Common Causes Of Fever In The Returning Traveller Flashcards
What are the common causes of undifferentiated fever in those returning from travel?
- no cause in 40%
- sub-saharan Africa = P. Falciparum (malaria) most common
- south-central Asia = enteric/Dengue fever
- southeast Asia = Dengue fever
Describe how an anophoele mosquito causes malarial infection
- mosquito breaches the skin of the host and has a blood meal releasing sporozoites
- these go into the blood to the liver to develop
- they then leave the liver and parasitise red cells
- leading to symptomatic infection
Describe the diagnostic tests for malaria
- antigen testing
- blood films (thick = to determine if malaria or not, thin = determine type of malaria)
- PCR
What species is included in non-falciparum malaria and its features?
- P. Vivax
- P. Ovale
- P. Malariae
- P. Knowlsei
- tend to cause non-severe disease
What is unique about P. Vivax and P. Ovale malarial infections?
- they have the ability to relapse due to hypnozoite stage
- liver stage where the infection can lie dormant and be secreted later to cause infection
What is the management of non-falciparum malaria?
- oral chloroquine (blood stages)
- artemether containing therapies
- oral primaquine (hypnozoites)
What is a main feature of severe malaria?
- sludging up of microcirculation (when cells stick together)
Causes symptoms such as:
- renal impairment
- hypoglycaemia
- spontaneous bleeding/DIC
- low Hb (haemolysis)
- haemoglobinuria
What is the management of uncomplicated falciparum?
- supportive management
- oral antimalarial therapy:
- artemether + lumafantrine/riamet (3 days)
- quinine + doxycicline (5-7 days)
- atovaquone + proguanil/malarone (3 days)
What is the management of severe falciparum malaria?
- supportive treatment (euvolaemia, monitor for hypoglycaemia, antibiotics for secondary bacterial infection, haemofiltration/seizure treatment if needed)
- prompt antimalarial therapy (IV artesunate)
What are the causative organisms of enteric fever and the mode of transmission?
- S. typhi
- S. paratyphi
- human to human (no animal reservoir)
- contaminated food/water
Describe the pathogenesis of enteric fever
- organism ingested in contaminated food/water
- microorganism spreads from Peyer patches in small intestine to the reticular endothelium
- here is causes a bacteraemia leading to infection
What are the symptoms of enteric fever?
- fever
- myalgia
- headache
- cough
- abdo pain
- constipation
- diarrhoea
- septic shock -> death (in severe cases)
What is the methods of diagnosing enteric fever?
- blood culture (best)
- stool culture
- serology (poor sensitivity/specificity)
What is the treatment of enteric fever?
- quinolones eg. Ciprofloxacin (best - resistance)
- cephalosporins eg. Ceftiaxone (empiric for 14 days)
- azithromycin
What are the symptoms of Dengue fever?
“Breakbone fever”
- headache
- fever
- retro-orbital pain
- arthalgia/myalgia
- rash
- cough
- sore throat
- nausea
- diarrhoea
