Episodic obstruction to air flow caused by allergens, infections (viral or bacterial), other triggers (smoke, pollution etc.)
Between episodes, airflow can be normal
Acute exacerbations present with sudden worsening of obstruction from combination of: bronchoconstriction, mucosal edema and increased mucous production
Over time, in particular if disease modifying treatments are not used (e.g. inhaled steroids) or ineffective, airflow obstruction can become irreversbile
Risk Factors
Family hx
Exposures to medications (e.g. aspirin) or environmental (e.g. pollen, ragweed, smoke, etc.) triggers
Symptoms
Recurrent bouts of wheezing, cough, clear or colored sputum
Often viral or allergen as precipitant
Often asx between episodes if well rx
Childhood onset common→can outgrow it/persist/or develop later in life
Physical Exam Findings
Wheezing on exam when symptomatic
Lungs can be clear if patient has no symptoms
As symptoms become more severe, patient is more compromised (i.e. can by tachynpenic, tachycardic, unable to speak more than a few words due to breathlessness, seated up right in effort to improve respiratory mechanics)
Diminished or absent breath sounds are an ominous finding in setting acute exacerbation (ie indicate little or no air movement)