Causes of Fever in a Returning Traveller Flashcards
What are the most causes of fever in the following countries:
* Sub-saharan Africa
* South Central Asia
* Southeast Asia
- Sub-Saharan Africa - P. falciparum
- South Central Asia - Enteric Fever
- Southeast Asia - Dengue
How is malaria diagnosed?
- Antigen testing
- Blood films (thick and thin)
- PCR (more common)
What are the different parasites causing malaria?
- P. vivax, P. ovale, P.malariae, P.knowlsei, P. falciparum
- Vivax and ovale have the ability to cause relapse due to hypnozoites which lay dormant.
What is the management of non falciparum malaria?
- Artemether containing therapies (most common)
- Oral chloroquine (blood stages)
- Oral primaquine for hypnozoites
What are the clinical features of severe falciparum malaria?
- Impaired consciousness or seizures
- Renal impairment
- Lactic acidosis’
- Hypoglycaemia
- Pulmonary oedema
- Anaemia
- DIC
- Shock
- Haemoglobinuria
- Parasitaemia >10% (>2% indicates an increased risk of progression to severe malaria)
What is the treatment for uncomplicated falciparum malaria
- Supportive management (especially in groups at risk of progressing to severe: parasitaemia >2%, children, non immunes, elderly, pregnant women)
- Artemether and lumafantrine
- Quinine and doxycycline
- Atovaquone and proguanil.
What is the treatment for severe falciparum?
- Supportive management (Keep euvolaemic, monitor for hypoglycaemia, give antibiotics for secondary bacterial infections, haemofiltration if required, and treatment of seizures.)
- Promt antimalarial treatment with IV artesunate
What are the causes of enteric fever?
- Salmonella typhi,
- Salmonella paratyphi
- Human to human transmission as there are no animal reservoir
Describe the pathogenesis of enteric fever
- Occurs from consuming contaminated water or food
- It travels through the GI and is absorbed by endoreticular system and then into the blood, causing a bacteraemia
What are the clinical features of enteric fever
- Incubation period is around 5 - 21 days
- Starts with fever, myalgia, headache, cough, abdo pain, constipation or diarrhoea (similar to malaria)
- Can progress to septic shock and death
How is the diagnosis of enteric fever made?
- Travel history (area visited, food and drink, vaccination status)
- Blood culture x2 is most sensitive and should always be done before antibiotics. Stool culture is less sensitive and serology has poor sensitivity
What is the treatment for enteric fever
- Quinolones which are the most effective but increasing resistance
- Cephalosporins (require longer therapy)
- Azithromycin
Ceftriaxone or azithromycin
Describe features of dengue fever
- Caused by ades mosquitoes which are well adapted to living in densily populated and polluted areas. Day biting occurs and have an incubation period of 5-14 days
What are the clinical features of dengue fever
- headache
- Fever
- Retro-orbital pain
- Arthralgia/myalgia
- Rash
- (less common are cough, sore throat, nausea, diarrhoea)
What are the laboratory findings in dengue fever and treatment
- Leucopenia
- Thrombocytopenia
- Transaminitis
- treatment is supportive
What is dengue haemorrhagic fever?
- A rare complication of dengue fever.
- It causes increased vascular permability causing oedema, thrombocytopenia, fever and bleeding
What are the different viral haemorrhagic fevers
Lassa - Caused by contacts with rats
Ebolla/Marburg - contact with bats
Crimean-congo haemorrhagic fever - contacts with ticks
South american HF,
Rift Valley fever, DHF and yellow fever - all caused by contacts with mosquitoes
Explain the clinical presentation of a patient with viral haemorrhagic fever
- 21 day incubation period
- Followed by non specific febril illness
- Haemorrhagic manifestations
- Followed by sepsis then death
What are the treatments for viral haemorrhagic fever?
- Supportive
- Coreect coagulopathy/anaemia
- Ebola antivirals
- Ribavirin?
