Lecture 37: Febrile returned traveller Flashcards
50 y/o man emigrated from Zimbabwe in 2003 and returned 6 days ago from a 18 day trip back to Zimbabwe.
Too tired to work since flight (last Sat) and now (fri morning) is febrile (38.9) and non-communicative.
Exposure to infections?
Air - influenza, TB
Food and water - Salmonella typhi, Salmonella enteritidis, Campylobacter jejuni, HepA
Infective vectors - Malaria, dengue
Infected people - HIV syphilis
Things to consider when narrowing down?
- How long you were away for
- When you got sick relative to when you got there/when you left (think about incubation periods)
- Where you went
- Where you stayed
- What type of things you were doing there
Malaria is cause by _____? Transmission
A protozoa which has a number of species
- Plasmodium falciparum - potentially fatal
- Plasmodium vivax - Relatively benign
- Other rare species
Anopheles mosquito (female) is a vector and is NOT found in NZ
Infection of the Liver multiplying for minimum of 10 days causes infected RBC that can then be transmitted. After a number of days RBC burst and immune response occurs causing fever through shivering and then sweating to cool down.
Malaria complications?
P. falciparum
- Able to infect any RBC
- High parasite load >1% of erythrocytes infected
- Insert a protein into RBC membranes that adgeres to CD36 and ICAM1 on capillary membranes
- Sequestration of erythtocyes in capillaries - especially brain and kidneys
- Death from come and renal failure
Does NOT occur with P vivax
- Only infects young RBC
- Doesn’t cause RBC sequestration
- NO risk of severe disease
- Relapses result (months or even years) from repeated release of liver hypnozites.
Malaria treatment?
P falciparum - need to kill merozoites in erythrocytes
- Quinine and doxycycline
- Artemether and lumefantrine
P vivax
- Chloroquine to kill merozoites
- Primaquine to kill hypnozoites in liver
Salmonellae infections?
Very closely realted to E. Coli
Salmonella enteritidis
- Aquired from animals and birds
- infects colonic mucosa
- causes colitis
- common cause of “infective colitis” in NZ and oversease
Salmonella typhi - “typhoid fever”
- Aquired form people (human faeces not animal)
- Infects Peyers patches in terminal ileum within macrohages
- Causes bacteraemia and septicaemia as they spill over into the blood.
- Common cause of persistent fever in travellers but NOT in NZ
Outcomes for Thyphoid fever
Is an enteric fever - fever, rigors, sweats, cough, headache, confusion (not usually diarrhoea), may be constipated
Risk of perforation of Peyer’s patch resulting in peritoitis and risk of erosion of ileal blood vessels resulting in catastrophic intestinal bleeding
10% mortality without treatment (mostly children)
Minority have gall bladder colonisation and excrete S typhi in faeces - source of infection for others
Treatment of typhoid fever?
Blood cultures may be required before the organism is isolated
Treatment with ceftriaxone IV or ciprofloxacin orally
Vaccination is about 70% effective
