Asthma; Basis Of Current Management

Basis of Current Management in Asthma AE Orimadegun 06/06/09

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OUTLINE… Definition  Epidemiology  Pathogenesis/Pathophysiology  Risk Factors  Mechanisms  Diagnosis and Classification  Education and Delivery of Care  Six Part Asthma Management Plan 

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Definition of Asthma 

Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role



Chronic inflammation causes an associated increase in airway hyperresponsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning

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These episodes are usually associated with widespread but variable airflow obstruction that is often reversible either spontaneously or with treatment

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Facts and figures 

Most common chronic illness in childhood worldwide

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Between 100 - 150 million people suffer from asthma worldwide1

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Worldwide prevalence rates are increasing, on average, by 50% per decade1

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Worldwide costs of asthma greater is than HIV / AIDS and tuberculosis combined1

1. WHO, Bronchial Asthma Fact Sheet 2000 06/06/09 2. GINA Guidelines 1998

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Facts and figures… 

Prevalence rates in Nigeria:

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Sofowora & Clark - 2.4% in a school survey at Ibadan.

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Falade et al using ISAAC Questionnaire found 16.7% (13-14yrs) and 7.2% (6-7yrs) in Ibadan.

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Okoromah reported 3% in Enugu (6-13yrs)

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Oviawe - 0.7% in a rural community at Edo

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Highest prevalence reported from UK, New Zealand, and Australia (Isaac) 06/06/09

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Trends in Prevalence of Asthma By Age, U.S., 1985-1996 80

Rate/1,000 Persons Age (years)

70

<18

60

18-44 45-64

50

65+ Total (All Ages)

40 30 20

85 86 06/06/09

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88 89 90 91 92 93 94 Year

95 96 6

Death Rates for Asthma By Race, Sex, U.S., 1980-1998 Rate/100,000 Persons 5 Black Female 4

Black Male

3

White Female

2 White Male

1 0 1980 06/06/09

1985

1990 Year

1995

2000 7

Pathogenesis/Pathophysiology 

Complex, chronic inflammatory disorder of the airway

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Immunopathologic features include: 

Denudation of airway epithelium

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Collagen deposition beneath the basement membrane

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Oedema

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Mast cell activation

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Inflammatory cell infiltration 

Neutrophils



Eosinophils

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Lymphocytes (TH2-like cells)

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Pathogenesis/Pathophysiology 

Airway inflammation results in:      

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Hyperresponsiveness Limitation of airfow Airway oedema Acute bronchoconstriction Mucus plug formation Disease chronicity

Atopy is the strongest predisposing factor for asthma

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Modern view of pathophysiology… Allergen

Macrophage/ dendritic cell

Mast cell

Th2 cell

Neutrophil Eosinophil

Mucus plug

Nerve activation

Plasma leak Oedema

Mucus hypersecretion Hyperplasia

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Vasodilatation New vessels

Epithelial shedding

Subepithelial fibrosis Sensory nerve activation Cholinergic reflex Bronchoconstriction Hypertrophy / hyperplasia

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Inflammatory processes

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Pathogenesis/Pathophysiology Risk Factors (for development of asthma)

INFLAMMAT ION Airway Hyperresponsiveness

Risk Factors (for exacerbations) 06/06/09

Airflow Obstruction

Symptoms 12

Risk Factors for Asthma 

Host factors: predispose individuals to, or protect them from, developing asthma



Environmental factors: influence susceptibility to development of asthma in predisposed individuals, precipitate asthma exacerbations, and/or cause symptoms to persist

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Risk Factors for Asthma Host Factors     

Genetic predisposition Atopy – IgE mediated response to allergen Airway hyperresponsiveness Gender Race/Ethnicity

Environmental Factors • Indoor allergens – dust mites, animal dander, cockroaches, fungi • Outdoor allergens – pollens, fungi • Occupational sensitizers • Tobacco smoke – passive, active 06/06/09

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Risk Factors that Lead to Asthma Development Environmental Factors (cont’d) • Air Pollution – outdoor, indoor • Respiratory Infections • Parasitic infections • Socioeconomic factors • Family size • Diet and drugs • Obesity 06/06/09

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Factors that Exacerbate Asthma       

Allergens Air Pollutants Respiratory infections Exercise and hyperventilation Weather changes Sulfur dioxide Food, additives, drugs

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Is it Asthma? 

