Last reviewed: 25 Sep 2021
Last updated: 25 Feb 2021



History and exam

Key diagnostic factors

  • presence of risk factors
  • diarrhoea
  • nausea and vomiting

Other diagnostic factors

  • abdominal pain
  • bloating
  • fever
  • dehydration
  • blood or mucus in stool
  • profuse rice-water stool
  • reactive arthritis
  • skin changes
  • difficulty swallowing
  • diplopia
  • slurred speech
  • weakness
  • hepatobiliary disease
  • pulmonary symptoms
  • other intestinal features
  • manifestations of ectopic infection

Risk factors

  • older people, children, and pregnant women
  • chronic disease
  • recent history of travel
  • immunocompromised state
  • history of contact with cases of food poisoning
  • consumption of undercooked meat
  • consumption of raw seafood
  • consumption of homemade canned foods
  • consumption of unpasteurised soft cheeses
  • consumption of deli meats
  • consumption of unpasteurised milk or juice
  • consumption of raw eggs
  • improper food handling and storage
  • gastric acid suppression

Diagnostic investigations

1st investigations to order

  • stool microscopy for WBC and red blood cells (RBC)
  • stool culture
  • stool O+P
  • FBC with differential
  • serum creatinine and electrolytes

Investigations to consider

  • stool/serum botulinum toxin detection test
  • blood culture
  • serum lipase or amylase
  • LFTs
  • hepatitis A IgM antibodies
  • hepatitis E IgM antibodies
  • acute abdominal series
  • sigmoidoscopy/colonoscopy
  • oesophagogastroduodenoscopy
  • biopsy
  • duodenal aspirate
  • polymerase chain reaction (PCR) of stool

Treatment algorithm



Philip Allan, MBBS, DPhil, FRCP

Consultant Gastroenterologist

Department of Gastroenterology

John Radcliffe Hospital




PA has consulted for Takeda (Shire) and BaxterHealthcare. PA has received travel, accommodation, and conference fees from Takeda (Shire).


Dr Philip Allan would like to gratefully acknowledge Dr Satish Keshav, Dr Michael Bennish, Dr Willem J.S. de Villiers, and Dr Houssam E. Mardini, the previous contributors to this topic. Unfortunately, we have been made aware that Dr Satish Keshav has passed away.


MB received funds, salary, and/or research funding greater than 6 figures USD. MB declares that he has no other competing interests. WJSDV and HEM declare that they have no competing interests.

Peer reviewers

Franz Allerberger, MD, MPH

Professor of Clinical Microbiology

Austrian Agency for Health and Food Safety (AGES)




FA declares that he has no competing interests.

Nancy Crum-Cianflone, MD, MPH

Department Head

Naval Health Research Center

San Diego



NCC declares that she has no competing interests.

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