Asthma

1. Asthma

2. Introduction • Chronic inflammatory disease of the airways • Most common childhood chronic disease • Affects ~4.8 million (CDC, 1995) • >100 million days of restricted activity • 470,000 hospitalizations/yr

3. Introduction • >5000 deaths annually • Highest in blacks ages 15-24 • Hospitalizations highest in blacks & children

4. Pathogenesis and Definition • Key points • Chronic inflammatory disorder of the airways • Immunohistopathologic features • denudation of airway epithelium • collagen deposition beneath basement membrane • edema • mast cell activation

5. Immunohistopathologic features • inflammatorycell infiltration • Neutrophils (sudden, fatal asthma) • Eosinophils • Lymphocytes • Airway inflammation (AI) contributes to hyperresponsiveness, airflow limitation, symptoms & chronicity

6. AI causes types of airflow limitation: • Bronchoconstriction, edema, mucus plug formation, airway wall remodeling • Atopy is strongest predisposing factor for developing asthma

7. Asthma is a chronic inflammatory disorder of the airways in which many cells & cellular elements play a role (mast cells, eosinophils, T lymphocytes, macrophages, neutrophils, & epithelial cells).

8. In susceptible individuals , inflammation causes recurrent episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night/early morning. These episodes are associated with variable airflow obstruction often reversible spontaneously/treatment

9. Child-onset asthma • Associated with atopy • IgE directed against common environmental antigens (house-dust mites, animal proteins, fungi • Viral wheezing Infants/children, allergy/allergy history associated with continuing asthma through childhood

10. Adult-onset asthma • Many situations • Allergens important • Non-IgE asthma have nasal polyps, sinusitis, aspirin sensitivity or NSAID sensitivity • Idiosyncratic asthma less understood

11. Adult-onset asthma • Occupational exposure • animal products, biological enzymes, plastic resin, wood dusts, metal • removal from workplace may improve symptoms although symptoms persist in some

12. Airway Inflammation & Lung Function • The cells that influence &/or regulate inflammation results in different types of AI: • Acute- early recruitment of cells • Subacute - cells activated to cause more persistent inflammatory pattern • Chronic - persistent level of cell damage & repair. Abnormal changes may be permanent

13. Airway Inflammation & Lung Function • Airway hyperresponsiveness • Exaggerated bronchoconstrictor response • Post exposure wheezing & dyspnea • Degree correlates to asthma severity • Measured by methacholine/histamine inhalation challenge or non-drug stimuli (cold, dry air)

14. Airway hyperresponsiveness • Correlation to airway inflammation clear but complex • airway inflammation markers • tx. of asthma & modification of ai markers reduce symptoms & hyperresponsiveness

15. Airflow limitation • Acute bronchoconstriction • IgE -dependent mediator release from mast cell (leukotrienes, histamine, tryptase, prostaglandins) • aspirin /NSAID • non-IgE response (cold air, exercise, irritants)

16. Airflow limitation • Acute bronchoconstriction • stress - mechanisms ?? • Airway edema • mediators • increase microvascular permeability/ leakage • mucosal thickening & airway swelling • airway rigidity

17. Airflow limitation • Chronic mucus plug formation • secretions & inspissated plugs • persistent airflow limitation in severe intractable asthma • Airway remodeling • irreversible component of airflow limitation secondary to structural airway matrix changes

18. Airflow limitation • Airway remodeling • attributed to chronic, severe airway inflammation • early intervention with anti-inflammatory therapy suggests prevention of permanent airflow limitation

19. Measures of Assessment and Monitoring • Asthma diagnosis criteria • + episodic symptoms of airflow obstruction • Airflow obstruction partially reversible • R/O alternative dx

20. Techniques to establish diagnosis • History • Physical exam (resp. tract, skin, chest) • Spirometry to demonstrate reversibility • Additional studies : • evaluate alternative dx., ID precipitating factors • assess severity, ID potential complications • Asthma Specialist

