Pulmo Flashcards
Unit of respiration
Bronchioles (w/o cartilage and submuco)-> terminal bronchiole -> acinus -> respi bronchiole -> alveolar duct -> alveolar sac -> alveoli
Permit passage of bacteria, exudates, air between alveoli
Pores of Kohn
Loss of lung volume by inadequate expansion of air spaces
Atelectasis
When obstruction prevents air from reaching distal airway
Air present becomes aborbed and alveolar collapse follows
Usually by mucus
Resorption atelectasis
Passive, relaxation
Accumulation of fluid, blood or air within pleura mechanically collapsing adjacent lung
Pleural effusion
Pneumothorax
Compression pneumothorax
Cicatrization
Local or generalized fibrotic changes in lung or pleura hamper expansion and inc elastic recoil during expiration
Contraction atelectasis
Bilateral (endothelial and epithelial) damage
Acute lung injury
ALI caused by (3)
1 acute onset dyspnea
2 dec arterial oxygen pressure (hypoxemia)
3 bilateral pulmo infiltrates on chest
In absence of L heart failure (non cardiogenic pulmonary edema)
Clinical syndrome by diffuse alveolar capillary and epithelial damage
Rapid life-threatening respiratory insufficiency, cyanosis, severe arterial hypoxemia refractory to oxygen therapy -> multiple organ failure
Acute Respiratory Distress Syndrome
ARDS histo pathognomonic
Diffuse alveolar damage (DAD)
ARDS is caused by imbalance of
pro inflammatory and anti inflammatory mediators
Cells with important role in ARDS
Called by
Neutrophils
IL-8
Mediators involved in ARDS
IL-8 IL-1 Macrophage Neutrophil TNF B, PDGF
Balanced by IL-10 (anti inflam)
Vascular leakiness and loss of surfactant render the unit unable to expand but the degree of injury and severity is determined by
Balance between destructive and protective factors
Dark red, firm, airless and heavy
Capillary congestion, necrosis of epithelial cell, interstitial and intra-alveolar edema and hemorrhage
Neutrophil in capillary
Acute phase of ards
Most characteristic finding
Fibrin-rich edema fluid admixed with remnants of necrotic epithelial cell
Hyaline membrane
Similar to rds in newborn
Vigorous proliferative type II pneumocyte to regenerate alveolar lining
Organization of fibrin exudate with intra-alveolar fibrosis
Thickening of septa by proliferation of interstitial cell and collagen dep
Organizing stage of ARDS
85% of patients with ALI or ARDS develop within
3 days after injury
Syndrome of progressive respiratory insufficiency by diffuse alveolar damage in setting of sepsis, severe trauma or diffuse pulmonary infection
ARDS
Alveolar edema, epithelial necrosis, accum of neutrophil, hyaline membrane lining alveoli
ARDS
Diffuse obstructive disorders
Emphysema
Chronic bronchitis
Bronchiectasis
Asthma
In obstructive lung disease,
FVC
FEV1
FEV/FVC Ratio
FVC normal or slightly decreased
FEV1 SIGNIFICANTLY decreased
Ratio DECREASED
In diffuse restrictive disease,
FVC
FEV
FEV/FVC ratio
FVC decreased
FEV normal or dec proportionately
FEV/FVC ratio: Near Normal
Restrictive diseases causes by (2)
1 chest wall disorder in a normal lung (obesity, pleural problem, GBS)
2 acute or chronic ILD (pneumoconiosis, intersitial fibrosis, sarcoidosis)
Abnormal permanent enlargement of air spaces with destruction of walls distal to terminal bronchioles and without fibrosis
Emphysema
Site: Bronchus
Mucuous gland hypertrophy and hyperplasia with hypersecretion
Tobacco smoke, air pollutant
Cough and sputum production
Chronic bronchitis
Site: Bronchus
Airway dilation and scarring
Persistent and severe infection
Cough, purulent sputum and fever
Bronchiectasis
Site: Bronchus
Smooth muscle hypertrophy, hyperplasia, excessive mucus and inflammation
Immunologic and undefined cause
Episodic wheezing, cough, dyspnea
Asthma
Site: Acinus
Air space enlargement, wall destruction
Tobacco smoke
Dyspnea
Emphysema
Site: bronchiole
Inflammatory scarring, partial obliteration of bronchiole
Tobacco smoke, air pollutant
Cough, dyspnea
Small airway disease
Bronchiolitis
Small airway disease
Alveolar wall destruction
Overinflation
Emphysema
Small airway disease
Productive cough
Airway inflammation
Chronic bronchitis
Reversible obstruction
Bronchial hyperresponsiveness by allergen, infection
