ASTHMA: DIAGNOSIS AND MANAGEMENT

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ASTHMA DIAGNOSIS AND MANAGEMENT

• Asthma Clinical Quality Team
• NMCSD
• 2004

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Burden of DiseaseGeneral

• 26 million adults and children in the USA have
  received a diagnosis of asthma sometime during
  their lifetime
• 8.6 million were under 18 years of age
• 10.6 million individuals experienced an asthmatic
  episode during the previous 12 months
• 3.8 million were children
• Hospitalizations increased 6.7 between1988 and
  1997

National Center for Health Statistics. Raw Data
from the National Health Interview Survey, US,
1997-1998. (Analysis by the American Lung
Association Best Practices Division, Using SPSS
and SUDAAN software)
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Burden of DiseaseDeath Rate, 1979 to 1997
1.8
Female
Male Female
1.6
Male
Deaths per 100,000 Population
1.4
1.2
1
0.8
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Year
National Center for Health Statistics. Raw Data
from the National Health Interview Survey, US,
1997-1998. (Analysis by the American Lung
Association Best Practices Division, Using SPSS
and SUDAAN software)
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Asthma definition

• Inflammatory airways disorder involving mast
  cells, eosinophils, PMNs, epithelial cells,
  macrophages and T cells.
• This inflammation leads to clinical sequelae of
  episodic bronchospasm (wheezing), breathlessness,
  chest tightness and cough
• Episodes are usually associated with variable
  airflow obstruction that is reversible

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Pathophysiology (inflammation)

• Allergens (or other inciting agents) in the
  airway trigger local inflammation which exists
  chronically (multiple cell types)
• Leads to airway hyperresponsiveness to various
  precipitants (cold air, exercise).
• In addition to smooth muscle spasm, see mucosal
  edema and mucus hypersecretion of the airways

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Clinical presentation

• Episodic wheezing, shortness of breath, coughing
  paroxysms
• Often related to specific triggers (cold air,
  exercise, post-viral URI)
• Patients will sometimes relate a history of
  frequent bronchitis as a child
• Often have a personal or family history of atopic
  disorders (AR, asthma,eczema)

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Diagnosing asthma

• Asthma is a clinical diagnosis. Historical and
  objective data must be combined to arrive at the
  diagnosis.
• History Cough, recurrent wheeze, SOB. Symptoms
  worsen with triggers such as allergen exposure,
  exercise, pollutants. Sx occur or worsen at
  night, resulting in awakening.
• Physical exam wheezing is not always asthma
  asthma pts dont always wheeze.

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Diagnosis

• Objective lung studies To document clinically
  suspected reversible airways obstruction,
  spirometry is used. There are 3 ways to
  document reversible obstruction.
• (1) Spirometry, pre- and post- inhaled
  bronchodilator therapy (eg, albuterol)
• (2) Spirometry before and after a course of
  sytemic or inhaled steroids.
• (3) Bronchoprovocation studies

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Spirometry diagnosis

• Classically, see a low FEV1 (amount of air
  expired in one second with maximal effort) with a
  decreased FEV1/FVC ratio (FVC is a rough measure
  of lung capacity) in an asthmatic with active
  disease.
• To document asthma, must see a greater than or
  equal to 12 increase in FEV1 post
  bronchodilator or after a course of steroids.
• Failure to see 12 increase or greater does not
  mean asthma excluded

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Bronchoprovocation

• Bronchoprovocation studies include cold air
  challenge, histamine challenge, exercise
  challenge, and methacholine challenge.
• All of these studies attempt to demonstrate the
  airway hyperresponsiveness seen in asthma.
  Useful in individuals where the diagnosis of
  asthma is uncertain.
• Methacholine challenge done by inhaling
  increasing doses of the agent, then performing
  spirometry. Asthmatics will have a decline in
  their FEV1 and FEV1/FVC ratio after this
  challenge.

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Methacholine challenge

• Looking for a drop of 20 or greater in FEV1 from
  baseline as a positive test. The dose that
  causes this drop is called the PD20.
• The lower the PD20 dose, the more supportive the
  result is of asthma diagnosis. Generally, a PD20
  of 8 mg/ml or less is considered positive. A
  higher PD20 could represent a false positive.
• A negative full dose challenge is strongly
  suggestive that the patient is not asthmatic.

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Positive methacholine challengeat 5mg/ml dose
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Precipitating/sustaining factorsfor asthma

• Allergen exposure
• Exercise
• Viral URIs
• Rhinosinusitis
• GERD

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Viral respiratory infections

• The vast majority (80) of acute asthma
  exacerbations are secondary to viruses
• Most common agent is rhinovirus
• Mechanism is poorly understood. Most plausible
  is that existing airway inflammation is
  up-regulated.
• Frequent handwashing and routine influenza
  vaccination can prevent viral-induced asthma
  exacerbations.

