ASTHMA

1. ASTHMA By Dr Aguilera

2. Definition: • Chronic inflammatory disorder of the respiratory airways which includes 3 components • bronchial hyperresponsiveness to a variety of stimuli (i.e. allergens, respiratory viruses, environmental exposures and others) • reversible airflow obstruction • associated with recurrent episodes of respiratory symptoms (i.e. most commonly wheezing, SOB, chest tightness and cough)

3. Pathophysiology • Asthma has 2 mechanisms of reaction: • Allergen induced bronchoconstriction • IgE mediated response mast cell stimulation mediators released • Other stimuli induced bronchoconstriction • Inflammatory mediated response inflam cell stimulation neuro/hormonal reflexes in the lungs • Both cause edematous swelling of airway walls hyperresponsiveness and ultimately  airflow obstruction, which can occur in minutes, hours, days or weeks

4. Epidemiology: 2000 • Prevalence is increasing • 17 million patients with asthma in the US • Age: • >18 yrs = 11 million (62%) • 2-17 yrs = 6 million (38%) • Race: • 8.9 million Caucasian (52%) • 3.5 million Latino (21%) • 3.3 million African American (19%) • 1.3 million other (8%) • Gender: Male 42%, Female 58%

5. Morbidity and Mortality • Most often associated with failure to appreciate severity of exacerbation by pt and/or provider: • Deaths: > 5,000/year but decreasing overall since 1990, probably due to better management from PCP • Hospitalizations: 466,000 in 2000 • 5% required ICU • ED Visits: • 1.9 million in 2000 • females 2X > than males • the 11th most common diagnosis • 20-30% of these required hospitalization

6. Morbidity and Mortality Cont’d • Costs: > $6 billion/year • average annual cost/pt with attack =$600 compared with $170 with no attack • cost includes the 3 million lost workdays in the US per year • Important Note: Most ED visits, and therefore, hospitalizations are preventable. A useful practice is to assume that every exacerbation is potentially fatal.

7. Risk factors for death from Asthma • Past history of sudden, severe exacerbations • Prior intubation • Prior admission to ICU • More than 2 hospitalizations in past year • More than 3 ED visits in the past year • Recent use/withdrawal from systemic steroids • Comorbid conditions • Difficulty perceiving severity of disease (more common in males)

8. Asthma Attack Evolution • Two different pathogenic scenarios involved: • Airway inflammation predominant: • pts show a progressive deterioration over 6 hours, days or weeks (slow onset attack). • The prevalence is 80-90% in adults and usually assoc with infectious causes. • Have a slower therapeutic response • Bronchospasm predominant: • Pts present with a sudden onset attack over minutes to 3-6 hrs (asphyxic or hyperacute attack). • Usually associated with allergens, exercise and stress. • Have a more rapid and complete response

9. Diagnosis • Usually cannot be done in the first visit • History and Physical exam • Classic triad • Cough, SOB and wheeze • Not all that wheezes is asthma and not all asthma wheezes. • Presence of wheezing is a poor predictor of airflow obstruction, therefore need to use other findings • Vital signs, RR, mentation, accessory muscle use

10. Diagnosis Cont’d • Pulmonary Funtion Testing • Peak Expiratory Flow Rate (PEFR) • Measured by age and height • Spirometry with bronchodilator evaluation • FEV1, FVC and FEV1/FVC ratio • > 80% predicted borderline obstruction • 60-80% mild obstruction • 40-60% moderate obstruction • <40% severe obstruction • Serial testing over time • Bronchoprovocation testing with methacholine • Same deal as with exercixe stress testing in angina

11. Diagnosis Cont’d • CXR • Only on initial evaluation • Can see flattened diaghrams from hyperinflation • Blood tests • none • Allergy testing • Allergy skin test • Blood radioallergosorbent test (RAST)

12. Classification of Asthma

13. Overall Management • 4 key component to success • Patient Monitoring • Controlling Triggers • Pharmacotherapy • Patient Education

14. Overall Management cont’d • Monitoring • Peak Expiratory Flow Rate (PEFR) can be used to follow impact of change in therapy upon lung fxn and/or to assess severity of attack, NOT to detect presence of airflow obstruction • Measurement is highly dependent on users technique • Measure with patient standing and should be a evening trial • Record best of 3 tries • Pts should have device at home, however, to establish a baseline • Encouraged to be used at least by pts with mod-severe disease • Mixed data on whether or not home monitoring is beneficial • For the future: • Sputum Eosinophilia as a marker for treatment • Exhaled nitric oxide as a way to predict airway inflammation and asthmatic control

15. Overall Management Cont’d • Controlling Trigger Factors • Identify and avoid triggers • They vary from person to person and time to time (for females most commonly have exacerbations in premenstrual phase) • Generally fall into 6 categories: • 1. Allergens (pollen), 2. Irritants (air pollutants), 3. Respiratory infections (viruses), 4. Physical activity, 5. Chemicals (foods and drugs) and 6. Emotional stress. These are the main ones identified clinically • Allergic rhinitis, chronic sinusitis, polyposis, GERD, menses, and pregnancy are others that may also contribute to exacerbations • Once identified: a.) avoid the trigger, b.) limit exposure if cannot be completely avoided, c.) take an extra dose of bronchodilator before exposure, but careful with exceeding normal amounts

16. Overall Management Cont’d • Pharmacologic Therapy • This is the mainstay of management in most patients with asthma, and varies with type and severity of asthma. • Relievers vs. Controllers • Fast acting Slow acting • Relieve bronchospasm Controls inflammation • Stops symptoms Prevents symptoms • Take PRN Take everyday

