Features of a severe attack

In a severe attack the patient may be fearful and exhausted. Various clinical features are significant in assessing its severity:

• difficulty in speaking: the patient is so tachypnoeic and breathless that they have difficulty in forming phrases or sentences
  
  
• tachycardia - greater than 110 per minute; in a very severe attack the pulse becomes bradycardic
  
  
• pulsus paradoxus - this indicates severe airflow limitation
  
  
• silent chest - in a patient who is extremely breathless this implies that airflow restriction is severe enough to totally restrict airflow to parts of the lung
  
  
• drowsiness due to hypercapnia - this occurs only in a preterminal attack and is a very sinister sign
  
  
• cyanosis may also occur in the preterminal state

Investigations may reveal type II respiratory failure.