Gastro Medecine - Bacterial Gastroenteritis

Question 1

Campylobacter jejuni?

Answer 1

• Most common cause of acute infective diarrhoea
• Spiral, gram negative rods
• Usually infects caecum and terminal ileum. Local lymphadenopathy is common
• May mimic appendicitis as it has marked right iliac fossa pain
• Reactive arthritis is seen in 1-2% of cases

Question 2

Shigella spp?

Answer 2

• Members of the enterobacteriaceae
• Gram negative bacilli
• Clinically causes dysentery
• Shigella soneii is the commonest infective organism (mild illness)
• Usually self limiting, ciprofloxacin may be required if individual is in a high risk group

Question 3

Salmonella spp?

Answer 3

• Facultatively anaerobic, gram negative, enterobacteriaceae
• Infective dose varies according to subtype
• Salmonellosis: usually transmitted by infected meat (especially poultry) and eggs

Question 4

E. coli?

Answer 4

• Enteropathogenic
• Enteroinvasive: dysentery, large bowel necrosis/ulcers
• Enterotoxigenic: small intestine, travelers diarrhoea
• Enterohaemorrhagic: 0157, cause a haemorrhagic colitis, haemolytic uraemic syndrome and thrombotic thrombocytopaenic purpura

Question 5

Yersinia enterocolitica?

Answer 5

• Gram negative, coccobacilli
• Typically produces a protracted terminal ileitis that may mimic Crohns disease
• Differential diagnosis acute appendicitis
• May progress to septicaemia in susceptible individuals
• Usually sensitive to quinolone or tetracyclines

Question 6

Vibrio cholera?

Answer 6

• Short, gram negative rods
• Transmitted by contaminated water, seafood
• Symptoms include sudden onset of effortless vomiting and profuse watery diarrhoea
• Correction of fluid and electrolyte losses are the mainstay of treatment
• Most cases will resolve, antibiotics are not generally indicated