Resident Editor: Faren Clum, M.D.

Faculty Editor: Maria Wamsley, M.D.

Background

• Asthma affects 5% of Americans; prevalence increasing
• Chronic inflammatory disease of the airways, with airway hyper-responsiveness, reversible airflow limitation, and respiratory symptoms.

Signs and symptoms

• Wheezing, intermittent dyspnea, cough, difficulty taking a deep breath, chest tightness
• Consider in all adults with chronic cough (especially if nocturnal, seasonal, or occupational).

Differential diagnosis

• COPD
• interstitial lung disease
• vocal cord dysfunction
• CHF
• Bronchiectasis
•  OSA
• CF
• pulmonary hypertension
• GERD
• BPA, Churg-Strauss
• hypersensitivity pneumonitis
• pneumoconiosis
• PE:
•  “Not all that wheezes is asthma.”

Evaluation

• History – assess symptoms (cough, SOB, chest tightness), limitations in activity, frequency of use of short-acting inhalers at every visit; evaluate,frequency and severity of past attacks (history of intubation, number of ED visits, use of oral steroids), medication adherence and side effects
• Physical – can be normal!
  • wheezing, hyperexpansion, and prolonged expiratory phase during flares
  • non-asthma diagnoses: dry crackles, focal wet crackles, abnormal cardiac exam, clubbing
• Diagnostics –
  • Spirometry: FEV1/FVC <0.70 defines obstruction
  • Reversibility of airflow obstruction defines asthma (increase in FEV1 >200mL OR > 12% from baseline after bronchodilator)
  • FEV1 (% of normal) correlates with severity
  • Normal spirometry does not rule out asthma; if clinical history still concerning, proceed to methacholine challenge (bronchoprovocation test), which is sensitive and has high negative predictive value.
  • Peak flow: best used as a monitoring, not diagnostic tool.

Table 1: NHLBI Asthma Classification, 2007

Treatment

Goals of therapy are to reduce impairment and reduce risk. With treatment, patients should fall into “intermittent” category for sx frequency and severity.

Table 2: Stepwise therapy for asthma

• Rescue therapy with short-acting bronchodilator is required for all stages.
• Step up (and step down) therapy as above based on symptom severity and frequency
  • Before stepping up therapy check diagnosis, med adherence, inhaler technique.
  • Consider step down if asthma is well-controlled for 3 months. Patients are likely to do well with step down if they have filled 3 or fewer rescue inhalers and had no more than 1 exacerbation in the past 12 months.
  • In appropriate patients there is no increase in exacerbations when ICS or ICS/LABA dose decreased
  • Risk of exacerbation may be decreased if LABA or leukotriene receptor antagonist added while decreasing ICS dose
  • Stopping ICS or LABA entirely carries greater risk of exacerbation
  • SIDE EFFECTS of inhaled corticosteroids (ICS): cough, candidiasis, hoarseness, dysphonia.
    • For high doses there may be risk of systemic effects:  osteoporosis, glaucoma, cataracts, dermal thinning, adrenal suppression
• Patient education: teach proper MDI use, peak flow measurements, and asthma triggers; create an “asthma action plan” based on peak flow and symptoms; use anticipatory short-acting preventive bronchodilators if patients know they will be exposed to triggers.
• Avoid triggers: inhaled allergens (animal/cockroach/outdoor allergens, house-dust mites, indoor fungi/molds), respiratory irritants (though inadequate evidence to recommend routine air cleaning/dehumidifiers), industrial cleaning agents (ask about pt employment), sulfites (found in preservatives and wine; may trigger attacks in 5% of patients), medications (including NSAIDs and beta-blockers, even the small amount found in glaucoma drops), cold weather, exercise
• Vaccination: Pneumovax, yearly influenza

Acute exacerbations

• Most common causes are URIs, allergies, cold temperature, medication nonadherence
• All patients should have a step-wise asthma action plan
• Present to an urgent care or ED if unable to control symptoms at home, if peak flow reduced etc.
• Oral corticosteroids are mainstay (eg prednisone 60 mg po daily) x5-14 days
• Antibiotics are NOT part of treatment
• When to hospitalize – no clear-cut guidelines, but consider hospitalization when post-clinic or ED treatment peak flow remains <70% of predicted.
• Risk for fatal asthma attack increased with prior intubation, multiple exacerbations, ED visits for asthma, low corticosteroid adherence, low SES.

When to Refer

Pulmonary:

• Before provocative pulmonary function testing
• Difficulty controlling symptoms on combination ICS + LABA
• Patients requiring oral steroids >2x/year or hospitalized for exacerbations
• Patients who have experienced life-threatening exacerbations

Allergy:

• referral for allergy testing if strong seasonal or allergic component
• such patients may benefit from immunotherapy or anti-IgE (omalizumab) or anti-IL-5 therapy (benralizumab, mepolizumab, reslizumab)

References

Apter, A. Advances in adult asthma diagnosis and treatment and HEDQ in 2010.  J Allergy and Clinical Immunology. 2011. 127(1): 116-22.

Dinakar, C. Update on asthma step-therapy.  Allergy and Asthma Proceedings. 2010. 31 (6): 444-51.

Gionfriddo, Michael R, et al. “Why and How to Step down Chronic Asthma Drugs.” Bmj, 2017, doi:10.1136/bmj.j4438.

Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention, 2018. Available from: www.ginasthma.org

Lapi F. et al. The use of inhaled corticosteroids and the risk of adrenal insufficiency. Eur Respir J. 2013 Jul;42(1):79-86.

NHLBI. Expert panel report III: Guidelines for the diagnosis and management of asthma. Bethesda, MD: National Heart, Lung, and Blood Institute. 2007.  Available at: http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm. Accessed April 12, 2018 [MW1] .

Panettieri RA. In the clinic: asthma. Annals of Internal Medicine. June 5, 2007:ITC6.1-ITC6.16.

Wechsler, M. Managing Asthma in Primary Care. Mayo Clin Proc. 2009. 84(8): 707-71[MW2] .