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Allergen exposure

• Estimated that 50 or so of asthmatics are
  atopic. In these individuals, allergens are
  believed to be a major driving factor in chronic
  inflammation.
• Most significant are indoor allergens dust mite
  and cat. Also important in some environments is
  cockroach. Outdoor aller-gens can also sustain
  airway inflammation.
• Elimination of indoor allergens mentioned above
  can result in disease improvement.

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Exercise-induced bronchospasm

• Probably not a distinct disease entity, but
  rather a subset of asthma.
• Those with symptoms exclusively during exercise
  are probably mild asthmatics who only get
  symptoms at the extremes of exertion.
• Classically, see worst symptoms and airway
  obstruction 5 to 10 minutes after exercise.
• Possibly due to cool,dry air inspiration that
  results in drying/irritation of bronchial mucosa

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GERD and asthma

• GERD has been proposed by many authors as a
  chronic and acute driving factor for asthma,
  likely via a vagal reflex.
• Role is controversial, but evidence mounting
  perfusion of acid into the esophagus leads to an
  increase in cough response and increased airways
  hyperresponsivess.
• Studies show medical treatment with PPI can
  improve asthma symptom control, but not objective
  lung studies (PEF,FEV1). Some studies suggest
  a 70 improvement in symptoms.
• Fundoplication may provide even better results
  than medical management.

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GERD and asthma

• Spivak et al (1999) looked at 39 pts who had
  fundoplication for GERD aggravating asthma. Sx
  improved overall, and 7 of 9 steroid dependent
  asthmatics able to d/c steroids
• GERD is probably worth investigating in asthmatic
  who is on multiple meds, poorly controlled, and
  has no other driving factors.
• Certainly, significant asthmatic with reflux
  symptoms should be started on empiric therapy

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Rhinosinusitis and asthma

• NIH guidelines recognize an association between
  asthma and rhinosinsitis that was first noted
  hundreds of yrs ago
• By unkown mechanism (neural?), inflammation of
  nose and sinuses appears to drive or worsen
  asthma in some individuals
• Most marked in those with opacified/ infected
  sinuses. Curing the sinus/nasal disease often
  markedly improves the asthma.

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Rhinosinusitis and asthma

• Rhinitis/asthma link supported by studies which
  show lower airway dynamics (FEV1, methacholine
  challenge) are affected by nasal allergen
  challenge. Also, exhaled lower airway NO (a
  marker of lower airway inflammation) is decreased
  by nasal steroid use.
• 2002 Harvard Pilgrim study (Adams et al) of all
  asthmatics in a managed care organization over a
  5 year period. Regular use of nasal steroids
  reduced ED visits for asthma by 30-50, depending
  on rate of use.

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Asthma classification

• NIH guidelines classify asthmatics into 4 groups
  based on severity
• Classification is important for physician
  communication and so appropriate therapy can be
  used based on published guidelines.
• NHLBI/NIH guidelines for the diagnosis and
  management of asthma available online
  www.nhlbi.nih.gov/guidelines/asthma

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Classification of Asthma Severity Clinical
Features Before Treatment

• Days With Nights With PEF
  or PEF
• Symptoms Symptoms FEV1
  Variability
• Step 4 Continuous
  Frequent ?60 ?30
• Severe
• Persistent
• Step 3 Daily
  ?5/month ?60-lt80 ?30
• Moderate
• Persistent
• Step 2 3-6/week
  3-4/month ?80 20-30
• Mild
• Persistent
• Step 1 ?2/week ?2/month
  ?80 ?20
• Mild
• Intermittent
• Footnote The patients step is determined by
  the most severe feature.

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Stepwise Approach to Therapy for Adults and
Children gtAge 5 Maintaining Control

• Step down if possible
• Step up if necessary
• Patient education and environmental control at
  every step
• Recommend referral to specialist atStep 4
  consider referral at Step 3

STEP 4 Multiple long-term-control medications,
includeoral corticosteroids
STEP 3 gt 1 Long-term-control medications
STEP 2 1 Long-term-control medication
anti-inflammatory
STEP 1 Quick-relief medication PRN
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Asthma therapy

• One goal of asthma therapy is to prevent symptoms
  that limit activity and/or result in missed
  school/work days
• Avoid hospitalizations/ER visits
• Avoid asthma deaths (3,000 - 5,000/year)
• Another goal Prevent unchecked inflammation
  that may lead to airway remodeling and
  irreversible damage

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Asthma therapy

• Obvious triggers, drivers of the airway
  inflammation should be treated and/or avoided if
  possible.
• Treat sinusitis, GERD.
• Full physical activity should not be discouraged.
• Allergen avoidance may be useful adjunct to meds
  (for identified indoor allergens).

