T8-L4: Pleura Pathology Flashcards
What are the different layers of the pleura?
The Pleura is made of 2 layers:
- Visceral Pleura: Made up of 2 layers - Connective tissue and Mesothelium
- Parietal Pleura: Made of 2 layers - Mesothelium and connective tissue layers
Below this is the intercostal muscles.
What is the lubricating fluid secreted by the mesothelial cells rich in?
The mesothelial cells secrete surfactant rich in the glycosaminoglycan hyaluronic acid.
Give causes of pleuritis.
- Primary inflammatory diseases such as SLE, RA, Erythematous
- Infections such as tuberculosis, secondary to pneumonia, primary coxackie B etc.
- Pulmonary infarction - secondary to pulmonary arterial thromboembolism
- Emphysema
- Neoplasms
- Theraputic
- Iatrogenic
How does pleuritis present?
- Pleuric chest pain if there is no plural effusion - two layers rubbing against each other, auscultation of a pleural rib
- If there is a pleural effusion breathlessness as the effusion compresses the lung. Little/no pleuritc pain as the two layers of the pleura are not in contact. Also dull percussion and reduced breath sound.
How do you describe pleuritic pain?
Pleuritic chest pain is characterized by sudden and intense sharp, stabbing, or burning pain in the chest when inhaling and exhaling. It is exacerbated by deep breathing, coughing, sneezing, or laughing.
What is Pleural fibrosis?
This is fibrosis secondary to inflammation. Fibrosis can prevent normal lung expansion and compression of the lung during respiration causing breathlessness. Fibrous adhesions can be wholly or partly obliterate the pleural cavity. Asbestos associated pleural fibrosis comes in two varieties:
- Parietal pleural fibrous plaques - usually asymptomatic
- Diffuse pleural fibrosis - due to a high level of exposure (also usually bilateral) and can stop the lung functioning properly
Define the following:
(a) Pleural effusion
(b) Empyema
(c) Haemothorax
(d) Chlyothorax
(e) Pneumothorax
(a) Serous fluid in the pleural cavity
(b) Pus in the pleural cavity
(c) Blood in the pleural cavity
(d) Lymph in the pleural cavity
(e) Air in the pleural cavity
What is the difference between an exudate pleural effusion and a transudate effusion?
Transudate is due to highly vascular hydrostatic pressure and/or low capillary oncotic pressure. This means the capillary retain semipermeability and so is low protein and low LDH. Causes include left ventricular failure, renal failure and hypoalbuinaemia.
Exudate is when the capillaries loose semipermeability. There is normal capillary oncotic pressure and normal vascular hydrostatic pressure. This means the fluid has a high protein and high LDH. Causes include inflammation +/- infection and neoplasm (primary or secondary).
How is pleural effusion treated?
Removal of the fluid will treat the breathlessness. If there is recurrent pleural effusion you can consider a permanent pleural drain or obliterate the pleural cavity. But the underlying cause must be treated e.g. inflammation, neoplasm, TB, granulomatous disease, Most are systemic such as nephrotic syndrome.
What is the difference between an open and closed pneumothorax?
Open pneumothorax: This is a chest wall perforation usually traumatic - this connects the body surface to the pleural cavity. External air is drawn into the pleural cavity during inspiration, reducing poetical lung expansion.
Closed pneumothorax: A lung perforation. This is not usually traumatic and connects the lung air spaces to the pleural cavity. Causes include a ruptured emphysema, TB, CF, fractured rib injuring the lung or iatrogenic caused.
What is a tension pneumothorax?
The perforation into the pleural cavity in an open or aa closed pneumothorax allowing air into the cavity during inspiration but not out during expiration. The pressure in the pneumothorax can rise above atmospheric. this can decompress the mediastinal structures including the vena cava, the heart and can compress the contralateral lung. This is a potentially lifet-threatening condition.
What are the signs and symptoms of pneumothorax?
Symptoms
• Breathlessness
• Pleuritic chest pain – due to damaged pleura
• Many small pneumothoraxes are be asymptomatic
Signs – signs of impaired respiratory ability
• Cyanosis
• Tachycardia
• Contralateral tracheal deviation in tension pneumothorax
• Percussion – hyperresonant
• Auscultation – reduced breath sounds – air is not moving in and out of the pneumothorax
Investigations to support the diagnosis
• Imaging – ultrasound, chest radiograph, CT
• Symptomatic pneumothoraces are often initially treated without further investigation
Which carcinomas typically metastases to the lung?
Breast, Lung, Prostate, Colorectal etc.
Others include lymphomas, melanomas and others.
What are malignant mesotheliomas?
A neoplasm of the mesothelial cells that line serous cavities - pleura, peritoneum, pericardium, tunica vaginalis. 92% are pleural and 8% are peritoneal. Both commoner in men. Mesothelial generally have a stronger association with asbestos. Tend not to metastasise widely - not to lymph nodes but tend to go to the opposite pleural cavity and the peritoneal cavity.
A small tumour can produce a large pleural effusion. The lung will not expand properly, be susceptible to infection which can spread to the other lung.
What are causes of malignant mesothelioma?
- 80% caused by asbestos
- Thoracic irradiation
- BAP1 mutations
Malignant mesotheliomas is relatively common. 1.5% of cancer deaths. It is more common in men than women.
Tends to occur in the elderly population. Survival rate is terrible - almost negligible. Has no effective treatment, just symptomatic.
