Asthma Diagnosis: Anatomy and Pathophysiology of Asthma

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Asthma Diagnosis: Anatomy and Pathophysiology of Asthma Karen Meyerson, MSN, RN, FNP-C, AE-C Asthma Network of West Michigan April 21, 2009 Acknowledgements: LeRoy M. Graham, MD, Atlanta, GA Allan T. Luskin, MD, Madison, WI

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Asthma Diagnosis: Anatomy and Pathophysiology of Asthma. Karen Meyerson, MSN, RN, FNP-C, AE-C Asthma Network of West Michigan April 21, 2009 Acknowledgements: LeRoy M. Graham, MD, Atlanta, GA Allan T. Luskin, MD, Madison, WI. Definition of Asthma. - PowerPoint PPT Presentation

Transcript of Asthma Diagnosis: Anatomy and Pathophysiology of Asthma

Page 1: Asthma Diagnosis: Anatomy and Pathophysiology of Asthma

Asthma Diagnosis:Anatomy and Pathophysiology of

Asthma

Karen Meyerson, MSN, RN, FNP-C, AE-CAsthma Network of West Michigan

April 21, 2009Acknowledgements: LeRoy M. Graham, MD, Atlanta, GA

Allan T. Luskin, MD, Madison, WI

Page 2: Asthma Diagnosis: Anatomy and Pathophysiology of Asthma

Definition of Asthma

Chronic inflammatory disease of the airways characterized by: Recurrent episodes of wheezing Shortness of breath Chest tightness/pain Coughing

Airflow limitation is at least partially reversible Airways are supersensitive and react to a variety of

stimuli or triggers

Page 3: Asthma Diagnosis: Anatomy and Pathophysiology of Asthma

Asthma Pathophysiology

In response to a trigger: Airway inflammation Bronchial smooth muscles constriction

(bronchospasm) Increased mucus production The airways become narrow and breathing

becomes difficult

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Normal Airways

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Asthma Airways

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Mechanisms Underlyingthe Definition of Asthma

INFLAMMATIONINFLAMMATION

Risk FactorsRisk Factors(for development of asthma)(for development of asthma)

AirwayAirwayHyperresponsivenessHyperresponsiveness Airflow LimitationAirflow Limitation

SymptomsSymptomsRisk FactorsRisk Factors

(triggers)(triggers)

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Asthma Airways

Before 10 Minutes After Allergen Challenge

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Airway Remodeling

AsthmaticAsthmaticNormalNormalJeffery P. Asthma. 1998.

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The “Tip” of the Iceberg

Airway inflammation

Airflow obstruction

Bronchial hyperresponsiveness

ASTHMA Symptoms

National Asthma Education and Prevention Program. Highlights of the Expert Panel Report 2: Guidelines for the Diagnosis and Management of Asthma. Bethesda, MD., May 1997. NIH Publication No. 97-4051A.

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Factors Predicting Persistent Asthma Family history of asthma (maternal > paternal) Atopy (IgE/positive skin tests, eczema, rhinitis) Allergen exposure (dust mites / animals) Viral (RSV) infection Gender (males > females) Smoking (passive or active) The strongest predictor for wheezing that

develops into asthma is ATOPY

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Asthma Diagnosis

Symptoms Medical history Physical exam Measurements of lung function

Diurnal variation in peak flow

Evaluation of allergic status Exclude alternative diagnoses

Bronchiolitis, cystic fibrosis, GERD, foreign body aspiration

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Asthma DiagnosisAssessing Symptoms

Cough Wheeze Dyspnea Nocturnal symptoms Activity affected?

