Ppt

1. Overview of childhood
asthma
Professor S Wa Somwe
08/19/25 1

2. What is Asthma?
A condition that
• is chronic
• produces recurring episodes of
breathing problems
• is potentially life-threatening
• is not contagious
• cannot be cured, but can be
controlled
08/19/25

3. Burden of Asthma
 Asthma is one of the most common chronic
diseases worldwide with an estimated 300
million affected individuals
 Prevalence increasing in many countries,
especially in children
 A major cause of school/work absence

4. How common is asthma?
• Asthma is a frequent disease in most countries
of the world including African countries
• It is common in both rich and poor countries
• In Zambia, official statistics on asthma are not
available
• An unpublished study (Somwe et al, 2013)
suggested it affects about 6-8 % of school
going children in Lusaka.
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5. Risk Factors for Asthma
 Host factors: predispose individuals to, or
protect them from, developing asthma
 Environmental factors: influence
susceptibility to development of asthma in
predisposed individuals, precipitate asthma
exacerbations, and/or cause symptoms to
persist

6. Factors that Influence Asthma
Development and Expression
Host Factors
 Genetic
- Atopy
- Airway
hyperresponsiveness
 Gender
 Obesity
Environmental Factors
 Indoor allergens
 Outdoor allergens
 Occupational sensitizers
 Tobacco smoke
 Air Pollution
 Respiratory Infections
 Diet

7. Pathophysiology of asthma

8. Pathophysiology of asthma

9. Source: Peter J. Barnes, MD
Source: Peter J. Barnes, MD
Pathophysiology of asthma

10. Factors that Exacerbate Asthma
 Allergens
 Respiratory infections
 Exercise and hyperventilation
 Weather changes
 Sulfur dioxide
 Food, additives, drugs

11. • Exercise
• Changes in
weather and
temperature
• Infections in the upper
airways, such as colds
• Physical expressions
of strong feelings
(crying or laughing
hard, yelling)
Common triggers of asthma
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12. Allergens such as
• Furred and
feathered animals
• Dust mites
• Cockroaches
• Pollens
from grass and
trees
• Molds (indoors
and outdoors)
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13. Irritants such as
• Environmental
tobacco smoke
• Scented
products
• Strong fumes or
odors
• Outdoor air
pollution
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14. What Happens During an Episode of
Asthma?
• The lining of the airways
become narrow and
easily irritated due to
inflammation
• The airways produce a
thick mucus
• The muscles around the
airways tighten and
make airways narrower
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15. What Happens During an Episode of Asthma?
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17. What are the symptoms of asthma?
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How is asthma diagnosed in
children?

21. How is asthma diagnosed?
• Medical history
– Recurring cough, wheeze, difficulty breathing
– Night cough, chest tightness
– Family history of asthma
– Allergies, eczema
• Physical examination
• Tests
– Test for lung function
– Test for allergies
– ? X-ray
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Most of the times doctors rely on accurate description of
the symptoms and examination in making the diagnosis.

22. Asthma Diagnosis
 History and patterns of symptoms
 Measurements of lung function
- Spirometry
- Peak expiratory flow
 Measurement of airway responsiveness
 Measurements of allergic status to identify risk
factors
 Extra measures may be required to diagnose asthma
in children 5 years and younger and the elderly

23. Is it Asthma?
 Recurrent episodes of wheezing
 Troublesome cough at night
 Cough or wheeze after exercise
 Cough, wheeze or chest tightness after
exposure to airborne allergens or pollutants
 Colds “go to the chest” or take more than
10 days to clear

24. 24
CHILD with symptoms that may be due to asthma
Clinical assessment
High Probability Low Probability
Intermediate Probability
Yes No
Continue Rx
Response?
Consider referral
Yes
Trial of Treatment
Response?
Asthma diagnosis confirmed
Continue Rx and find minimum effective dose
No
Assess compliance
and inhaler technique.
Consider further
investigation and/or
referral
Consider tests of lung
function and atopy
Investigate/treat
other condition
Further
investigation
Consider
referral

25. CONFIRM THE DIAGNOSIS
CONFIRM THE DIAGNOSIS
REVERSIBLE
REVERSIBLE
OBSTRUCTION
OBSTRUCTION
Variability
Variability
POSITIVE BPT
THERAPEUTIC TEST

26. Other investigations
Tests for airway hyperresponsiveness
. Metacholine
. Exercise
. Mannitol
Tests for eosinophilic airway inflammation
. Induced-sputum
. [ FENO]
Tests of atopy
. Skin prick tests
. Blood eosinophilia
. RAST
CXR

32. Spirometry
Is the preferred method of
Is the preferred method of
measuring airflow limitation
measuring airflow limitation
and severity
and severity

34. Typical Spirometric (FEV1) Tracings
1
1
Time (sec)
2
2 3
3 4
4 5
5
FEV1
Volume
Normal Subject
Normal Subject
Asthmatic (After Bronchodilator)
Asthmatic (After Bronchodilator)
Asthmatic (Before Bronchodilator)
Asthmatic (Before Bronchodilator)
Note: Each FEV1 curve represents the highest of three repeat measurements

36. Measuring Variability of Peak
Expiratory Flow

37. Measuring Airway Responsiveness

38. 3 categories of wheezers
(1) Transient early wheezing
. Prematurity
. Parental smoking
. Outgrown by 3 years of age
(2) Persistent early-onset wheezing < 3 years
. No atopy
. No family history of asthma/atopy
. Recurrent viral-induced wheeze
. Outgrown by 12 years

39. 3 categories of wheezers, continued
(3) Late-onset wheezing/asthma
. Atopic
. Wheeze persists into adulthood
. Airway pathology characteristic of asthma

42. ANY QUESTIONS?