asthma Flashcards
– Hyperresponsive airways
– Airway inflammation
– Reversible airway obstruction caused by bronchial smooth muscle
constriction (bronchospasm)
- more common in children
asthma
Atopy:strongest identifiable predisposing factor
■ Inherited predisposition, body produces way too much IgE in response to antigen
■ Associated with atopic dermatitis (eczema), allergic rhinitis, asthma
– More common type
– Often diagnosed in childhood
– Family history
Extrinsic / Allergic / Atopic / Type 2 asthma
– Normal serum IgE
– Often diagnosed in adulthood, no significant family history
– Exercise induced, medication induced, chronic infection, etc
- most likely diagnosed in adulthood
Intrinsic / Nonallergic / Nonatopic / Non-Type 2 asthma
Exposure to allergens trigger a cascade of cellular activation in the airways resulting in inflammation.
– Antigen exposure activates IgE (main antibody responsible for allergic reaction)
– IgE binds to and activates mast cells
– Activation of mast cells leads to
release of mediators that cause
bronchoconstriction and inflammation
■ Histamine, leukotrienes,
prostaglandins
■ Mucus production
pathophysiology of asthma
common triggers of asthma
■ Air pollution
■ Tobacco smoke
■ Certain occupational exposures / fumes
■ Mites, animal dander, cockroaches, fungi, mold, pollen
■ Infections – typically viral
■ Diet
■ GERD
■ Exercise induced
■ Menstruation
■ Medications
– Beta-blockers
– Aspirin
Aspirin induced asthma / aspirin exacerbated respiratory disease
■ 3 main features:
– Aspirin / NSAID intolerance
– Asthma
– Nasal polyps / rhinitis
■ Nonallergic / intrinsic
Samter’s Triad
■ Wheezing - expiratory
wheezes**
■ Dyspnea
■ Chest tightness
■ Cough
– Can be dry or productive
■ Symptoms worse at night***
■ Physical exam findings:
– Nasal polyps / swelling
– Eczema / dermatitis
– Prolonged expiratory
phase
– Accessory muscle usage
asthma symptoms
how to diagnose asthma
- get a thorough history
- PFT: spirometry (gold standard)
what is the FEV1/FVC ratio that indicates obstruction
less than 70%
what % indicates reversibility after bronchodilator
more than 12%
what percent indicates a positive asthma in bronchoprovacation testing
Decrease in FEV1 of more than 20%
after exposure to agent is +
■ Inhaled agents trigger
bronchoconstriction to evaluate
responsiveness
■ Decrease in FEV1 of more than 20%
after exposure to agent is +
■ Methacholine (triggers inflammatory response and causes bronchoconstricition), histamine
Bronchoprovocation testing
■ Handheld, portable way to assess severity of symptoms
■ ”normal” values are based on age, height, & biologic sex
– Patient’s have their own “normal”,
knowing their baseline is important
Peak Expiratory Flow Rate
■ Measures exhaled Nitric Oxide, gas
produced by cells associated with
eosinophils
■ Can help determine efficacy of current regimen and guide medication management
FeNO testing
adjunct diagnostics to asthma
■ Chest X-Ray
– May show hyperinflation over time, not specific to asthma
■ ABG
– More helpful in the acute setting w/ exacerbation
– Can help to assess impeding respiratory failure
■ Skin testing
■ Serum IgE
asthma management: First steps
■ Goals of management:
– Maintain ADLs, reduce exacerbations / hospital visits
– Maintain lung function
■ Every asthmatic should be prescribed a rescue inhaler,
regardless of frequency of symptoms
■ Additional medication regimen based on classification /
severity of disease
■ Reduce risk factors
– Avoid known triggers
– Smoking cessation, weight loss, allergy treatment
■ Frequent reassessment
– Albuterol (onset with minutes, lasts 6 hours) & Levalbuterol (Xopenex)
– Provide immediate relief of symptoms
– Binds to beta receptors, cause smooth muscle relaxation
Short Acting Beta Agonists (SABAs):
– Formoterol (onset time 1-2 minutes, lasts 12 hours), Salmeterol
– Never used on their own, given with ICS (often combo inhaler)
Long Acting Beta Agonists (LABAs)
– Mainstay of treatment. Indicated for all persistent asthmatics
– Strong anti-inflammatory properties.
– Improved lung function
– Slow onset, must be taken daily for several weeks for improvement
Inhaled Corticosteroids (ICS)
■ Status asthmaticus
■ Very diminished lung sounds
■ Inability to speak in full sentences
■ Cyanosis
■ Accessory muscle usage
■ ABG
– Decreasing pH & PaO2, increasing PaCO
severe exacerbations
Severe Exacerbations / ER treatment
■ ABCs always #1, ensure adequate IV access. Start treatment ASAP.
■ Maintain SpO2 >90%
– May need bipap for increased WOB
– Try and avoid intubation
■ Albuterol, lots of it. Often requires back-to-back or continuous nebulizer
treatments
– Commonly will add ipratropium bromide
■ Systemic Steroids
– Start immediately
-Methylprednisolone,dexamethasone
■ Magnesium Sulfate
– 2 g IV over 20 minutes
Management: Patient Education
■ Asthma action plans
– Ensure patients have a
written asthma action plan
they can understand and
follow
■ MDI w/ Spacer technique:
– Drastically Improves delivery
of medication.
– No coordination required
■ Peak Expiratory Flow Rate
(PEFR) measurement:
asthma complications:
■ Respiratory failure, hypoxia
■ Acidosis
■ Pneumothorax
■ Infection
