CHILDHOOD ASTHMA

By: M.A. Kibel

and

E. Weinberg

Question 1

How would you define asthma?

Answer 1

DEFINITION OF ASTHMA

A lung disease characterised by:• Airway obstruction (or narrowing)• usually reversible, either spontaneously

or with treatment• Airway inflammation• Airway hyper responsiveness to a

variety of stimuli

Contd

1 continued

Asthma is a condition characterised by episodes of cough, wheezing and breathing difficulty due to reversible

narrowing of the airways, in response to various stimuli. Airway narrowing and obstruction result from a combination of

1 continued

* airway smooth muscle spasm

* oedema of the mucosa

* plugging of smaller airways by mucus

* inflammation

Contd

1 continued

"Any child, regardless of age, who has had three or more episodes of wheezing and/or dyspnoea,should be considered as having asthma until proved otherwise".

Question 2

How common is asthma?

Answer 2 In industrialised

countries asthma occurs in 1 to 2 out of every 10 school children. Limited studies in South Africa show a prevalence of between 3.5 and 6%, and it appears to be less prevalent

Contd

2 continued

in rural than in urban settings. It is certainly the commonest chronic disorder of childhood, and hospital admissions for asthma show a rising incidence world-wide.

Question 3

What causes asthma?

Answer 3

Inflammation is now known to be the key factor in the pathology of asthma. Exposure to allergens and other irritants activate pulmonary mast cells, setting off immediate bronchospasm,

3 continued

followed later by inflammation, in which eosinophil and lymphocytic infiltration, subepithelial collagen deposition and epithelial damage are all involved.

The cascade of effects leading to the asthmatic attack are shown in the following 2 slides:

THE ASTHMATIC INFLAMMATORY CASCADE

Cell Activation/Mediator Release:Eosinophils Mast Cells Mascrophages

Neutrophils T cellsBronchial epithelial cells

ASTHMATIC INFLAMATION

Bronchial Hyperresponsiveness

Clinical Asthma

Inflammatory Stimuli

THE ASTHMATIC INFLAMMATORY CASCADE

Inflammatory StimuliAllergens Infections Generic factors

Environmental factorsOther

Cell Activation/Mediator Release

Question 4

What factors can bring on asthma?

Answer 4

There are many factors that precipitate attacks. Most important are:• allergen exposure• viral respiratory infections• irritants: tobacco smoke• other forms of smoke• exercise• climatic change• emotional factors

Question 5

What are the key elements in the history which will lead you to the diagnosis?

Answer 5 Diagnosing Asthma: the Medical History

Review symptom onset, duration, frequency &

pattern Possible allergic components Precipitating & aggrevating factors,

including lifestyle changes Management & treatment history Family history

Contd

5 continued

full family history must be taken. There are often other family members with asthma or other allergies. A history of night-time coughing or wheezing, or such symptoms after exercise are strong pointers to a diagnosis of asthma. Details as to seasonality and exposure to possible allergens such as pets or grasses must be elicited.

Question 6

What are the findings on clinical examination?

Answer 6 Diagnosing Asthma: The Physical Exam

• Examine the character of breath sounds• Check for non-wheezing signs of asthma• Note other allergic diseases• Look for generalised lung hyperinfection

However• Typically, signs and symptoms are episodic• physical exam maybe completely normal• Exclude asthma look - a - likes

Contd

6 Continued

While a thorough examination of the respiratory system may elicit abnormalities, these are often lacking at the time of examination. Simple respiratory function tests are an essential part of the clinical examination, and can readily be carried out in children of 5 years and older.

Question 7

How is respiratory function testing performed?

Answer 7

A peak flow meter is the simplest and cheapest method to estimate the maximum flow of air during expiration.

Reference must be made to a chart of normal values, based on the child's height.

Contd

7 continued

A reduction of 15% after exercise, or an improvement of 15% after inhalation of a beta2 agonist are strong evidence of asthma.

