Gastroenteritis Flashcards
What is supportive managment?
No antibiotics
Fluids
Name 6 GI infections
Bacterial gastroenteritis Viral gastroenteritis Intra-abdominal sepsis Antimicrobial stewardship Parasites/Travel STI/HIV related infections Viral Hepatitis
How many deaths per year occur from GI illness?
1.4 Million
What are the 6 risk factors for GI infections?
Malnutrition Closed/Semi-closed communities Exposure to contaminated food/water/travel Winter congregating/summer flood Age <5 not breastfeeding Older age
What infections are most common due to Acid suppression?
Yersinia enterocolitica, Helicobacter pylori, Clostridium difficile, Vibrio cholera, Non-typhoidal Salmonella etc
What infections are most common due to Immunosuppression?
Salmonella
Campylobacter
Shigella
What are 6 bacterial factors that affect the likeliness of infection?
Adherence/attachment to the GI mucosa
Cellular invasion
Production of exotoxins
Changes in epithelial cell physiology
Loss of brush border digestive enzymes and/or cell death
Increased intestinal motility, net fluid secretion, influc of inflammatory cells and intestinal hemorrhage
What is inoculum size?
The median infecting dose required to cause disease in 50% of patients
What is diarrhoea?
>3 unformed stools/day No other cause Stool holds shape of container Departure from normal bowel habit Use Bristol stool chart
What is dysentery?
Inflammation of the intestine, particular the colon, causing diarrhea associated with blood and mucus
What organisms can cause dysentery?
Shigella
Campylobacter
How long is acute gastroenteritis?
<2 weeks
What bacteria may cause gastroenteritits?
Yersinia enterocolitica
What is gastroenteritis?
An illness causes by eating food contaminated with micro-organisms, toxins, poisons etc
What are important history features in gastroenteritis?
Diarrhoea frequency, blood, mucus, time course Other symptoms Epidemiology Food History Contacts Age Comorbidities Medication history
How long is a short incubation time?
1 to 6 hours
What food is likely to contain pre-formed toxins?
Starchy foods - reheated rice
Heat resistant spores
Causing Profuse vomiting
What is a preformed toxin in food?
Staph Aureus
Bacillus Cereus
What are the characteristics of traditional methods of laboratory identification?
Less expensive Slower More narrow Only live bugs grow Higher quality specimen required
What are the characteristics of molecular methods of laboratory identification?
Shorter turn around time Expensive Broad range No sensitivities Data interpretation
What are all stool samples tested for?
Salmonella Shigella Campy O157 Cryptosporidium C diff
who is my favourite Irish person?
Moya McDevitt
Shigella McDevitt
Ella for short
What do Shiga-toxin producing e-coli compete with?
Normal bacterial bowel flora
Where do the ST e-coli adhere to?
Intestinal epithelial cells
What is the process of Shiga toxin e-coli?
Compete with normal bacterial bowel flora,
Adhere to the intestinal epithelial cells, and elaborate Shiga toxin.
Toxins bind to absorptive enterocytes on the luminal surface of the small and large intestines, enter the cell, and irreversibly inhibit protein synthesis, resulting in death of enterocytes.
Shiga toxins can then enter the bloodstream via damaged intestinal epithelium and cause the death of vascular endothelial cells by the same mechanism.
Endothelial cell lysis is accompanied by platelet activation and aggregation, cytokine secretion, vascular constriction contributing to fibrin deposition, and clot formation within the capillary lumen.
Microangiopathy propagates distally as the toxins are carried to the kidneys, causing the clinical syndrome of hematuria and renal failure (HUS). The development of HUS is associated primarily with serotypes that produce Shiga toxin 2.
What are the 2 types of Agar used in EHEC?
McConkey agar
Sorbitol McConkey agar
Anti-sera for stereotypes
ELISA indentifies toxins