Asthma
Cluster of 3-5 acinu
Lobule
4 major types of emphysema
Centriacinar
Panacinar
Distal acinar
Irregular
Central or proximal acini formed by respiratory bronchioles affected with sparing of distal alveoli
Centriacinar
Centrilobular
Centriacinar lesions are located in
upper lobes
apical
Centriacinar emphysema occurs bec of
Smoking in people without alpha1 antitrypsin deficiency
acini uniformly enlarged from bronchiole to terminal blind alveoli
alpha1 antitrypsin deficiency
Panacinar
Panlobular emphysema
Pancinar emphysema tends to occur
On lower lung zones and in alpha 1 antitrypsin deficiency
Distal emphysema proximal portion of acinus normal but distal is primarily involved
More striking adjacent to pleura along lobular CT septa at margin of lobule and adjacent to areas of fibrosis, scarring and atelectasis
Distal acinar
Paraseptal
Distal acinar paraseptal emphysema is more common in
upper half of lungs
Multiple contiguous large spaces ranging in diameter from less than 0.5 to more than 2 cm Cystic structure with progressive enlargement becoming bullae Cause unknown (spontaneous pneumothorax)
Distal acinar paraseptal emphysema
acinus irregularly involved
invariably associated with scarring from healed inflammatory disease
Most common form
Irregular emphysema
Atelectasis pathogenesis
Toxic exposure (tobacco and pollutants)
Inflammation with neutrophil, mac, IL8 and oxidant
Epithelial injury and proteolysis of ECM, elastin degradation
80% of patients with congenital alpha 1 antitrypsin def develops
panacinar emphysema
Gene polymorphism influence susceptibility to development of COPD resulting to inadequate repair of elastin injury
TGFB
Results from insufficient wound repair, loss of epithelial, endothelial and mesenchymal cell
Emphysema
Pathogenic role in emphysema
MMP 9 and 12
Pale voluminous lung obscuring heart at autopsy
Panacinar emphysema
Deep pink less voluminous with upper 2/3 affected
Destruction of alveolar walls without fibrosis with enlarged spaces
Dec alveolar capillaries
Loss of elastic tissue
Bronchiolar inflamm and submucosal fibrosis
Centriacinar emphysema
Barrel chested
Dyspneic
Prolonged expiration
Sitting forward hunched position
Severe air space enlargement and low diffusing capacity
Pink puffer bec of dyspnea and adequate oxygenation
Emphysema without bronchitic component
Pink puffer
Pronounced chronic bronchitis
History of recurrent infection with purulent sputum
Less prominent dyspnea with diminished drive
Retains CO2, hypoxic and cyanotic
Obese
Blue bloater
CHF/Cor pulmonale
Blue bloaters
Arises from pulmonary vascular spasm inducing hypoxia and loss of pulmo capillary surface from alveolar destruction
Secondary pulmonary hypertension
Compensatory dilation of alveoli in resp to loss of lung substance elsewhere
Surgical removal of lobe
Compensatory emphysema
Lung expansion bec of air trapping
Subtotal obstruction by tumor or foreign object
Life threatening
Obstructive overinflation
Large subpleural bleb or bullae >1cm diameter
Subpleural and may rupture leading to pneumothorax
Bullous emphysema
Air entry into CT of lung, mediastinum and subcu tissue
Inc intraalveolar pressure (vomiting or whooping cough), partial obstruction of bronchiole on respirator, fractured rib
Swelling of head and neck with chest crepitation
Mediastinal interstitial emphysema
Persistence of productive cough for at least 3 consecutive months in at least 2 consecutive years
Smokers and cigarette dwellers aged 40-65y M
Chronic bronchitis
Distinctive feature of chronic brochitis
Single most important cause
Hypersecretion of mucus in large airway
Smoking
Cigarette and pollutants induce
hypertrophy of mucous glands in trachea and main bronchi
Marked inc in mucin-secreting globlet cell with infiltration of CD8 lympho, mac and neutro without eo
Morphologic basis of airflow limitation in chronic bronchitis
1 peripheral, small airway disease (goblet cell metaplasia with mucus plug, inflamm and wall fibrosis)
2 coexistent emphysema
Mucus secretion is mediated by
IL 13 from T cell
Tobacco exposure induces
transcription of mucin gene MUC5AC and neutrophil elastase
Coexistent secondary role in maintaining inflamm and exacerbating symptom
