GI: Diarrhoea Flashcards
Define diarrhoea
> 3 loose or watery stool per day
Define acute diarrhoea
< 14 days
Define chronic diarrhoea
> 14 days
Give some causes of acute diarrhoea
1) gastroenteritis
2) diverticulitis
3) Abx therapy
4) constipation causing overflow
How does diverticulitis present?
Classically causes left lower quadrant pain, diarrhoea and fever.
Causes of chronic diarrhoea?
1) IBS
2) Crohn’s
3) UC
4) Colorectal cancer
5) Coeliac disease
Is tenesmus more common in UC or Crohn’s?
UC
What is tenesmus?
Tenesmus is the feeling that you need to pass stools, even though your bowels are already empty.
What is C. diff?
Clostridium difficile is a Gram positive rod often encountered in hospital practice.
When does C. diff develop?
Clostridium difficile develops when the normal gut flora are suppressed by broad-spectrum antibiotics.
What is the 1ary cause of C. diff diarrhoea?
It may colonise the intestines without causing any symptoms or issues.
When antibiotics interrupt the normal intestinal microbiome, C. difficile can proliferate and get out of control
What are the 5 most commonly implicated Abx in C. diff diarrhoea?
Broad spectrum:
1) Cephalosporins
2) Clindamycin
3) Co-amoxiclav
4) Ciprofloxacin (and other fluoroquinolones)
5) Carbapenems (e.g., meropenem)
How is C. diff transmitted?
Faecal-oral route, with spores contaminating surfaces, hands, and medical equipment.
What are some risk factors for C. diff diarrhoea?
- advanced age
- prolonged hospitalization
- immunosuppression
- recent gastrointestinal surgery or procedures.
These factors contribute to the disruption of gut microbiota, increased susceptibility to infection, and a higher risk of complications.
Pathophysiology behind C. diff diarrhoea?
1) The pathogenicity of C. difficile is primarily attributed to the production of two large exotoxins: toxin A (TcdA) and toxin B (TcdB).
2) Both toxins are cytotoxic and proinflammatory, causing damage to the intestinal epithelium, fluid secretion, and inflammation.
3) C. difficile toxins also stimulate the production of cytokines and chemokines, leading to the recruitment of neutrophils and other immune cells to the site of infection.
4) This immune response exacerbates tissue damage and contributes to the pathogenesis of diarrhoea.
What is C. diff infection associated with?
1) repeated use of antibiotics
2) proton-pump inhibitors (e.g., omeprazole)
3) healthcare settings
Presentation of C. diff infection?
Colonisation is usually asymptomatic.
Infection presents with diarrhoea, nausea and abdominal pain.
Severe infection with colitis can present with:
- Dehydration
- Systemic symptoms (e.g., fever, tachycardia and hypotension)
- Toxic megacolon
How is a diagnosis of C. diff infection made?
By testing stool samples:
1) C. diff antigen: this only shows exposure to the bacteria, rather than current infection
2) C. diff toxin (CDT) detection in stool
What C. diff antigen is specifically tested for?
glutamate dehydrogenase
Describe stages of C. diff infection:
a) mild
b) moderate
c) severe
d) life-threatening
a) normal WCC
b) raised WCC (<15), typically 3-5 loose stools per day
c) raised WCC (>15), or an acutely raised creatinine (>50% over baseline), or a temp of >38.5 degrees, or evidence of severe colitis(abdominal or radiological signs)
d) hypotension, partial or complete ileus, toxic megacolon, or CT evidence of severe disease
1st line management of C. diff infection?
Current antibiotic therapy should be reviewed and antibiotics stopped if possible.
1st line –> oral vancomycin for 10 days
1st, 2nd and 3rd line therapies for C. diff infection?
1st: oral vancomycin for 10 days
2nd: oral fidaxomicin
3rd: oral vancomycin +/- IV metronidazole
Recurrence rate of C. diff infection?
Recurrent infection occurs in around 20% of patients, increasing to 50% after their second episode
What is medical management of RECURRENT C. diff infection:
a) within 12 weeks of symptom resolution
b) after 12 weeks of symptom resolutio
a) oral fidaxomicin
b) oral vancomycin OR fidamoxicin
Medical management of life-threatening C. diff infection?
Oral vancomycin AND IV metronidazole.
