Pleural diseases Flashcards
What is the pleura?
Single layer of mesothelial cells
What is the pressure inside the pleural cavity?
-0.66kPa
What is the turnover of pleural fluid?
30-75% an hour
What causes the dynamic turnover of pleural fluid?
Osmotic/oncotic pressure drawing fluid out
Pulmonary and systemic arterial pressure pushing fluid into intrapleural space
What is a pleural effusion?
Abnormal collection of fluid in the pleural space
What are the symptoms of a small pleural effusion?
Asymptomatic
What are the symptoms of a larger pleural effusion?
Increasing breathlessness Pleuritic chest pain Dull ache Dry cough Weight loss, fever, malaise, night sweats
What are the 2 types of pleuritic chest pain in pleural effusion?
Inflammatory- early, may improve as fluid accumulates
Malignancy- progressively worsens
What are the signs of pleural effusion?
Chest on affected side- reduced expansion, stony dullness to percussion, reduced breath sounds and vocal resonance
Other- clubbing/tar staining of fingers, cervical lymphadenopathy, increased jugular venous pressure, trachea being pushed away, peripheral oedema
What are the causes of pleural effusion?
Transudates- imbalance of hydrostatic forces influencing formation and absorption of pleural fluid
Exudates- increases permeability of pleural surface and/or capillaries
Are the 2 types of pleural effusion more common in one or both lungs?
Transudate- bilateral
Exudate- unilateral
How can transudate and exudate be distinguished in the lab?
Pleural fluid protein levels
Transudate= <30g/L
Exudate= >30g/L
What are common causes of transudate pleural effusion?
Left ventricular failure
Liver cirrhosis
Hypoalbuminaemia
Peritoneal dialysis
What are less common and rare causes of transudate pleural effusion?
Hypothyroidism Nephrotic syndrome Mitral stenosis Pulmonary embolism Constrictive pericarditis Ovarian hyperstimulation syndrome Meigs' syndrome
What are the common causes of exudate pleural effusion?
Malignancy- lung, breast, mesothelioma, metastatic
Parapneumonic
What are the less common and rare causes of exudate pleural effusion?
Pulmonary embolism/infarction Rhematoid arthritis Autoimmune disease Benign asbestos effusion Pancreatitis Past MI Yellow nail syndrome Drugs
What drugs can cause an exudate pleural effusion?
Amidarone Nitrofuratoin Phenytoin Methotrexate Carbamazepine Penicillamine Bromocriptine Pergolide
When is investigation required for transudate pleural effusion?
Usually none required
Investigate if- unusual features, failure to respond to appropriate treatment
What investigations are done for pleural effusion?
Chest xray Contrast enhanced CT thorax Pleural aspiration and biopsy Pleural biopsy Thorascopy
What is a chest xray used for in pleural effusion and what are the limitations?
Detecting pleural effusion, but only if there if more than 200ml of fluid
What is the purpose of a CT thorax in pleural effusion and what does it detect?
Differentiates between benign and malignant
- Nodular pleural thickening
- Mediastinal pleural thickening
- Parietal pleural thickening >1cm
- Circumferenal pleural thickening
- Malignant manifestations in lung/liver
How can a pleural aspiration be analysed in the ward?
Foul smelling- anaerobic empyema Pus- empyema Food particles- oesophageal rupture Milky- cyclothorax Blood stained- possible malignancy Blood- harm-thorax or trauma
How can pleural aspiration be analysed in the lab?
High amylase- pancreatitis Glucose <3.3M- empyema, rheumatoid arthritis, TB, malignancy Gram stain Acid alcohol fast Culture
What are possible complications of lung aspiration?
Pneumothorax Pulmonary oedema Empyema Vagal reflex Air embolism Tumour cell seeding Haemothorax
