Infectious Diarrhoea Flashcards

1
Q

Define diarrhoea vs dysentery vs gastro-enteritis?

A

Diarrhoea is increased frequency/fluidity of stool
Dysentery is colonic inflammation due to infection leading to bloody diarrhoea
Gastro-enteritis is 3 or more loose stools/day along with accompanying features of infection such as fever, vomiting, pain and blood/mucous in stool.

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2
Q

What are the two different types of gastro-enteritis and example of each/

A

Inflammatory e.g. Shigella
Non-inflammatory e.g. Cholera or E. Coli
Mixed: C.diff

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3
Q

Whats the main difference between inflammatory &non-inflammatory gastro-enteritis?

A

Non-inflammatory involves fluid secretions from the small intestine –> Frequent watery stools with little pain

Inflammatory involves invasion or toxin induced inflammation of the gut –> Pain, systemic upset e.g fever and bloody stools

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4
Q

How is gastro-enteritis transmitted?

A

Contaminated food e.g. campylobacter in chicken
Bad food storage
Travel
Person-person

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5
Q

Risk factors for gastro-enteritis?

A
  • Food history (unreliable)
  • Contacts
  • Travel
  • antimicrobials
  • Occupation
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6
Q

How do you test for gastro-enteritis?

A

Assess the patient:

  • timing? >2wks it’s unlikely
  • Risk Factors?
  • Hydration? postural BP/Skin turgor/tachycardia/urine flow/muscle cramp
  • Inflammation? Fever And WCC
  • Electrolytes
  • Stool/blood cultures
  • Serology
  • FBC, U&E + Creatinine
  • AXR
  • Sigmoidoscopy
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7
Q

How is gastroenteritis treated?

A

Oral rehydration - Sodium chloride + glucose + AAs

Antimicrobials if:

  • Traveller’s
  • Severe
  • Immunocompromised
  • Co-morbidities e.g. renal/resp disease
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8
Q

What are the major Gastroenteritis pathogens?

A
Campylobacter (Jejuni)
Salmonella
E. Coli
Shigella
cholera
C. Difficile

Giardia Lamblia
Cryptosporidium Parvum
Entamoeba Histolytica

Noravirus
Rotavirus

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9
Q

Where does campylobacter infection come from?

A

Undercooked chicken/ contaminated milk

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10
Q

How does Campylobacter Gastroenteritis present?

A

7 day incubation and clears within 3 wks
Abdo pain can be severe

Can have post-infective syndromes such as guillain barre or Reactive Arthritis

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11
Q

how does Salmonella Gastroenteritis present?

A

<48hr incubation & lasts >10days (so shorter than campylobacter)

Can cause post-infective IBS

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12
Q

What is the most dangerous form of E. Coli?

A

E. Coli O157:H7 aka enterohaemorrhagic E. coli

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13
Q

Where do you get E. Coli O157:H7?

A

Cattle Reservoir;

  • Contaminated Meat
  • Stepping in Slurry
  • Person-person
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14
Q

How does E. Coli O157:H7 present

A

Haemolytic Uraemic Syndrome (HUS)
The toxin gets into the blood and causes platelet aggregation –> RBC & renal capillary damage –> Renal failure & anaemia

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15
Q

What are the other forms of E.Coli other than O157:H7?

A

Enterotoxigenic - traveller’s Diarrhoea
Enteroinvasive
Enteropathogenic

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16
Q

Describe Traveller’s Diarrhoea and the most common causes?

A

Diarrhoea usually <1wk, can be treated with Abx.

Mostly Enterotoxigenic E. Coli but also Campylobacter and Shigella

17
Q

What type of infectious diarrhoea can cause HUS & Seizures?

A

Shigella

E. Coli O157 causes HUS but not seizures

18
Q

Whats the main form of Antibiotic Associated DIarrhoea and what causes it?

A

Clostridium Difficile, it produces 2 toxins (A & B)

Mainly caused by the 4Cs:

  • Cephalosporins
  • Ceftriaxone (& other quinalones)
  • Co-amoxiclav
  • Clindamycin
19
Q

How do we detect C. Diff?

A

Stool Culture
Toxin Detection
Sigmoidoscopy

20
Q

How do we treat C. Diff?

A
  • Metronidazole
  • Oral Vancomycin (If severe)
  • Fidaxomicin (For relapses)
  • Stool Transplant
  • Surgery

We’d also isolate symptomatic patients & follow hygiene

21
Q

List some parasites that can cause Diarrhoea?

A
  • Giardia Lamblia
  • Cryptosporidium Parvum
  • Entamoeba Histolytica aka amoebic dysentery
22
Q

Where do we get Giardia Lamblia and how does it present?

A

Contaminated Water

Causes diarrhoea, malabsorption & Failure to thrive

23
Q

How do we detect Giardia Lamblia?

A

Sick patients - Vegetative form found on a duodenal biopsy

Asymptomatic patients have inactive cysts that can be detected on stool microscopy

24
Q

How do we treat Giardia Lamblia?

A

Metronidazole

Tinidazole

25
Q

How do we get Cryptosporidium Parvum?

A

Cattle Reservoir via infected water e.g. private water supplies out of cattle fields

26
Q

How do we detect and treat cryptosporium Parvum?

A

With stool microscopy looking for cysts

Usually its self-limiting

27
Q

How do we test for and treat Entamoebic Histolytica?

A

Duodenal biospy - Vegetative form in symptomatic patients
Stool Microscopy - Cysts in asymptomatic patients

Treated with metronidazole (Symptomatically) or furamide if asymptomatic

28
Q

What are the main viruses causing diarrhoea?

A

Rotavirus

Noravirus

29
Q

How do you test for Noravirus?

A

With Serum PCR

30
Q

How do we get & test for rotavirus?

A

Faecal-oral Route

Antigen Testing

31
Q

What are the main pathogens behind Food Poisoning?

A

1) Staph Aureus Toxins - survive cooking
2) Bacillus Cereus - re-heated rice
3) Clostridium Perfringens - Undercooked Meat