Gastroenteritis

Definition/diagnostic criteria Gastroenteritis is defined as inflammation of the gastrointestinal tract, primarily the stomach and small intestine, leading to symptoms such as diarrhoea, vomiting, abdominal pain and cramping. It is commonly caused by a variety of pathogens including viruses, bacteria and parasites. In the UK, diagnostic criteria involve the acute onset of diarrhoea (≥3 loose stools in a 24-hour period) typically accompanied by vomiting or nausea, with symptoms lasting less than two weeks.

Epidemiology Gastroenteritis is a significant health concern in the UK, affecting all ages but predominantly children and the elderly. It’s a leading cause of hospital admission for children. Viral gastroenteritis, particularly norovirus and rotavirus, accounts for the majority of cases. Bacterial infections such as Campylobacter, Salmonella and Escherichia coli, while less common, are significant causes of foodborne illness. The disease’s prevalence peaks in winter months, especially for viral causes.

Diagnosis
Clinical features: Clinical diagnosis primarily depends on symptom presentation.

• Key features include sudden onset of diarrhoea, vomiting, abdominal pain, and sometimes fever.
• The illness is usually self-limiting. Severity can vary from mild, watery diarrhoea to severe, bloody diarrhoea with dehydration, especially in vulnerable populations.

Investigations: Laboratory investigations are not routinely recommended for all patients but are reserved for severe, persistent, or bloody diarrhoea, suspected outbreaks, or in vulnerable groups.

• Stool cultures can identify the causative organism.
• Blood tests may be needed in severe cases to check for dehydration or electrolyte imbalance.
• Typical abnormalities include raised inflammatory markers or electrolyte imbalances in severe cases.

Treatment Management primarily focuses on hydration and symptomatic relief.

• Oral rehydration solutions are recommended, especially for at-risk populations.
• Antiemetic and anti-diarrhoeal medications may be used in certain cases but are generally not recommended for children.
• Antibiotics are not routinely used but may be necessary for specific bacterial infections or in severe cases.
• Advice on hygiene and preventing spread is crucial, especially in norovirus outbreaks, where isolation and stringent cleaning are important.

Prognosis Most cases of gastroenteritis are self-limiting and have a good prognosis with appropriate management of symptoms and hydration. Complications can include severe dehydration, particularly in young children and the elderly, and post-infection irritable bowel syndrome. Recurrence can occur, especially in viral causes or if hygiene practices are not adequately followed. Long-term effects are rare but can include persistent diarrhoea or, in cases of certain bacterial infections, conditions like reactive arthritis or Guillain-Barré syndrome.

References:

• NICE CKS: Gastroenteritis. 2023.
• Public Health England. Norovirus: managing outbreaks in acute and community health and social care settings. 2012.