Diarrhoea Notes Flashcards
Give the definition of diarrhoea:
Inc. frequency + fluidity of stools (subjective)
Give the definition of Gastro-enteritis:
3 or more loose stools a day + accompanying features
Give definition of dysentery:
Large bowel inflammation –> bloody stools
What chart is used to look at stools?
Bristol Stool Chart
How many types does the bristol stool chart have?
Type 1 to Type 7
Gastro-Enteritis (GE): What are the sources of GE?
food contamination Storage of produce Travel related infections Isolated campylobacter cases Person to person spread
how is contamination of food a source of GE?
Due to increased intensity of farming
how is storage of food a source of GE?
due to increased bacterial proliferation at room temp
what is a travel related infection that causes GE?
Salmonella
what is the name of the person to spread virus that causes GE?
norovirus
What are some defence mechanisms against Enteric infections?
1) hygiene
2) stomach acidity: inc. susceptible when using PPIs/ antacids
3) Normal flora: when there is dec. flora then there is inc. C.diff
4) Immunity–> HIV –> Salmonella
What are the 2 types of diarrhoea?
1) Non-inflammatory/ Secretory- Cholera
2) Inflammatory
Describe Non-inflammatory/ Secretory- Cholera diarrhoea:
Secretory toxin mediated;
Cholera causes inc. cAMP levels + Cl (Chloride) secretion
Enterotoxigenic E.coli
Frequent watery stools with little abdominal pain
What is the treatment of Non-inflammatory/ Secretory- Cholera diarrhoea?
Rehydration
Describe inflammatory diarrhoea:
Inflammatory toxin damage + mucosal destruction = Pain + fever
Bacterial infection/ amoebic dysentery
Bloody + mucous diarrhoea
What is the treatment of inflammatory diarrhoea?
Treatment = rehydration
+ Antibiotics when appropriate
When assessing a patient with suspected Gastro-enteritis, what are you looking for?
1) Symptoms + duration; longer than 2 weeks–> unlikely to be GE
2) Risk of food poisoning
3) Hydration- how to check: postural BP/ skin turgor/ Pulse
4) Sepsis: Fever/ raised WCC
What investigations are used in Gastro-enteritis?
1) stool culture
2) blood culture
3) renal function
4) blood count: neutrophilia/ haemolysis
5) abdominal xray- toxic dilatation of colon
What are the differential diagnosis of someone with Gastro-enteritis?
1) Inflammatory bowel disease
2) Spurious diarrhoea- secondary to constipation
3) Carcinoma
4) Diarrhoea + fever can occur with sepsis outside gut ; lack of abdo pain/ tenderness, no blood/ mucous in stools
What is the general treatment of Gastro-enteritis?
1) Rehydration: IV/ Oral
2) Antimicrobials: Not routinely given
3) Treatment of complications
Name the 3 most common Gastro-enteritis pathogens:
1) Campylobacter Gastroenteritis
2) Salmonella Gastroenteritis
3) E.coli O157
Name some other bacteria that cause Gastro-enteritis:
shigella other forms of E.coli Staph aureus (toxin) Bacillus cereus (re-fried rice) Clostridium perfringens (toxin)
When do you give antibiotics with Gastro-enteritis?
GE WITH: -Immunocompromised -Severe sepsis/ invasive infection -Valvular heart disease -Chronic illness/ diabetes NOT IN HEALTHY PATIENTS WITH NON-INVASIVE INFECTIONS
The GE pathogen: Campylobacter Gastroenteritis: Describe it:
- Up to 7 days’ incubation
- Stools negative within 6 weeks
- Abdominal pain (can be severe)
- <1% invasive
- Commonest cause of bacterial food poisoning in UK
- Specialised culture conditions
- Isolated cases rather than outbreaks
What pathogen is responsible for being the most common cause of bacterial food poisoning in the UK?
campylobacter gastroenteritis
The GE pathogen: Salmonella Gastroenteritis: Describe it:
• Symptom onset <48 hours after exposure
• Diarrhoea lasts <10 days
• <5% positive blood cultures
• 20% patients have positive stools after 20 weeks
o Prolonged carriage may be associated with gallstones
• Post infectious irritable bowel is common
• Screened out as lactose non-fermenters antigen + biochemical tests
• Most common – Salmonella enteritidis + typhimurium
The GE pathogen: E.coli O157: Describe it:
• Infection from – Contaminated meat / person to person spread
• Typical illness characterised by frequent bloody stools
• Produced verocytotoxin that can get into blood (but E.coli itself stays in gut)
• Toxin can cause haemolytic-uraemic syndrome (HUS)
o Stimulates platelet activation clump and block capillaries
o RBCs cannot pass so break down (haemolysis)
o Occurs in mesangial cells renal failure + urea
When a patient presents with Clostridium Difficile diarrhoea , what do they usually have a history of?
previous antibiotic treatment
wide spectrum- wipes out normal flora
What are the treatment options for c.difficile diarrhoea?
- metronidazole
- oral vancomycin
- surgery
What are some preventative measures (prevention) for c.difficile diarrhoea?
- Reduction in prescribing of broad spectrum antibiotics
- Antibiotic management team
- Isolate symptomatic patients
- Wash hands between patients
what is the management of c.difficile diarrhoea?
- stop prescribing antibiotic
- metronidazole/ oral vancomycin
Parasites: Give 2 classes of parasites that can cause disease in humans?
Protozoa + helminths
How are parasitic infections diagnosed?
diagnosed by microscopy
Name 2 UK parasites:
Giardia lamblia & Cryptosporiduium parvum
Describe giardia lamblia:
o Contaminated water
o Diarrhoea / malabsorption / failure to thrive
o Cysts on stool microscopy
o Treatment – Metronidazole
What is the treatment of giardia lamblia?
metronidazole
Describe Cryptosporiduium parvum:
o Contaminated water (animal faeces)
o Cysts on microscopy
o No treatment
Name an imported parasite:
Entamoeba histolytica
What does Entamoeba histolytica cause?
amoebic dysentery
What is amoebic dysentery?
Amoebic dysentery is an infection of the intestines by a parasite causing diarrhoea that contains blood or mucus. Amoebic dysentery, also called amoebiasis, is caused by a single-celled parasite called Entamoeba histolytica. (from google so probs not important)
Describe Entamoeba histolytica – Amoebic dysentery:
o Vegetative form in symptomatic patient
o Cysts in asymptomatic patient
o Amoebic liver abscess – long term
What is the treatment for entamoeba histlytica- amoebic dysentery:
metronidazole
What is viral diarrhoea in children under 5 called?
Rotavirus in children under 5
What is viral diarrhoea called in people over 5?
Norovirus
Describe rotavirus:
o Common in winter
o Diagnosis by antigen detection
o Vaccine available
Describe Norovirus:
o Diagnosis by PCR
o Very infectious
o Strict infection control measures needed