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Pharmacotherapy(long-term control meds)

• Inhaled steroids
• Long-acting beta agonists
• Anti-leukotriene agents
• Theophylline

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Mild intermittent

• NIH guidelines dictate that patients may be
  treated with prn bronchodilators as long as
  symptoms continue to occur two or less times
  weekly and spirometry is normal (at baseline)

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Mild persistent

• Most easily remembered as patients with symptoms
  more than twice weekly (but not daily) who have
  normal baseline spirometry
• Require anti-inflammatory medication
• Vast majority of experts/clinicians use inhaled
  steroids as first line.
• Some advocate use of anti-leukotrienes

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Mild persistent

• Concern is that anti-LT drugs only attack one arm
  of the inflammatory process, while inhaled
  steroids have broader activity. So steroids
  preferred.
• Low dose inhaled steroids (e.g., Flovent 44
  mcg/puff 2 puffs BID or Azmacort 4 puffs BID)
  usually sufficient in this group.
• If not controlled with the above, pt is behaving
  more like a moderate persistent patient

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Moderate persistent

• Patient with daily symptoms/need for albuterol,
  or baseline FEV1 60-80 pred
• Three choices at this point
• (1) Going from low to medium dose steroids (eg,
  Flovent 110 2 puffs bid)
• (2) Add a long-acting bronchodilator
• (3) Add an anti-leukotriene agent (eg,
  Singulair)
• All are reasonable options. Which is correct?

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Moderate persistent

• Studies suggest that if pt not controlled on
  this, adding Serevent is the next best option
  (Busse et al, 1999 Kelsen et al, 1999). This is
  reflected in recently updated NIH guidelines,
  where the addition of a long-acting B-agonist is
  recommended prior to using higher dose inhaled
  steroids or leukotriene receptor antagonists.
• Therefore, option 2 is the most correct choice.

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Long-acting beta agonists (Serevent)

• If needed, these agents should only be used in
  conjunction with an anti-inflammatory medication
  (act synergistically).
• Serevent is available in combination with Flovent
  as Advair (100/50, 250/50, or 500/50).
• Therapy with Serevent alone may just be
  bronchodilating without any effect on the
  underlying inflammation. This can result in
  undesirable clinical outcomes.

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Severe persistent

• These are pts with contiual sx, baseline FEV1
  under 60, frequent nighttime awakenings,
  multiple hospitalizations and intubations.
• Need high dose inhaled steroid,Serevent, and
  possibly Singulair as well.
• Theophylline, and finally oral steroid may be
  needed to fully control such patients.
• A detailed investigation for causes of difficult
  to treat asthma should be undertaken

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Monitoring asthma therapy

• Patient self-reporting of asthma symptoms is
  variably reliable in assessing control.
• Important sx exercise tolerance, nighttime
  awakenings, prn albuterol use, missed school/work
  days
• NIH guidelines suggest that objective monitoring
  (periodic peak flow and/or spirometry) should be
  performed at regular intervals. This data should
  be combined with patient symptoms to direct
  therapy.

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Monitoring asthma

• Spirometry should be repeated at least every 1 to
  2 years to assess the maintenance of airway
  function (NIH guidelines).
• Peak flow meter use is recommended for moderate
  and severe asthmatics, especially those who
  perceive obstruction poorly.
• Patients should be given instructions on how to
  proceed depending on peak flow results (asthma
  action plan). Written asthma action plans
  specifically have been shown to improve outcomes.

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The Effect of a Peak Flow-Base Action Plan

• 150 asthmatics randomized to 1 of 3 groups
• No action plan
• Symptom-based plan
• Peak flow-based plan
• All received asthma education
• No plan
  PF plan Symptom
• 
  plan
• urgent care visits 55
  5 45
• admissions 12
  2 6

Cowie RL, et al. Chest 19971121534-38
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Peak Flow Symptom-Based Home Action Plan
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Managing exacerbations in ED

• Supplemental O2. Repeat albuterol/atrovent nebs
  (3). The practice of adding atrovent to albuterol
  improves outcomes
• If exacerbation initially seems severe, or pt not
  responding, systemic steroids are indicated
  (several hour effect time).
• Magnesium use is controversial little evidence
  of effect except possibly in very severe
  exacerbations
• If impending or actual respiratory failure
  occurs, pt may require intubation first.
• If patient fails to improve (doesnt reach 70
  of predicted or best PEF as a general guideline),
  hospitalization needed. High dose systemic
  steroids and frequent nebs the usual treatment
  course, with slow taper of steroids as an
  outpatient.