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Flashcards in Gastroenteritis Deck (51):
1

Define gastroenteritis

Syndrome of diarrhoea and vomiting that refers to non-inflammatory involvement of the upper small bowel or inflammation of the colon.

2

What is the most common cause of gastroenteritis?

Infection.
The vast majority is caused by a virus.
Bacteria - 20%
Parasites < 6%

3

What percentage of gastroenteritis cases are not infectious?

15%

4

Give some non-infectious diarrhoea examples

GI bleed
Ischaemic gut
Diverticulitis
Endocrine disorders
Numerous drugs
Fish toxins
WIthdrawal

5

What is the approach to any clinical infection syndrome?

What are the key clinical symptoms and signs that suggest the infection?
Differential diagnosis
Severity of Infection
Site and microbiological diagnosis: investigations
Antibiotic and supportive management
Infection Control
Public Health

6

What is another name for the norovirus?

Norwalk agent

7

Which pathogens cause toxin-mediated food poisoning?
Which of these pathogens pre form toxins and which are formed in vivo?

Preformed:
Staph aureus
Clostridium perfringens
Bacillus cereus
In vivo production:
Vibrio
Enterotoxigenic E. coli

8

What are the presenting clinical syndromes of food poisoning?

1. Acute enteritis (i.e. inflammation of the small intestine):
Fever
Diarrhoea
Vomiting
Abdominal pain
2. Acute colitis:
Fever
Pain
Bloody diarrhoea
3. Enteric fever-like illness:
Fever
Rigors
Pain
Little diarrhoea

9

List infective and non-infective causes of bloody diarrhoea

Infection:
bloody diarrhoea usually indicates colonic inflammation
Campylobacter. spp
Shigella. spp
E. coli 0157
Amoebiasis

Non infective:
IBD
Malignancy
Ischaemia

10

Describe the symptoms of enteric fever-like illness

Fever
Systemically unwell
Abdominal pain
Constipation but possibly short history of diarrhoea

11

What is typhoid?

A bacterial infection that can spread throughout the body involving multiple organs.

12

Where does Typhoid come from?

It is almost always imported
From:
Indian subcontinant, South East Asia, Far east, middle east, Africa, central/south america, Increasing in Eastern Europe.

13

How is typhoid transmitted?

Food, water or carrier

14

How can typhoid present?

It can be asymptomatic
It can be mild
It can cause bacteraemia
it can cause enterocolitis

15

How is typhoid diagnosed?

Blood cultures are the key to diagnosis.
Stool and urine cultures also done.

16

How is typhoid treated?

Chloramphenicol and ciprofloxacin- some strains resistant to this
Ceftriaxone or azithromycin

17

How can typhoid be prevented?

There is an IV or oral vaccine.
It is not effective against paratyphoid.

18

What are key features in a gastroenteritis history?

Diarrhoea: frequency, nocturnal, constistency, colour, presence of blood
Associated symptoms: abdominal pain, vomiting, fever, urgency, incontinence
Anyone in family or work with similar symptoms
Occupation
Pets and animal contact
Travel abroad
History of medication- particularly recent Abx and PPIs

19

What are key features in a gastroenteritis examination?

Fever
Skin rashes, e.g. rose spots, erythema nodosum
Dehydration: pulse, mental state, dry tongue, skin turgor, blood pressure, postural drop
Abdominal tenderness
Abdominal distension
PR exam: stool, blood, tenderness

20

What investigations are carried out to help diagnosis a gastroenteritis?

Stool microscopy when appropriate (e.g. history of travel, for giardia, amoeba etc)
Stool culture: Salmonella, Camppylobacter, Shigella
Stool toxin for C diff (culture not routinely done), adn cytotoxin for E. coli
Blood cultures (salmonella)
PCR : .e.g norovirus
FBC- wcc key in severity of CDI
U, Es - renal function important
AXR

21

What are severity markers of CDI?

One or more of the following:
Suspicion of PMC or toxic megacolon or ileus or colonic dilatation in CT/AXR of >6cm
WCC > 15 cells/mm3
Creatinine > 1.5 x baseline

22

What are intestinal complications of bacterial enteritis?

Severe dehydration and renal failure
Acute colitis, toxic dilatation
Post infective irritable bowel
Transient secondary lactase intolerance

23

What are extra-intestinal complications of bacterial enteritis?

