Gastroenteritis

Question 1

Define gastroenteritis

Answer 1

Acute inflammation of the lining of the GI tract, manifested by nausea, vomiting, diarrhoea & abdominal discomfort

Question 2

Aetiology of gastroenteritis

Answer 2

Caused by viruses, bacteria, protozoa or toxins contained in contaminated food or water

(faecal-oral route)

Question 3

Causative agents of gastroenteritis - viral

6

Answer 3

Rotavirus 
Adenovirus
Astrovirus
Calcivirus
Norwalk virus
Small round structures viruses

Question 4

Causative agents of gastroenteritis - bacterial

7

Answer 4

Campylobacter jejuni
Escherichia coli (O157)
Salmonella
Shigella
Vibrio cholerae
Listeria
Yersinia enterocolitica

Question 5

Causative agents of gastroenteritis - protozoal

3

Answer 5

Entamoeba histolytica
Cryptosporidium parvum
Giardia lamblia

Question 6

Causative agents of gastroenteritis - toxins

7

Answer 6

Staphylococcus aureus
Clostridium botulinum 
Clostridium perfringens
Bacillus cereus
Mushrooms
Heavy metals
Seafood

Question 7

Causative agents of gastroenteritis - common foods

5

Answer 7

Improperly cooked meat
Old rice
Eggs & poultry
Milk & cheeses
Canned food

Question 8

Epidemiology of gastroenteritis

prevalence + location

Answer 8

COMMON

Serious cause of morbidity & mortality in the developing world

Question 9

Presenting symptoms of gastroenteritis

3 + 2 onset + 2 other

Answer 9

Sudden onset N&V & anorexia
DIARRHOEA (bloody or watery)
Abdo pain or discomfort
Fever & malaise

Time of onset
Toxins = 1-24hrs
Bacterial/viral/protozoal = 12+hrs

Other effects of toxins -
Botulinum causes paralysis
Mushrooms can cause fits, renal or liver failure

Question 10

Signs of gastroenteritis on physical examination

3 +4 severe

Answer 10

Diffuse abdo tenderness
Abdominal distention
Bowel sounds often INCREASED

In severe gastroenteritis:
Pyrexia
Dehydration
Hypotension
Peripheral shutdown

Question 11

Investigations for gastroenteritis

4

Answer 11

Bloods
Stool
AXR or US
Sigmoidoscopy

Question 12

Investigations for gastroenteritis - bloods

3

Answer 12

FBC
Blood culture (identify bacteraemia)
U&Es (dehydration)

Question 13

Investigations for gastroenteritis - stool

2

Answer 13

Faecal microscopy & analysis for toxins

C.difficile causes pseudomembranous colitis

Question 14

Investigations for gastroenteritis - AXR or US

Answer 14

Exclude other causes (e.g. bowel perforation)

Question 15

Investigations for gastroenteritis - sigmoidoscopy

Answer 15

Unnecessary unless IBD needs to be excluded

Question 16

Management of gastroenteritis

5

Answer 16

Bed rest
Fluid & electrolyte replacement w/ oral rehydration solution (glucose & salt)
IV rehydration for severe vomiting
Most infections are self limiting
Antibiotic treatment only used if severe or infective agent has been identified

Question 17

Complications of gastroenteritis

8

Answer 17

Dehydration
Electrolyte imbalance
Pre renal failure (due to dehydration)
Secondary lactose intolerance (infants particularly)
Sepsis & shock
Haemolytic uraemic syndrome (associated w/ E. coli)
Guillain-Barre syndrome may occur weeks after recovery from Campylobacter gastroenteritis
Botulism can lead to respiratory muscle weakness/paralysis

Question 18

Prognosis for gastroenteritis

Answer 18

Good prognosis as most cases are self limiting