Asthma Flashcards
What is asthma?
- Chronic inflammatory disorder of the airways
- Characterized by variable and recurring symptoms, airflow obstruction, bronchial hyperresponsiveness, and underlying inflammation
- Airflow limitation is generally reversible, but may eventually lead to airway remodeling
What is the most prevalent chronic disease of childhood?
Asthma
Genetic risk factors
-Atopy or family history of atopic disease
-Parental history of asthma
60-80% of susceptibility
Environmental risk factor
- Socioeconomic status
- Family size
- Second hand tobacco exposure
- Allergen exposure
- Occupational exposure
Inflammation leads to….
-Airway hyper responsiveness
-Airway obstruction
both lead to clinical symptoms.
Anatomy of an Asthma attack
- Smooth muscle spasm- tightening of the airway, swelling and inflammation
- Occur due to fluid build up, infiltration by immune cells, excess mucous secretions.
Symptoms
- Cough
- Recurrent wheezing
- SOB or chest tightness
- Nocturnal cough
- Exercise-induced cough or wheezing
- Onset of symptoms after exposure to airborne allergens or other stimuli
- History of respiratory tract infections
- Associated conditions
Signs
- Evidence of bronchial obstruction
- Wheezing
- Prolonged expiration
- Airway obstruction at least partially reversible
- Evidence of atopy on physical exam (nose, eyes, and skin)
diagnosis
- Patient medical & family hx
- Physical exam of upper rest. tract & skin
- Confirmatory spirometry required for diagnosis & grading of asthma severity
What is spirometry?
Objective test to assess severity of lung dx and response to tx.
What does spirometry measure?
- Forced Expired Volume in One Second (FEV1)
- Forced Vital Capacity (FVC)
- FEV1/FVC ratio gives a clinically useful index of airflow limitation
What result is diagnostic for exercise- induced asthma?
FEV1 of greater 15%
What result is diagnostic for asthma?
Reversible airflow obstruction with 12% increase in FEV1 after bronchodilator.
What is FEV1?
volume of air pt can breath out after having full lungs
What is FVC?
Volume of air in lungs that is exhaled fully when lungs are full.
What are the treatment goals?
Reduce impairment and reduce risk
Reduce impairment:
- Prevent chronic symptoms
- Require infrequent use of rescue medications
- Maintain near normal lung function
- Maintain near normal activity levels
Reduce Risk:
- Prevent exacerbations
- Minimize need for emergency care and hospitalization
- Prevent loss of lung function
- Minimize adverse effects of therapy
Severity categories
To initiate therapy:
- Intermittent
- Persistent (mild, moderate, severe)
Control:
To monitor and adjust therapy (follow-up visits)
- Controlled
- Partially controlled
- Uncontrolled
Initial visit steps
- Diagnose asthma
- Assess asthma severity
- Initiate medication and demonstrate us
- Develop written asthma action plan
- Schedule follow-up appointment
Asthma triggers
- Smoking (most common)
- Indoor allergens
- Outdoor allergens
- Exercise
- Cold air
- Pollutants
- Mediations
- Sulfites
- Resp. tract infections
- Medical comorbidities
Follow-up visit steps
- Assess & monitor asthma control
- Review medication techniques & adherence; assess side effects; review environmental control
- Maintain, step up, or step down medication
- Review asthma action plan, revise as needed
- Schedule next follow-up visit.
Modifying therapy: well controlled
- Maintain current step
- Consider step down if well controlled for 3 months
Modifying therapy: not well controlled
-Step up at least 1 step
Modifying therapy: very poorly controlled
-Step up 1-2 steps and consider short course of oral steroids.
Rescue medications (as needed)
- Short-acting Beta 2 agonists (SABAs)
- Systemic corticosteroids (for acute exacerbation).
Controller medications (daily)
- Inhaled corticosteroids (ICS)
- Long-acting beta2 agonists (LABA)
- Leukotriene receptor antagonists (LTRAs)
- Mast cell stabilizers
- Methylxanthines.
