Malaria

Question 1

What is malaria?

Answer 1

• Parasitic infection caused by protozoa of the genus plasmodium → plasmodium falciparum is the most life-threatening
• Widely distributed throughout tropical and subtropical regions - travellers account for majority of disease in western countries

Question 2

What are the different types of plasmodium?

Answer 2

o Plasmodium falciparum - MOST SERIOUS
o Plasmodium vivax
o Plasmodium ovale
o Plasmodium malariae
o Plasmodium knowlesi

Question 3

What populations have innate immunity to malaria?

Answer 3

o Sickle cell trait
o G6PD deficiency
o Pyruvate kinase deficiency
o Thalassemia

Question 4

Summarise the epidemiology of malaria

Answer 4

● Endemic in the tropics
● 250 million people worldwide
● Common in young children, pregnant women, travellers and immunodeficient

Question 5

What are the presenting symptoms of malaria?

Answer 5

• Haemolytic Anaemia → causes jaundice and may turn urine dark
• Splenomegaly
• Headache
• Weakness
• Myalgia (muscle aches and pain)
• Arthralgia (pain in a joint)
• Anorexia
• Diarrhoea

● Feverish traveller (incubation period can be up to 1 year)
● Symptoms are CYCLICAL:
-High fever
-Flu-like symptoms
-Severe sweating
-Shivering cold “chills”/rigors
-NOTE: the interval between cycles of symptoms are slightly different in different types of malaria
● Cerebral Malaria Symptoms:
-Headache
-Disorientation
-Coma

Question 6

What signs of malaria can be found on physical examination?

Answer 6

● Pyrexia (fever)
● Anaemia (haemolytic)
● Jaundice
● Hepatosplenomegaly

Question 7

What investigations are used to diagnose/ monitor malaria?

Answer 7

1. Thick/Thin Blood Films- detects asexual or sexual forms of the parasites inside erythrocytes
   o Thick for quantifying
   o Thin for identifying type of malaria
2. Bloods
   o FBC - haemolytic picture
   o U&Es
   o LFTs
   o ABG
3. Urinalysis -check for blood or protein
4. Rapid Diagnostic Tests (RDTs) → detection of parasite antigen or enzymes

Question 8

How is malaria managed?

Answer 8

1. Chloroquine (ok during pregnancy) or Hydroxychloroquine

Prevention → avoid exposure (nets, repellent, protective clothing) and prophylaxis

Question 9

How does malaria affect red blood cells?

Answer 9

Invasion by the malaria parasite, P. falciparum brings about extensive changes in the host red cells. These include loss of the normal discoid shape, increased rigidity of the membrane, elevated permeability to a wide variety of ionic and other species, and increased adhesiveness, most notably to endothelial surfaces.

Question 10

How does malaria affect the liver?

Answer 10

The infection of liver cells by the sporozoites form of the malarial parasite can cause organ congestion, sinusoidal blockage, and cellular inflammation. These changes in hepatocytes can lead to the leakage of parenchymal (transaminases) and membranous (alkaline phosphatase) enzymes of the liver to the circulation.