Asthma

Question 1

INTRODUCTION
Definition

Answer 1

A clinical condition due to airway hyper-responsiveness, characterised by airway inflammation and manifesting clinically as wheezing, cough, difficulty in breathing, and chest tightness

It may resolve spontaneously or following treatment.

Question 2

Introduction

Answer 2

It is a common chronic disease
- 2nd commonest after Pulmonary Tuberculosis

The prevalence is increasing due to urbanisation

Asthma is a syndrome characterised by;
airway inflammation and remodelling
airway hyper-responsiveness
variable but reversible airway/airflow obstruction.

Asthma is a heterogeneous condition where genetic and environmental factors may interact.

There is strong evidence that childhood asthma consists of a range of separate disorders.
Asthma characteristically affects the small and medium-sized bronchi usually 2 to 5mm in diameter.

The airflow limitation results from bronchial spasm, mucosal oedema, excessive tenacious secretions.

Majority of subjects are genetically predisposed.

Environmental pollutants and other trigger factors play a major role in asthma exacerbation.

Asthma manifests with a variety of symptoms, none of which is specific to asthma.

Two main age groups are discernable in childhood asthma
- younger children (younger than 12 years) d
adolescent (aged 12 years and above)

Question 3

Epidemiology

Answer 3

One of the most common chronic diseases of childhood
Prevalence is increasing worldwide
More common in:
Children with family history of atopy
Urban populations
Male predominance in early childhood; female predominance in adolescence

Question 4

Etiology and Risk Factors

Answer 4

1. Genetic Factors
   Polygenic inheritance
   Strong association with:
   Atopy
   Allergic rhinitis
   Eczema
   Family history of asthma or allergy
2. Environmental Factors
   House dust mites
   Pollens
   Animal dander
   Cockroaches
   Mold
   Tobacco smoke (prenatal and postnatal)
   Air pollution
3. Triggers
   Viral respiratory infections (especially RSV, rhinovirus)
   Exercise
   Cold air
   Emotional stress
   Drugs (e.g., aspirin, NSAIDs in susceptible children)
   Strong odors and fumes

Question 5

Pathophysiology

Question 6

Pathogenesis

Question 8

Trigger factors

Answer 8

1. Viral infections
2. Dusts and pollutants including cigarette smoke
3. Allergens such as HDM, pollens, molds, animal danders, certain foods, spores, etc
4. Exercise
5. Drugs
6. Changes in weather patterns and cold air
7. Psychological factors such as stress and emotion

Question 9

Asthma phenotypes

Answer 9

The outward, external and physical manifestation of a disease condition (asthma)
A cluster of clinical or pathologic features that are associated with the disease
Useful in managing the patient or understanding the mechanism of the disease

Aspirin and other non-steroidal anti-inflammatory drugs
Environmental allergens
Occupational allergens or irritants
Exercise

Basically
1. Transient wheezing (<1yr)
2. Non-atopic wheezing in toddlers (1-3 yrs)
3. Ig E mediated wheeze/asthma (4-12 yrs)
4. Late onset childhood asthma (> 12 yrs)

Question 10

Asthma phenotypes chat gpt

Answer 10

Asthma phenotypes refer to clinically recognizable patterns of asthma based on age of onset, triggers, clinical course, inflammatory profile, and response to therapy.

1. Wheezing Phenotypes in Early Childhood (Nelson-Based)
   a. Transient Early Wheezers
   Onset: Infancy
   Wheeze mainly during viral infections
   No atopy
   Normal lung function by school age
   Usually resolves by 3–5 years

b. Persistent Wheezers
Onset: Early childhood
Symptoms continue beyond 5 years
Often associated with atopy
Reduced lung function
Progresses to chronic asthma

c. Late-Onset Wheezers
Onset: After 3 years
Often allergic
Symptoms persist into adolescence