Question 8

How may these objective measurements of lung function be used?

Answer 8Objective Measures of Lung Function

Enable the Physician to: Diagnose

• airflow obstruction• reversibility

Monitor• changes over time• daily variation

Manage Exacerbations• severity of obstruction• response to therapy

Contd

8 Continued

In younger children a therapeutic trial with a bronchodilator can be used to establish the diagnosis. A significant lessening in symptoms strongly favours the diagnosis of asthma. Parents can be given an asthma diary to record the frequency and severity of symptoms.

Question 9

What are the important conditions which can mimic asthma?

Answer 9

Ascariasis

Tuberculous mediastinal glands

Cystic Fibrosis

Contd

9 Continued

Although the list of conditions which can cause recurrent cough and/or wheezing is a long one, 3 disorders stand out because of their importance and/or frequency; they should always be considered.

Question 10

What are the important environmental triggers?

Answer 10

ENVIRONMENTAL TRIGGERSALLERGENS IRRITANTS

OUTDOOR INDOOR Tobacco smoke

Pollen House dust mites Wood smoke

Mould Animal Dander Odours or sprays

Mould Air Pollutants

Cockroaches

Contd

10 Continued

The major allergens in Southern Africa are:

House dust mite

cat

dog

grasses

Question 11

How would you treat an acute attack?

Answer 11

Managing Acute Exacerbations in the Emergency Department: Initial Treatment

Inhaled short-acting B2 agonist x3 doses over 60 to 90 minutes - or

subcultaneous B2 agonist x3 doses over 60 to 90 minutes

Contd

11 continued

Supplemental oxygen for:• hypoxemic patients• all patients if oximeter is unavailable

Consider systemic corticosteroids if:• no response within 1 - 2 hours - or• patient is regularly taking oral steroids.

Contd

11 continued Beta2 agonists in inhaled form are the

most useful preparations, and the metered dose inhaler (MDI) is the most convenient and cost- effective method of administration (examples: salbutamol and fenoterol). In young children who cannot inhale the aerosol efficiently, a paper cup can be used as a face mask. A hole is cut in the base of the cup large enough to take the mouth piece of the MDI.

11 continued

Specially designed spacer devices are also available for this purpose.

Nebulisers are convenient for home use. These are simply air compressors which nebulise the solution via a face mask. Infants and young children often respond better to ipratropium bromide solution, which can be added to the beta2 agonist solution.

Contd

11 continued

DOSAGES AND METHODS OF ADMINISTRATION OF SALBUTAMOL, FENOTEROL, IPRATROPIUM

Infants and under 5's spacer/cup 3 puffs 2-3 hr nebuliser 0.5 ml in

1ml saline

5 - 8 years powder inhaler 1 every 3-4 hrs

over 8 years MDI 2 puffs 2- 3 hrs

Question 12

When should an attack be regarded as severe?

Managing Acute Exacerbations in the Hospital

Assess severity

Initial treatment

Reassess Severe episode

Poor response

Admit to ICU

Moderate Episode

Good Response

Discharge

IncompleteResponse

ImprovedNot

Improved

Admit toHospital

12 continued

Status asthmaticus should be diagnosed when

There is no response to 2 puffs of beta agonist, 30 minutes apart, or to 2 nebulisations.

the child is anxious, with breathing so laboured that speech is not possible.

12 continued

child uses accessary muscles of respiration, with marked chest hyperinflation.

diminished breath sounds with intense wheezing on auscultation.

pulsus paradoxicus greater than 10 mm during inspiration.

Question 13

What are the important principles of management?

Answer 13

THE 4 H'S

HOSPITALISE

TREAT HYPOXIA

ADMINISTER HYDROCORTISONE

HYDRATE ADEQUATELY

Question 14

What are the asthma triggers in the environment that we can most easily modify?

Answer 14

Tobacco smoke. Smoking parents harm their children: the greater the exposure to passive smoking the worse the symptoms. This is the most important preventable factor.

