Endgames OnExamination Question

Asthma

BMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c3779 (Published 21 July 2010) Cite this as: BMJ 2010;341:c3779

This week’s question is on asthma and is taken from the OnExamination revision questions for the MRCP Part 1 exam.

Which of the following signs and symptoms, if any, indicate a severe asthmatic attack in a teenager?

  • A A peak expiratory flow rate of less than 50% of predicted rate

  • B A respiratory rate of more than 25 breaths a minute

  • C A PaCO2 of more than 37.5 mm Hg (5.0 kPa)

  • D A PaO2 of 67.5 mm Hg (9 kPa)

  • E Loud expiratory and inspiratory wheezes

Answer

Answers A, B, C, and D are correct; answer E is incorrect.

Defining asthma severity is difficult, as accounts in the literature vary. However, severity can be estimated using the “5 Ps”:

  • Pulse rapid (or slow)

  • PaCO2 normal or high

  • PaO2 reduced

  • Peak expiratory flow rate less than 50% of predicted rate

  • Pulsus paradoxus (that is, blood pressure declines as the patient inhales and increases as the patient exhales)

The following signs are also indicative:

  • Silent chest (suggests life threatening asthma if present)

  • Limited speech

  • Respiratory rate of more than 25 breaths a minute

The British Thoracic Society1 defines acute severe asthma as any one of the following:

  • Peak expiratory flow rate of less than 50% of predicted rate

  • Respiratory rate of 25 breaths a minute or more

  • Pulse rate of 110 beats a minute or more

  • Cannot complete sentences in one breath

Notes

Cite this as: BMJ 2010;341:c3779

Footnotes

References

View Abstract

Sign in

Log in through your institution

Subscribe