Resident Editor: Faren Clum, M.D.
Faculty Editor: Maria Wamsley, M.D.
BOTTOM LINE ✔ Constipation is extremely common but only rarely due to life threatening disease ✔ If feasible, discontinue meds that can cause constipation before considering testing ✔ Add suppository or enema if impacted or severely constipated |
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
Components of Severity |
Classification of Asthma Severity (Assign severity to the most severe category in which any feature occurs.) |
|||
Intermittent |
Mild Persistent |
Moderate Persistent |
Severe Persistent |
|
Symptoms |
<2 days/wk |
>2 days/wk |
Daily |
Throughout the day |
Nighttime awakenings |
≤2x/month |
3-4x/month |
>1x/wk |
Often nightly |
Short-acting beta agonist use for sx control |
≤2 days/wk |
>2 days/wk, not more than 1x/day |
Daily |
Several times daily |
Interference with normal activity |
None |
Minor limitation |
Some limitation |
Extreme limitation |
Lung function |
Normal FEV1 between exacerbations |
FEV1≥80% predicted; FEV1/FVC normal |
60%<FEV1<80% predicted; FEV1/FVC reduced 5% |
FEV1<60% predicted; FEV1/FVC reduced >5% |
Exacerbations requiring oral steroids |
0-1/yr |
≥2/yr |
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
Step 1 |
Short-acting beta-agonist as needed (for intermittent asthma as defined above) |
Step 2 |
Low-dose inhaled corticosteroid (ICS) Alternative: cromolyn, theophylline, montelukast |
Step 3 |
Low-dose ICS + long-acting beta-agonist Alternative: medium-dose ICS |
Step 4 |
Medium-dose ICS + long-acting beta-agonist |
Step 5 |
High-dose ICS + long-acting beta-agonist Consider tiotropium by mist inhaler Consider anti-IgE (omalizumab) or anti-IL-5 therapy (benralizumab, mepolizumab, reslizumab) for allergic (eosinophilic) asthma |
Step 6 |
High-dose ICS + long-acting beta-agonist + oral corticosteroids |
- 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] .