Malaria**** Flashcards
What is the name of the parasite that causes malaria?
Epidemiology:
Part of world affected?
What animal spreads the parasite?
Plasmodium
5 strains of these parasites cause disease:
- P. vivax
- P. ovale
- P. malariae
- P. FALCIPARUM
- …………
Tropics - Africa, Southern Asia
Female mosquitoes
Plasmodium Life Cycle:
How do the sporozoites enter the body?
Where does the sporozoites go to once it enters the body?
What do the sporozoites multiply into once at the above?
Via the female anopheline mosquito
The liver
Merozoites
Plasmodium Life Cycle:
How does the merozoites enter the blood?
P. vivax and P. ovale become hypnozoites which can incubate in the liver for months or even yrs which can cause recurrent disease !!!!!
They enter the RBCs and become trophozoites, then schizonts. which form further merozoites.
What does infiltration into the RBCs cause? - 2
When the hepatocytes rupture
Rupture - hence haemolysis and fever within 48-72 hrs
S+S:
They get a fever. How often does their temp tend to spike which could hint to malaria? - RARE
Absence of fever does NOT rule out malaria.
What other systemic symptoms do they have which are very non-specific?
Why does hepatosplenomegaly occur?
What may you notice on their skin?
Every 48 hours - but fever is usually irregular initially
Rigours
Headache
D&V
Myalgia
Due to infiltration into hepatocytes
Due to increased RBC clearance due to haemolysis
Plus immune response to the malaria parasite
Jaundice
S+S - severe:
Why do they get below?
Cerebral malaria - what do they get?
What may they develop in their kidneys?
What is blackwater fever?
Why does bleeding occur in severe malaria?
How may bleeding present
Due to sequestration of the blood - leads to microemboli as well as microvascular occlusion
Altered mental status Seizures Coma Decerebrate posturing Teeth grinding
AKI
They get dark urine due to haemoglobinuria
Bleeding in severe malaria results from several pathological processes such as thrombocytopenia, consumptive coagulopathy, and impaired clotting factor synthesis.
DIC
Retinal haemorrhages
S+S - severe:
Metabolic:
- Why do they get hypoglycaemia?
- What acid/base imbalance could occur?
They could also get splenic rupture, ARDS and pulmonary oedema.
Inhibition of gluconeogenesis due to liver damage
Metabolic acidosis - due to a range of things
Investigations:
IMMEDIATE BLOOD TESTING IS MANDATORY IN THE UK!
What type of blood test is done?
What can be used if above is not available?
How long will it take for results?
Bloods:
- FBC - what do you look at?
- Why do you do coag?
- Why do you measure glucose?
- Why is an ABG done?
- Why are U&E’s done?
Blood films - microscopy using:
- thick (if it’s malaria) blood film
- thin (which type) blood film
Rapid diagnostic test (RDT) which detects the parasite antigen.
4 hrs
DIC
Hypoglycaemia
Met acidosis
AKI
Classification of Severity:
UNCOMPLICATED: All of the following
- Parasitaemia <2%
- No schizonts
- No clinical complications
Potentially Severe:
- What 3 features would be classed as this?
What is classed as severe?
Parasitaemia <2% No schizonts No clinical complications ===== Parasitaemia >2% Parasitaemia <2% + schizonts Parasitaemia <2% + complications
Complications present, regardless of parasitaemia
Look at presentation to see what they look like.
Management:
What Rx is done for P. vivax, ovale and malariae if they cause hypnozoite formation?
Uncomplicated P. falciparum - what is prescribed?
Complicated P. falciparum - what is prescribed? - 2
- What other drug is prescribed alongside these 2?
Why is chloroquine not used in P. falciparum meaning it must be ruled out before being used in other types of malaria?
Primaquine for 2 wks
Artemether/lumefantrine (Riamet)
Artesunate IV or quinine IV + doxycycline IV/PO
Due to resistance so it will most likely be useless
Prevention - Non-pharmacological:
Where do mosquitos tend to breed?
What can be used to protect you when you are sleeping?
What can be used to prevent bites?
Standing water - so they should be gotten rid of
A mosquito/bed net
DEET repellent
Good clothing
Also think about accommodation
Prevention - Prophylaxis?
IT IS PRESCRIBED DEPENDING ON IF SOMEONE IS TRAVELLING TO A CHLOROQUINE RESISTANT AREA.
FOLLOW GUIDELINES
Causal:
- MOA?
- How long should you take this?
- Example?
Suppressive:
- MOA?
- How long should you take it?
- Example? - 2
MALORONE
Directed against hepatic stage (i.e. schizonts)
Prevents progression to erythrocytic stage
Exposure time + 7 days post exposure
Directed against erythrocytic stage
Continue 4 wks after
Chloroquine
Doxycline
e
Antimalarials:
How do they work?
Most prevent plasmodium conversion of haemoglobin
Quinine:
Why does it need ECG monitoring?
Affects sodium channels leading to cardiac toxicity
In EXAMS, what other differential can you say for this?
Dengue
Malaria and dengue present very similarly
