23 Gastroenteritis

Question 1

What are the presenting complaints of gastroenteritis?

Complications?

Answer 1

Acute onset V+D with mucous + blood. Abdo pain, fever.

Dehydration, toxic megacolon, renal failure, GBS, HUS, Salmonella.

Question 2

What are the investigation for gastroenteritis?

Answer 2

Bloods: FBC, U&E, CRP, culture.
AXR if severe.
Stool MC&S, OCP, C.diff toxin, viral PCR.

Question 3

What is the most common cause of viral gastroenteritis?

Disease course? Management?

Answer 3

Norovirus.
Projectile vomiting.
24-48hrs. Prevent dehydration.

Question 4

Which organisms cause parasitic gastroenteritis?

Answer 4

Cryptosporidium
Guardia lambia.
Entamoeba histolyca.

Question 5

How is cryptosporidiosis spread?

Answer 5

Waterborne disease, oocytes are resistant to chlorine based disinfectants.

Question 6

Which bacterial gastroenteritis’ are caused by enterotoxin production? (6)

Answer 6

Vibrio cholerae.
Escherichia coli (ETEC  + VTEC).
Clostridium perfringens.
Staph aureus.
Bacillus cereus.
C. diff.

Question 7

Which bacterial gastroenteritis’ are caused by adherence of the organism? (4)

Answer 7

Shigella sonnei/flexneri.
E. coli (EAEC).
Campylobacter jejuni.
Salmonellae.

Question 8

Which strains of E.coli result in HUS?

How?

Answer 8

Enterohaemorrhagic.
EHEC/VTEC.
e.g. E.coli O157 - shiga toxin virulence factor- premature destruction of RBCs, detritus blocks kidneys.

Question 9

How is gastroenteritis treated?

Answer 9

Supportive - avoid antibiotics as may increase salmonella carriage duration and worsen HUS.
Except in young, very old, campylobacter infection of sepsis.

Question 10

What is antibiotic associated diarrhoea?

Answer 10

2-30% patients after antibiotics.

Disruption of microflora, change in metabolism and overgrowth of pathogenic organisms.

Question 11

Which organisms are responsible for antibiotic associated diarrhoea?

Answer 11

C. diff.

C.perfrinfens, S.aureas, Candida, Klebsiella, Salmonella.

Question 12

Which antibiotics are high risk for C.diff infection?

Answer 12

Cephalosporins.

Clindamycin.

Question 13

Which antibiotics are medium risk for C.diff infection?

Answer 13

Ampicillin/amoxycillin.
Co-trimoxazole.
Macrolides.
Fluoroquinolones (O217 completely unaffected by these).

Question 14

What is the therapy for C. diff infection?

Answer 14

Oral metronidazole/vancomycin until resolution of diarrhoea.
Risk factor for VRE selection.
New: Oral fidaxomicin.