2. Atopic (Allergic) Asthma
   Most common pediatric phenotype
   Strong family history of atopy
   Elevated IgE
   Associated with:
   Allergic rhinitis
   Eczema
   Good response to inhaled corticosteroids
3. Non-Atopic (Intrinsic) Asthma
   No evidence of allergen sensitization
   More common in younger children
   Triggered mainly by:
   Viral infections
   Irritants
   Less eosinophilic inflammation
   Variable response to inhaled corticosteroids
4. Virus-Induced Asthma
   Wheezing episodes mainly during viral URTI
   Asymptomatic between episodes
   Common in preschool children
   May progress to persistent asthma in atopic children
5. Exercise-Induced Bronchoconstriction
   Symptoms occur during or after exercise
   Common in school-aged children and adolescents
   Triggered by cold, dry air
   Responds well to short-acting β₂-agonists
6. Severe Therapy-Resistant Asthma
   Poorly controlled despite high-dose inhaled corticosteroids
   Frequent exacerbations
   Requires specialist care
   May involve non-eosinophilic inflammation
7. Obesity-Related Asthma (Adolescent Phenotype)
   More common in adolescents
   Less atopy
   Reduced response to inhaled corticosteroids
   Mechanical and inflammatory factors involved
8. Cough-Variant Asthma
   Chronic cough as the predominant or only symptom
   Minimal wheeze
   Common in children
   Good response to bronchodilators and inhaled corticosteroids

Question 11

Clinical features

Answer 11

Asthma is a dual-component disease

• inflammation and bronchospasm

Symptoms and signs depend on the severity of the disease.

Common symptoms
- wheeze,
shortness of breath
chest tightness cough

The hallmark of asthma is that these symptoms tend to be:
variable
intermittent
worse at night
provoked by triggers including exercise.

Signs
Wheeze (bilateral, diffuse, expiratory, polyphonic)
Reduced lung function

• Decreased peak flow
• Obstructive pattern on spirometry
  Evidence of hyperinflation

Question 12

Clinical features

Answer 12

1. Symptoms
   a. Wheeze
   Most characteristic symptom
   Typically expiratory, polyphonic
   Recurrent and episodic
   Often worse at:
   Night, Early morning

Precipitated by:
Viral infections, Exercise, Cold air, Exposure to allergens

b. Cough
Common presenting symptom in children
Usually:
Dry or minimally productive,
Worse at night or early morning,
May be the only symptom (cough-variant asthma)

c. Breathlessness (Dyspnea)
Episodic
Occurs during acute exacerbations
May limit play or physical activity in children

d. Chest Tightness
Older children and adolescents may complain
Often accompanies wheeze and dyspnea

2. Pattern of Symptoms (Key Nelson Point)
   Recurrent episodes with symptom-free intervals
   Symptoms worsen at night (nocturnal asthma)
   Seasonal variation common
   Improvement with bronchodilators
3. Features During Acute Asthma Exacerbation
   Mild to Moderate Attack
   Tachypnea
   Expiratory wheeze
   Prolonged expiration
   Use of accessory muscles
   Tachycardia
   Severe Attack
   Severe respiratory distress
   Inability to speak full sentences
   Marked use of accessory muscles
   Nasal flaring
   Intercostal and subcostal retractions
   Life-Threatening Features
   Silent chest
   Cyanosis
   Altered sensorium
   Exhaustion
   Bradycardia or hypotension (late signs)
4. Physical Examination Findings (Inter-Critical Period)
   Often normal
   Mild wheeze may be present
   Prolonged expiration
   Hyperinflated chest in long-standing disease
5. Associated Atopic Manifestations
   (Common in allergic asthma)
   Allergic rhinitis
   Eczema (atopic dermatitis)
   Conjunctivitis
   Family history of atopy or asthma
6. Age-Related Clinical Presentation
   Infants and Young Children
   Recurrent wheeze with viral infections
   Feeding difficulty during attacks
   Poor weight gain in severe cases
   Older Children and Adolescents
   Exercise-induced symptoms
   Nocturnal cough or wheeze
   Chest tightness
7. Effect on Growth and Activity
   Poorly controlled asthma may lead to:
   Reduced physical activity
   School absenteeism
   Impaired quality of life
   Growth may be affected indirectly due to chronic illness or steroid misuse

Question 13

CONDITIONS THAT LOOK LIKE ASTHMA..

Answer 13

Reflux oesophagitis, TOF etc.