Specialist advice - surgery may be considered
What monoclonal Ab is sometimes used in the management of C. diff infection?
bezlotoxumab: targets C. difficile toxin B
What may be considered in C. diff infection for patients who’ve had 2 or more previous episodes?
faecal microbiota transplant
How long do patients with C. diff infection need to be isolated for?
Patients need to be isolated until 48 hours after the last episode of diarrhoea
Complications of C. diff infection?
1) Pseudomembranous colitis
2) Toxic megacolon
3) Bowel perforation and sepsis
What is pseudomembranous colitis?
Characterised by inflammation in the large intestine, with yellow/white plaques that form pseudomembranes on the inner surface of the bowel wall.
It is seen during a colonoscopy and confirmed with biopsies to examine the histology.
Transmission of E. coli
- contaminated food or water
- person-to-person contact
- zoonotic transmission.
Where is E. coli found?
Escherichia coli is a predominantly commensal bacterium in the human GI tract.
What do outbreaks of E. coli often involve?
Contaminated produce, undercooked meat, and unpasteurised dairy products.
Give some strains of E. coli and what diseases they cause
Enterotoxigenic E. coli (ETEC): travellers diarrhoea
Enteropathogenic E. coli (EPEC): relevant in paediatric diarrhoea
Enterohaemorrhagic E. coli (EHEC): includes E. coli 0157 that produces Shiga-like toxins
What severe complication can E. coli0157 cause?
Hemolytic uremic syndrome (HUS).
Which E. coli pathotype is often liked to outbreaks from contaminated food?
Enterohaemorrhagic E. coli (EHEC) e.g. E. coli 0157
How does E. coli 0157 cause haemolytic uraemic syndrome (HUS)?
E. coli 0157 produces the Shiga toxin.
This causes abdominal cramps, bloody diarrhoea and vomiting. The Shiga toxin destroys blood cells and leads to haemolytic uraemic syndrome (HUS).
Why should Abx be avoided if E. coli gastroenteritis is considered?
The use of antibiotics increases the risk of haemolytic uraemic syndrome
Clinical features of E. coli diarrhoea?
1) Acute watery diarrhoea
2) Bloody diarrhoea
3) Fever
4) N&V
5) Malaise & muscle aches
6) Abdo cramps
What type of E. coli is bloody diarrhoea typically seen in?
Notably seen in enterohaemorrhagic E. coli (EHEC) and enteroinvasive E. coli (EIEC), described as ‘haemorrhagic colitis.’
How long does E. coli diarrhoea typically last?
Most cases resolve within 5–10 days without medical intervention.
What type of E. coli is persistent diarrhoea mainly seen with?
Seen mainly with enteroaggregative E. coli (EAEC), lasting for two weeks or more.
Who are the at risk populations for E. coli diarrhoea?
1) Children & elderly: More severe and prolonged symptoms, risk of complications like dehydration and malnutrition.
2) Immunocompromised: Atypical presentations and higher risk for complications.
How can haemolytic uraemic syndrome present?
Presents with haemolytic anaemia, thrombocytopenia, and acute renal failure post 5–10 days of diarrhoea.
Investigations in E. coli diarrhoea?
Stool sample:
1) Stool culture & sensitivity: gold standard for identifying E. coli strains and antibiotic susceptibility.
2) Polymerase chain reaction (PCR)
Other investigation in E. coli diarrhoea?
Bloods: Looking for thrombocytopenia, acute kidney injury that may indicate HUS
Management options in E. coli?
Mainly supportive:
- Oral Rehydration Solution (ORS) for mild to moderate dehydration.
- Intravenous fluids for severe dehydration or in cases where oral rehydration is not possible.
Abx:
- Generally not recommended unless specifically indicated by culture and sensitivity results.
- Exceptions include severe illness with systemic symptoms, or in cases caused by specific pathotypes such as EIEC.
Complications of E. coli diarrhoea?
- Dehydration
- Prolonged diarrhoea (can lead to nutritional deficiencies and weight loss)
- Electrolyte imbalance: often 2ary to dehydration
- HUS
Gastritis vs enteritis?
Acute gastritis is stomach inflammation and presents with epigastric discomfort, nausea and vomiting.
Enteritis is inflammation of the intestines, and presents with abdominal pain and diarrhoea.
What is gastroenteritis?
Gastroenteritis is inflammation all the way from the stomach to the intestines and presents with pain, nausea, vomiting and diarrhoea.