infection - travel related infections: enteric fever

Question 1

what are investigations for typhoid & paratyphoid (enteric fever)?

Answer 1

Hb, WCC, U&E, ALT, ALP, CRP, CXR, AXXR

splenomegaly

Question 2

what is the causative organism for typhoid & paratyphoid fever? mechanism of infection?

Answer 2

salmonella typhi
mainly Asia (africa & s. america) - poor sanitation
faecal-oral (contaminated food / water) 
human carriers
(clean water & food, vaccine)

Question 3

Describe Salmonella enterica & virulence factors

Answer 3

EnteroBacteriaCeae, aerobic (gut) gram neg rod
gram-negative ENDOTOXIN - damage gut epithelial cells
invasin allows intracellular growth
fimbriae adhere to epithelium over ILEAL lymphoid tissue (Peyer’s patches)

Question 4

what are the signs and symptoms of enteric fever?

Answer 4

systemic disease (bacteriaemia)
incubation period (7-14 days)
fever, headache, abdominal discomfort, constipation, dry cough
relative BRADYcardia
complications: intestinal haemorrhage & perforation (peyer’s patches ileum)
paratyphoid tends to be milder

Question 5

enteric fever investigations?

Answer 5

moderate anaemia
relative lymphopenia
raised LFTs (transaminase & bilirubin)
culture: blood & faeces
serology not reliable (Ab detection)

Question 6

treatment for enteric fever?

Answer 6

ceftriaxone or azithromycin for 7-14 days

Question 7

enteric fever prevention?

Answer 7

food & water hygiene precautions
typhoid vaccine (high risk travel / lab personnel) - live attenuated / Vi capsular polysaccharide antigen (effect 50-75%)

Question 8

what are non-typhoidal salmonella infections? causative organisms? symptoms?

Answer 8

‘food-poisoning’ salmonella
S. typhimurium, S. enteritidis
D&V, fever, abdo pain
generally self limiting, deep-seated infections can occur