Obstructive & Restrictive Lung Diseases Flashcards
Define emphysema
Abnormal irreversible dilatation of air spaces distal to terminal bronchioles accompaied by destruction of their walls without fibrosis.
Compare centriacinar & panacinar emphysema
C: central (proximal) part of acinus with spared distal part, common in upper lobes, associated with smoking/chronic bronchitis.
PA: the whole acinus is uniformly involved, common in lower lobes, associated with alpha-1-antitrypsin deficiency.
Compare paraseptal & irregular emphysema
PS: the distal part of acinus while proximal part is normal, more common in upper lobes, adjacent to the pleura, along the lobular connective tissue septa & margins of lobules. Unknown cause, leads to spontaneous pneumothorax.
I: the acinus is irregularly involved, associated with scarring.
Mention the main steps of pathogenesis of emphysema
Lung damage and inflammation by inflammatory cells & mediators
Protease-Anti-Protease Imbalance
Oxidative stress
Insufficient wound repair
Loss of elastic tissue causing the respiratory bronchioles to collapse during expiration, leading to functional (not mechanical) obstruction.
Describe the gross & microscopic features of emphysema
G: panacinar it is pale & voluminous in lower lobes, centriacinar less pale and less voluminous thant PA, present in upper 2/3.
M: destruction alveolar wall without fibrosis, enlarged air spaces & decreased number of alveoli.
Mention clinical features of predominant emphysema
- Dyspnea, in chronic bronchitis or chronic asthmatic bronchitis, wheezing can occur.
- Weight loss
- Hyperventilation or better hyper respiration
- Barrel shaped chest
- Prolonged expiration: sitting in hunched position
Mention the reason of secondary pulmonary hypertension in COPD with
1, Predominant emphysema
2, Predominant chronic bronchitis
1, due to loss of pulmonary capillary surface area from alveolar destruction
2, due to hypoxia induced vascular spasm
Write a note on conditions confused with emphysema
- Compensatory emphysema: dilatation following surgical removal of diseased lung lobe.
- Obstructive Over-inflation: due to subtotal obstruction of an airway
- Bullous emphysema
- Mediastinal emphysema: air in mediasium , interstitium m subcutaneously. Due to whooping cough, excess vomitting or accidents and fractured ribs.
Define chronic bronchitis
Persistent cough with sputum production for at least 3 months in at least 2 consecutive years in the absence of any other identifiable cause.
Pathogenesis of chronic bronchitis
- Mucus hypersection, smoke interfere with ciliary action, prevent clearance of mucus & predisposes to infection
- Inflammation: neutrophils, lymphocytes, mabrophages, end with fibrosis & obstructive airway disease.
- Infection
Mention the most important diagnostic criterion of chronic bronchitis
Increased Reid Index
Mention microscopic features of chronic bronchilitis
Goblet cell metaplasia, mucus plugging, inflammation & fibrosis (bronchiolitis oblterans)
Clinical features and complications of chronic bronchitis
- Persistent productive cough
- Dyspnea with effort
- Hypercapnia, hypoxemia and mild cyanosis
- Repeated infection
- Cor pulmonale
Define bronchiectasis
Its is permenant dilatation of bronchi & bronchioles caused by destruction of the muscle and the supporting elastic tissue resulting from or associated with chronic necrotizing infection.
Mention predisposing factors of bronchietasis
- Bronchial obstruction
- Necrotizing/suppurative inflammation. Post-tuberculous bronchiectasis, Staph aureus, Klebsiella.
- Immunodeficiency states
Describe the pathogenesis of bronchiectasis
Obstruction AND chronic persistent infection
Either normal secretions are hindered by obstruction so secondary infection will follow
Or infection causes accumulation of sectretion and obstruction
Weakening of bronchial walls, traction & irreversible dilatation
Describe bronchiectasis grossly
Lower lobes of lung, most distal bronchi & bronchioles can be followed to pleural surface.
Segmental affection
Describe bronchiectasis microscopically
- Extensive desquamtion and ulceration of the surface epithelium
- Dense inflammatory cellular infiltrate
- Fibrosis
- Dilatation
- Lung abscess formation
- Mixed flora can be cultures
Mention clinical features & complications of bronchiectasis
- Severe persistent cough, sputum with changing position
- Dyspnea
- Hemoptysis
- Lung abscess
- Hypoxemia, hypercapnia, pulmonary hypertension , cor pulmonale
- Spread
- Amyloidosis
Define bronchial asthma
Chronic inflammatory disorder of airways that causes recurrent episodes of wheezing, breathlessness, chest tightness & cough.
