asthma and allergy Flashcards
most common phenotypes of asthma
- Allergic (or eosinophilic) asthma
- Nonallergic asthma
- Late-onset asthma
- Asthma with fixed airflow limitation
- Asthma with obesity
chronic inflammation in asthma
- Inflammation in asthma is a complex process driven by a variety of responses of the immune system
- Exposure of the airway epithelium to triggers releases alarmins which activate inflammatory immune responses
most common mechanism leading to airway inflammation of asthma
activation of the type 2 humoral pathway
chronic inflammation leads to airway remodeling, which can include:
- Subepithelial fibrosis
- Hypertrophy of the airway smooth muscle
- Angiogenesis
two major sources for guidelines for the management of asthma
- National Asthma Education and Prevention Program (NAEPP)
- Global Initiative for Asthma (GINA)
Both advocate for a stepwise approach to asthma medications based on severity of disease
NAEPP guidelines discuss two components of asthma severity
impairment and risk
impairment as a component of asthma severity
how much the asthma is affecting activities, sleep and objective lung function
risk as a component of asthma severity
how often a patient is having significant exacerbations requiring high-risk medications (such as oral corticosteroids)
asthma meds are categorized into two classes
quick relief meds and controller meds
what are quick relief meds used for?
treat acute symptoms
what are controller meds used for?
to achieve and maintain control of persistent asthma
quick relief meds in asthma
- SABA
- SAMA
- oral corticosteroid bursts
SABA
Short-acting beta2-agonists (SABAs)
- First choice for quick relief of asthma s/s
- Albuterol is the most commonly used SABA
SAMA
- Best known is ipratropium
- NAEPP recommends this as an add-on medication to albuterol
- Especially in the management of asthma exacerbations in the ED setting
oral corticosteroid bursts for asthma
Recommended if the patient is not responding to bronchodilator therapy during an exacerbation
controller meds for asthma
- ICS
- LABA
- LAMA
- leukotriene receptor antagonists
- monoclonal antibody therapies
inhaled corticosteroids (ICS)
considered the cornerstone of asthma treatment
MOA of ICS
To suppress the generation of cytokines, recruitment of airway eosinophils, and release of inflammatory mediators
in asthma
LABAs
- Typically utilized as an add-on medication to inhaled steroids in the treatment of asthma
- Not indicated for use as monotherapy in asthma
LAMAs
- Provide long-lasting bronchodilator effects
- Recommended by NAEPP and GINA as add-on therapy for patients requiring additional controlled medications
EX: tiotropium - One triple therapy option for asthma is currently available in the US
- Combines an ICS, LABA, and LAMA into a once-daily dry powder inhaler
leukotriene receptor antagonists
With airway stimulation from allergens, leukotrienes C4 and D4 are released
- These substances cause contraction of the airway smooth muscle and increase the permeability of the airway vasculature
two leukotriene receptor antagonists have indications for treating asthma
- Montelukast (Singlulair)
- Zafirlukast (Accolate)
formoterol
has quick onset of action, similar to SABA but effects are long lasting
SMART dosing meaning
single maintenance and reliever therapy
how to use SMART dosing
Uses an ICS/LABA product containing formoterol as both the controller and quick-reliever
In the US, the currently available formulations for SMART therapy are:
- Budesonide/formoterol (Symbicort)
- Mometasone/formoterol (Dulera)
pathophysiology of allergies
In an immediate hypersensitivity reaction, IgE molecules are sensitized to a particular antigen
- These molecules are bound to receptors on the surface of basophils and mast cells
- With future exposure to the antigen, the IgE molecule is cross-linked, leading to mast cell degranulation
When the mast cell breaks down, substances such as histamine, leukotrienes, platelet activating factors, and kinins are released
- These chemicals leads to tissue inflammation that manifests as local and/or systemic reactions
goals of therapy for allergic rhinitis
goal is to reduce the daily burden of chronic respiratory symptoms and prevent recurrent sinusitis and ear infections
goals of therapy for patients with life threatening anaphylaxis
goal is strict avoidance of the triggers
- Preparation for accidental exposures with injectable epinephrine devices and an emergency plan always available
rational drug selection for patients with life threatening allergic reactions
an epinephrine autoinjector device should be prescribed