Microbial infection
Hyperemic swollen airway
Mucinous secretion with enlargement of glands
Chronic bronchitis
Ratio of thickness of submucosal gland layer to that of bronchial wall
N =
Reid index
0.4
Goblet cell metaplasia, mucous plugging, inflammation, fibrosis
Complete obliteration of lumen due to fibrosis
Chronic bronchiolitis
Intermittent reversible airway obstruction
Chronic bronchial inflamm with eosinophil
Bronchial smooth muscle cell hypertrophy and hyperactivity
Inc mucus secretion
Asthma
Hygiene hypothesis
Eradication of infection alter immune homeostasis and promote allergic and harmful immune response
Evidence of allergen sensitization in a patient with allergic rhinitis, emphysema
Atopic
Bronchospasm is triggered by
Respiratory infection - viral Irritants Cold air Stress Exercise
Etiologic factors of asthma
1 genetic predisposition to Type I hypersensitivity (atopy)
2 acute and chronic airway inflammation
3 bronchial hyperresponsiveness
Critical role in the pathogenesis of asthma
TH2 helper t cell
Excessive TH2 reaction against environmental agents
Cytokines produced
Classic atopic form
IL4
IL5
IL13
stimulates IgE production
IL4
Activates eosinophil
IL5
Stimulated mucus production and promotes IgE by B cell
IL13
Bronchoconstriction
Inc mucus production
Variable vasodilation
Early immediate reaction
Inflammation
Activation of eosinophil, neutro and T cell
Chemokine production that recruit more TH2 and eo
Late phase reaction
Chemoattractant and activator of eo
Eotaxin
Structural changes from repeated inflammation
Hypertrophy of smooth muscle and mucus gland
Inc vascularity and
Subepithelial collagen deposition
airway remodelling
Susceptibility loci of asthma
Long arm of ch 5q (IgE, mast cell and eo)
ch 20q ADAM 33 (proliferation of bronchial smooth ms and fibroblast) - airway remodelling
High serum YKL 40 correlates
with severity of asthma
Most common type of asthma
Positive family history of atopy
By various environmental trigger
Atopic asthma
Atopic asthma is an example of
Type I IgE mediated hypersensitivity reaction
No evidence of allergen sensitization
Negative skin test result
Triggered by respiratory infection due to viruses and inhaled air pollutants
Non-atopic form
Virus induced inflamm of respiratory mucosa lowers
threshold of subepithelial vagal receptor to irritant
Drug that provokes asthma
Aspirin
Recurrent rhinitis and nasal polyp, urticaria and bronchospasm
Stimulated by fumes (epoxy resin, plastic), organic and chemical dust and gases
Occupational asthma
Occlusion of bronchi and bronchiole by thick tenacious mucous plug
Asthma
Whorls of shed epithelium
Curschmann spirals
Crystalloid made up of eosinophil protein
Charcot-Leyden crystal
Severe dyspnea, wheezing
Difficulty in expiration with difficulty to get air in and out leading to progressive hyperinflation with distal air trapping
Asthma
Severe paroxysm not responding to therapy and persisting for days and weeks
Status asthmaticus
Key inflammatory cell in all subtypes of asthma
Produce MBP
Eosinophil
Airway remodelling
Subbasement membrane thickening
Hypertrophy of bronchial gland and smooth muscle
Permanent dilation of bronchi and bronchiole by destruction of ms and elastic tissue assoc with necrotizing infection
Secondary persisting to infection or obstruction
Cough, expectoration of copious amounts aof purulent sputum
Bronchiectasis
Tumors, foreign body, mucus impaction
Localized to obstructed lung segment
Bronchial obstruction
Widespread severe bronchiectasis from obstruction by secretion of viscid mucus
Cystic fibrosis
Rare autosomal recessive associated with bronchiectasis and sterility in males
Structural abnormalities of cilia impair mucociliary clearance leading to persistent infection and reduces mobility of spermatozoa
Kartegener syndrome
Pathogenesis of bronchiectasis
1 obstruction
2 chronic persistent infection
Bronchiectasia affects the
lower lobes bilaterally particularly air passages that are vertical
Most severe at distal bronchi and bronchiole
Intense acute inflammatory exudate within walls of bronchi and bronchioles, desquamation and ulceration
Peribronchiolar fibrosis in chronic case
Bronchiectasis