Recurrent episodes of wheezing

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Troublesome cough at night

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Cough or wheeze after exercise

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Cough, wheeze or chest tightness after exposure to airborne allergens or pollutants

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Colds “go to the chest” or take more than 10 days to clear

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Asthma Diagnosis 

History and patterns of symptoms



Physical examination

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Measurements of lung function

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Reversibility test

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Diurnal variation

Measurements of allergic status to identify risk factors

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Reversible and variable airflow limitation  Reversibility

of airways’ obstruction

– increased PEF >15% 15-20 minutes after inhaling ß2-agonist  Variability

of airways’ obstruction

– PEF varies between morning and evening >20% in patients taking bronchodilator >10% in patients not taking bronchodilator

 Exercise-induced

airways’ obstruction

– decreased PEF >15% after 6 minutes of exercise  **Bronchoprovocative

challenge test

– Pc20 FEV1 methacholine and histamine

06/06/09 GINA Guidelines 1998

**not covered by GINA

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Classification of Severity CLASSIFY SEVERITY

Clinical Features Before Treatment Symptoms STEP 4 Severe Persistent STEP 3 Moderate Persistent STEP 2 Mild Persistent STEP 1 Intermittent

Nocturnal Symptoms

Continuous Limited physical activity

Frequent

Daily Attacks affect activity

> 1 time week

> 1 time a week but < 1 time a day

> 2 times a month

< 1 time a week Asymptomatic and normal PEF between attacks

≤ 2 times a month

FEV1 or PEF ≤ 60% predicted Variability > 30% 60 - 80% predicted Variability > 30% ≥ 80% predicted

Variability 20 - 30%

≥ 80% predicted Variability < 20%

The presence of one feature of severity is sufficient to place patient in that category.

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Six-Part Asthma Management Program 1. Educate Patients 2. Assess and Monitor Severity 3. Avoid Exposure to Risk Factors 4. Establish Medication Plans for Chronic Management 5. Establish Plans for Managing

Exacerbations

6. Provide Regular Follow-up Care 06/06/09

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Six-part Asthma Management Program

Goals of Long-term Management   

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 

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Achieve and maintain control of symptoms Prevent asthma episodes or attacks Maintain pulmonary function as close to normal levels as possible Maintain normal activity levels, including exercise Avoid adverse effects from asthma medications Prevent development of irreversible airflow limitation Prevent asthma mortality

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Six-Part Asthma Management Program

.

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The most effective management is to prevent airway inflammation by eliminating the causal factors

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Asthma can be effectively controlled in most patients, although it can not be cured

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The major factors contributing to asthma morbidity and mortality are underdiagnosis and inappropriate treatment

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Six-Part Asthma Management Program

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Any asthma more severe than intermittent asthma is more effectively controlled by treatment to suppress and reverse airway inflammation than by treatment only of acute bronchoconstriction and symptoms 06/06/09

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Six-part Asthma Management Program

Part 1: Educate Patients to Develop a Partnership  Patient education involves a partnership between the patient and health care professional(s) with frequent revision and reinforcement  Aim is guided self-management – giving patients the ability to control their asthma  Interventions, including use of written action plans, have been shown to reduce morbidity in both children and adults 06/06/09

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Six-part Asthma Management Program

Part 1: Educate Patients to Develop a Partnership  Guidelines on asthma management should be available but adapted and adopted for local use by local asthma planning teams  Clear communication between health care professionals and asthma patients is key to enhancing compliance 

Educate continually 06/06/09

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Part 2: Assess and Monitor Asthma Severity with Symptom Reports and Measures of Lung Function Symptom

reports Use of reliever medication Nighttime symptoms Activity limitations

Spirometry

for initial assessment. Peak Expiratory Flow for follow-up: Assess severity Assess response to therapy

