Last reviewed: 19 Sep 2021
Last updated: 08 Jul 2021

Summary

Definition

History and exam

Key diagnostic factors

  • shortness of breath
  • cough
  • wheeze
  • risk factors
  • progressive chest tightness
  • progressive decrease in lung function
  • tachypnoea
  • tachycardia
  • silent chest
  • accessory muscle use
  • sleep disturbance

Other diagnostic factors

  • exercise limitation
  • collapse
  • altered consciousness
  • skin symptoms
  • cyanosis
  • arrhythmia
  • hypotension
  • exhaustion
  • stridor

Risk factors

  • viral infection
  • uncontrolled asthma symptoms
  • high use of short-acting beta-2 agonists
  • inadequate use of inhaled corticosteroids
  • incorrect inhaler technique
  • low forced expiratory volume in 1 second (FEV1)
  • high bronchodilator reversibility
  • current smoker or exposure to second-hand cigarette smoke
  • exposure to allergens (including history of seasonal allergic rhinitis)
  • atopic eczema
  • air pollution
  • poor indoor air quality
  • obesity
  • chronic rhinosinusitis
  • gastro-oesophageal reflux disease
  • confirmed food allergy
  • history of asthma
  • history of hospitalisation for asthma exacerbations
  • one or more severe exacerbations in the last 12 months
  • use of oral corticosteroids
  • poor adherence to asthma treatment
  • pregnancy
  • blood eosinophils
  • elevated fractional exhaled nitric oxide (FeNO)
  • respiratory bacterial infection

Diagnostic investigations

1st investigations to order

  • arterial blood gas (in hospital)
  • peak flow (in the community and in hospital)
  • pulse oximetry (in the community and in hospital)
  • chest x-ray (in hospital)

Investigations to consider

  • full blood count (in hospital)
  • urea and electrolytes (in hospital)
  • C-reactive protein (in hospital)
  • theophylline levels (in hospital)
  • ECG (in hospital)

Treatment algorithm

Contributors

Expert advisers

Jonathan Bennett, MD

Honorary Professor of Respiratory Sciences

University of Leicester

Respiratory Consultant

Glenfield Hospital

Leicester

UK

Biography

JB is Chair of the British Thoracic Society.

Disclosures

JB declares that he has no competing interests.

Richard Russell, MBBS, PhD, MRCP

Specialty Registrar in Respiratory Medicine

Glenfield Hospital

Leicester

UK

Disclosures

RJR received sponsorship from AstraZeneca to attend a conference, May 2018 (covering travel, accommodation, and conference fee).

Acknowledgements,

BMJ Best Practice would like to gratefully acknowledge the previous expert contributors, whose work has been retained in parts of the content:

Sourav Majumdar, MD

Clinical Assistant Professor (Affiliated)

Division of Pulmonary, Allergy and Critical Care Medicine

Department of Medicine

Stanford University School of Medicine

Stanford

Lauren Eggert, MD

Fellow

Division of Pulmonary, Allergy and Critical Care Medicine

Department of Medicine

Stanford University School of Medicine

Stanford

Disclosures

SM and LE declare that they have no competing interests.

Peer reviewers

Pujan H Patel, MD

Consultant in Respiratory Medicine

Royal Brompton Hospital

London

UK

Disclosures

PP has received speaker fees for educational lecture events from GlaxoSmithKline.

Editors

Emma Quigley,

Section Editor, BMJ Best Practice

Disclosures

EQ declares that she has no competing interests.

Tannaz Aliabadi-Oglesby,

Lead Section Editor, BMJ Best Practice

Disclosures

TAO declares that she has no competing interests.

Julie Costello,

Comorbidities Editor, BMJ Best Practice

Disclosures

JC declares that she has no competing interests.

Adam Mitchell,

Drug Editor, BMJ Best Practice

Disclosures

AM declares that he has no competing interests.

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