Short-acting beta2 agonists (SABA): mechanism
Relax airway smooth muscle (bronchodilator)
Short-Acting β2-Agonists (SABA) adverse effects
-tacycardia, tremor, palpitation, dizziness, headache
Inhaled Corticosteroids (ICS) MOA
-Cornerstone of asthma therapy
-Mechanism:
Decrease inflammation and hyperresponsiveness
Inhaled Corticosteroids (ICS) indication
- Reduce symptoms, improve qualify of life, and improve lung function
- Reduce frequency and severity of exacerbations
- Reduce asthma mortality
Inhaled Corticosteroids (ICS) adverse efects
-Cough, dysphonia
-Oral thrush
Ensure patients RINSE MOUTH AFTER EACH USE
- Systemic adverse effects are minimal
ICS inhalers: metered-dose inhalers
- Beclomethasone (Qvar HFA)
- Fluticasone propionate (Flovent HFA)
- Mometasone (asmanex HFA)
ICS Inhalers: Dry-Powder inhalers
- Fluticasone proporzionate (Flovent Diskus)
- Fluticasone furoate (arnuity ellipse)
- Mometasone (Asmanex TwistHaler)
Long-Acting β2-Agonists (LABA) MOA
-Relax airway smooth muscle with longer duration of action
Long-Acting β2-Agonists (LABA) Indication
- NOT for acute exacerbations or mono therapy
- Black box warning: increase risk of asthma-related deaths
- Add-on therapy to ICS; prescribe in combo
Long-Acting β2-Agonists (LABA) Adverse effects
Tachycardia, skeletal muscle tremor, hypokalemia.
Salmeterol & Fometerol
Long-Acting β2-Agonists (LABA)
Leukotriene Receptor Antagonists MOA
Interfere with pathway of leukotriene mediators. which are released from mast cells, eosinophils, and basophils.
- Added therapy for mild to moderate
- No relief from corticosteroids alone
Leukotriene Receptor Antagonists Indication
- Alternative to inhaled steroids in mild persistent
- Can be adjunctive to ICS but not preferred in children > 12 and adults compared to addition of LABA
Leukotriene Receptor Antagonists Adverse effects
-Headache, GI upset, hepatotoxicity
Montelukast, Zafirlukast, Zileuton
Leukotriene Receptor Antagonists
First line therapy for all
Rescue inhaler and short acting corticosteroid.
Last line agent
Mast Cell Stabilizers, only available as nebulizer
Mast Cell Stabilizers: MOA
Stabilize mast cells and interfere with chloride channel function
Weak anti-inflammatory effects
Mast Cell Stabilizers: Indication
- Alternative, but not preferred
- Can be used for exercise-induced bronchospasm
- May need 4-6 week trial to determine max benefit
- Used 3-4 times daily
Mast Cell Stabilizers: adverse effects
- Unpleasant taste
- Cough
- Dry throat
- Headache
- N/V
Methylxanthines MOA
Relaxation of smooth muscle, modest anti-inflammatory properties
Methylxanthines: Indication
May be beneficial as add-on therapy to ICSs but less effective than LABA
Methylxanthines: Adverse effects
- N/V
- Loose stools
- Tachycardia
- Cardiac arrhythmias
- Seizures
- Headache
Methylxanthines: Caution
- Mutliple drug interactions
- Monitoring required! Narrow therapeutic range, 5-15 mcg/ml.
Peak flow 80-100%
Doing well
- Breathing is good
- Able to do all usual things
Peak flow 50-80%
Caution
- Has breathing problems
- Can do some, but not all, activities
Peak flow <50%
Medical alert
- Breathing is hard and fast
- Cannot do usual activities
Follow up care
- Every 2-6 wks while gaining control
- Every 1-6 months to monitor control
- Every 3 months if step down therapy is anticipated.
What is an asthma exacerbation?
- Exacerbation – acute episode of progressively worsening SOB, cough, wheezing, or chest tightness
- Characterized by decrease in expiratory airflow
Asthma exacerbation goal
Relieve airflow obstruction and hypoxemia and prevent future relapses.
Oral corticosteroids
- Primary use as a rescue medication for acute asthma exacerbations.
- Short oral burst for 3-10 days, taper may or may not be needed.
Prednisone, prednisolone, methylprednisolone
Oral corticosteroids.
Acute use oral corticosteroid adverse effects
- Fluid retention
- Mood changes
- Sleep disturbances
- Appetite increase
- Hypokalemia (additive with other drugs)
- Hyperglycemia
- Hypertension
Chronic use oral corticosteroid adverse effect
- Cushingoid changes
- Growth suppression in children
- Cataracts
- Osteopenia, osteoporosis
- HPA axis suppression
Pediatric considerations
- Use spacers ± mask for infants and smaller children
- Provide duplicate rescue inhaler prescription for school
- ICS use may slow growth rate, but no decrease in adult height
- Risk vs. benefit; utilize lowest dose possible
Elderly considerations
-consider dexterity and ability to use devices
Pregnancy considerations
- SABAs, LABAs, cromolyn and ICSs are safe in pregnancy
- Inhaled corticosteroids are preferred long-term control medication
Asthma Clinical Pearls
-Steroids are the cornerstone of therapy
-As low of a dose of ICS is needed to maintain control of symptoms
-Assess PRN SABA use
Ensure every patient has a SABA for PRN use
-Patient education and environmental control
-Do not use LABAs alone