House dust mite. Use the minimum of curtains and carpeting. Beat mattress and bedding outside regularly, and expose them to sunlight.

Avoid SULPHUR DIOXIDE in cool drinks

Question 15

What can we do to lessen exposure to house mites?

Answer 15

Measures to Control House Dust Mites Essential

• encase mattress and pillow in an airtight cover

• wash bedding weekly in hot water• avoid lying on upholstered furniture

Desirable• reduce indoor humidity to <50%• remove carpets from bedroom and those

laid over concrete

Question 16

What are the most important agents we use in chronic management?

Answer 16

Short acting inhaled beta-2 agonists

Sodium cromoglycate

Ketotifen

Inhaled steroids

Oral steroids

16 continued Theophylline preparations were the main

standby of treatment for many years. They are no longer recommended as a first choice because of the narrow range between effective action and unwanted side effects.

Newer, long acting beta-2 agonists will have an increasing role, particularly in night time attacks.

Question 17

What agents are NOT recommended for management of asthma?

Answer 17

AGENTS NOT RECOMMENDED• Tranquillisers• Antihistamines• Mucolytics• Ionisers• Desensitisation• Physiotherapy• Antibiotics (only used if bacterial

infection is strongly suspected)

17 continued Tranquillisers: Anxiety in acute asthma

is a danger sign requiring immediate oxygen, steroids and bronchodilators, NOT respiratory suppression.

Antihistamines: These are not recommended, including a form combined with steroids (Celestamine), which is widely used in practice.

Mucolytics and Ionisers: These are ineffective in asthma.

Contd

Question 18

Give a plan of action for management of chronic asthma.

Answer 18

Desensitisation: Ineffective, and may be dangerous.

Physiotherapy: Ineffective, and may be dangerous in acute attack.

Question 19

Give a plan of action for management of chronic asthma.

Answer 19

Firstly it is necessary to assess severity. This is done using 4 criteria:

(1) Frequency of attacks (2) Night time cough or wheeze (3) Previous admissions (4) Peak expiratory flow rate.

Contd

19 continued

DEFINITION OF ASTHMA SEVERITYAsthma Symptoms Frequency of

attacks/weekResponse to

bronchodilators (up to3 doses/week)

Mild Discrete attacks orminor, more frequent,

wheeze

good

Moderate Discrete attacks </= 1 good

Severe Discrete attacks >1 poor

Question 20

How would you manage a mild case?

Answer 20

Allergen avoidance

Intermittent bronchodilator

Sodium chromoglycate before exercise

Question 21

How would you manage a moderate case?

Answer 22

Regular bronchodilator

Regular sodium cromoglycate

Possibly inhaled steroids

Question 23

How would you manage a severe case?

Answer 23

Bronchodilator/ home nebuliser

Inhaled steroids

Possibly oral steroids

Question 24

What should be the aims of management of chronic asthma?

Answer 24 To reduce to the minimum the

number of attacks to avoid hospital admission to encourage full participation in

school activities, including sport to ensure uninterrupted sleep at

night to promote normal growth and

development

Question 25

How would you handle regular episodes of coughing and wheezing at night?

Answer 25

Long Acting Theophyllines• microphylline granules• Nuelin SA• Theodur

Long Acting Beta-2 Agonists• Foradil• Serevent

25 continued

This usually indicates poor asthma control and the need for more effective therapy, including environmental control. There is a role here for long-acting theophyllines taken at bed-time, or for the newer long acting beta-2 agonists.

Conclusion

Many children at school who cough or wheeze in the cold or after PE have asthma, and go unrecognised. Deaths may occur because children have not been able to use their inhalers before vigorous exercise. What are the important messages about asthma in school-children?

Contd

Education of teachers about asthma is important

as is good liaison with doctors and nurses

School non-attendance may be due to poor

Children should be allowed to keep their MDI's on them and take responsibility for their use (see next slide).

Contd