Recurrent episodes of cough (+ wheeze) are frequently due to asthma Coughing may be the only symptom present

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Asthma DiagnosisMedical History

Repeated cough, wheeze, chest tightness

Repeated diagnoses of reactive airway disease, allergic bronchitis or wheezy bronchitis

Symptoms worsened by viral infection, smoke, allergens, exercise, weather

Symptoms occur/worsen at night

Reversible airflow limitation

Wheezing may or may not be present

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Asthma DiagnosisPhysical Exam

Coughing, wheezing Prolonged forced expiration Use of accessory muscles Retractions Hyperexpansion of the chest Signs of other allergic diseases:

Atopic dermatitis Allergic rhinitis

Physical examination of the chest may be normal

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Asthma Predictive Index (API)High risk children (under age 3) who:

have had > 4 wheezing episodes in the past year that

lasted more than one day and affected sleep are significantly more likely to have persistent asthma after the age of 5 if they have either (1) of the following:

Castro-Rodriguez J et al. Castro-Rodriguez J et al. AJRCCM AJRCCM 2000; 162:1403-1406.2000; 162:1403-1406.

One major criteria Parent with asthma Physician diagnosis of

atopic dermatitis Evidence of sensitization

to aeroallergens

Two minor criteria Evidence of sensitization

to foods >4 percent blood

eosinophilia Wheezing apart from colds

OROR

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Asthma Predictive Index (API)

Birth cohort followed through 13 years of age. 76% of children diagnosed with asthma after 6

years of age had a positive asthma predictive index before 3 years of age.

97% of children who did not have asthma after 6 years of age had a negative asthma predictive index before 3 years of age.

Castro-Rodriguez J et al. Castro-Rodriguez J et al. AJRCCM AJRCCM 2000; 162:1403-1406.2000; 162:1403-1406.

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Asthma DiagnosisMeasurements of Lung Function

FEV1 (Forced Expiratory Volume in 1 Second) – this is the volume of air expired in the first second during maximal expiratory effort. The FEV1 is reduced in both obstructive and restrictive lung disease.

FVC (Forced Vital Capacity) – this is the total volume of air expired after a full inspiration.

FEV1/FVC – this is the percentage of the vital capacity which is expired in the first second of maximal expiration.

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Spirometry: Flow-Volume LoopObstruction

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Asthma DiagnosisMeasurements of Lung Function

Spirometry: An FEV1 response of >12% post-bronchodilator is

suggestive of asthma

BUT, Spirometry is difficult in children <4 years old Some children cannot perform spirometry

adequately until >7 years of age

Alternative assessment: PEF variability

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?Cough

especially if:• after exertion• breathing cold

air• at night• after colds• paroxysmal

Wheezing• tightness

• noisy

breathing Dyspnea(Breathlessness

)

especially if:• intermittent or

variable• after exertion• at night

Asthma Diagnosis

Page 21: Asthma Diagnosis: Anatomy and Pathophysiology of Asthma

?Cough

especially if:• after exertion• breathing cold

air• at night• after colds• paroxysmal

Wheezing• tightness

• noisy

breathing Dyspnea(Breathlessness

)

especially if:• intermittent or

variable• after exertion• at night

Asthma Diagnosis

Page 22: Asthma Diagnosis: Anatomy and Pathophysiology of Asthma

?Cough

especially if:• after exertion• breathing cold

air• at night• after colds• paroxysmal

Wheezing• tightness

• noisy

breathing Dyspnea(Breathlessness

)

especially if:• intermittent or

variable• after exertion• at night

Asthma Diagnosis

Page 23: Asthma Diagnosis: Anatomy and Pathophysiology of Asthma

?Cough

especially if:• after exertion• breathing cold

air• at night• after colds• paroxysmal

Wheezing• tightness

• noisy

breathing Dyspnea(Breathlessness

)

especially if:• intermittent or

variable• after exertion• at night

Asthma Diagnosis

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Cough

especially if:• after exertion• breathing cold

air• at night• after colds• paroxysmal

Wheezing• tightness

• noisy

breathing Dyspnea(Breathlessness

)

especially if:• intermittent or

variable• after exertion• at night

Asthma Diagnosis

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Questions?

Download the Guidelines at: http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.pdf

Download the Summary Report at: http://www.nhlbi.nih.gov/guidelines/asthma/asthsumm.pdf