Diarrhoea Flashcards
Define diarrhoea
fluidity and frequency
Define gastro-enteritis
Three or more loose stools/day
Accompanying features
Define dysentery
Large bowel inflam
Bloody stools
Bristol stool chart
Type 1; seperate hard pieces, hard to pass
Type 2; sausage shape, lumpy
Type 3; sausage, cracked surface
Type 4; sausage, soft and smooth
Type 5; soft blobs, clear-cut edges
Type 6; fluffy pieces with ragged edges, mushy
Type 7; watery, no solid pieces
Epidemiology of gastroenteritis
Contamination of foodstuff
Poor produce storage
Travel-related infections; salmonella
Person-to-person spread; norovirus
What is the most common cause of infectious intestinal disorder?
Viruses
Campylobacter most common bacterial pathogen
Salmonella causes the most hospital admissions
Defences against enteric infections
Hygiene
Stomach acidity
Normal gut flora
Immunity; HIV and salmonella
Clinical features of diarrhoeal illness
Non-inflammatory/secretory i.e. cholera
- frequent watery stools, little abdo pain
- rehydration mainstay of therapy
Inflammatory i.e. shigella dysentery
- pain and fever
- rehydration ± antimicrobials
Mixed picture i.e. C diff
Examination assessment of a patient with diarrhoeal illness
Symptoms and duration
- >2/52 unlikely infective gastroenteritis
Risk of food poisoning
Assess hydration
Features of inflammation
- fever, raised WCC
Describe fluid and electrolyte loss in diarrhoea
Can be severe
Hyponatraemia due to sodium loss with fluid replacement by hypotonic solutions
hypokalaemia due to K loss in stool
Investigations for a patient with diarrhoeal illness
Stool culture ± molecular or Ag testing
Blood culture
Renal function
Blood count; neutrophils, haemolysis
Abdo x-ray/CT if abdo distended/tender
Differential diagnoses in diarrhoeal illness
Inflammatory bowel disese
Spurious diarrhoea; secondary to constipation
Infectious
Carcinoma
Rare; sepsis outside gut
Treatment of gastroenteritis
Rehydration; IV or oral
- oral with salt/sugar solution
- IV saline
Describe post-infectious issues in campylobacter
Guillain-barre syndrome
Reactive arthritis
What two campylobacter species cause the most infections?
C. jejuni
C. coli
What are the commonest isolates of salmonella in UK?
S. enteritidis
S. typhimurium
Describe E.coli O157
Typical illness = frequent bloody stools
Produces Shiga toxin
E.Coli stays in gut but toxin enters blood
Toxin can cause haemolytic anaemia and renal failure
Describe haemolytic uraemic syndrome (HUS)
Renal failure
Haemolytic anaemia
Thrombocytopenia
Caused by toxin from E. Coli which stimulates platelet activation
When should antibiotics be given in the case of diarrhoea?
Indicated in gastroenteritis for
- immunocompromised
- severe sepsis or invasive infection
- chronic illness e.g. malignancy
Not indicated for healthy patient with non-invasive infection
What are the common previous antibiotics in the history of a C.diff patient?
4 C’s
- cephalosporins
- co-amoxiclav
- clindamycin
- ciprofloxacin
What does C.diff produce?
enterotoxin and cytotoxin
How do we treat C.diff?
- Metronidazole
- oral vancomycin
- fidaxomicin (new and expensive)
- stool transplants
- surgery may be required
How do we prevent CDI?
Reduce broad spectrum AB prescribing
Avoid 4C’s
Antimicrobial management team and local antibiotic policy
Isolate symptomatic patients
WASH hands between patients - contact precautions
Cleaning environment
Management of CDI
Stop precipitating AB if possible
Follow published treatment algorithm; oral metronidazole if no severity markers
Oral vancomycin is 2 or more severity markers
C.diff severity markers
- Temperature >38.5°C
- WBC > 15 cells/mm3
- Creatinine > 1.5 x
baseline - Suspicion of PMC
- Toxic megacolon
- Ileus
- CT evidence of severe disease
How are parasites diagnosed?
Protozoa and helminths
Generally by microscopy
Send stool with request “parasites, cysts and ova please” or P, C and O
Describe Giardia duodenalis
Protozoa in UK causing diarrhoea, gas, malabsorption, failure to thrive
Transmission by direct contact w/cattle, cats, dogs, other people or food/water contaminates w/faeces
Cysts on stool microscopy
Treat with metronidazole
Describe Cryptosporidium parvum
Carried by >150 species of mammals
Diarrhoea, nausea, vomiting, abdo pain
Infected animals/faeces, contaminated water/food
Oocysts on microscopy
No specific treatment usually required
Describe entamoeba histolytica
Amoebic dysentery
Invasive extraintestinal amoebiasis
Usually no bowel symptoms
Cysts seen formed in stool
Intestinal disease: metronidazole + luminal agent to clear colonization
Liver abscess (anchovy pus) = long term complication
Describe viral diarrhoea
Rotavirus, norovirus, adenovirus
Rotavirus = children <5yoand diagnosed by antigen detection in stool
Noroviruses diagnosed by PCR (sometimes cruise ships)
