Asthma Flashcards
Define Asthma
A chronic inflammatory disorder of the airways. Variable and recurring symptoms. Airflow obstruction. Bronchial hyperresponsiveness. Underlying inflammation
Pathophysiology of air flow obstruction
airway narrowing increases resistance. loss of elastic recoil of the lung decreases driving pressure. Inflammation of the airways due to mucosal edema
and increased mucous production
What happens as a result of persistent inflammation?
Goblet cell hypertrophy .Mucus hypersecretion. Loss of ciliated epithelium. Squamous metaplasia
Destruction of alveolar walls. Peribronchiolar fibrosis
What are causes of airflow limitations?
Bronchoconstriction. Bronchial smooth muscle contraction in response to exposure to a variety of stimuli
What causes airway hyperresponsiveness?
Exaggerated bronchoconstrictor response to stimuli
What causes airway edema?
Edema, mucous hypersecretion, formation of thickened mucous plugs
Symptoms
Cough.Wheezing (end expiratory). Shortness of breath. (symptoms may have a seasonal and/or diurnal variations)
Inflammatory response involves which cells
mast cells, t-lymphocytes, macrophages, eosinophils and epithelial cells.
What is the role of eosinophils in astha?
release granular protein that damages bronchial epithelium and promotes airway hyper-responsiveness.
What is the role of lymphocytes in asthma?
produce Cytokines, Leukotriene B-4 and C-4, prostaglandin and histamine.
What is the role of Mast Cells in asthma?
initiate arousal condition in IgE receptors
What do Leukotrienes (Potent Inflammatory Mediators) do?
Increase vascular permeability/edema.Increase mucus production.Decrease mucociliary transport.
Inflammatory cell recruitment
Asthma Classic triad
Wheezing
Chronic episodic dyspnea
Chronic cough
Asthma Associated Symptoms (during attack)
Tachypnea, tachycardia, and systolic hypertension
Audible harsh respirations, prolonged expiration, wheezing
Sputum production
Chest pain or tightness
Diminished breath sounds during acute exacerbations
When can symptoms be worse
At night
Diagnosis of Asthma
History
Signs and symptoms suggestive of asthma
Confirmation of variable expiratory airflow limitation, preferably by spirometry
Exclusion of alternative diagnoses
When should you use spirometry?
Order before and after bronchodilators. Or can have pt monitor peak flows at home for a month and keep diary of symptoms.
How would you work up asthma in clinic visit?
Can do a quick challenge in the office with a peak flow meter before and after a bronchodilator.
Chest xray only if you need to exclude other causes or if you are suspecting new onset asthma in a middle aged adult
Asthma DDx
COPD Anaphylaxis Foreign body ingestion Congestive heart failure Pulmonary embolism Panic disorder, hyperventilation syndrome Pneumonia, bronchitis Alpha1-Antitrypsin Deficiency GERD Sarcoidosis Vocal Cord Dysfunction Cough secondary to drugs (ACE inhibitors)
Describe Atopic Extrinsic Asthma
Most common. Onset is usually the first two decades of life. Associated with other allergic manifestations and Family history. Serum IgE and eosinophil count are usually elevated
How is asthma managed?
Routine monitoring. Patient education.Control of triggers and comorbid conditions. Pharmacologic therapy
Peak Flow
used to measure how well air moves out of the lungs. Measures how fast air comes out of the lungs with forceful exhalation after inhaling fully.
Benefits of Peak Flow measurments
Learn what triggers their asthma
Decide if the asthma action plan is working
Decide when to add or adjust asthma medications
Know when to seek emergency care
can help providers and their patients monitor their asthma.
Can help the patient when their asthma is getting worse
Peak flow may show changes before the patient feels them.
Green Zone
80 to 100 percent of the patients usual or “normal” peak flow rate signals all clear
A reading in this zone means that your asthma is under reasonably good control. It would be advisable to continue your prescribed program of management.
Yellow Zone
50 to 80 percent of the patients usual or “normal” peak flow rate signals caution. It is a time for decisions.
Your airways are narrowing and may require extra treatment. Your symptoms can get better or worse depending on what you do, or how and when you use your prescribed medication. You and your provider should have a plan for yellow zone readings.
Red Zone
Less than 50 percent of the usual or “normal” peak flow rate. Severe airway narrowing may be occurring. Take your rescue medications right away. Contact your provider now and follow the plan he/she has given you for red zone readings.
Contributing factors to Asthma
Inhaled allergens (medical rx and avoidance) Food allergies? Tobacco smoke (first and second hand). Rhinitis/sinusitis.GERD.Occupational exposures. Viral respiratory infections
What does leukotriene 4 (LTD4) do?
profound bronchoconstriction, about 1000 x more potent than histamine
What is the “bronchoprovocation test”?
inhalation of irritating agent such as metacholine used if spirometry was normal, but asthma is still suspected diagnosis
What type of medications are used for quick relief of asthma symptoms?
Short-acting beta-2 agonists and anticholinergics
What type of medications are used for long-term control of asthma?
Long-acting beta-2 agonists, Corticosteroids, Mast cell-stabilizing agents, Leukotriene modifiers, Methylxanthines
Describe metered dose inhalers as an administration technique?
Releases specific amount of aerosolized particles
Use a spacer
Describe nebulizers as an administration technique?
Liquid medicine used in machine. Provides “nebulized” particles with moist continuous airflow.
Ideal for pediatric patients or those unable to use MDI
Describe inhaled powder as an administration technique?
