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Last reviewed: 14 Mar 2025
Last updated: 14 Mar 2025

Summary

Definition

History and exam

Key diagnostic factors

  • intermittent abdominal pain
  • abdominal distention
  • nausea
  • vomiting
  • change in bowel habit
  • presence of risk factors
  • hard faeces
  • soft stools
  • empty rectum
  • recent weight loss
  • rectal bleeding
  • palpable rectal mass
  • palpable abdominal mass
  • tympanic abdomen
  • abnormal bowel sounds
  • fever
  • abdominal tenderness
  • abdominal rigidity

Risk factors

  • current or previous malignancy
  • diverticular disease
  • colonic volvulus
  • current or previous hernia
  • gynaecological conditions
  • diabetes
  • previous abdominal surgery
  • megacolon
  • laxative abuse
  • previous radiotherapy
  • diet

Diagnostic investigations

1st investigations to order

  • computed tomography
  • full blood count
  • electrolytes
  • C-reactive protein
  • urea/creatinine ratio
  • glucose
  • clotting, group and save, or cross-match
  • arterial blood gas (including lactate)
  • serum amylase/lipase

Investigations to consider

  • beta-human chorionic gonadotrophin
  • urinalysis
  • ultrasound
  • water-soluble contrast study
  • lower gastrointestinal endoscopy or flexible sigmoidoscopy

Treatment algorithm

Contributors

Expert advisers

Jennifer Straatman

Consultant Upper GI Surgeon

Queen Alexandra Hospital

Portsmouth

UK

Disclosures

JS declares that she has no competing interests.

Acknowledgements

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

George Malietzis, MBBS, MSc, MRCS

Colorectal Registrar

Department of Coloproctology

St Mark's Hospital

London

UK

John T. Jenkins, MD

Consultant Colorectal Surgeon

Department of Coloproctology

St. Mark's Hospital

London

UK

Disclosures

GM and JTJ declare that they have no competing interests.

Peer reviewers

Ceri Beaton, BMedsci, BMBS, MSc, FRCS

Consultant Colorectal and General Surgeon

North Devon Healthcare NHS Trust

Devon UK

Disclosures

CB declares that she has no competing interests.

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.

Sue Mayor

Lead Section Editor, BMJ Best Practice

Disclosures

SM works as a freelance medical journalist and editor, video editorial director and presenter, and communications trainer. In this capacity, she has been paid, and continues to be paid, by a wide range of organisations for providing these skills on a professional basis. These include: NHS organisations, including NICE, NHS Choices, NHS Kidney Care, and others; publishers and medical education companies, including the BMJ Group, the Lancet group, Medscape, and others; professional organisations, including the British Thoracic Oncology Group, the European Society for Medical Oncology, NCEPOD, and others; charities and patients’ organisations, including the Roy Castle Lung Cancer Foundation and others; pharmaceutical companies, including Bayer, Boehringer Ingelheim, Novartis, and others; and communications agencies, including Publicis, Red Healthcare, and others. She has no stock options or shares in any pharmaceutical or healthcare companies; however, she invests in a personal pension, which may invest in these types of companies. She is managing director of Susan Mayor Limited, the company name under which she provides medical writing and communications services.

Annabel Sidwell

Comorbidities Editor, BMJ Best Practice

Disclosures

AS 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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