When viewing this topic in a different language, you may notice some differences in the way the content is structured, but it still reflects the latest evidence-based guidance.

Last reviewed: 15 Mar 2025
Last updated: 24 Jan 2023

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • intractable cough
  • fever
  • dyspnoea
  • wheezing
  • hypoxia
  • crackles
  • reduced conscious level
  • cyanosis
  • bronchospasm

Risk factors

  • swallowing dysfunction
  • cerebrovascular disease
  • impaired conscious level (Glasgow coma scale score <9)
  • substance misuse
  • during general anaesthesia (or other oropharyngeal procedures) or in the intensive care unit
  • gastrointestinal disorder
  • older age
  • poor cough
  • increased severity of illness
  • upper gastrointestinal studies with barium
  • male sex
  • presence of a feeding tube
  • head and neck cancers
  • polytrauma
  • gastro-oesophageal reflux disease
  • supine position
  • obesity
  • drugs that reduce oesophageal sphincter tone

Diagnostic investigations

Investigations to consider

  • chest CT
  • bronchoscopy
  • arterial blood gas

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 deputy medical director of RCP Invited Service Reviews, and speaker at national meetings for organisations including the British Thoracic Society, Primary Care Respiratory Society, and Society for Cardiothoracic Surgery.

Disclosures

JB declares that he has no competing interests.

Melvyn Jenkins-Welch, MBBS, BSc, MSc, FRCA, FFICM

Consultant Critical Care Medicine

Cardiff and Vale ULHB

Cardiff

UK

Disclosures

MJW declares that he has no competing interests.

Acknowledgements

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

Madison Macht, MD

Volunteer Clinical Faculty

Division of Pulmonary Sciences and Critical Care Medicine

University of Colorado Denver

Aurora

CO

Disclosures

MM declares that he has no competing interests.

Peer reviewers

David G. Smithard, BSc, MB, MD, FRCP, FRCSLT (Hon)

Visiting Professor

University of Greenwich

Consultant in Elderly Medicine

Queen Elizabeth Hospital

Lewisham and Greenwich NHS Trust

Greenwich

UK

Disclosures

DGS declares that he has no competing interests.

Editors

Annabel Sidwell

Section Editor and Comorbidities Editor, BMJ Best Practice

Disclosures

AS declares that she has no competing interests.

Rachel Wheeler

Lead Section Editor, BMJ Best Practice

Disclosures

RW declares that she has no competing interests.

Adam Mitchell

Drug Editor, BMJ Best Practice

Disclosures

AM declares that he has no competing interests.

Use of this content is subject to our disclaimer