Bronchiolitis, pneumonia, sinusitis etc.
Pulmonary tuberculosis, laryngeal papillomatosis etc.
Cardiac failure and dilated cardiomyopathies
Inhaled foreign bodies
Tracheomalacia and bronchomalacia
Vocal cord dysfunction

Question 14

Diagnosis

Answer 14

1. History/clinical feature
2. Basic investigations include

eosinophils, Ig E levels (total and specific)

• Prick skin test, Blood gas analysis, Pulse oximetry
• Chest radiography (when indicated)

Lung Function Test

• PEFR

FEV/FVC 25-759 - Spirometry: FEV₁, FVC, FEV,

• Provocation test: exercise test, methacholine/histamine

Question 15

Objective assessment

Answer 15

1. Bronchodilator responsiveness
2. Diurnal variability in airway calibre/volume
3. Free running exercise (6 minutes running exercise)
4. Asthma diagnosis is based on a demonstration of airway reversibility and variable airflow limitations.
   Measured with
   - Spirometer (FEV, and FVC)
   peak expiratory flow (PEF) meter

FEV1/FVC ratio less than 75%; or PEFR less than 80% of predicted or best

PEFR increase more than 15%; 15-20 mins after inhalation of a rapid-acting ẞ,- agonist

PEFR decrease more than 15% 15-20 mins after inhalation of cholinergic drug

PEFR fall more than 15% after a 6-minute of sustained running or other exercises

PEFR varies more than 20% from morning measurement upon rising to measurement 12 hrs later in patients taking bronchodilators (more than 10% in patients who are not on bronchodilators)

Question 16

Classification (severity)

Question 17

Classification of asthma

Answer 17

1. Classification by Etiology / Triggers
   a. Allergic (Atopic) asthma
   Associated with atopy, eczema, allergic rhinitis
   Positive skin-prick tests; elevated IgE
   Common in childhood
   b. Non-allergic (Intrinsic) asthma
   No clear allergic sensitization
   Often adult onset
   Triggers include infections, irritants, stress
   c. Mixed asthma
   Features of both allergic and non-allergic asthma
   d. Occupational asthma
   Triggered by workplace exposures (e.g., chemicals, dust, fumes)
   Improves away from work
   e. Exercise-induced bronchoconstriction
   Symptoms precipitated by physical activity
   f. Infection-related asthma
   Common in children; viral URTIs are typical triggers
2. Classification by Age of Onset
   Childhood-onset asthma
   Adult-onset asthma
3. Classification by Severity (Based on symptom frequency, lung function, and exacerbations)
   (Traditional severity classification)
   a. Intermittent asthma
   Symptoms ≤2 days/week
   Night symptoms ≤2/month
   Normal lung function between attacks
   b. Mild persistent asthma
   Symptoms >2 days/week but not daily
   Night symptoms 3–4/month
   FEV₁ ≥80% predicted
   c. Moderate persistent asthma
   Daily symptoms
   Night symptoms >1/week
   FEV₁ 60–80% predicted
   d. Severe persistent asthma
   Symptoms throughout the day
   Frequent night symptoms
   FEV₁ <60% predicted
4. Classification by Level of Asthma Control (GINA-based)
   a. Well-controlled asthma
   b. Partly controlled asthma
   c. Uncontrolled asthma
   (Assessed using symptoms, activity limitation, reliever use, and exacerbations)
5. Classification by Inflammatory Phenotype
   a. Eosinophilic asthma
   High sputum or blood eosinophils
   Steroid-responsive
   b. Neutrophilic asthma
   Often severe; poor steroid response
   c. Mixed granulocytic asthma
   d. Paucigranulocytic asthma
   Minimal airway inflammation
6. Classification by Clinical Phenotypes
   Allergic asthma
   Non-allergic asthma
   Late-onset asthma
   Obesity-related asthma
   Asthma with fixed airflow limitation
   Aspirin-exacerbated respiratory disease (AERD)
7. Classification by Special Forms
   Cough-variant asthma
   Nocturnal asthma
   Brittle asthma
   Status asthmaticus (acute severe, life-threatening asthma)