GI Infections Flashcards
What is dysentery?
Bloody diarrhoea due to infection of GI tract causing inflammation
What is meant by gastroenteritis?
Non-specific term used to characterise symptoms of acute diarrhoea, nausea, vomitting and abdo pain. It is often used loosely to be synonymous with infective diarrhoea.
State some potential causative organisms of gastroenteritis
- Clostridium difficile
- Camplylobacter jejuni
- Salmonella spp.
- Shigella
- Bacillus cereus
- E-coli (ETEC)
- E-coli (EHEC, 0.157:H7)
- Giardia lamblia
- Entamoeba histolytica
- Norovirus
- Rotavirus
For campylobacter jejuni, state:
- Source
- Clinical features
- Management
- Potential complications
- Contaminated water, animal droppings, unpasteurised milk
-
Clinical features:
- Fever
- Dysentery
-
Management:
- Self limiting for first 7 days
- Severe forms may respond to erythromycin
-
Complications:
- Guillian-Barre syndrome
- Reactive arthritis
For salmonella spp, state:
- Source
- Clinical features
- Management
- Potential complications
- Contaminated water, foods (eggs, poultry, meat)
- Clinical features:
- Dysentery
- Vomitting
- Abdo pain
- Fever
- Management:
- Usually self-limiting
- Ciprofloxacin can be used if bacteraemia
- Complications
- Reactive arthritis
For shigella, state:
- Source
- Clinical features
- Management
- Potential complications
- Contaminated food & water (spread via faecal oral route)
- Clinical features:
- Dysentery
- Colicky abndo pain
- +/- fever
- Management:
- Ciprofloxacin
- Improve hand hygiene
- Complications:
- Reactive arthritis
For Bacillus cereus, state:
- Source
- Clinical features
- Management
- Reheated rice or sauces
- Clinical features:
- Watery diarrhoea
- Vomitting
- Management:
- Self limiting (24-48hr)
For Listeria monocytogenes, state:
- Source
- Clinical features
- Management
- Potential complications
- Unpasteurised milk, cheese, raw meats
- Clinical features:
- Watery diarrhoea
- Colicky abdo pain
- Vomitting
- Management:
- Ampicillin
- Complications:
- Pneumonia
- Meningoencephalitis
For Escherichia coli (ETEC), state:
- Source
- Clinical features
- Management
- Most common cause of traveller’s diarrhoea
- Clinical features:
- Watery diarrhoea
- Vomitting
- Management:
- Self limiting (3-5 days)
- Ciprofloxacin may be considered
For Escherichia coli (EHEC, 0157:H7) state:
- Source
- Clinical features
- Management
- Potential complications
- Contaminated food products (usually occurs as outbreaks)
- Clinical features:
- Dysentery
- Constant abdo pain
- Management:
- Supportive (antibiotic therapy may worsen symptoms)
- Haemodialysis if required
- Complications:
- Haemolytic uraemic syndrome
What is haemolytic uraemic syndrome?
Haemolytic uraemic syndrome is a form of thrombotic microangiopathy affecting predominantly the kidney and characterised by a triad of thrombocytopenia, mechanical haemolytic anaemia, and acute kidney injury.
Most cases of HUS occur in children and are due to infection with Shiga Toxin producing E-coli (EHEC, 0157:H7)
For Giardia lamblia, state:
- Sources
- Clinical features
- Management
- Contaminated water, common in tropics
- Clinical features:
- Offensive diarrhoea
- Vomitting
- Abdo pain
- Distension
- Management:
- Tinidazole stat and metronidazole for 10 days
For cryptosporidiosis, state:
- Sources
- Who seen in
- Clinical features
- Management
- Contaminated water
- ONLY seen in immunocompormised pts
- Clincial features:
- Diarrhoea
- Intermittent abdo pain
- Management:
- Usually self-limiting
- If sever co-trimoxazole for 7 days
For Entamoeba histolytica, state:
- Source
- Clinical features
- Management
- Potential complications
- Contaminated food (via faecal oral route)
- Clinical features:
- Dysentery with intermittent constipation
- Management:
- Acute phase: metronidazole or tinidazole
- Paromomycin or diloxanide for up to 10 days to elimated intra-intestinal cysts
For norovirus, state:
- Who it is common in
- Clinical features
- Management
- Common in adults
- Clinical features:
- Profuse watery diarrhoea
- Projectile vomitting
- Colicky abdo pain
- Managment:
- Self-limiting
- Contact precaution
For rotavirus, state:
- Who it is common in
- Clinical features
- Management
- Children
- Clinical features:
- Watery diarrhoea
- Vomitting
- Management:
- Self limiting
- Contact precaution
Remind yourself of the 5 organisms that can cause dysentry
- Campylobacter jejuni
- Salmonella spp
- Shigella
- E.coli (EHEC, 0157:H7)
- Entamoeba histolytica
For Clostridium difficile, state:
- Gram stain
- Shape
- Anaerobic or anaerobic
- Whether it forms spores
- Virulence factors
- Gram positive
- Rod
- Obligate anaerobe
- Spore forming
- Virulence:
- Enterotoxin A: hypersecretion of fluid & induces cytokine production which stimulates inflammatory response
- Cytotoxin B: disrupts protein synthesis and causes disorganisation of cytoskeleton
- Spores
What can cause C.diff (pseudomembranous) colitis?
C.diff is present in ~3-5% adult population- remaining dormant in presensce of normal gut flora. However, natural balance can be disrupted by use of antibiotics resulting in infection.
State some antibiotics which are commonly/hugely associated with C.diff colitis
- Co-amoxiclav
- Cephalosporins
- Ciprofloxacin
- Clindamycin
How long, following antibiotic use, do symptoms of C.diff colitis usually manifest?
5-10 days afer antibiotic therapy
Discuss the pathophysiology of C.diff colitis
- C.diff produces enterotoxins A & B
- Toxins trigger inflammatory response in colonic membrane
- Subsequently leads to increase in vascular permeability and pseudomembrane formation. Accumulation of inflammatory cells, fibrin & necrotic debris contribute to pseudomembrane
State some risk factors for developing C.diff (pseudomembranous) colitis
- Antibiotics
- PPIs (any acid supressing drugs)
- Advanced age
- IBD
- HIV
- CKD
State the signs & symptoms of C.diff colitis
- Profuse watery diarrhoea
- Colicky abdo pain
- Fevers & rigors (in some cases)
