Malaria

Question 1

Define Malaria

Answer 1

parasitic infection caused by protozoa Plasmodium
5 main types of plasmodium, with falciparum being the most dangerous and common one

naturally transmitted by transfusion but can also be via blood transfusion
tropical/subtropical
travelers in western countries

Question 2

Aetiology and risk factors of malaria

Answer 2

5 forms of plasmodium
Plasmodium falciparum-most severe, endemic to africa, Southeast Asia, oceania, amazon
p.vivax-asia, america, 80%in ethipia, india,pakistan
P.ovale-africa
p-malaria-like falciparum
p.knowlesi-southeast Asia

Plasmodium is injected during a mosquito blood meals and goes to hepatocytes-sporozoites replicate there
Then release to blood-merozytes enter RBC–time before enters blood is pre-patent period-7-30 days for falciparum
much longer in vivax/ovale-latent hepatocyte period
merozytes duplicate in RBC, burst and infect more (72h for falciparum, 24 h knowlesi, 48h others)-repeating cycle (causes cyclical fever)
rupture of RBC is what produces cytokines and toxins, causing the Sx-usually cyclical
Falciparum is the most Sx one

risk factors:
travelling/living in endemic area
Innapropriate anti-malarial prophylaxis
bad use of anti-mosquito 
migrants from endemic area

disease worse if young, pregnant, immunocompromised

Question 3

Epidiemology of malaria

Answer 3

219 million cases worldwide, with 500 000 deaths
92% were in africa, and mainly caused by facliparum

pregnant women and children are most vulnerable
cases in western countries are travellers

Question 4

Signs and Sx of malaria

Answer 4

facliparum-present 1st month after exposure

very non-specific
Fevers (chills, rigors,night sweats,)
patterns of fever develop over time but are not diagnostic

headache, weakness, arthralgia, myalgia can present
anorexia, weight loss, nausea, vom, diarrhoea, abode pain are less common

focus Hx on risk factors, and travel Hx (in anything that sounds like it)
ask about prophylaxis

exam:
severe malaria complications: -more likely in falciparum:
heamolytic anaemia
jaundice, hepatosplenomegaly, pallor/aneamia

also confusion, seizures, low GCS, hypotense, anuria,

can also get 2ndary bacterial infection

Question 5

Investigations of malaria

Answer 5

Giemsa stained blood smears-in trained hands, best way-see trozophytes in RBC (ring shaped)
PCR are also great

Rapid detection test-see antigen

FBC might show thrombocytopenia, anaemia, variable WCC

LFT-raised markers
can have unconjugated mild bilirubin rise
want U&E , clotting, renal function for base

LP, CXR can help with differentials

severe disease: hypoglycaemia, acidosis, anaemia, renal impairment
(and tons of Sx)