Pleural Pathology Quiz

Study Notes

Connective tissue lined by mesothelial cells surrounding the lung and the thoracic cavity.
Visceral pleura covers the lung.
Parietal pleura covers the thoracic wall, diaphragm, heart, and mediastinum.

Pleuritis (pleurisy): Inflammation of the pleura, often accompanied by effusion.
Causes of pleuritis:
- Infection:
  - Primary infections, such as Cryptococcus.
  - Secondary infections via pneumonia, tuberculosis (TB), lung abscesses.
  - Result from penetrating injuries.
- Connective tissue disorders: Includes rheumatic fever, rheumatoid arthritis, and systemic lupus erythematosus (SLE).
- Pulmonary infarct leading to pleural inflammation.
- Neoplasms involving lung or pleura.
Healing processes after inflammatory episodes:
- Resolution: Complete recovery.
- Adhesions: Formation of fibrous bands between pleural surfaces.
- Plaques: Asymptomatic patches, often due to asbestos exposure, leading to thickened pleura from fibrosis.
- Fibrosis: Localized or diffuse thickening from previous inflammation, often linked to asbestosis or malignancies.

Types of collections:
- Air: Causes pneumothorax.
- Fluid:
  - Hydrothorax: Pleural effusion (can be transudate or exudate).
    - Transudate: Low in protein; associated with cardiac, renal, or liver failure.
    - Exudate: High in protein; linked to inflammation, infections, and tumors.
- Blood: Causes hemothorax.
- Lymphatic fluid: Chylothorax (lymph presence).
- Pus: Leads to pyothorax (empyema).

Causes various complications, including malignancies and fibrotic changes in the pleura.

Benign tumours: Rare, e.g., solitary fibrous tumor characterized by a proliferation of fibroblastic cells in a collagen-rich stroma.
Malignant tumours:
- Primary:
  - Mesothelioma: Strongly associated with asbestos exposure; especially crocidolite and amosite.
- Secondary: Metastasis from lung or breast cancers.

A malignant condition characterized by carcinoma of the mesothelial lining in the pleura.
Development typically occurs 30 years post-exposure to asbestos.
Begins as a localized nodule, later spreading as a sheet to encase the lung and chest wall.
Infiltrates local structures and lymphatics, with occasional hematogenous spread (30%).
Histologically presents as either epithelioid (epithelial-shaped cells) or sarcomatous (spindle-shaped cells) mesotheliomas within a fibrous stroma.
Median survival rate is approximately 11 months post-diagnosis.

Example case: A 55-year-old man experiences weight loss and chest pain; CT scan reveals pleural abnormalities indicative of pleural pathology, potentially including mesothelioma or other neoplasms.