Respiratory System 5 + 6 Flashcards
(15 cards)
What is the definition of pulmonary hypertension?
Systolic blood pressure in the pulmonary circulation exceeding 25 mm Hg at rest, measured during right heart catheterization.
What are the causes of pulmonary hypertension secondary to cardiac conditions?
- Congenital cardiac shunt
- Increased left atrial pressure
- Left ventricular failure
What are the vascular changes in the lungs due to congenital cardiac shunt?
- Hypertrophy of the media of the small pulmonary arteries
- Migration of smooth muscle cells from media to the intima forming an intimal myofibroblast proliferation in the pulmonary arteries & arterioles
- These changes lead to occlusion of the small pulmonary arteries
- Followed by dilation of small arteries arising proximal to the site of occlusion to maintain the blood flow to the pulmonary capillary bed
What are ‘Plexiform lesions’ in the context of pulmonary hypertension?
Proliferation of myofibroblasts & mesenchymal cells occurs within the angiomatoid lesion in a plexiform pattern forming the ‘Plexiform lesions’ which are characteristic of pulmonary hypertension due to congenital cardiac shunt.
What are the effects of chronic hypoxia on pulmonary arteries?
In chronic hypoxia, the vascular changes include smooth muscle hypertrophy in the media of pulmonary arterioles, leading to increased pulmonary vascular resistance causing pulmonary hypertension. Intimal fibrosis is insignificant, therefore pulmonary hypertension of chronic hypoxia is reversible.
What are the four major histologic types of lung carcinomas?
- Adenocarcinoma
- Squamous cell carcinoma
- Neuro-endocrine tumors
- Large-cell carcinoma
What is the most important risk factor for bronchial carcinoma?
The most important risk factor is smoking.
What is Pancoast’s syndrome, and what type of tumor causes it?
Pancoast’s syndrome is caused by a tumor at the apex of the lung that extends to the lower cords of the brachial plexus and sympathetic chain, producing pain and sensory disturbances. This tumor is called Pancoast’s tumor.
What are the characteristics of small-cell lung cancer (SCLC)?
Small-cell lung cancer (SCLC) has metastasized by the time of diagnosis and is not curable by surgery. It is best treated by chemotherapy, with or without radiation therapy.
What is the difference between typical and atypical carcinoid tumors?
• Typical Carcinoid: Slowly growing, low-grade malignant tumor with lymph node metastasis in < 10% of cases.
• Atypical Carcinoid: Has histological features of malignancy, is more aggressive, and has lymph node metastasis in 70% of cases.
What is the association between malignant mesothelioma and asbestos exposure?
Malignant mesothelioma is associated with exposure to asbestos, with a very long latent period of 20 years or more. The tumor affects both visceral and parietal pleura, forming diffuse thickening of the pleura that ensheaths and compresses the lung, often accompanied by severe hemorrhagic pleural effusion.
What are the macroscopic types of bronchial carcinoma?
- Hilar (central) type: Arises in a main bronchus.
- Peripheral type: Arises in a peripheral bronchus.
What are the histological changes in pulmonary arteries due to left atrial pressure elevation?
There is medial hypertrophy and intimal fibrosis with muscularization of the pulmonary arterioles and veins, leading to pulmonary hypertension.
What is the WHO classification of neuroendocrine tumors of the lung?
- Small cell carcinoma
- Large cell neuroendocrine carcinoma
- Carcinoid tumors (Typical carcinoid tumor and Atypical carcinoid tumor)
What are the characteristics of adenocarcinoma of the lung?
• It is the most common lung cancer.
• Mainly of peripheral type.
• Grows slowly and is smaller in size than other types.
• Tends to metastasize widely at an early stage.
• Malignant cells in sputum in 50% of cases.
