Asthma
Definition
Syndrome of recurrent episodes of airway obstruction in the setting of different airway inflammation
Pathophysiology
- Multiple mechanisms can lead to the syndrome of asthma
- Most common is atopic or allergic asthma
Epidemiology
- Most present before the age of 25
- History of atopy in around 80% of patients
- House dust mite is an important allergen causing asthma
- Respiratory tract viruses the most frequent trigger for exacerbation
Social Determinants of Health and Determinants of Equity
- Historically redlined census tracts in California (or the discriminatory practice of ranking non-white neighborhoods as too risky for credit resulting in only 2% of Federal Housing Authority mortgage insurance being available to non-white families) was associated with significant higher rates of ED visits related to asthma
- Addressing allergens in children who live in urban areas, a RCT found that a home-based comprehensive intervention for reducing indoor allergens decreased asthma-associated morbidity
Time Course
Chronic with recurrent paroxysmal exacerbations (precipitating factor should be evaluated)
Salient Symptoms and Signs
History
- During attack, shortness of breath with wheezing, cough, and anxiety
- Can only have cough, hoarseness, or inability to sleep through night (more common in adult patients)
- Important to identify any provoking stimuli
Physical Exam
- During attack, prolonged expiratory phase, hyperresonant chest to percussion, diminished tactile fremitus, classic polyphonic wheezing on expiration (softer on inspiration)
Diagnostics
- if normal spirometry (which may be the case since flares are intermittent), may try bronchial challenge testing which is usually performed with methacholine
- A reduction of FEV1 is very sensitive for asthma but not necessarily as specific
Treatment
- avoid triggers
- step-wise therapy with 1) short acting beta agonist (SABA) 2) + inhaled corticosteroid 3) + long acting beta agonist 4) higher doses 5) expert consultation
- for acute attacks in ED, give SABA + IV vs. PO corticosteroids
References
- Bryant-Stephens TC, Strane D, Robinson EK, Bhambhani S, Kenyon CC. Housing and asthma disparities. J Allergy Clin Immunol. 2021 Nov;148(5):1121-1129.
- Drazen, Jeffrey M., and Elisabeth H. Bel. “Asthma.” Goldman-Cecil Medicine, by Lee Goldman et al., Elsevier, 2019, pp. 527-535.
- Usmani, Omar S., and Peter J. Barnes. “Asthma: Clinical Presentation and Management.” Fishman’s Pulmonary Diseases and Disorders, Fifth Edition Eds. Michael A. Grippi, et al. New York, NY: McGraw-Hill, 2015.
- Morgan, Wayne J., et al. “Results of a Home-Based Environmental Intervention among Urban Children with Asthma.” New England Journal of Medicine, vol. 351, no. 11, 2004, pp. 1068–1080.
- Nardone A, Casey JA, Morello-Frosch R, Mujahid M, Balmes JR, Thakur N. Associations between historical residential redlining and current age-adjusted rates of emergency department visits due to asthma across eight cities in California: an ecological study. Lancet Planet Health. 2020 Jan;4(1):e24-e31.
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