21. Symptoms Continual Limited physical activity Frequent exacerbations Frequent nighttime symptoms Lung Function FEV1 or PEF < 60% of predicted PEF variability >30% Severe Persistent Asthma

22. Symptoms Daily symptoms Daily use of inhaled short-acting beta2 agonist Exacerbations affect activity; > 2 X/wk; may last days Nighttime symptoms >1 time/wk Lung Function FEV1 or PEF > 60% - < 80% predicted PEF variability >30% Moderate Persistent Asthma

23. Symptoms Symptoms > 2 X/wk but <1 X/day Exacerbations may affect activity Nighttime symptoms > 2 X/mo Lung Function FEV1 or PEF > 80% predicted PEF variability 20-30% Mild Persistent Asthma

24. Symptoms Symptoms < 2 X/wk Asymptomatic and normal PEF between exacerbations Exacerbations brief (few hrs - few days); intensity may vary Nighttime symptoms < 2 X/mo Lung Function FEV1 or PEF > 80% predicted PEF variability < 20% Mild Intermittent Asthma

25. Asthma Management • Goals of therapy • Prevent symptoms • Maintain (near) “normal” PF • Maintain normal activity • Prevent exacerbations & minimize ER visits/hospitalizations • Optimal drug tx, minimal problems • Patient/family satisfaction

26. Recommended monitoring • S & S • PFT • Quality of life/functional status • Exacerbations • Drugs • Patient/provider communication & satisfaction

27. Monitor using clinician assessment/pt. self-assessment • Spirometry tests • Initial assessment • Post tx after patient’s symptoms and PF stabilize • Minimally Q 1-2 yrs

28. Written action plan based on: • Signs & symptoms &/or PEF • Patient education: • Recognition need for additional therapy

29. Patient education: • How & when to do PF monitoring

30. Assessment Measures • Asthma treatment effectiveness • Monitor signs & symptoms - daytime, nocturnal, early morning symptoms response to short-acting Beta agonist • Pulmonary function (spirometry, PF) • patients with moderate-to-severe persistent asthma should learn how to monitor PEF at home • PF during exacerbations in pts. with moderate-to-severe asthma is recommended

31. Asthma treatment effectiveness • PF monitoring • long term daily PF monitoring in moderate-to-severe asthma is helpful • if long-term PF monitoring is NOT used, short term period of PF monitoring is recommended • establish individual’s personal best • identify time relationships between changes in PF to exposure • evaluate response to chronic maintenance therapy

32. Personal best • 2-3 wk period pt. records early afternoon PEF • Measure after each use of short-acting beta-2 agonist for symptom relief • ? course of oral steroids to establish personal best • Don’t use outlyer PEF values

33. Asthma treatment effectiveness • Monitoring quality of life/functional status • missed work, school • activities • sleep • changes in caregivers activities due to child’s asthma • Monitoring asthma exacerbation history • self-treated, or by HC providers

34. Asthma treatment effectiveness • Monitoring asthma exacerbation history • unscheduled visits/telephone calls/urgent or emergent care • frequency, severity & causes of exacerbations • hospitalization info - length of stay, intubation, ICU

35. Asthma treatment effectiveness • Monitoring Drug Therapy • patient compliance • inhaler technique • frequency of use the short-acting beta2 agonist • frequency of oral steroid “burst” therapy • dose changes of inhaled anti-inflammatory meds.

36. Asthma treatment effectiveness • Periodic assessment by clinician and patient • clinician assessment • medical history and physical exam with PFT • mild intermittent-to-mild persistent asthma under control for 3 mos. should be reassessed Q 6 mos • uncontrolled &/or severe persistent should be seen more often

37. Asthma treatment effectiveness • Periodic assessment by clinician and patient • patient self-assessment • daily diary - symptoms, PF, med. use • periodic self-assessment filled out at the time of the clinic visit - self perception of asthma control, self-skills, satisfaction • population based assessment - HMO’s