Complete pathophysiology of asthma and COPD

1. Pathophysiology
Bronchial Asthma
& COPD
RVS Chaitanya Koppala

2. Asthma
 Common and chronic inflammatory condition of the airways, whose
cause is not completely understood
 Common symptoms are
 Hyper-responsive airways (coughing, wheezing, chest tightness and
shortness of breath)
 Broncho contriction
 Asthma means laboured breathing refer to a disorder of the respiratory
system that leads to episodic difficulty in breathing
 Chronic disorder of the airways associated with variable airflow
obstruction and an increase in the airway response to a variety of
stimuli

4. Epidemiology
Exact prevalence of asthma remains uncertain because of differing ways
in which airway restriction is reported
Diagnostic uncertainty (children under 2 yrs.) overlaps with chronic
obstructive pulmonary disease (COPD)
Over 5 million people in UK , around 300 million worldwide
Mortality is estimated around 1400 deaths/yr
5-12% in children with a higher occurrence in boys than girls or parents
have a allergic disorder
30-70% of children become symptom free by adulthood

5. COPD vs Asthma
In COPD, both the airways and lung parenchyma are
affected by the disease and airflow limitation is progressive.
COPD is predominantly diagnosed in patients >40 years old
&
In Asthma only the airways are affected. Asthma is usually
present from childhood

7. Aetiology
• Two main causes of symptoms are
Airway hyperresponsiveness (?)
Bronchoconstriction(?).
• Trigger factors is the allergen in faeces of the
house dust mite (bedding carpets and soft
furnishing.)
• Pollen from grass (seasonal asthma)
• Increased industrialization (occupational
asthma)
• Drug induced asthma (Beta blocker drugs and
prostaglandin synthetase inhibitors) ex:
Aspirin and other NSAIDS (?)

8. Pathophysiology
Eosinophilic Non Eosinophilic
Extrinsic Asthma Intrinsic Asthma
Causative factor is allergen Causative factor is Virus
More common in children More common in Adults
Dust mite, IgE antibodies,
Rhinovirus (during first 3 yrs of life)
Non allergic factors, viral infection , irritants like
epithelial damage , mucosal inflammation,
emotional upset, parasympathetic input
Triggers activated Th2 lymphocytes and mast cells Triggers epithelial cell damage and Macrophages
Effected cells are eosinophil Effected cells are neutrophils
Causes airway inflammation Causes airway inflammation
Airway hyperesponsiveness, irritation, Oedema,
mucous plugging, remodeling
Airway hyperesponsiveness, irritation, Oedema,
mucous plugging, remodeling

9. Cellular mechanism involved in airways

12. Clinical manifestation
Persistant cough
Dyspnoea
Wheezing (a high pitched noise due to turbulent airflow/ narrowed
airway)
Reversible airflow obstruction
Atopy
Allergic rhinitis

13. Acute severe asthma
Requires Hopitalization
Immediate emergency treatment
Bronchospasm (breathless at
rest, cardiac stress)
Breathlessness Cannot talk or
cannot lie down
Air trapped
Peak flow rate >100L/min
Air beneath mucosal inflammation
Pulse rate >110beats/min
Hyperexpansion of thoracic cavity
Lowering of diaphragm
Rapid breathing (>30 breath/min)
Lower oxygen saturation (SpO2 <92%)
Fatigued, cyanosed, confused, lethargic
Hypercapnia (High PaCO2 level)

19. Investigations
• Function of the lung can be measured to help diagnose and monitor various
respiratory diseases
FEV (Forced Expiratory Volume)– spirometer (inhales deeply and
exhales forcibly)
FVC (Forced Vital Capacity)– max volume of air exhaled with
maximum capacity)
PEF (Peak Expiratory Flow)—the maximum flow rate that can be
forced during expiration assess the improvement of deterioration and
effectiveness of treatment.