Infections in the GI tract Flashcards
What is GALT?
Gut- associated lymphoid tissue
What is the peyers patch and why is it special?
Has M cells (microform cells)
Adapted to interact with molecules and particles within the lumen, take up antigens by endocytosis
Cell membrane at the base of these cells is folded around lymphocytes and dendritic cells
Antigens are transported through M cells by transcytosis and delivered to antigen-presenting cells and lymphocytes of the mucosal immune system
Why is Bacteria important in gut immune response?
If pathogen recognised signal innate immune system through specific receptors that binds to specific molecules on bacteria leading to release of peptides, cytokines and white blood cells
What are the functions of Gut microbiome?
Metabolism
Produce vitamins, synthesise amino acids, biotranform bile, digestion
Immune system development
Produce antimicrobial compounds and compete with other bacteria for nutrients and sites of attachment- barrier
GALT
Gut- brain axis
Stress influences the gut microbiome
What happens if there is an imbalance in gut microbiome?
Imbalance may cause Gastrointestinal conditions such as inflammatory bowel disease, Irritable bowel disease or even diabetes
What would you do if someone came in with what looked like gastroenteritis (diarrhoea)
History Normal history taking as well as travel and exposure history Examination Include hydration status Investigation Samples of stool Treatment Supportive with or without antimicrobials Implement infection prevention
Where is cambylobacter infections come from?
Lives in the GI tract of animals like poultry
How is cambylobacter infections transmitted?
by contaminated food, water or direct contact with animals or products
What organisms can cambylobacter be caused by?
C.jejuni and C.coli
What are the symptoms of a cambylobacter infection?
Symptoms- Abdominal pain, cramps, diarrhea, nausea, prodromal symptoms, colitis, may mimic appendicitis, may cause: cholecystitis, peritonitis, rash, pericarditis, myocarditis etc
May cause reactive arthritis and Guillain Barre syndrome after a long time
What is the treatment for Cambylobacter infections?
supportive and fluroquinolone
What are the features of a salmonella infection?
Half-3 days after exposure and Last 4-7 days
Salmonella bongori and salmonella enterica
Spreads via contaminated meat, eggs or milk, or faeco0oral
Treatment- oral rehydration and ceftriaxone
What are the features of a Shigella infection?
Develops after a day or 2 and lasts 5-7 days
Symptoms- diarrhea, fever, stomach cramps
Treatment- rehydration and ciprofloxacin
What are the features of norovirus?
Peak in winter, affects all ages, short lived immunity and reinfections can occur, outbreaks in hospitals, schools, nurseries etc
Faeco-oral person to person transmission
Viral particles in stool and vomit so can contaminate environment
Incubation period of 24-48 hours
Treatment- supportive e.g. fluids
Prevention- wash hands, isolation, environment cleaning, 48 hour rule
What can cause travellers diarrhoea and how is it spread?
Coccidian parasite is associated with travellers diarrhea and well as Giardia and Entamoeba
Faeco-oral transmission
What are the symptoms of travellers diarrhoea?
Anorexia, nausea, flatulence, abdominal cramps, watery diarrhea, low grade fever, weight loss
Abrupt single episode of illness or a waxing and waning course
Incubation period of 7 days after ingestion
Length of illness around 3 weeks
What is the treatment of travellers diarrhoea from coccidian parasite?
Treatment- Supportive, Trimethoprim
Longer and higher doses if Immunocompromised
How could you prevent travellers diarrhoea?
Attention to food hygiene when travelling
How can GI infections be prevented?
Infection can be prevented by:
Cleaning areas
Cooking and washing meats and animal products
Isolation
Washing hands
48 hour rules
This will stop the infection being spread
What are the main bacteria causes of diarrhoea?
Salmonella Campylobacter shigella enterotoxigenic E coli Clostridium difficile
What are the main virus causes of diarrhoea?
Norovirus
Rotavirus
Adenovirus
What are the main parasite causes of diarrhoea?
Cryptosporidium
Giardia
Cyclopora
Entamoeba
