History and exam
Key diagnostic factors
common
cough
An increase in cough may be the first symptom of an asthma exacerbation.
Atypical presentation with predominant cough should raise the possibility of pertussis infection, which can be a mimic or trigger of an asthma exacerbation.[1]
wheezing
Progressive worsening observed in an asthma exacerbation.
shortness of breath
Progressive worsening observed in an asthma exacerbation.
A patient with asthma in extremis without wheezing is likely to be on the verge of respiratory failure.
The degree of breathlessness is an aid in determining the severity of the exacerbation.
chest tightness
Can be a sign of impaired airflow.
sleep disturbance
Nocturnal awakenings due to uncontrolled asthma or asthma-induced cough are common and are one of the criteria commonly used to stratify recent asthma control.[1]
accessory muscle use
Use of accessory muscles, including the scalenes, parasternal, and sternocleidomastoids, during breathing is a sign of respiratory distress. Accessory muscle use is a sign of severe asthma exacerbation.[1]
tachypnea
Tachypnea is an important sign of dyspnea and airflow obstruction. A respiratory rate of >30 breaths/minute suggests a severe asthma exacerbation.[1]
tachycardia
A heart rate of <100 bpm is indicative of a mild exacerbation. A heart rate of 100 to 120 bpm is characteristic of a mild to moderate exacerbation and a heart rate >120 bpm suggests a severe exacerbation.[1]
wheezing, poor air movement, or diminished breath sounds
Noted on auscultation of lung fields.
Wheezing can indicate airflow obstruction. In severe exacerbations, wheezing may not be present (i.e., "silent chest").[1] This indicates that not enough air exchange is occurring to produce a wheeze, and is a sign of severe obstruction and life-threatening asthma exacerbation.
Auscultation sounds: Expiratory wheeze
Auscultation sounds: Polyphonic wheeze
uncommon
inability to speak
Inability to complete sentences as a result of dyspnea is a strong indicator of severe airflow obstruction and impending respiratory failure.
Other diagnostic factors
common
uncommon
stridor
May also indicate an alternative etiology of the clinical presentation, such as vocal cord dysfunction.
cyanosis
Indicates severe hypoxemia.
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