ASTHMA guidelines GINA 2008

Things you should know about asthma

what is asthma?
- asthma is chronic inflammatory disorder of airways characterized by bronchial hyperresponsiveness leading to widespread bronchoconstriction.
-asthma is reversible
REMEMBER: airway narrowing and airway hyper-responsiveness

Factors which cause asthma
- host factors - atopy
- environment factor - allergen, infection, air pollution, smoking, diet etc

Mechanism of asthma:
inflammation involving these cells and mediators result in airway hyper-responsiveness and asthma symptoms
- inflammatory cells (mast cell, eiosinophil and T lymphocytes)
- inflammatory mediators (chemokine, cytokine, cysteinyl leukotriene, histamine,NO, PG etc)

Airway narrowing due to:
- airway smooth muscle constriction
- airway edema
- airway thickening
- mucus hypersecretion

airway hyper-responsiveness
- err.. no need to know la..

special mechanism in asthma
acute exacerbation
- due to triggers
nocturnal symptoms
- due to circadian rhythm of hormones (epinephrine,cortisol,melatonin etc)

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Management depends on presentation
- (acute/chronic) and
- severity

how to assess the severity?
- by clinical examination and ix (peak flow/spirometry)

classification of severity?
- intermittent
- mild/moderate/severe persistent

so, after patient already on treatment, you have to assess level of control. how u do that?
ask for:
-day symptoms
-night symptoms
-frequency of reliever tx
-limitation of activities
-lung function (PEF/FEV1)
-exacerbations (acute asthma attack)

Levels of control are:
-controlled
-partly controlled
-uncontrolled

Treatment of asthma
- reliever (bronchodilator)
- preventer (anti-inflammatory)

hmm.. what is bronchodilator?
- B2-agonist (salbutamol, salmeterol)
- anti-cholinergics (ipratropium bromide)
- methylxanthines (oral theophylline, iv aminophylline)
- cysteinyl-leukotriene antagonist (montelukast)

What is anti-inflammatory then?
- steroid (beclomethasone, fluticasone, budesonide, oral prednisolone, iv hydrocortisone)
- cromones (sodium cromoglicate)

now you know the medication, so now, how do you manage chronic asthma?
- ok, the principle is 'lowest dose possible to achieve control'
- so if not control, step up the medication
- this is call step-wise approach (step up/ step down)
1) SABA when necessary
2) SABA + low dose steroid
3) SABA + low dose steroid + LABA
4) SABA + moderate/high dose steroid + LABA
5) SABA + oral prednisolone (lowest dose)


then, what about exacerbation? what is it and how to treat?
ok, exacerbation is progressive SOB, chest tightness, cough or wheeze, characterized by reduction of expiratory flow.
it needs repeatitive SABA tx, early steroid tx and O2 supplementation

severity of exacerbation
- mild
- moderate*
- severe*
- respi arrest immenent*
*important

important facts
1) GERD is 3 times more common in asthma
2) ~30% asthmatic adult have acute exacerbation due to aspirin/NSAID
3) in pregnancy, 1/3 become worse, 1/3 stable, 1/3 less severe
4) majority of asthma patients have hx of rhinitis. (30% rhinitis develop asthma)
5) near 70% polyps patient will develop asthma (almost 90% aspirin-intolerant have polyps)
6) viral (not bacteria) respi infection assoc with asthmatic symptom. virus include rhinovirus, para-influenza, influenza, coronavirus, adenovirus