Septicaemia
Metastatic infection: meningitis, aortitis, osteomyelitis, endocarditis
Reactive arthritis
Meningism
Neurological- Guillian-Barre syndrome
haemolytic uraemic syndrome

24

What is supportive treatment for gastroenteritis?

Oral rehydration
IV fluids (saline important)

25

What is specific treatment for gastroenteritis?

Anti-spasmodics
Anti-motility agents
Antibiotics- only in specific situations

26

Name 2 antisecretory antidiarrhoeal agents

Chlorpromazine
Bismuth subsalycilate

27

Name 2 absorbant antidiarrhoeal agents

kaolin
charcoal

28

When are patients given empirical antibiotic therapy for gastroenteritis?

1. They must have 3 or more unformed stools per day as well as one or more of: abdominal pain, nausea, vomiting, fever, blood in stool, tenesumus
2. As well as 1, patients must either a) be high risk:
immunocomprimised
hypochlorhydria
inflammatory bowel disease
prosthetic intravascular device
or b) have dysenteric symptoms:
fever
bloody diarrhoea
abdominal pain
3. A stool sample or rectal swab for culture is taken from these patients
4. Patients are given ciprofloxacin 500mg BD for 3-5 days and their progress is reviewed

29

What kind of bacterium is C difficile?

Anaerobic gram positive spore forming bacillus

30

What are risk factors for C diff infection?

Antibiotics:
All, but greatest risk with broad spectrum e.g. fluoroquinolones, cephalosporins, clindamycins, broad spectrum penicillins
Medications:
PPI
H2RA
Advanced age - at least 65 years old
Chemotherapy, chronic renal disease, underlying IBD

31

What drugs should be avoided in pseudomembrinous colitis?

Antibiotics which may be precipitating it
opiates
Anti-peristaltic drugs
PPIs

32

What is the treatment for pseudomembranous colitis?

Oral therapy more reliable than parenteral therapy
Non-severe: metronidazole
Severe/failure of metronidazole: vancomycin
Do not use IV vancomycin

33

What is the treatment for the 1st presentation of uncomplicated CDI?

Oral metronidazole for 14 days
Stop other antibiotics
Review PPIs
Dont use anti-motility agents
No re testing unless symptomatic
Should improve within 3-5 days

34

What is the treatment for CDI if it responds poorly to oral metronidazole, if the disease is severe, or if there is more than one severity marker?

Get help
Start oral vancomycin 125mg qds 10-14 days
Vancomycin isn't absorbed so stays in the bowel to kill bacteria

35

Why can C diff infection relapse?

Because although the bacteria are killed, they can leave behind spores

36

What should be considered in persistent diarrhoea that lasts for more than a week?

Parasites
Screen for IBD

37

Should antibiotics be used to treat Ecoli 0157?

No

38

Which pathogens cause travel-related diarrhoea?

Amoebiasis
Giardiasis
Cryptosporadiasis

39

What is the average duration of untreated traveller's diarrhoea?

4 days

40

How long can traveller's diarrhoea persist for?

Up to 2 months, but this is only in 1-2% of people

41

What is amoebiasis?
How is it spread?
How is it diagnosed?

A protozoal infection
It is spread by faeco-oral route or by an ill or asymptomatic carrier
Diagnosed by examination of hot stool for ova and cyts.
Serology may be of use, especially in extra-intestinal disease

42

What can amoebiasis cause?

Acute bloody diarrhoea
Extra-intestinal spread to produce an abscess can occur

43

What is giardiasis?

Protozoon Giardia lambia trophozoites colonizes the small bowel mucosa to produce diarrhoea and malabsorption; often explosive, protracted and foul smelling

44

How is giardiasis spread?

Infection spread by cysts found in normal drinking water

45

How is Giardiasis diagnosed?

Diagnosis is examination of stools for ova and cysts but more accurately by duodenal aspiration

46

What is an important cause of traveller's diarrhoea?

enterotoxigenic E coli

47

What is Cryptosporidiosis?

A parasitic disease cryptosporidium, which is a protozoan parasite.

48

How is Cryptosporidiosis transmitted?

Water, food, contact with animals. It is highly infectious and resilient.

49

Does Cryptosporidiosis require treatment?

It is self limiting.
It is severe in immunosuppressed patients

50

How is Cryptosporidiosis diagnosed?

Duodenal aspirate/stool

51

What is the treatment for Cryptosporidiosis?

Supportive

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