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Part 2: Assess and Monitor Asthma Severity with Symptom Reports and Measures of Lung Function

• PEF monitoring at home – Important for those with poor perception of symptoms – Daily measurement recorded in a diary – Assesses the severity and predicts worsening – Guides the use of a zone system for asthma self-management

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Typical Spirometric (FEV1) Tracings Volume FEV1 Normal Subject Asthmatic (After Bronchodilator) Asthmatic (Before Bronchodilator)

1

2 3 4 Time (sec)

Note: Each FEV1 curve represents the highest of three repeat measurements 06/06/09

5

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Six-part Asthma Management Program

Part 3: Avoid Exposure to Risk Factors  Methods to prevent onset of asthma are not yet available but this remains an important goal  Measures to reduce exposure to causes of asthma exacerbations (e.g. allergens, pollutants, foods and medications) should be implemented whenever possible 06/06/09

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Six-part Asthma Management Program

Part 3: Avoid Exposure to Risk Factors 

Reduce exposure to indoor allergens

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Avoid tobacco smoke

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Avoid vehicle emission

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Explore role of infections on asthma development, especially in children and young infants

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Six-part Asthma Management Program

Part 4: Establish Medication Plans for LongTerm Asthma Management in Infants and Children  At present, inhaled glucocorticosteroids are the most effective controller medications and are recommended for persistent asthma at any step of severity  Long-term treatment with inhaled glucocorticosteroids markedly reduces the frequency and severity of exacerbations 06/06/09

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Six-part Asthma Management Program

Part 4: Establish Medication Plans for Long-Term Asthma Management 

A stepwise approach to pharmacological therapy is recommended

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The aim is to accomplish the goals of therapy with the least possible medication

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Part 4: Long-term Asthma Management

Stepwise Approach to Asthma Therapy The choice of treatment should be guided by: 

Severity of the patient’s asthma

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Patient’s current treatment

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Pharmacological properties and availability of the various forms of asthma treatment

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Economic considerations

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Cultural preferences and differing health care systems need to be considered.

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Part 4: Long-term Asthma Management

Pharmacologic Therapy Controller Medications:  Inhaled

glucocorticosteroids  Systemic glucocorticosteroids  Cromones  Methylxanthines  Long-acting inhaled β -agonists 2  Long-acting

oral β2-agonists

 Leukotriene

modifiers

 Anti-IgE 06/06/09

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Part 4: Long-term Asthma Management

Pharmacologic Therapy Reliever Medications:  Rapid-acting  Systemic

inhaled β2-agonists

glucocorticosteroids

 Anticholinergics  Methylxanthines  Short-acting

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oral β2-agonists 36

Part 4: Long-term Asthma Management

Allergen-specific Immunotherapy Greatest benefit of specific immunotherapy using allergen extracts has been obtained in the treatment of allergic rhinitis 

Specific immunotherapy should be considered only after strict environmental avoidance and pharmacologic intervention have failed to control asthma 



Perform only by trained physician

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Six-part Asthma Management Program

Part 4: Establish Medication Plans for Long-Term Asthma Management in Infants and Children  Childhood and adult asthma share the same underlying mechanisms. However, because of processes of growth and development, effects of asthma treatments in children differ from those in adults. 06/06/09

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Six-part Asthma Management Program

Part 4: Establish Medication Plans for LongTerm Asthma Management in Infants and Children  Long-term treatment with inhaled glucocorticosteroids has not been shown to be associated with any increase in osteoporosis or bone fracture  Studies including a total of over 3,500 children treated for periods of 1 – 13 years have found no sustained adverse effect of inhaled glucocorticosteroids on growth 06/06/09

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Six-part Asthma Management Program

Part 4: Establish Medication Plans for Long-Term Asthma Management in Infants and Children  Rapid-acting inhaled β2- agonists are the most effective reliever therapy for children  These medications are the most effective bronchodilators available and are the treatment of choice for acute asthma symptoms 06/06/09

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Recommended Asthma Medications Step 1: Children Younger Than 5yrs Severity

