Respi - obstructive and restrictive lung diseases Flashcards
obstructive diseases
+ examples
limitation of airflow
total lung capacity remains, reduced expiratory flow rate (problem w/ ventilation)
exhalation requires more effort + obstruction -> wheezing
e.g: COPD, bronchiectasis, asthma, emphysema
obstructive sleep apnoea (OSA)
+ more common in who
episodic - partial/complete closing of upper airways during sleep
pt need to wake up and gasp for air
more common in men who are obese: jaw and tongue fall backwards and obstruct the airways
effect: hypoxemia and poor sleep (cause need to keep waking up for air) -> daytime somnolence, fatigue
Asthma
- causes (atopic vs non-atopic)
obstructive
chronic, affects bronchioles
recurring episodes of bronchospasms and excessive production of mucus
atopic (allergy) causes: foods/drugs/animal antigens
- IgE mediated response: activation of mast cells -> recruitment of eosinophils -> bronchoconstriction/ vascular permeability/ mucus secretion
non-atopic causes: hypersensitive airways/ irritants
asthma complications
- treatment
- repeated episodes: over-reactivity -> remodelling of airways
- severe: bronchospasms + mucus plugging -> resp failure
treatment
- treat bronchospasm and chronic inflammation
structural changes in asthma
- hyperactivity and hypertrophy of bronchus SM
- hypersecretion of mucus
- mucosal edema
- infiltration of bronchial mucosa by inflammatory cells
- collagen deposition in epithelium
COPD
common in chronic smokers
irreversible effects, progressive disease
COPD pathology
- emphysema - effect on alveoli
- chronic bronchitis
- bronchiolitis
emphysema pathogenesis
caused by a1 antitrypsin (protects body from immune complexes formed) def
- Destruction of airspaces -> reduced surface area for gas exchange (like the destructed alveoli not able to be ventilated) = ventilation defect
- destruction of alveolar walls -> airway elastic tissue destruction -> loss of elastic recoil -> airways cannot be kept open -> premature closure and air trapping
causes pink puffers COPD
chronic bronchitis pathogenesis
chronic cough w/ sputum for >2 yrs
- Mucus plugs in airways -> narrow lumen -> alveolar hypoventilation -> V/Q mismatch (shunt)
- premature closure of airways in expiration -> air trapping
- Airway obstruction -> stasis -> increased risk of infection
- Squamous metaplasia -> reduced mucociliary clearance -> risk of LRTI
causes blue bloaters COPD
bronchiolitis
inflammation in small bronchioles
- airway walls filled w/ macrophages & lymphoid cells
- causes scarring and narrowing of airways
risk factors of COPD
- prolonged smoking
- childhood infection
- occupational exposure to dust / poor air quality
COPD: pink puffers
mainly cause by
pink complexion
main cause is EMPHYSEMA**
hyperventilation compensation - so dh CO2 retention
COPD: blue bloaters
mainly caused by
+ treatment considerations
main cause: CHRONIC BRONCHITIS**
no hyperventilation compensation
poor ventilation -> hypoxemia, hypercapnia
right heart tries to pump harder to perfuse the lung -> RHF
too much oxygen can reduce rate of ventilation further - monitor closely
COPD treatment
treat infection
O2
bronchodilators
ventilation equipment
restrictive diseases
total lung capacity reduced, expiratory rate normal
usually chest wall disorders
diffuse parenchymal lung / lung scarring -> cause stiffness and poor compliance of lungs
examples of restrictive disease
- ARDS
- atypical pneumonia
- sarcoidosis
- allergy - hypersensitivity pneumonitis (organic)
- external factors: drug-induced/ radiation/ smoking/ inorganic dusts (pneumoconiosis)
- idiopathic pulmonary fibrosis - most common chronic restrictive disease
diffuse parenchymal lung
inflammatory in the interstitium -> edema and fibrosis of alveolar walls
reduce lung compliance
reduced gas exchange
diffuse parenchymal lung microscopy
- hemorrhage and fibrin exudation into alveoli
- edema and inflammation of interstitium
- macrophage accumulation in alveoli
- fibrosis
ARDS
+ x-ray appearance
acute respiratory distress syndrome
caused by diffused alveolar and capillary damage
- systemic sepsis, trauma, inhalation of toxins
-> injury to pneumocytes and endothelium
-> more inflammatory and pulmonary damage
high mortality (70%)
appears diffused, w/ interstitial markings??
ARDS phases + microscopy features
- acute exudative phase
pink hyaline membranes (w/ fibrin rich fluid and necrotic epithelial cells)
interstitial edema and high protein exudation into alveoli - late organisation phase (recovery)
organisation of hyaline membranes w/ fibrosis
regeneration of type 2 alveolar lining
honeycomb lung
end stage pulmonary fibrosis
leads to chronic resp impairment + reduced diffusion capacity
looks like honeycomb cause loss of normal alveoli tissue, replaced by fibrosis
histological patterns of restrictive diseases
i think dn to know for ca2?
acute:
- DAD (diffuse alveolar damage)
chronic:
- UIP (usual interstitial pneumonia) : idiopathic pulmonary fibrosis
- NSIP
- COP
- RB-ILD
- DIP
idiopathic pulmonary fibrosis
most common chronic restrictive disease
progressive
UIP pattern
hypersensitivity pneumonitis
inhaled organic antigens (animal droppings/ fungi/ hay)
acute exposure: type 3 hypersensitivity
repeated exposure: type 4 hypersensitivity -> can progress to chronic pulmonary fibrosis
pneumoconiosis
inhalation of INorganic (compared to hypersensitivity)
- silica/ coal dust/ asbestos
worsened w/ smoking
cause inflammation: release cytokines + stimulate fibrosis
asbestos
for buildings/ fire resistant materials
can cause diseases:
- pleural plaques
- pleural effusions
- asbestosis (progressive chronic lung fibrosis)
- malignant mesothelioma (unique to asbestos) = malignant tumour
- lung carcinoma
Emphysema appearance
ballooning of air spaces (hyperinflation)
enlarged
blebs and bullae (air entering pleural cavity forming pneumothorax)
causes of emphysema
- cigarette
- environmental pollution
- pneumoconiosis
- a1-AT (protects lung) def - inherited
emphysema complications
- cor pulmonale leading to RV failure
- respiratory failure
- pneumothorax (air in pleural cavity)
- hypercapnia (decreased gaseous exchange) -> risk of peptic ulcer - why??
differentiating COPD from asthma
- COPD caused by smoking/ environmental hazards/ infection
asthma usually seen in childhood days - COPD: chronic persistent cough
asthma: wheezing and breathlessness - asthma relieved by bronchodilators but not COPD
COPD gross and micro appearance
gross: ballooning of air spaces (hyperinflation), enlarged lung, alveoli filled with mucus and inflammatory cells
Microscopy: chronic inflammation – macrophages
