Asthma

Definition and epidemiology (Lancet 2018;391:783)

  • Chronic inflam disorder w/ airway hyperresponsiveness + variable airflow obstruction
  • Affects 5–10% population; ~85% of cases by age 40 y

Clinical manifestations (NEJM 2013;369:549)

  • Classic triad = wheezing, cough, dyspnea; others include chest tightness, sputum; symptoms typically chronic with episodic exacerbation
  • Precipitants (triggers)
    • respiratory irritants (smoke, perfume, etc.) & allergens (pets, dust mites, pollen, etc.)
    • infections (URI, bronchitis, sinusitis)
    • drugs (eg, ASA & NSAIDs via leukotrienes, βB via bronchospasm, MSO4 via histamine)
    • emotional stress, cold air, exercise (increase in ventilation ies out airways)