GI: Diarrhoea + Food poisoning Flashcards
What causes acute diarrhoea?
Infection, typically bacterial
What does chronic diarrhoea indicate?
Underlying organic disease, e.g. ulcerative colitis, Crohn’s
What are the three classes of diarrhoea?
Osmotic
Secretory
Inflammatory
What is osmotic diarrhoea? What causes it?
Fluid is drawn into the intestine due to non-absorptive substances, producing watery stools
Diagnosis based on the fact the diarrhoea stops when the patient fasts or non-absorptive substance, e.g. laxative, is stopped
Could be caused by laxative abuse or a malabsorption defect
What is secretory diarrhoea? What causes it?
There is active secretion of fluids + electrolytes causing decreased absorption, producing watery stools
Diagnosis is based on the fact the diarrhoea persists when the patient fasts
Caused by toxins released from E.Coli + Cholera
What is inflammatory diarrhoea? What causes it?
Damage to the mucosa causes loss of fluid + blood, decreasing absorption and producing watery, bloody stools
Organic disease causes: Ulcerative colitis, Crohn’s, diverticulitis
Infective causes: shigella, salmonella, E.Coli O157, campylobacter
What are the symptoms of travellers diarrhoea? Which is the most common causative organism?
Diarrhoea Abdominal cramps Fever Nausea Vomiting
E.Coli O157
What does diarrhoea lasting weeks in duration after travel suggest?
Infection with protozoan parasites
Which organism is the most common cause of food poisoning?
Campylobacter
What foods does campylobacter typically colonise?
Poultry
Meat
Milk
What organisms are likely to cause outbreaks of food poisoning?
Salmonella and E.Coli O157
What foods does salmonella typically colonise?
Poultry
Eggs
Meat
What foods does E.Coli O157 typically colonise?
Meat
Milk
Water
What is the name of the toxin released by E.Coli? What condition can it cause?
Verotoxin
Haemolytic Uraemic Syndrome- commonest cause of renal failure in under 5’s
Which antibiotics are given in E.Coli O157 infection?
NONE!
Antibiotics will increase the amount of verotoxin produced
The appearance of ‘rice water stools’ suggests infection by which organism?
Cholera
Severe abdominal pain, diarrhoea and vomiting after raw milk suggests infection by which organism?
Campylobacter
Vomiting after eating re-heated rice suggests infection by which organism?
Bacillus cereus
Which virus is known as the winter vomiting bug? How is it spread?
Norovirus
Droplets + faecal oral
Which virus is the commonest cause of viral diarrhoea in children under 3? How is it spread?
Rotavirus
Faecal oral
How is norovirus/rotavirus diagnosed?
Stool/vomit PCR
Stool culture is appropriate for diagnosing which organisms?
Salmonella
Campylobacter
Shigella
Stool microscopy is appropriate for diagnosing which organisms?
Giardia
Amoebas
Paracites
Stool toxin analysis is appropriate for diagnosing which organisms?
E.Coli
C.Diff
Fever + salmon pink rash suggests what condition?
Typhoid, caused by salmonella
What is the incubation period for staph aureus and bacillus cereus?
SHORT
1-6 hours
What is the incubation period for Salmonella and Cl.Perfringens?
MEDIUM
12-48 hours
What is the incubation period for Campylobacter and E.Coli?
LONG
2-14 days
Which 3 markers assess the severity of C.Diff infection?
WCC greater than 15
High creatinine
Suspicion of colitis/toxicmegacolon
What is SIRS? What criteria?
Systemic inflammatory response syndrome
Temp over 38 or less then 36
RR over 20
WCC less than 4 or over 12