What are the hallmarks of bronchial asthma?
Intermittent and reversible airway obstruction, bronchial muscles hypertrophy, hyper-activity, increased mucus secretion & chronic bronchial inflmmation with eosinophils.
Describe clinical picture of bronchial asthma
Sym:
Coughing more at nigh & excercise, dyspnea, tight chest, short breath & wheezing.
Signs:
Chest: high pitch wheezes with expiration
Skin/nose allergy
Underlying aetiology of bronchial asthma, most important cellular & humoral agents.
Type 1 hypersensitvity
TH2, mast cells, basophils
IL4,5,13
Late phase reaction of bronchial asthma occurs with ….. of contact with antigen
2-4 hrs
Compare type 2 & non-type 2 asthma
Type 2: severe, airway/systemic eosinophilia, responsive to corticosteroids & inhibitors of type 2 inflammation, may be atopic with early onset, IgE mediated, positive skin test.
Non-type 2: older age of onset, viral infection may play a role, neutrophilic, smooth-muscle mediated, less severe, no eosinophilia, no response to corticosteroids. No evidence of allergy or positive skin test.
Mention types of type 2 asthma
Allergic (atopic, extrinsic)
Exercise-induces asthma
Late onset eosinophilic asthma
Comapre early & late phases of asthma
Early: within 30-60 min, immediate bronchospasm, mucus production, inc vascular permeability & chemotaxis.
Late: 2-4 hrs, exaggerated initial response, epithelial damage, inflammation & wall edema , inc chemostaxis.
Describe gross & microscopic picture of bronchial asthma
G: overdistended with areas of atelactasis
M: Curschman spirals & charcot crystal, thickened BM, hyperplasia of mucus glands and smooth muscles, eosinophils & increased vascularity in submucosa.
Hallmark features of restrictive lung disease
Reduced compliance with increased effort of breathing
Hypoxia with abnormalities in V/Q ratio,
Mention genetic defects associated IPF
Telomerase gene defect, MUC5B, surfactant gene defects
Mention proposed causes of injury in IPF
GERD, smoking, occupational irritants, toxins & viral infection
TGF beta downregulates …. Which
Fibroblast caveolin
Inhibits pulmonary fibrosis
Mention gross features of IPF
Pleural surface shows cobblestone appearance due to retraction of scars along ther interlobar septa.
Honeycomb appearance, fibrosis, firm rubbery greyish white areas.
Describe microscopic features of IPF
- Early, exuberant fibroblastic foci, late, it is more collagenous less cellular.
- Cystic spaces lines by type II pneumocytes or bronchiolar epithelium (honeycomb fibrosis)
Clinical features of IPF
- Dyspnea & dry cough
- Dry crackles during inspiration
- Hypoxemia, cyanosis & clubbing
- Gradual deterioration
- Acute execration
Non-specific interstitial pneumonia is associated with
Collagen vascular disorders as rheumatoid arthritis
Describe morphology of NSIP
Cellular (inflmmatory cells) pattern: mild to moderate interstitial inflammation.
Fibrotic pattern: diffuse or patchy fibrosis, no temporal heterogeneity or honeycombing.
The lung reaction in pneumoconiosis depends on
Size of particles
Reactivity
Manifestions of complicated coal worker pneumocniosis
Pulmonary massive fibrosis Caplan syndrome (rheumatoid arthritis & pneumoconiosis)
Mention disaeses caused by silica in the lung
Acute silicosis
Chronic silicosis with concentrically arranged hyaline collagen fibers
PMF
Mention effects of asbestos on pleura
Pleural effusions, fibrous plaques, diffuse pleural fibrosis, mesothelioma.
Mention malignancies associated with asbestosis
Mesothelioma, bronchogenic carcinoma & laryngeal carcinoma.
Mention features of asbestosis
Interstital fibrosis in lower lobes & subpleural, enlarged air spaces enclosed by areas of fibrosis (honeycomb appearance)
GR: Silicosis causes increased frequency of TB
As it affects the capability of macrophages to kill the bacilli
