, malignancy, TB, RA, SLE
pH– <7.2 in empyema, malignancy, TB, RA, SLE
LDH- ↑ (pleural : serum >0.6) in empyema, malignancy, TB, RA, SLE
Amylase– ↑ in pancreatitis, carcinoma, bacterial pneumonia, oesophageal rupture
Microscopy and culture
Auramine stain (for TB)
Cytology = look for malignant cells
Neutrophils ↑- parapneumonic effusion, PE
Lymphocytes ↑- malignancy, TB, RA, SLE, sarcoidosis
Mesothelial cells- pulmonary infarct
Abnormal mesothelial cells- mesothelioma
Multinucleated giant cells- rheumatoid arthritis
Lupus erythematosus cells- SLE
Immunology (if indicated) =
Rheumatoid factor- rheumatoid arthritis
Complement- reduced in RA, SLE, malignancy, infection
–Pleural biopsy: if pleural analysis is inconclusive, consider parietal pleural biopsy. Thoracoscopic or CT-guided pleural biopsy increases diagnostic yield.
-Manage the underlying cause
–Drainage: if symptomatic, drain the effusion, repeatedly, if required. This can be by aspiration or with an intercostal drain.
–Pleurodesis: sticking the two pleural layers together, obliterating the pleural space, with tetracycline, bleomycin or talc may be helpful for recurrent effusions.
Thoracoscopic talc pleurodesis is most effective for malignant effusions.
Empyemas are best drained using a chest drain, inserted under USS or CT guidance.
–Surgery- required if persistent collections and increasing pleural thickness