Obstructive Lung Disease Flashcards
Where is pseudostratified ciliated columnar epithelium found in the lung?
Airways proximal to RBs lined by pseudostratified ciliated columnar epithelium
Where does the normal acinus start?
starts distal to terminal bronchiole
What types of cells are in the alveolus?
Type I pneumocytes:
cover 95% of alveolar
surface and are the diffusion surface
Type II pneumocytes: Produce surfactant & Repair of alveolar
epithelium
What are pores of Kohn?
alveola septa are not continuous but have the pores of Kohn
Define OPD:
Diseases that cause obstruction to airflow out of the lungs
What are the types of COPD?
– Emphysema
– Chronic bronchitis
– Asthma
– Bronchiectasis
What is FVC?
Forced vital capacity (FVC)– Lungs are forcibly emptied at maximal speed from point of full inspiration
What is FEV1?
Forced expiratory volume in 1 second
What is the FEV1:FVC ratio used for?
useful for detecting obstruction and differentiating obstructive from restrictive lung disease
What happens in obstructive airway disease?
- Airway disorder – trachea to terminal bronchiole
- Increased resistance to air flow and limited expiratory rates on forced expiration
- Reduced FEV1:FVC ratio
What happens in restrictive airway disease?
- Parenchymal disorder -respiratory bronchiole, alveoli and alveolar ducts
- Decreased expansion with reduced Total Lung Capacity, O2 diffusing capacity, Lung Volumes and compliance
- Increased FEV1:FVC ratio
What is Emphysema?
Permanent enlargement of all or part of the respiratory unit (respiratory bronchioles, alveolar ducts, alveoli) accompanied by wall destruction without obvious fibrosis due to a protease imbalance
What are some causes of emphysema?
– Smoking (tobacco, marijuana)
– Air pollution
– α1-antitrypsin deficiency
What are the two types of emphysema?
– Centriacinar (centrilobular) – 95% cases
– Panacinar
What is the pathogenesis of emphysema?
Increased numbers of macrophages, CD8+ T lymphocytes and neutrophils activated by tissue damage from cigarette smoke
Elastase and free radicals derive from neutrophils and macrophages –> Destruction of elastic tissue –>Increased compliance and decreased elasticity
What is a disease of Elastic tissue → keeps airway lumens open by applying traction → elastic destruction causes collapse of airways on expiration → prevents exit of air → trapped air distends part of respiratory unit that has lost the elastic support → dilatation and destruction of alveoli and alveolar ducts (also distal/terminal bronchioles)?
Emphysema
What is Centriacinar emphysema?
Smokers’ emphysema in Apical segments of upper lobes
How does smoking cause Centriacinar emphysema?
Tobacco smoke contains “free radicals” which deplete these antioxidants and Oxidative injury also inactivates native antiproteases – “functional α1-antitrypsin deficiency”
What is Panacinar emphysema?
α1-antitrypsin deficiency: Lower lobes All parts of the respiratory unit are affected by elastic tissue destruction
What causes Panacinar emphysema?
genetic or aquired (smoking)
genetic is autosomal dominant with phenotypes associated with severe deficiency of α1-antitrypsin enzyme production in the liver
What are the clinical findings with emphysema?
– Severe and early onset of dyspnea
– Pink puffers
– Coexistence with chronic bronchitis (smokers’ emphysema)
– Cor pulmonale – less common than in chronic bronchitis
– Diminished breath sounds due to hyperinflation
What can you see on a chest xray of emphysema?
– Increased AP diameter
– Hyperlucent lung fields
– Vertical heart
– Depressed diaphragm
What are some other types of emphysema?
- Paraseptal emphysema (Subpleural involvement, Spontaneous pneumothorax, No COPD)
- Irregular emphysema (Localized, scar associated, No COPD)
What is chronic bronchitis?
Productive cough for at least 3 months for 2 consecutive years
What are some causes of chronic bronchitis?
– Smoking
– Cystic fibrosis
What is the pathogenesis of chronic bronchitis?
– Inhaled smoke (irritant) → mucous hypersecretion in bronchi → airflow obstruction in terminal bronchioles (more proximal than in emphysema) → irreversible fibrosis of terminal bronchioles
– Infection: Maintenance of disease andAcute exacerbations
– Bronchospasm
How do airways look in chronic bronchitis?
mucous overproduction, constriction of bronchiole with bronchospasm/smooth muscle hyperplasia, edema, erythema
What are the clinical findings with chronic broncnitis?
– Productive cough – Cyanosis (due to decreased O2 saturation from hypoxemia) – “Blue bloaters” – Dyspnea – Expiratory wheezing and rhonchi – Cor pulmonale
What would you see on a chest xray of chronic bronchitis?
– Enlarged heart, horizontally oriented
– Increased bronchial markings
What about on histology for chronic bronchitis?
blue inflammatory cells, mucous gland hyperplasia, thickening of walls, narrow lumens
How is mucous gland hyperplasia measured?
Reid Index
• Ratio of the thickness of the mucous gland layer to the thickness of the wall between the epithelium and cartilage
What is Bronchiectasis?
Permanent destruction and dilatation of bronchi and bronchioles involves cartilage and elastic tissue
What are some causes of Bronchiectasis?
– Cystic fibrosis
– Infections: TB, Adenovirus, H influenzae, staph aureus
– Bronchial obstruction
– Primary ciliary dyskinesia
– Allergic bronchopulmonary aspergillosis
What are the clinical findings of Bronchiectasis?
– Copious sputum
– Hemoptysis
– Digital clubbing
– Cor pulmonale
What would you see on a chest xray of Bronchiectasis?
Bronchial markings extending to the periphery of the lungs
What are the gross findings of Bronchiectasis?
dilated airways filled with mucous and pus
What are the microscopic findings of Bronchiectasis?
– Intense acute and chronic inflammatory exudate in bronchial walls, necrotizing ulceration
– Squamous metaplasia of bronchial epithelium
– Lung abscesses may be present
– Fibrosis of bronchial walls leading to bronchiolitis obliterans
– Cultures are usually positive
What is cystic fibrosis?
Autosomal recessive Deletion on chromosome 7 causing Defective CF transmembrane conductance regulator (CFTR) for chloride ions
What is the pathogenesis of CF?
Increased Na and water reabsorption from luminal secretions and decreased Cl secretions from epithelial cells into lumen so Dehydration of body secretions due lack of NaCl – bronchioles, pancreatic ducts, bile ducts, meconium, seminal fluid
What are the clinical findings in CF?
– Nasal polyps – Respiratory infections → Respiratory failure – Malabsorption – Type I diabetes mellitus – Infertility in males – Meconium ileus – Secondary biliary cirrhosis
A pt has recent 20 lb weight loss associated with rapid onset SOB what is the most likely diagnosis?
lung cancer
Do swollen feet and significant sputum production occur in asthma?
Nope
What if a pt has seasonality to their breathing symptoms?
probably allergies and asthma
Asthma is usually _____ airway obstruction while COPD is usually _______
asthma: reversible
COPD: not reversible
– Usually related to smoking exposure
– Obstruction generally not reversible with a beta-agonist
– Reduced gas exchange
– Emphysema
– Chronic bronchitis
– Associated diseases: Right heart failure / Congestive heart failure & Lung cancer
What’s going on here?
COPD
– Usually develops early in life: Viral induction and exacerbation & Exacerbated but not caused by smoke exposure
– Associated with allergies
– Obstruction is usually reversible with a beta-agonist
– No defect in gas exchange
– Associated diseases: Allergic rhinoconjunctivitis & Atopic dermatitis
What’s going on here?
Asthma
