GI Infections

Question 1

Organisms causing Secretory diarrhoea

Answer 1

Bacillus cereus, staph aureus, E. coli, Cholera
BSEC

Question 2

Organisms causing inflammatory (bloody) diarrhoea

Answer 2

Campylobacter jejuni
Haemorrhagic E. Coli (EHEC)
Entamoeba histolytica
Salmonella enteritides
Shigella
CHESS

Question 3

Diarrhoea same day after eating reheated rice

Answer 3

Bacillus cerus (Gram+ve Rod)
Vomiting and watery diarrhoea
Self-limiting

Question 4

Diarrhoea 2hrs after eating suspicious food

Answer 4

Staph aureus
Vomiting, watery diarrhoea
Self-limiting

Question 5

Diarrhoea after travelling

Answer 5

Enterotoxigenic E. Coli (ETEC)
Self-limiting
Gram-ve

Question 6

Rice water stool, comma-shaped bacteria

Answer 6

Vibrio cholera (gram-ve)
Self-limiting
Africa/Middle-east

Question 7

Diarrhoea after chicken at a BBQ, prodrome of fever and headache, abdo cramps, bloody diarrhoea lasting 10 days

Answer 7

Campylobacter jejuni (Gram-ve)
Erythromycin if in first 5 days

2-4 day incubation period

Question 8

Diarrhoea 12hrs after eating poultry and eggs

Answer 8

Salmonella enteritides
Non bloody diarrhoea
Self-limiting, ceftriaxone if required

Question 9

Descending paralysis after eating uncooked beans or an infant eats honey

Answer 9

Clostridium botulinum - cleaves SNARE proteins to prevents Ach release from peripheral nerves
Mx: Antitoxin

Question 10

Water diarrhoea after eating reheated meat & cramps, lasting 24hrs

Answer 10

Clostridium Perfringens
Can cause gas-gangrene

Question 11

Bloody diarrhoea, flatulence, tenesmus with flask-shaped ulcer on histology. RUQ pain, weight loss, fevers (liver abscess), 4 nuclei

Answer 11

Entamoeba histolytica
Mx: metronidazole

Question 12

Foul-smelling non-bloody diarrhoea, pear-shaped trophozoite in immunocompromised, 2 nuclei

Answer 12

Giardia Lamblia
Most common protozoal intestinal infection
Metronidazole

Question 13

Severe prolonged diarrhoea in immunocompromised. Kinyoun Acid Fast Stain

Answer 13

Cryptosporidium Parvum (protozoa)
Mx: Paromomycin

Question 14

Secretory diarrhoea in <2yo or immunocompromised

Answer 14

Adenovirus - self-limiting

Question 15

Secretory diarrhoea in <6yo at nursery

Answer 15

Rotavirus

Question 16

Secretory diarrhoea & V outbreak in adults, self-limiting

Answer 16

Norovirus

Question 17

Constipation, fever, rose spots, splenomegaly in a returning traveller

Answer 17

Salmonella Typhi/Paratyphi (Typhoid fever)
Mx: IV Ceftriaxone then PO azithromycin

Question 18

Severe diarrhoea following a course of Abx

Answer 18

C. difficile (caused by 3C’s - cephalosporins, ciprofloxacin, clindamycin)
1st line: PO Vancomycin, stop Abx where possible
(Pseudomembranous colitis)

Question 19

Mucosal inflammation, bloody diarrhoea, abdo pain, fever after eating poultry

Answer 19

Shigella
Self-limiting

Question 20

Bloody diarrhoea & HUS

Answer 20

EHEC 0157 (shiga-toxin)

Question 21

Common cause of infantile diarrhoea

Answer 21

EPEC (enteropathogenic E. coli)