Malaria Flashcards
What organism causes malaria?
Most are 5 species of plasmodium, of which most infections are Plasmodium Falciparum
Describe the life cycle of malaria?
1) Female Anopheles Mosquito injects sporozoites into the blood during feeding
2) They migrate to liver and produce merozoites
3) Merozoites replicate in RBCs
4) 2nd mosquito drinks RBCs containing gametocytes
5) Gametocytes –> Zygote –> Sporozoites in the mosquito
How does malaria present?
Basically with flu-like symptoms although most patients just get paroxysms of fever and tachycardia until complications arise
What are the advanced presentations of malaria?
- Cerebral Malaria
- Blackwater Fever
- Pulm. Oedema
- Jaundice
- Severe Anaemia & associated symptoms
- Algrid Malaria
What characterises cerebral malaria?
Coma
Convulsions
Altered mental status
What are the features of blackwater fever?
Severe haemolysis by merozoites –> Anaemia, haemoglobinuria & renal failure
What is algrid malaria?
hypotension –> Shock
Due directly to the malaria or to concomitant septicaemia
How do we test for malaria?
Thick and thin blood films - shows up parasitaemia
Quantitative buffy coat (QBC)
RApid antigen test
How does QBC work?
Centrifuge the blood so you can visualise a layer of parasitized RBCs (allows you to quantify the infection)
Whats special about the rapid antigen test?
It can be done with no training and no access to a lab, so great for the developing world
What factors would indicate severe/complicated malaria?
- Impaired consciousness
- Hypoglycaemia
- Parasite count >2%
- Haemoglobin <8mg/dl
- Spontaneous bleed or DIC (disseminated Intravascular Coagulation)
- Haemoglobinuria
- Renal impairment or Acidosis
- Pulm oedema or ARDS
- Shock (Algrid Malaria)
How do we treat uncomplicated Malaria?
3 Days or Riamet which is Artermether and Lumefantrine together.
This is because a lot of strains are resistant to chloroquine and to multiple drugs so combination therapy is best
How do we treat complicated malaria?
IV Artesunate
How do we treat non-falciparum malaria?
3 Days of chloroquine
Actually the best drug but almost all falciparum is resistant now so only used for other types like Plasmodium Ovale.
If they have plasmodium Ovale or Vivax add 14 days of primaquine.
What measures can prevent malaria infection?
- Bed nets & mesh windows
- Anti-malarials e.g. malarone
- Mosquito sprays e.g. DDT
- Drainage of standing water to remove breeding grounds
- Larvacides
