Malaria

Question 1

what is the typical presentation of malaria?

Answer 1

CYCLICAL/ INTERMITTENT symp: HIGH Fever, sweating, Rigors, vomiting, jaundice (falciparum), hepatomegaly, Anaemia, reduced consciousness/ fits, renal failure, PO, bleeding/DIC

Question 2

what are the high risk areas for malaria?

Answer 2

Africa, Asia, S+C America

Question 3

define malaria?

Answer 3

Infection with protozoan Plasmodium

Question 4

what are the 5 types of plasmodium?

Answer 4

Mosquitos Know Our Vital Fear

Plasmodium malariae: mild in progression but is much more chronic and can last for years.

Plasmodium knowlesi- v. Rare but can cause severe malarial symptoms.

Plasmodium ovale:often remain dormant in the liver as hypnozoites reactivating at a later date. Infection symptoms tend to be relatively mild, with a slower progression of anaemia and recovery within 6 weeks.

Plasmodium vivax: often remain dormant in the liver as hypnozoites reactivating at a later date. Infection symptoms tend to be relatively mild, with a slower progression of anaemia and recovery within 6 weeks.

Plasmodium falciparum - MOST SERIOUS and MOST COMMON

Question 5

what is the most serious and most common plasmodium?

Answer 5

Plasmodium falciparum

Question 6

outline the aetiology of malaria?

Answer 6

Transmitted by the bite of the female Anopheles mosquito

The protozoa grow in red blood cells

Life Cycle

• Injection of sporozoitesinto the blood stream by mosquito
• Invasion and replication in hepatocytesto form merozoites
• These are released in to blood and enter RBCs
• They replicatewithin red blood cells and develop ringforms, and then trophozoites
• Red blood cells rupture and release merozoites, which reinfect other red blood cells
• Trophozoites form merozoites and gametocytes. Gametocytesare taken up when another mosquito feeds, and develop into sporozoitesin the gut of the mosquito

Question 7

which populations have an innate immunity to malaria?

Answer 7

Sickle cell trait

G6PD deficiency

Pyruvate kinase deficiency

Thalassemia

Question 8

summarise the epidemiology of malaria?

Answer 8

Endemic in the tropics

250 million people worldwide

Common in young children, pregnant women, travellers and immunodeficient

Question 9

what are the presenting symptoms of malaria?

Answer 9

Feverish traveller (incubation period can be up to 1 year)

• Symptoms are CYCLICAL:
• High fever
• Flu-like symptoms
• Severe sweating
• Shivering cold/rigors

Cerebral Malaria Symptoms:

• Headache
• Disorientation
• Coma

Question 10

what are the signs of malaria on physical examination?

Answer 10

Pyrexia

Anaemia(haemolytic)

Jaundice

Hepatosplenomegaly

Question 11

what are the appopriate investigations for malaria?

Answer 11

Thick/Thin Blood Films - useful to do on 3 consecutive days

• Thick for quantifying
• Thin for identifying type of malaria

Rapid diagnostic tests (RDTs)- detect presence of malaria antigen/ enzyme (but poor detection of species other than plasmodium falciparum)

Bloods

• FBC - haemolytic picture
• U&Es
• LFTs
• glucose
• ABG

Urinalysis -check for blood or protein