GI infections Flashcards
Symptoms of acute gastroenteritis
- Diarrhoea, > 3 loose stools per day,
- Nausea and Vomiting
- Abdominal pain
- Fever
Define Dysentery
Same symptoms as acute gastroenteritis plus blood
When is diarrhoea considered to be chronic
2-3 weeks
Bacteria that commonly cause GI infections
- Campylobacter
- Salmonella
- Shigella
- Escherichia coli
- E.coli O157
- Clostridium difficile
Viruses that commonly cause GI infection
- Norovirus
- Rotavirus
- Adenovirus
Protozoa that commonly cause GI infection
- Cryptosporidium
- Giardia lamblia
- Entamoeba histolytica
Protozoa more associated with travel
Most common causes of acute GE in UK
Salmonella and campylobacter,
More viral in children
Pathogens that cause Dysentry
- Campylobacter (Salmonella)
- Shigella
- Escherichia coli
- E.coli O157
- Clostridium difficile
Protozoa: Entamoeba histolytica
Causes of travelles diarrhoea.Bacterial, viral and protozoal
Bacterial: Campylobacter, Salmonella, Shigella, Escherichia coli
Viruses: Norovirus (e.g. cruise ships), Rotavirus, Adenovirus
Protozoa: Cryptosporidium, Giardia, Entamoeba histolytica
Chance of following groups being C diff positive:
AB diarrhoea
AB colitis
Pseudomembraneoud colitis
- 20-30%
- 50-75%
- >90%
AB effect on microflora
- Most ABs capable of killing commensal bacteria. Physioligaclly breakdown. If absent, bile damages colon
- Macrolide (vanco, erythromycin) breakdown products bind to receptors and promote gastric motolity
Causes of chronis diarrhoea
- Parasites in traveller’s
- Post infection syndromes
- Irritable bowel
- Malabsorption
Distal illium is especially critical due to its involvement in enterohepatic recycling.
Non-infectious causes of GI issues
- Inflammatory bowel disease
- Diverticular disease
- Ischaemic colitis
- Colorectal carcinoma
- Malabsorption
- Extra-intestinal infection e.g. pneumonia
Sampling a patient with diarrhoea
- Different pathogens
- Stool
- microscopy (ova, cysts and parasites – OCP) and culture
- Lab can also check for rotavirus antigen
- Clostridium difficile toxin (CDT) PCR
Aim for three specimens, especially with parasites as there are numerically fewer, so harder to pick up
General managment of diarrhoea
- Rehydration
- Analgesia e.g. paracetamol
- NB: Condeine is anti-motility, and NSAIDS on empty stomach may cause gastritis
- Antiemetics e.g. ondansetron
- Avoid antidiarrhoeal agents e.g. loperamide Isolation (in hospital)
- Notification to Public Health
2-4 slows motility, so might not be ideal in acute diarrhoea
ABs for C. dif diarrhoes
Metronidazole or vancomycin
Treating traveller diarrhoea
- ~ 80% due to bacteria
- Antibiotics are more likely to make a difference
Empirical ciprofloxacin
- 500 mg stat or
- 500 mg bd for 5 days
- Reduces the duration of symptoms by 1-2 days if started early
If due to parasites
- Confirmed on stool OCP
- Chronic symptoms
- No response to ciprofloxacin
Metronidazole
- Giardia (sometimes steatorrhoea)
- Entamoeba histolytica (dysentery)
Nitazoxanide if needed for Cryptosporidium
ABs for acute GE?
Controversial area. Window of opportunity small as (see illustration)
- Some evidence of benefit
- May shortens duration of illness by 1-2 days if started early
- No effect on mortality or severity of disease
Specific benefits
- Ciprofloxacin
- Macrolides for Campylobacter
Rehydration therapy
IV or oral
- Solution with water, salt and sugar
- Secretory diarrhoea; pumping out Cl, Na and water follow. absorption of Na has a symporter mechanism with glucose. So ORT solutions also contain glucose
Probiotics in treating GE/ diarrhoea
Poorly controlled evidence suggest benefit in preventing antibiotic associated diarrhoea
Less effect in treating established diarrhoea
