Pathology EMQ.

Theme: GI Infections

Name: Mohammed Hashmi

OPTION LIST

A	Bacillus cereus	I	Escherichia coli
B	Clostiridium botulinum	J	Listeria monocytogenes
C	Staphylococcus aureus	K	Campylobacter
D	S.typhi	L	Adenovirus
E	parahaemolyticus	M	Cytomegalovirus
F	Cryptosporidium parvum	N	Poliovirus
G	Rotavirus	O	Giardia lamblia
H	Entamoeba histolytica	P	Yersinia enterocolitica

For each scenario below, choose the most appropriate answer from the list above. Each option may be used once, more than once or not at all.

1. Produces enterotoxin that can act as a superantigen in the GI tract, releasing IL1 and IL2, causing prominent vomiting and watery, non bloody diarrhea. Gram positive cocci. Causes food poisoning. Catalase, coagulase positive coccus. Protein A is the main virulence factor. Appears in tetrads, clusters on gram stain. Beta haemolytic on blood agar.

2. Double stranded RNA “wheel like”. Replicates in mucosa of small intestine. Causes secretory diarrhoea, no inflammation. Watery diarrhoea caused by stimulation of enteric nervous system.

3. Transmitted via contaminated food and water with animal faeces ( poultry, meat, unpasteurised milk). Enterotoxin can cause watery, foul smelling diarrhoea, bloody stool, fever and severe abdominal pain. Treat with erythromycin or ciprofloxacin if in the first 4-5days

4. Pathogen ttransmitted only by humans, multiplies in Payer’s patches. Bacteraemia in 3% of carriers. Slow onset, can cause fever and constipation, splenomegaly, rose spots, anaemia, leucopaenia, bradycardia, haemorrhage and perforation. Treatment is usually with ceftriaxone or ciprofloxacin.

5. Causes foul smelling non-bloody diarrhoea, cramps, flatulence, but no fever. Diagnosis is from stool microscopy, ELISA & “string test”. Treatment is with metronidazole. The organism is trophozoite “pear shaped”, has 2 nuclei, 4 flagellas and a suction disk. Ingestion of cyst from fecally contaminated water & food. Causes malabsorption of protein and fat.

ANSWERS

1. C

2. G

3. K

4. D

5. O