MI: Fever in the Returning Traveller

Question 1

List some diseases caused by mosquitoes.

Answer 1

• Malaria
• Elephantiasis
• Dengue
• Yellow fever
• West Nile virus
• Zika virus

Question 2

What is the vector for malaria?

Answer 2

Anopheles mosquito (female)

Question 3

What are the five species of Plasmodium.

Answer 3

• Plasmodium falciparum
• Plasmodium vivax
• Plasmodium ovale
• Plasmodium malariae
• Plasmodium knowlesi

Question 4

Outline the life cycle of Plasmodium within humans.

Answer 4

• Within humans there is an erythrocytic stage and an extra-erythrocytic stage
• It reproduces within red blood cells and causes haemolysis
• There is also a liver stage where the parasite lays dormant within the liver

Question 5

List the components of malaria prevention.

Answer 5

• Awareness of risk
• Bite prevention
• Chemoprophylaxis
• Diagnose promptly and treat without delay

Question 6

Describe the clinical features of malaria.

Answer 6

• Cyclical or continuous fevers with spikes
• Malria paroxysms - chills, high fever, sweats

Question 7

List some clinical features of severe malaria.

Answer 7

• High parasitaemia (technically >2% - but might not make people from Africa particularly ill) OR 1 schizont (cell with multiple parasites)
• Altered consciousness
• ARDS
• Circulatory collapse
• Metabolic acidosis
• Renal failure
• Hepatic failure
• Coagulopathy
• Severe anaemia
• Hypoglycaemia

Question 8

What is the main investigation for malaria?

Answer 8

• Perform 3 thick and thin blood films
• Thick - screening for parasites (sensitive)
• Thin - identifying the species and quantifying the parasite (proportion of red cells that have been parasitised)

Question 9

List two examples of malaria rapid antigen tests.

Answer 9

Paracheck-PF

OptiMAL-IT

Question 10

Which stains are used for malaria?

Answer 10

Giemsa

Field’s

Question 11

Outline the treatment options for non-falciparum malaria.

Answer 11

• Chloroquine - 3 days
• Primaquine - 30 mg for 14 days

Question 12

What must you do before giving someone primaquine?

Answer 12

Screen for G6PD deficiency as primaquine can cause extensive haemolysis

Question 13

What are the complications of non-falciparum malaria?

Answer 13

Very rare but there are reports of splenic rupture

Question 14

What counts as ‘mild’ falciparum malaria?

Answer 14

• Not vomiting
• Parasitaemia < 2 %

Question 15

Outline the treatment options for mild falciparum malaria.

Answer 15

• First line = Artemisin combination therapy (ACT) e.g. Riamet (artemether-lumefantrine)
• Occasionally oral malarone (atovaquone and proguanil)*

Question 16

Outline the treatment of severe falciparum malaria.

Answer 16

• ABCDE approch
• Correct hypoglycaemia
• Cautious hydration
• Organ support if necessary
• IV artesunate
• Daily parasitaemia monitoring
• Follow on with oral antimalarials

Question 17

Why is quinine not used in this situation?

Answer 17

Extensive side effects:

• Cinchonism: tinnitus, dizziness, nausea and vomiting
• Arrhythmias
• Hyperinsulinaemia

Question 18

What is the vector for dengue?

Answer 18

Aedes mosquito

Question 19

Outline the clinical features of dengue.

Answer 19

• Fever
• Headache
• Myalgia
• Erythrodermic rash
• Bleeding
• Hepatitis
• Severe: encephalitis, myocarditis

Question 20

What are the complications of dengue? In which circumstances does this tend to occur?

Answer 20

• Dengue haemorrhagic fever and dengue shock
• This occurs in individuals who have previously been infected with a different dengue serotype

Question 21

Which tropical virus is similar to dengue? What is a key difference?

Answer 21

• Chikungunya
• Arthralgia is more severe

Question 22

List some diagnostic tests for dengue.

Answer 22

• Serology (IgM 5-7 days)
• PCR

Question 23

How is dengue treated?

Answer 23

Identify those at risk of severe disease

Supportive

Question 24

Outline the clinical course of dengue.

Answer 24

Fever reduces after about 4-5 days

Question 25

What is the term used to describe a high temperature with a relatively normal heart rate? List some causes.

Answer 25

• Sphygmothermic dissociation
• Causes: typhoid, yellow fever, brucellosis, tularaemia

Question 26

What is typhoid fever caused by?

Answer 26

Salmonella typhi and paratyphi

Question 27

What type of organism is Salmonella typhi?

Answer 27

Gram-negative rod

Question 28

Outline the clinical features of typhoid.

Answer 28

• High prolonged fever
• Headache
• Rose spots
• Constipation
• Dry cough

Question 29

What is the incubation period of typhoid?

Answer 29

7-18 days

Question 30

List some complications of typhoid.

Answer 30

• GI Bleeding
• Perforation
• Encephalopathy

Question 31

What is the treatment for Typhoid?

Answer 31

• Empirical ceftriaxone (2 g IV OD)
• Azithromycin PO 500 mg BD 7 days

Question 32

What is mononucleosis caused by?

Answer 32

EBV or CMV

Question 33

What is a characteristic clinical feature of mononucleosis?

Answer 33

Tonsillar enlargement with exudates

Question 34

List some investigations for mononucleosis.

Answer 34

• Monospot
• IgM EBV/CMV

NOTE: always consider HIV

Question 35

What is a characteristic microscopic feature of mononucleosis?

Answer 35

Atypical lymphocytes