ASTHMA

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ASTHMA

• By Dr Aguilera

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Definition

• Chronic inflammatory disorder of the respiratory
  airways which includes 3 components
• bronchial hyperresponsiveness to a variety of
  stimuli (i.e. allergens, respiratory viruses,
  environmental exposures and others)
• reversible airflow obstruction
• associated with recurrent episodes of respiratory
  symptoms (i.e. most commonly wheezing, SOB, chest
  tightness and cough)

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Pathophysiology

• Asthma has 2 mechanisms of reaction
• Allergen induced bronchoconstriction
• IgE mediated response? mast cell stimulation?
  mediators released
• Other stimuli induced bronchoconstriction
• Inflammatory mediated response? inflam cell
  stimulation? neuro/hormonal reflexes in the lungs
• Both cause edematous swelling of airway walls?
  hyperresponsiveness and ultimately ? airflow
  obstruction, which can occur in minutes, hours,
  days or weeks

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Epidemiology 2000

• Prevalence is increasing
• 17 million patients with asthma in the US
• Age
• gt18 yrs 11 million (62)
• 2-17 yrs 6 million (38)
• Race
• 8.9 million Caucasian (52)
• 3.5 million Latino (21)
• 3.3 million African American (19)
• 1.3 million other (8)
• Gender Male 42, Female 58

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Morbidity and Mortality

• Most often associated with failure to appreciate
  severity of exacerbation by pt and/or provider
• Deaths gt 5,000/year but decreasing overall since
  1990, probably due to better management from PCP
• Hospitalizations 466,000 in 2000
• 5 required ICU
• ED Visits
• 1.9 million in 2000
• females 2X gt than males
• the 11th most common diagnosis
• 20-30 of these required hospitalization

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Morbidity and Mortality Contd

• Costs gt 6 billion/year
• average annual cost/pt with attack 600 compared
  with 170 with no attack
• cost includes the 3 million lost workdays in the
  US per year
• Important Note Most ED visits, and therefore,
  hospitalizations are preventable. A useful
  practice is to assume that every exacerbation is
  potentially fatal.

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Risk factors for death from Asthma

• Past history of sudden, severe exacerbations
• Prior intubation
• Prior admission to ICU
• More than 2 hospitalizations in past year
• More than 3 ED visits in the past year
• Recent use/withdrawal from systemic steroids
• Comorbid conditions
• Difficulty perceiving severity of disease (more
  common in males)

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Asthma Attack Evolution

• Two different pathogenic scenarios involved
• Airway inflammation predominant
• pts show a progressive deterioration over 6
  hours, days or weeks (slow onset attack).
• The prevalence is 80-90 in adults and usually
  assoc with infectious causes.
• Have a slower therapeutic response
• Bronchospasm predominant
• Pts present with a sudden onset attack over
  minutes to 3-6 hrs (asphyxic or hyperacute
  attack).
• Usually associated with allergens, exercise and
  stress.
• Have a more rapid and complete response

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Diagnosis

• Usually cannot be done in the first visit
• History and Physical exam
• Classic triad
• Cough, SOB and wheeze
• Not all that wheezes is asthma and not all asthma
  wheezes.
• Presence of wheezing is a poor predictor of
  airflow obstruction, therefore need to use other
  findings
• Vital signs, RR, mentation, accessory muscle use

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Diagnosis Contd

• Pulmonary Funtion Testing
• Peak Expiratory Flow Rate (PEFR)
• Measured by age and height
• Spirometry with bronchodilator evaluation
• FEV1, FVC and FEV1/FVC ratio
• gt 80 predicted borderline obstruction
• 60-80 mild obstruction
• 40-60 moderate obstruction
• lt40 severe obstruction
• Serial testing over time
• Bronchoprovocation testing with methacholine
• Same deal as with exercixe stress testing in
  angina

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Diagnosis Contd

• CXR
• Only on initial evaluation
• Can see flattened diaghrams from hyperinflation
• Blood tests
• none
• Allergy testing
• Allergy skin test
• Blood radioallergosorbent test (RAST)

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Classification of Asthma
Stage Daytime symptoms Nighttime Symptoms PEFR of predicted FEV1 of predicted
Mild Intermittent Asthma lt 2x/wk lt 2 nights/wk gt80 lt20
Mild Persistent Asthma gt 2x/wk, but lt1x/day gt 2 nights/mo gt80, but fluctuates gt20 20-30
Moderate Persistent Asthma Daily Sx gt 1 night/wk 60 - 80 gt30
Severe Persistent Asthma Continual Frequent 4-7x/wk lt 60 gt30
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Overall Management