17. Overall Management Cont’d • Mild Intermittent Asthma: (refer to prior slide) • Includes exercise induced asthma • Short Acting Inhaled beta-agonists: Albuterol (Proventil, Ventolin) • Rapid onset of action, get maximal potency of bronchodilation and minimal side effects. • Encourage to use 10 minutes prior to exposure to a trigger • Meter dose inhalers (MDI’s) are now using ozone-safe propellants instead of chlorofluorocarbon (CFC) • Alternate delivery forms have been developed • Albuterol now comes in powder form • Ipratropium (Atrovent) is NOT a good reliever for asthma • Mast Cell Stabilizers (Cromolyn, Nedocromil) • Have no benefit to relieve immediately asthmatic symptoms • Limited role in adults

18. Overall Management Cont’d • Mild Persistent Asthma • All Persistent asthmatics need a controller • The assumption behind this recommendation is that regular medication use will reduce the frequency of symptoms, improve overall quality of life and decrease the risk of serious attacks and therefore lower the rate of ED visits and hospitalizations • Inhaled Steroids • The gold standard against which all other controlling therapy is compared • Decreases mast cell and airway inflammation • Side effects include: • Local effects (thrush, dysphonia, and bad taste) • Systemic effects (cataracts, bone loss, increase IOP, growth suppression) are dose related, rare and occur particularly in prolonged, high dose users • Using a spacer device is recommended in order to maximize medication delivery to the lung and minimize oral deposition • No advantage to using albuterol immediately prior to inhaled steroid to achieve more lung deposition • Using an inhaled steroid with a systemic oral steroid is not contraindicated, but should be limited

19. Not All Steroids Are Created Equal

20. Overall Management Cont’d • Moderate Persistent Asthma • Incorporates the mild asthmatic receiving treatment, yet remain symptomatic • Try to find the combination that works • Long Acting Beta Agonists • Formoterol (Foradil) and Salmeterol (Serevent) • Both have similar characteristics, but Foradil has a faster onset of action (5 min vs 20 min) • Inhaled meds that have long half lives which allow bid dosing. No longer in MDI, now in DPI • Found to be less efficacious than inhaled steroids in improvement in lung fxn, control of Sx and amt of attacks • Currently 2nd line after inhaled steroids, and not recom as monotherapy for mild asthma • Combo therapy (Advair) with inhaled steroid has shown more benefit in mod-severe persistent asthma.

21. Overall Management Cont’d Leukotriene Receptor Antagonists (LTRA’s) Zafirlukast (Accolate) – bid dosing Montelukast (Singulair) – qday dosing and therefore is the favored one • also approved for allergic rhinitis. • tolerated well because of low side effect profile • Approved down to age 2 • Currently positioned 3rd line, after inhaled steroids and long acting beta agonists. • Have a varied response among individuals with asthma • May be used as first line in very mild stage 2 asthma • May discontinue after 2-3 weeks in “non-responders”

22. Overall Management Cont’d • High-dose inhaled steroid • Fluticasone 100 -250 mcg • Budesonide 200 mcg • As the dose of inhaled steroid increases, the likelihood of systemic absorption and potential for significant side effects from long term use also increases. • Therefore, every effort should be made to reduce the dose of inhaled steroid, seeking to find the lowest dose that continues to maintain good control and minimize the risk of exacerbations • Systemic effects are far less frequent than with systemic oral steroids • Long-acting beta agonists • LTRA

23. Overall Management Cont’d • Severe Persistent Asthma • Patients who fail to achieve symptom control despite 2-3 controller medications • Long-acting oral bronchodilator (theophylline) • Used for its intrinsic anti-inflammatory effect, bronchodilation is considered secondary • Increases ciliary motility, mucus clearance and diaphragmatic motility • Not tolerated well because of Sfx – nausea, cramps, diarrhea, and insomnia • Narrow therapeutic index requiring check of serum levels • Toxicity can result in seizures and death • 24 hour preparations are preferred (Uniphyl) • Currently 4th line, after inhaled steroids, long-acting beta agonists, and LTRA. • Oral steroids • Want to avoid as much as possible. If going to use, then use in short spurts or tapering regimens

24. Overall Management Cont’d • Choosing a treatment strategy

25. Overall Management Cont’d • Adjunctive Medications • Treating comorbid conditions improves asthma • Antihistamines • Treating allergic rhinitis decreases responsiveness to triggers • Nasal steroids • Have been shown to improve symptoms in patients with both AR and asthma • Some studies indicate benefit in asthma alone • H2 blockers and/or PPI’s • Prevalence of GERD in asthmatics ranges from 34-80% in various studies • Improving reflux has been shown to improve control

26. Overall Management Cont’d • Patient Education • Medication Myths • Nebulizers offer improved medication delivery and are referable for more severe asthmatics • MDI’s used through a spacer can offer more efficient medication delivery at a fraction of the cost and time when compared to a nebulizer • Inhaled steroids increase birth defects or are risky in pregnancy • Recent studies have shown no increase in birth defects or decrease in birth weight with the use of any inhaled steroid • Category B or C, except Azmacort = D

27. Overall Management Cont’d • Asthma flow sheet (blue) • Found on left side of chart, along with diabetic flow sheet • Convenient tracking of symptoms, peak flows • There is a cheat sheet on bottom of page for staging • Can write on progress note: “see blue asthma flow sheet”

28. Overall Management Cont’d • The Asthma Action Plan • Helps patients and families understand complex regimen • The Green Zone (PEFR > 80% predicted) • What to do on normal days • The Yellow Zone (PEFR 50-80% predicted) • Caution • The Red Zone (PEFR < 50%) • Danger

29. The End