L23: Diarrhoea and acute GI illness Flashcards
Signs and symptoms of acute GI illnesses
Vomiting
Diarrhoea: acute, watery, bloody/dysentery, severe (>6/day)
Abdominal pain
Fever
Viruses - onset, symptoms, management
Onset: fast (hrs/day)
Probably diarrhoea, always vomiting, fever
Management: rehydration, no antibiotics
Bacteria - onset, symptoms, management
Onset: range
Always diarrhoea, probably vomiting, abdominal pain
Management: rehydration and sometimes antibiotics
Protozoa - onset, symptoms, management
Onset: slower (days/weeks)
Always diarrhoea, possibly vomiting, abdominal pain
Management: rehydration, probably antibiotics
Viruses
- Norovirus, rotavirus
- Fast onset
- Nausea and vomiting, watery diarrhoea, abdo cramps, muscle aches, low fever, headache
- Colonise small intestine
- Generally self-limiting (over in 48hrs)
- Supportive treatment with fluid replacement
- Be aware of outbreaks and potential for outbreaks
Bacteria mechanisms of action (3)
- Colonisation of intestine and production of toxins
- Colonisation of intestines and invasion of intestinal tissue
- Toxin produced in food and ingested (food poisoning)
Which bacteria colonise the intestine and produce toxins?
Clostridium difficile Shiga toxin producing E. coli* Shigella dysenteriae* Enterotoxigenic E. coli Vibrio cholerae (Often dysentery*, all begin with acute watery diarrhoea)
Which bacteria colonise the intestine and invade the tissue?
Campylobacter jejuni Non-typhoid salmonella Yersinia enterocolitica Enteroinvasive E. coli (may see blood in stool, abdo cramping common)
Which bacteria can produce toxins in food and be ingested?
S. aureus, Clostridium perfringens, Bacillus cereus
Vomiting within 2-7hrs of consumption
Symptoms cleared in 1-2 days
Protozoa
- Colonisation of small intestine
- Giardia lamblia, Cryptosporidium
- Food/water contaminated by human or animal faeces
- Incubation period of 1+ weeks, symptoms may last 4-6weeks
- Diarrhoea, flatulence, foul smelling stools, abdominal cramps
- Mostly self-limiting but may need antibiotics (metronidazole for giardia)
- Can cause serious illness in immunocompromised (esp. cryptosporidium)
- Chemical agents do not kill cysts (e.g. Cl tablets do not kill giardia, instead boil water)
Common causative agents in NZ
- Campylobacter
- Giardia lamblia
- Gastroenteritis (unknown cause)
- Salmonella
- Yersinia enterocolitica
Diarrhoeal disease in developing countries
- 2nd leading cause of death in children <5yrs
- Mainly affects children <2yrs
- Mainly: cholera, E. coli, rotavirus, norovirus
Transmission and outbreaks
Found in animal or human GI tract/faeces -> spread by oral/faecal route (direct or indirect)
Outbreak = 2 or more cases linked to common source
- Can be community-wide or person-to-person spread
- Norovirus outbreaks common
- Salmonella relatively high
Risk factors for acute GI illness
- Consume food from retail premises
- Consume at risk produce (soft cheese for listeria) or untreated water
- Contact with farm animals, faecal matter, symptomatic people, recreational water, sick animals
- Overseas travel with incubation period
Diagnostic tests for severe bacterial diarrhoea
Shigella, Campylobacter, Salmonella, Yersinia enterocolitica, Vibrio cholera (rice water stool, possibly seafood involved)
Stool sample (1 sample unless to confirm not a carrier - 3 tests required e.g. for a food worker Microscopy of limited value as large numbers of bacteria in faeces (wet mount can be helpful for motile bacteria e.g. campylobacter, vibrio
