ASTHMA IN THE UNITED STATES

Approximately 20 million Americans have asthma

Nine million of these cases occurred in children under the age of 18

From 1980 to 1994, prevalence has increased by a 75%

Asthma prevalence in children under five has increased by over 160% during this same time period

Annually, asthma contributes to about5,000 deaths1

WHAT IS ASTHMA??? “A common disorder in which chronic inflammation

of the bronchial tubes (bronchi) makes them swell, narrowing the airways. Asthma involves only the bronchial tubes and does not affect the air sacs (alveoli) or the lung tissue (the parenchyma of the lung) itself.”2

Three hallmark signs of asthma:a) Coughingb) Wheezingc) Dyspnea

The recurrent episodes that occur are due to airflow obstruction and are often reversible (spontaneously or with medication

NOCTURNAL ASTHMA Includes 70-80% of asthmatics

Asthma symptoms occur exclusively at night

Common Causes: Supine posture GE reflux Late phase reaction to antigens Exposure to allergens in bedding (mites) Fluctuations in airway caliber Impaired mucociliary clearance

PATHOPHYSIOLOGY A variety of changes in the airway are responsible

for limiting the airway, all of which are influenced by airway inflammation:

BronchoconstrictionAirway HyperresponsivnessAirway Edema

Causes of airway reactivity: Pharmacologic and Immunologic StimuliPhysical AgentsThermal Stimuli

PATHOGENISISa) Allergic

35-55% of asthmatic patients Antigen antibody reaction Animal dander, mites, cockroaches, mice

b) Physical Exercise Especially in cold weather Usually short in duration

c) Respiratory infection

d) Occupational Stimuli Animal handlers Bakers Platinum refiners Wood and vegetable sources

PATHOGENISISe) Environment and air pollution

Cold weather Ozone NO2

f) Pharmacologic Aspirin Tartrazine dye Beta-Blockers Sulfites Contrast Media

g) Psychological Anxiety Fear Stress Laughter

SIGNS OF AN ATTACK! Dyspnea, cough, wheezing

Chest tightness

Anxiety

Lungs hyperinflated

One word responses

Rapid pulse

GOAL OF THERAPY:CONTROL OF ASTHMA

Prevent bothersome and chronic asthma symptoms

Reduce the use of the inhaled SABA to ≤2 days per week

Maintain normal pulmonary function

Maintain normal activity levels (work, school, exercise)

Meet both the patient’s and family members’ satisfaction with asthma care

NON-PCOL1) Eliminate any precipitating factors

Smoking, pets, clean sheets more often

2) Keep hydrated Water, coffee

3) Avoid sedatives Respiratory Function

STEPWISE APPROACH Classify patient based on severity:

STEPWISE APPROACH Use lowest level of treatment required to maintain asthma

control:

MEDICATIONSMDI Products

SABA: short-acting beta agonist

Generic Name

Brand Name(s)

Dosage Form

Onset of Action

Duration of

Action

Albuterol Proventil HFAVentolin HFAProAir HFP

108mcg per actuation

5-15 min 4-6 hrs

Epinephrine Primatene MistBronchial Mist

200mcg epinephrine per actuation

1-5 min 1-3 hrs

Levalbuterol HFA

Xopenex HFA 45mcg/puff 10-17 min 6-8 hours

MEDICATIONSMDI Products

LABA: long-acting beta agonist

Generic Name

Brand Name Dosage Form

Onset of Action

Duration of

Action

Formoterol Foradil 12mcg powder per capsule

1-3 min 12 hrs

Metaproterenol

Alupent 650mcg per actuation

5-30 min 2-6 hrs

Pirbuterol Maxair Autohaler

200mcg per actuation

Within 5 min

5 hrs

Salmeterol Serevent Diskus

25 mcg per actuation

Within 20 min

12 hrs

MEDICATIONSTheophylline

Very narrow therapeutic window (5 to 15 mcg/ml) Available IV and PO Many drug interactions due to metabolism via

CYP450’s Side Effects:

GI- nausea, vomiting, abdominal painCNS- nervousness, insomnia, headacheCardiac-increased heart rate, ventricular tachycardia, and seizures

Bottom line: not used anymore in asthma

MEDICATIONS

Corticosteroids

Known as the “backbone” of asthma therapy Downfall: side effects affect every organ By-mouth therapy

May be required at any step of therapyQOD therapy is usually ineffective Initial prednisone dose is 40-60mg/day then

taper

MEDICATIONS MDI Products

REFERENCES: 1. see notes 2. asthma def.

www.emedicinehealth.com