• 4 key component to success
• Patient Monitoring
• Controlling Triggers
• Pharmacotherapy
• Patient Education

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Overall Management contd

• Monitoring
• Peak Expiratory Flow Rate (PEFR) can be used to
  follow impact of change in therapy upon lung fxn
  and/or to assess severity of attack, NOT to
  detect presence of airflow obstruction
• Measurement is highly dependent on users
  technique
• Measure with patient standing and should be a
  evening trial
• Record best of 3 tries
• Pts should have device at home, however, to
  establish a baseline
• Encouraged to be used at least by pts with
  mod-severe disease
• Mixed data on whether or not home monitoring is
  beneficial
• For the future
• Sputum Eosinophilia as a marker for treatment
• Exhaled nitric oxide as a way to predict airway
  inflammation and asthmatic control

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Overall Management Contd

• Controlling Trigger Factors
• Identify and avoid triggers
• They vary from person to person and time to time
  (for females most commonly have exacerbations in
  premenstrual phase)
• Generally fall into 6 categories
• 1. Allergens (pollen), 2. Irritants (air
  pollutants), 3. Respiratory infections (viruses),
  4. Physical activity, 5. Chemicals (foods and
  drugs) and 6. Emotional stress. These are the
  main ones identified clinically
• Allergic rhinitis, chronic sinusitis, polyposis,
  GERD, menses, and pregnancy are others that may
  also contribute to exacerbations
• Once identified a.) avoid the trigger, b.) limit
  exposure if cannot be completely avoided, c.)
  take an extra dose of bronchodilator before
  exposure, but careful with exceeding normal
  amounts

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Overall Management Contd

• Pharmacologic Therapy
• This is the mainstay of management in most
  patients with asthma, and varies with type and
  severity of asthma.
• Relievers vs. Controllers
• Fast acting Slow acting
• Relieve bronchospasm Controls inflammation
• Stops symptoms Prevents symptoms
• Take PRN Take everyday

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Overall Management Contd

• Mild Intermittent Asthma (refer to prior slide)
• Includes exercise induced asthma
• Short Acting Inhaled beta-agonists Albuterol
  (Proventil, Ventolin)
• Rapid onset of action, get maximal potency of
  bronchodilation and minimal side effects.
• Encourage to use 10 minutes prior to exposure to
  a trigger
• Meter dose inhalers (MDIs) are now using
  ozone-safe propellants instead of
  chlorofluorocarbon (CFC)
• Alternate delivery forms have been developed
• Albuterol now comes in powder form
• Ipratropium (Atrovent) is NOT a good reliever for
  asthma
• Mast Cell Stabilizers (Cromolyn, Nedocromil)
• Have no benefit to relieve immediately asthmatic
  symptoms
• Limited role in adults

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Overall Management Contd

• Mild Persistent Asthma
• All Persistent asthmatics need a controller
• The assumption behind this recommendation is that
  regular medication use will reduce the frequency
  of symptoms, improve overall quality of life and
  decrease the risk of serious attacks and
  therefore lower the rate of ED visits and
  hospitalizations
• Inhaled Steroids
• The gold standard against which all other
  controlling therapy is compared
• Decreases mast cell and airway inflammation
• Side effects include
• Local effects (thrush, dysphonia, and bad taste)
• Systemic effects (cataracts, bone loss, increase
  IOP, growth suppression) are dose related, rare
  and occur particularly in prolonged, high dose
  users
• Using a spacer device is recommended in order to
  maximize medication delivery to the lung and
  minimize oral deposition
• No advantage to using albuterol immediately prior
  to inhaled steroid to achieve more lung
  deposition
• Using an inhaled steroid with a systemic oral
  steroid is not contraindicated, but should be
  limited

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Not All Steroids Are Created Equal
Drug Low dose Medium dose High dose
Beclomethasone MDI (Vanceril) 40 mcg 2-6 pfs/day 16-12 pfs/day gt12 pfs/day
Budesonide DPI (Pulmacort) 200mcg 1-3 pfs/day 3-6 pfs/day gt6 pfs/day
Flunisolide MDI (Aerobid) 250 mcg 2-4 pfs/day 4-8 pfs/day gt8 pfs/day
Fluticasone DPI (Flovent) 50mcg 2-6 pfs/day 100 mcg 6-12 pfs/day 250 mcg gt12 pfs/day
Triamcinolone MDI (Azmacort) 100 mcg 4-10 pfs/day 10-20 pfs/day gt20 pfs/day
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Overall Management Contd

