Microbiology 24 - Fever in the Returning Traveller

Question 1

Recall some differentials for fever and rash in the returning traveller

Answer 1

Viral: dengue, chickungunya, measles
Bacterial: typhoid (look for rose spots)

Question 2

Recall some differentials for fever and abdo pain in the returning traveller

Answer 2

Typhoid fever
Amoebic liver abscess

Question 3

Recall some differentials for fever and cytopaenias in the returning traveller

Answer 3

Dengue, chickungunya, typhoid, malaria

Question 4

Recall some differentials for fever and haemorrhage in the returning traveller

Answer 4

Viral haemorrhagic fevers (dengue/ ebola)
Meningococcaemia

Question 5

Recall a differential for fever and eosinophilia in the returning traveller

Answer 5

Schistosomiasis

Question 6

Recall some differentials for fever > 6 weeks post-travel in the returning traveller

Answer 6

Vivax malaria
Acute hepatitis
TB
Amoebic liver abscess

Question 7

What type of mosquito carries malaria?

Answer 7

Female Anopheles

Question 8

Recall the different types of malaria

Answer 8

Falciparum
Vivax
Ovale
Malariae
Knowelsi

Question 9

what do double dotted rings on blood film suggest?

Answer 9

Plasmodium falciparum Double-dotted rings

Question 10

what are the clinical features of malaria?

Answer 10

Fevers – cyclical or continuous with spikes

Malaria paroxysm – chills, high fever, sweats

severe -> end organ damage

Question 11

Why is malaria sometimes known as ‘blackwater fever’?

Answer 11

Due to the haemaglobinuria

Question 12

What % of parasitaemia constitutes a severe malaria?

Answer 12

Child, severe = >2%

Adult, severe = >10%

Question 13

What is the gold standard test for malaria?

Answer 13

3 thick and thin blood smears:

Field’s or Giemsa (better for species identification) stain

Thick: screen for parasites (sensitive)

Thin: identify species and quantify parasitaemia

Malaria antigen detection tests (rapid antigen test):

Paracheck-PF Detect plasmodial HRP-II (Histidine-Rich Protein II)

OptiMAL-IT Detect parasite LDH

Question 14

What acid base abnormality may be seen in malaria?

Answer 14

Metabolic acidosis

Question 15

What is the treatment for falciparum malaria?

Answer 15

Mild Falciparum Malaria

• Artemisinin Combination Therapy (ACT)
• Artemisinin; AND Lumefantrine
• Adults - Oral malarone (atovaquone and proguanil), QDS, 3 days
• Oral quinine, TDS - doxycycline, OD, 7 days

Severe Falciparum Malaria:

ABC approach, Correct hypoglycaemia, Cautious hydration (avoid overload)

• IV Artesunate > IV quinine
• Hyperinsulinaemia - worst hypoglycaemia

Question 16

What are the treatments for non-falciparum malaria?

Answer 16

Primaquine and chloroquine

Question 17

What type of mosquito is a vector for dengue virus?

Answer 17

Aedes

Question 18

What are the symptoms of dengue?

Answer 18

• Fever
• Headache (retro-orbital)
• Myalgia
• Erythrodermic rash (50%)
• Bleeding Hepatitis

Severe:

• Encephalitis Myocarditis

conjunctivital injection

Question 19

What cytopaenias are expected in dengue infection?

Answer 19

Thrombocytopaenia
Neutropaenia

Question 20

What is the vector for dengue fever?

Answer 20

Aedes mosquito

mostly in urban areas

Question 21

describe the clinical course for Dengue

Answer 21

Reduction in fever occurs around day 4-5

Complications often develop around this time (Critical Phase)

Question 22

investigations for Dengue

Answer 22

Serology (IgM 5-7 days)

PCR

Dengue cross-reacts with other flavivirus IgG (JE, yellow fever)

Question 23

treatment for dengue fever

Answer 23

Usually a mild, self-limiting illness however, it can progress to dengue haemorrhagic fever and dengue shock

rare in travellers

Occur in individuals previously infected with a different Dengue serotype due to an excessive immune response

Question 24

what is Faget’s sign?

Answer 24

a high fever with a relatively (to the fever) normal HR

A fever should send the HR much higher

If this does not occur → “Faget Sign” = sphygmothermic dissociation = fever + bradycardia

Question 25

What are the possible causative organisms in typhoid (enteric) fever?

Answer 25

Salmonella typhi/ paratyphi

Question 26

What is the phrase "himalaya peak fevers" pathognemonic for?

Answer 26

Typhoid fever

Question 27

what type of organism causes typhoid fever?

Answer 27

gram negative rods

Question 28

What is the treatment of typhoid fever?

Answer 28

Initially ceftriaxone, 2g IV, OD → changed to Meropenem at day 3 Careful monitoring and supportive care Empirical ceftriaxone (IV, 2g) → Azithromycin (PO, 500mg BD, 7 days)

Question 29

which population of travellers have the highest risk of tropical infection

Answer 29

visiting friends and relatives

Question 30

what are the side effects of quinines

Answer 30

Quinine SEs = cinchonism (tinnitus, dizziness, N&V), arrhythmias, hyperinsulinaemia

Question 31

what are the clinical features of typhoid fever?

Answer 31

High prolonged fever Headache Rose spots (rare) Constipation Dry cough Insidious onset (incubate 7-18 days; up to 60d) Most imported from South Asia (Indian Subcontinent) Vaccine is only partially protective against typhi and offers no protection against S. paratyphi

Question 32

What are atypical lymphocytosis pathonomonic for?

Answer 32

EBV/CMV mononucleiosis

Question 33

What does a skin rash and eosinophilia suggest?

Answer 33

KATAYAMA FEVER - freshwater swimming

Question 34

which disease causes fever, headache, myalgia ± eschar

Answer 34

Rickettsial Disease