Daily Controller Medications

• None Step 1: Intermittent

Other Options (in order of cost) • None

Reliever Medication: Rapid-acting inhaled β2- agonist prn, not more than 3-4 times a day. Once control is achieved and maintained for at least 3 months, gradual reduction of therapy should be tried. 06/06/09

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Recommended Asthma Medications Step 2: Children Younger Than 5 yrs Severity

Daily Controller Medications

Other Options (in order of cost)

Step 2: Mild Persistent

• Low-dose inhaled • Sustained-release glucocorticosteroid theophylline, or • Cromone, or • Leukotriene modifier

Reliever Medication: Rapid-acting inhaled β2- agonist prn, not more than 3-4 times a day. Once control is achieved and maintained for at least 3 months, gradual reduction of therapy should be tried. 06/06/09 42

Recommended Asthma Medications Step 3: Children Younger Than 5yrs Severity

Daily Controller Medications

Other Options (in order of cost)

Step 3: Moderate persistent

• Medium-dose inhaled glucocorticosteroid

• Medium-dose inhaled glucocorticosteroid plus sustained-release theophylline, or • Medium-dose inhaled glucocorticosteroid plus long-acting inhaled β2- agonist, or • High-dose inhaled glucocorticosteroid, or • Medium-dose Inhaled glucocorticosteroid plus leukotriene modifier

Reliever Medication: Rapid-acting inhaled β2- agonist prn, not more than 3-4 times a day. Once control is achieved and maintained for at43 06/06/09 least 3 months, gradual reduction of therapy should be tried.

Recommended Asthma Medications Step 4: Children Younger Than 5yrs Severity

Daily Controller Medications

Step 4 Severe persistent

• High-dose inhaled glucocorticosteroid

Other Options

plus one or more of the following, if needed: - Sustained-release theophylline - Leukotriene modifier - Long-acting inhaled β2- agonist - Oral glucocorticosteroid

Reliever Medication: Rapid-acting inhaled β2- agonist prn, not more than 3-4 times a day. Once control is achieved and maintained for at 06/06/09 44 least 3 months, gradual reduction of therapy should be tried.

Six-part Asthma Management Program

Part 5: Establish Plans for Managing Exacerbations Primary therapies for exacerbations: • Repetitive administration of rapid-acting inhaled β2-agonist • Early introduction of systemic glucocorticosteroids • Oxygen supplementation Closely monitor response to treatment with serial measures of lung function 06/06/09

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Six-part Asthma Management Program

Part 5: Managing Severe Asthma Exacerbations  Severe exacerbations are lifethreatening medical emergencies  Care must be expeditious and treatment is often most safely undertaken in a hospital or hospital-based emergency department 06/06/09

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Acute Asthma Initial Assessment History, Physical Examination, PEF or FEV1 Initial Therapy Bronchodilators; O2 if needed Good Response Observe for at least 1 hour If Stable, Discharge to Home

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Incomplete/Poor Response

Respiratory Failure

Add Systemic Glucocorticosteroids Good Response

Poor Response

Discharge

Admit to Hospital

Admit to ICU

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Six-part Asthma Management Program

Part 6: Provide Regular Follow-up Care Continual monitoring is essential to assure that therapeutic goals are met. Frequent follow-up visits are necessary to review:  Home PEF and symptom records  Techniques in use of medications  Risk factors and their control Once asthma control is established, follow-up visits should be scheduled (at 1 to 6 month intervals as appropriate) 06/06/09

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Six-part Asthma Management Program: Summary

 Asthma can be effectively controlled, although it cannot be cured 

Effective asthma management programs include education, objective measures of lung function, environmental control, and pharmacologic therapy

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A stepwise approach to pharmacologic therapy is recommended. The aim is to accomplish the goals of therapy with the least possible medication 06/06/09

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Six-part Asthma Management Program: Summary (continued)

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Anything more than mild, occasional asthma is more effectively controlled by suppressing inflammation than by only treating acute bronchospasm

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The availability of varying forms of treatment, cultural preferences, and differing health care systems need to be considered 06/06/09

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Thank you for listening…

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