Mechanical crushing of tablet or capsule releases powder for inhalation (ex: rotacaps, disc-haler)
Describe systemic administration of asthma meds?
Oral or parenteral routes (SQ, IM, IV). Generally associated with more side effects
What do beta-2 agonists do?
Produce airway dilation. Stimulation of beta-adrenergic receptors. Activation of G proteins with resultant formation of cyclic AMP. Decrease release of mediators. Improve mucocilliary transport
What are some short acting beta-2 agonists?
Albuterol, Proventil, Ventolin, Levalbuterol (Xopenex)
Describe the use of short acting beta-2 agonists?
Rescue medication. active by all routes of administration. Inhalation increases bronchial selectivity, more rapid onset. Quick onset, lasts 4 to 6 hrs
What is the usual dosing for beta-2 agonists?
MDI: 2-4 puffs q4-6h and prn
What are some long acting beta-2 agonists?
Salmeterol (Serevent) inhaled, Formoterol (Foradil) inhaled. Oral: sustained-release albuterol
What are long acting beta-2 agonists used for?
widely used for maintenance therapy. Slower onset, long-lasting (9 to 12 h). not recommended for the treatment of acute episodes
What are some non-selective beta agonists?
epi, isoproterenol, metaproterenol, ioetharine
Why are non-selective beta agonists generally not recommended for asthma?
adverse cardiac effects because beta-1 agonists stimulate the heart. can cause myocardial damage and excess chronotropic/inotropic effects
What are some anticholinergic bronchodilators?
ipratropium bromide (Atrovent) and Tiotropium (Spiriva)
What are anticholinergic bronchodilators used for?
enhance the bronchodilation achieved by beta-agonists. minimal systemic side effects
beneficial in patients with heart disease. Synergistic with albuterol
What is an example of a methylxanthine bronchodilator?
theophylline
Describe the use of theophylline
medium-potency bronchodilator. narrow window, hard to achieve and maintain. rarely used
How do corticosteroids reduced asthma symptoms?
Reduce airway inflammation (not a bronchodilator).
Describe use of inhaled steroids for asthma treatment
Start aerosolized steroids in any patient who is not controlled by bronchodilators. If symptoms are not eliminated by standard dose, increase two fold or more. Greatly facilitate withdrawal of oral steroids
What are some side effects of inhaled corticosteroids?
thrush, dysphonia, adrenal suppression, cataract formation, decreased growth in children, interference with bone metabolism, and purpura
What are some common corticosteroids?
Fluticasone (Flovent). Budesonide (Pulmicort)
Beclomethasone (Vanceril, Beclovent, QVAR)
Triamcinolone (Azmacort).Flunisolide (Aerobid, Aerobid-M)
Describe the use of budesonide (pulmicort respules)
administered by Turbuhaler, DPI, or nebulizer
first nebulized corticosteroid studied in children aged 6mo.- 8 yrs. greater number of symptom-free days.decreased need for beta-agonists.
reduced hospitalization rates
What should you keep in mind with chronic treatment using oral corticosteroids?
continuous corticosteroid administration interrupts growth. Long-acting preparations (dexamethasone) should not be used: prolonged suppression of the pituitary-adrenal axis
What is in advair diskus (purple)?
fluticasone + salmeterol
What is in combivent MDI (orange and green)?
Ipratropium + albuterol
What are some mast cell stabilizer medications for asthma?
Cromolyn (Intal), nedocromil (Tilade)
How do mast cell stabilizers reduce asthma symptoms?
inhibit degranulation of mast cells. prevent release of chemical mediators of anaphylaxis
How are mast cell stabilizers (intal and tilade) used for asthma treatment?
most effective for seasonal disease. 4-6 weeks before beneficial effects. Dose: 2 puffs qid. prophylactically 15-20 min pre contact with precipitant
What are some leukotriene inhibitors used to treat asthma?
Montelukast (Singulair), Zafirlukast (Accolate), Zileuton (Leutrol, Zyflo)
What is the MOA of leukotriene inhibitors?
suppress action of cysteinyl leukotriene
What are some benefits of leukotriene inhibitors?
improvement in FEV1, asthma exacerbations. improvement in frequency of prn beta-agonist use
safe in children ages 6-14. adverse side effects minimal. effective in combination with corticosteroid or beta-agonist. alternative to inhaled corticosteroid
add-on therapy when response to inhaled corticosteroids is suboptimal. help reduce higher doses of inhaled corticosteroids
What are side effects of leukotriene inhibitors?
Liver function test abnormalities, headache, depression
What is an example of an anti-IgE monoclonal antibody medication?
omalizumab
What is the MOA of anti-IgE antibody medication?
Inhibits the binding of IgE to mast cells.Does not promote mast cell degranulation to already bound IgE. Lowers plasma IgE to undetectable levels
What is the step up therapy of asthma treatment?
Start treatment at step appropriate to asthma severity at time of evaluation. if control not achieved gradually step up therapy until successful. Gradually increase and add options. Consider alternative explanations for poor asthma control. Consider asthma specialist consult.
What is the step down therapy of asthma treatment?
Start treatment at step appropriate to asthma severity at time of evaluation exacerbation symptoms with aggressive management. Gradual reduction of long-term-control medications to lowest level possible to achieve maximum control. Continue to attempt reduction of daily oral steroid use.
What causative agents should be avoided for allergic asthmatics?
ASA, NSAIDs, tartrazine (coloring agent), sulfiting agents (preservatives)
