Asthma

Etiology

  • 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)

Tests

Links