Gastroenteritis and Infectious colitis

Question 1

Define:

Answer 1

• Acute inflammation of the lining of the GI tract, manifested by nausea, vomiting, diarrhoea and abdominal discomfort.

Question 2

Aetiology/risk factors:

Answer 2

• Caused by viruses, bacteria, protozoa or toxins contained in contaminated food or water (faecal-oral route)
• Common examples
o Outbreak of D+V in institutions: norovirus
o Dysentery: Shigella or E Coli O157
o Uni student with watery diarrhoea: C jejuni
o Rapid onset diarrhoea after a meal: S aureus or Bacillus cwreus
o Elderly on antibiotics: C difficile
o Traveller’s diarrhoea: E Coli
o Bloody diarrhoea (dysentery) can be caused by a

Commonly contaminated foods:
o Improperly cooked meat – S.aureus, C. perfringens
o Old rice – B cereus, S aureus
o Eggs and poultry - Salmonella
o Milk and cheeses – Listeria, Campylobacter
o Canned food – Botulinism

Question 3

Epidemiology:

Answer 3

Common.

Cause mortality and morbidity in developing countries.

Question 4

Symptoms:

Answer 4

• Sudden onset nausea, vomiting, anorexia
• DIARRHOEA (bloody or watery)
Note – dysentery is any type of gastroenteritis which causes bloody diarrhoea
• Abdominal pain or discomfort
• Fever and malaise
• IMPORTANT: enquire about recent travel, antibiotic use and recent food intake (how the food was cooked, sourced and whether anyone else is ill)

Time of Onset:
o Toxins = early (1-24 hours)
o Bacterial/viral/protozoal = 12+ hours

Pay attention to the other effects of toxins:
o Botulinum causes paralysis
o Mushrooms can cause fits, renal or liver failure

Question 5

Signs:

Answer 5

• Diffuse abdominal tenderness
• Abdominal distension
• Bowel sounds are often INCREASED
• In SEVERE gastroenteritis: pyrexia, dehydration, hypotension and peripheral shutdown

Question 6

Investigations:

Answer 6

• Bloods: FBC, blood culture (identify bacteraemia), U&Es (dehydration)
• C diff causes raised WCC
• Stool: faecal microscopy and analysis for toxins (particularly for the toxin causing pseudomembranous colitis (C. difficile toxin)
• AXR or ultrasound: exclude other causes of abdominal pain (e.g. bowel perforation)
• Sigmoidoscopy: usually unnecessary unless inflammatory bowel disease needs to be excluded

Question 7

Management:

Answer 7

• Bed rest – should stay at home until D+V cleared for 48h
• oral rehydration solution (contains glucose and salt)
• IV rehydration may be necessary in those with severe vomiting
• Most infections are self-limiting
• Antibiotic treatment is only used if severe or if infective agent has been identified

NOTE: if botulism is present (due to Clostridium botulinum) treat with botulinum antitoxin (IM) and manage in ITU

• C diff treatment:
• Isolate
• Oral metronidazole 10-14 days
• If refractory: vancomycin

Question 8

Complications:

Answer 8

• Dehydration
• Electrolyte imbalance
• Prerenal failure (due to dehydration)
• Secondary lactose intolerance (particularly in infants)
• Sepsis and shock
• Haemolytic uraemic syndrome (associated with toxins from E. coli O157)
• Guillain-Barre Syndrome may occur weeks after recovery from Campylobacter gastroenteritis
• NOTE: botulism can lead to respiratory muscle weakness or paralysis

Question 9

Prognosis:

Answer 9

Good as it is often self limiting