Malaria

Question 1

What are the five species of malaria which affect humans?

Answer 1

Plasmodium falciparum
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium knowlesi

Question 2

What is the most severe species of malaria

Answer 2

Plasmodium falciparum

Question 3

What is the vector for malaria?

Answer 3

Female Anopheles mosquito

Question 4

Incubation period for malaria

Answer 4

6 days to 1 year
P. falciparum - up to 4 weeks
P. vivax/ovale - up to 1 year

Question 5

What can the incubation time of plasmodium falciparum be?

Answer 5

Up to 4 weeks

Question 6

What can the incubation time of plasmodium vivax/ovale be?

Answer 6

Up to 1 year

Question 7

Presentation of malaria

Answer 7

• rigors
• paroxysmal fever
• malaise
• headache
• myalgia
• abdominal pain
• N+V
• jaundice + hepatosplenomegaly in later stage

Question 8

What is paroxysm fever?

Answer 8

Fever that occurs in short bursts

Question 9

Investigation needed for suspected malaria

Answer 9

Blood film x3 - thick + thin
Blood tests -FBC, U&E, LFT
Chest X ray
Head CT - neurological symptoms

Question 10

Investigation findings of malaria

Answer 10

• seen on blood film
• anaemia
• thrombocytopenia
• leukopenia
• abnormal LFTs
• high urea, bilirubin + CRP

Question 11

What is the characteristic image in malaria blood film?

Answer 11

Headphone/wedding ring

Question 12

What investigation findings exclude malaria?

Answer 12

three negative blood film samples taken over 3 consecutive days

Question 13

How do you grade the severity of malaria?

Answer 13

Parasitaemia
>5% indicates severe malaria
Calculated by the thin blood film

Question 14

Complicated vs uncomplicated malaria

Answer 14

• uncomplicated is less severe symptoms i.e no signs of organ dysfunction or life threatening complications | often caused by P.vivax/ovale/malariae
• complicated is life threatening + involves organ dysfunction + high parastic load | most commonly caused by P.falciparum

Question 15

Treatment of uncomplicated malaria

Answer 15

• first line: artemether + lumefantrine
• quinine + doxycycline
• malarone (proguanil + atovaquone)
• chloroquine (not P.falciparum)
• primaquine

Question 16

Treatment of complicated malaria

Answer 16

• first line: IV artesunate
• quinine dihydrochloride

Question 17

What drug should be used to treat liver related dormant malaria?

Answer 17

primaquine

Question 18

What drug shouldn’t be used for P. falciparum malaria?
Why?

Answer 18

Chloroquine
Widespread resistance

Question 19

Who should you not give primaquine to and why?

Answer 19

G6PD patients
can cause severe haemolysis

Question 20

Describe the life cycle of plasmodium falciparum

Answer 20

1- female Anopheles mosquito bites human
2- injects sporozoites
3- sporozoites infect hepatocytes
4- sporozoites mature to merozoites
5- merozoites burst out of cell + infect bloodstream
6- merozoites attach erythrocytes
7- plasmodium asexually replicate + mature in RBCs
8- merozoites burst out of erthyrocytes (schizont)
9- process repeats

Question 21

What is schizont?

Answer 21

The name of a erythrocyte when merozoites are ready to burst out of them

Question 22

Name of erythrocytes when merozoites are ready to burst out of them

Answer 22

Schizont

Question 23

How does malaria cause symptoms of haemolytic anaemia?
What is the exception?

Answer 23

Destruction of erthyrocytes

Plasmodium falciparum doesn’t

Question 24

What is icterus

Answer 24

Yellow eye - jaundice

Question 25

Prevention of malaria

Answer 25

Insecticide spray Clothing that covers whole body Mosquito nets Avoid still lakes Chemoprophylaxis

Question 26

Examples of antimalarial medications

Answer 26

- *malarone* (*proguanil with atovaquone*) - *doxycycline* - *mefloquine*

Question 27

Side effects of doxycycline

Answer 27

- diarrhoea - thrush - headache - angioedema - skin sensitivity to sunlight (increases sunburn risk)

Question 28

Side effects of mefloquine

Answer 28

- **psychiatric side effects** - anxiety - depression - diarrhoea - dizziness - sleep disorders - psychosis or seizures (rare)

Question 29

Why should you avoid still lakes to prevent malaria?

Answer 29

Anopheles mosquitoes lay eyes in stagnant water

Question 30

What are the categories for recurrent malaria?

Answer 30

- **Recrudescence** - original parasite not killed - **Relapse** - cleared merozoites, dormant hypnozoites in liver are no longer dormant - **Reinfection** - original cure, new case of infection

Question 31

Why does malaria caused by plasmodium falciparum not cause haemolytic anaemia?

Answer 31

1- P. falciparum cerastes sticky protein 2- protein coats surface of RBCs 3- RBCs clump together + occlude blood vessels 4- organ ischaemia

Question 32

where do plasmodium species remain dormant within the human body?

Answer 32

Liver

Question 33

ABCs of malaria prevention

Answer 33

**A**ssess risk **B**ite prevention **C**hemoprophylaxis

Question 34

Complications of plasmodium falciparum malaria

Answer 34

- cerebral malaria > seizures + neurological deterioration > death - AKI - pulmonary oedema - DIC - hypoglycaemia

Question 35

Protective factors from malaria

Answer 35

- sick cell trait - G6PD deficiency - HLA B53