Gastroenteritis

Pathology

Two main pathological processes are seen in acute gastroenteritis:

• Secretory diarrhoea: toxins interfere with the secretion or reabsorption of water and electrolytes from the small bowel
• Inflammatory diarrhoea: ileum/colon wall inflammation secondary to bacterial invasion/ toxin

Both features may coexist with the same pathogen.

Aetiology

Secretory

• Viruses: rotavirus, norovirus, coronavirus
• Bacteria: E. coli, Vibrio cholera, Bacillus cereus (typically from uncooked rice dishes), Campylobacter spp., Salmonella spp.
• Protozoa: Giardia intestinalis, Cryptosporidium parvum, Cyclospora cayetanensis

Inflammatory

• Viruses: rotavirus
• Bacteria: E. coli, Shigella spp., Campylobacter spp., Yersinia spp., Clostridium difficile
• Protozoa: Entamoeba histolytica, Balantidium coli

Symptoms

The main symptoms of acute gastroenteritis are anorexia, nausea and vomiting (especially in the first 24 hours), abdominal colic, diarrhoea, and fever.

Signs

Some of the physical signs of acute gastroenteritis are dehydration, fever, borborygmi, and abdominal tenderness.

Investigations

• Bloods: increased WCC in inflammatory diarrhoea, U&E
• Microscopy: stool cultures and microscopy

Treatment

Treatment of acute gastroenteritis usually consists of rehydration, which can be done orally with an rehydration solution, intravenously with IV fluids, and monitoring of fluid balance.

Complications

Complications of acute gastroenteritis may include dehydration and bacteraemic spread.

Prognosis

Frequent cause of infant mortality in developing countries, prognosis is an unavoidable and somber thought for many families. In adults, most are able to recover within a period of four days, although this is not guaranteed for all cases.