Respiratory: Pathology - Pleural pathology Flashcards
Five broad causes of pleural effusion with examples
- Increased hydrostatic pressure (e.g. HF)
- Decreased oncotic pressure (e.g. nephrotic syndrome)
- Decreased lymphatic drainage (e.g. mediastinal carcinomatosis)
- Increased intrapleural negative pressure (e.g. atelectasis)
- Increased vascular permeability (e.g. pneumonia)
How much pleural fluid is produced normally and what is its appearance and composition?
<15ml serous, acellular clear fluid
Describe the different types and subtypes of pleural effusion, with examples
- Inflammatory (exudative):
- Serous/serofibrinous/fibrinous (e.g. parapneumonic, TB, RA, SLE, infarcts)
- Purulent (empyema: due to bacterial seeding of pleural space, usually by adjacent infection likely pneumonia or subdiaphragmatic abscess) - Non-inflammatory (transudative):
- Hydrothorax (e.g. HF)
- Haemothorax (e.g. ruptured AAA, post-operatively)
- Chylothorax (e.g. thoracic duct trauma or obstruction)
Describe the appearance of the pleural fluid in chylothorax
Milky white due to emulsified fats
Three types of pneumothorax
- Spontaneous
- Traumatic
- Therapeutic
Three conditions most commonly associated with spontaneous pneumothorax
- Emphysema
- Asthma
- Tuberculosis
What is thought to be the underlying cause of spontaneous idiopathic pneumothorax?
Rupture of small peripheral (usually apical) subpleural blebs
What % of mesotheliomas are related to asbestos exposure?
90%
What is the lifetime risk of mesothelioma with heavy asbestos exposure?
7-10%
Is risk of mesothelioma further increased by smoking?
No, unlike asbestos-related lung cancer
What histological features are seen in mesothelioma?
Asbestos bodies and plaques
What % of patients with mesothelioma have concurrent pulmonary asbestosis?
20%
Where can mesotheliomas arise other than the pleura?
Peritoneum, pericardium, tunica vaginalis, genital tract
What two primary malignancies are the most common cause of metastatic malignancy of the pleura?
Lung and breast
