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
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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
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* airway smooth muscle spasm
* oedema of the mucosa
* plugging of smaller airways by mucus
* inflammation
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"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".
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
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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.
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,
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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
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
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
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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.
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
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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.
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.
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A reduction of 15% after exercise, or an improvement of 15% after inhalation of a beta2 agonist are strong evidence of asthma.
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
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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.
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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.
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
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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
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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.
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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.
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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.
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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
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
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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.
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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.
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
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
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.
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.
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Answer 18
Desensitisation: Ineffective, and may be dangerous.
Physiotherapy: Ineffective, and may be dangerous in acute attack.
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.
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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
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
Answer 25
Long Acting Theophyllines• microphylline granules• Nuelin SA• Theodur
Long Acting Beta-2 Agonists• Foradil• Serevent
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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?
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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).
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