• Moderate Persistent Asthma
• Incorporates the mild asthmatic receiving
  treatment, yet remain symptomatic
• Try to find the combination that works
• Long Acting Beta Agonists
• Formoterol (Foradil) and Salmeterol (Serevent)
• Both have similar characteristics, but Foradil
  has a faster onset of action (5 min vs 20 min)
• Inhaled meds that have long half lives which
  allow bid dosing. No longer in MDI, now in DPI
• Found to be less efficacious than inhaled
  steroids in improvement in lung fxn, control of
  Sx and amt of attacks
• Currently 2nd line after inhaled steroids, and
  not recom as monotherapy for mild asthma
• Combo therapy (Advair) with inhaled steroid has
  shown more benefit in mod-severe persistent
  asthma.

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Overall Management Contd

• Leukotriene Receptor Antagonists (LTRAs)
• Zafirlukast (Accolate) bid dosing
• Montelukast (Singulair) qday dosing and
  therefore is the favored one
• also approved for allergic rhinitis.
• tolerated well because of low side effect profile
• Approved down to age 2
• Currently positioned 3rd line, after inhaled
  steroids and long acting beta agonists.
• Have a varied response among individuals with
  asthma
• May be used as first line in very mild stage 2
  asthma
• May discontinue after 2-3 weeks in
  non-responders

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Overall Management Contd

• High-dose inhaled steroid
• Fluticasone 100 -250 mcg
• Budesonide 200 mcg
• As the dose of inhaled steroid increases, the
  likelihood of systemic absorption and potential
  for significant side effects from long term use
  also increases.
• Therefore, every effort should be made to reduce
  the dose of inhaled steroid, seeking to find the
  lowest dose that continues to maintain good
  control and minimize the risk of exacerbations
• Systemic effects are far less frequent than with
  systemic oral steroids
• Long-acting beta agonists
• LTRA

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Overall Management Contd

• Severe Persistent Asthma
• Patients who fail to achieve symptom control
  despite 2-3 controller medications
• Long-acting oral bronchodilator (theophylline)
• Used for its intrinsic anti-inflammatory effect,
  bronchodilation is considered secondary
• Increases ciliary motility, mucus clearance and
  diaphragmatic motility
• Not tolerated well because of Sfx nausea,
  cramps, diarrhea, and insomnia
• Narrow therapeutic index requiring check of serum
  levels
• Toxicity can result in seizures and death
• 24 hour preparations are preferred (Uniphyl)
• Currently 4th line, after inhaled steroids,
  long-acting beta agonists, and LTRA.
• Oral steroids
• Want to avoid as much as possible. If going to
  use, then use in short spurts or tapering regimens

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Overall Management Contd

• Choosing a treatment strategy

Start aggressively then step down once controlled Start with a single agent and step up until control is achieved
Controls symptoms quickly May take several months to achieve control
More side effects Less side effects
Recommended by NIH guidelines for asthma, expert panel report 2 Requires patience and very close follow-up
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Overall Management Contd

• Adjunctive Medications
• Treating comorbid conditions improves asthma
• Antihistamines
• Treating allergic rhinitis decreases
  responsiveness to triggers
• Nasal steroids
• Have been shown to improve symptoms in patients
  with both AR and asthma
• Some studies indicate benefit in asthma alone
• H2 blockers and/or PPIs
• Prevalence of GERD in asthmatics ranges from
  34-80 in various studies
• Improving reflux has been shown to improve control

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Overall Management Contd

• Patient Education
• Medication Myths
• Nebulizers offer improved medication delivery and
  are referable for more severe asthmatics
• MDIs used through a spacer can offer more
  efficient medication delivery at a fraction of
  the cost and time when compared to a nebulizer
• Inhaled steroids increase birth defects or are
  risky in pregnancy
• Recent studies have shown no increase in birth
  defects or decrease in birth weight with the use
  of any inhaled steroid
• Category B or C, except Azmacort D

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Overall Management Contd

• Asthma flow sheet (blue)
• Found on left side of chart, along with diabetic
  flow sheet
• Convenient tracking of symptoms, peak flows
• There is a cheat sheet on bottom of page for
  staging
• Can write on progress note see blue asthma flow
  sheet

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Overall Management Contd

• The Asthma Action Plan
• Helps patients and families understand complex
  regimen
• The Green Zone (PEFR gt 80 predicted)
• What to do on normal days
• The Yellow Zone (PEFR 50-80 predicted)
• Caution
• The Red Zone (PEFR lt 50)
• Danger

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• The End