Table 1

Differential diagnosis of asthma

Subjective assessmentObjective examination
History of: Episodic wheezingGeneral findings include wheeze and increasing dyspnoea
Nocturnal cough Moderate acute asthma:
Previous diagnosisPEFR>50% normal (table 2)
Previous episodes requiring intervention additional to maintenance drug therapyNormal speech Respirations<25
Increasing dyspnoea and wheezePulse<110
Decreasing wheeze in the absence of recovery is a serious finding suggesting grossly inadequate ventilationSevere acute asthma: PEFR 33–50% of normal (table 2)
Precipitating factor, including infection, exercise, exposure to allergen, exposure to cold airCannot complete sentences Respirations⩾25
Other atopy (for example, eczema, hay fever)Pulse⩾110
History of previous hospital admission (particularly ICU)/need for ventilation is cause for significant concern, suggesting brittle asthmaLife threatening acute asthma: PEFR<33% of normal (table 2)
Asthma medications may be evident (inhalers with β2 agonists and corticosteroids are usual in adults; nebulisers and oral corticosteroids suggest more significant problems)Spo2<92% on air/<95% on oxygen Silent chest (no wheeze) Cyanosis
Patient or other household residents may smokeFeeble respiratory effort
Possible limitations in activities of daily livingBradycardia or arrhythmia
Exhaustion, changed mental status, or falling GCS