Returned Traveller

Question 1

Malaria (Plasmodium spp.): About & Clinical Features

Answer 1

Female anopholes mosquito.

Incubation typically 1-6 weeks
Falciparum short, Malariae long.
PrEP can delay by months.
Any exposure within 12 months is significant

___________________

1- Infection
2- Liver replication
3- RBC invasion + haemolysis

Classically, 6-10 hour fever attacks that occur cyclically every 2-3 days.
–> Falciparum fevers less predictable, may be continuous

Other features:
- Flu-like (malaise, myalgia, arthralgia)
- Hepato/splenomegaly
- Mild jaundice

‘Severe’ features (Falciparum)
- >5% RBCs infected
- Cerebral malaria (ALOC, psychosis, seizure)
- ARDS
- Severe haemolytic anaemia
- Renal failure
- Haemoglobinuria (“blackwater”)
- DIC
- Metabolic acidosis
- Hypoglycaemia

Question 2

Specific features of the Plasmodium types:

Answer 2

FALCIPARUM
- Most severe/ fatal
- Higher parasitaemia %
- Chloroquine resistance
- 1-6week incubation
- NO LIVER PHASE- doesn’t relapse
- Tertian fever, often unpredictable or continues

MALARIAE
- Slower cycle, so
- Longer incubation up to 12mo
- QUARTAN FEVER
- Nephrotic syndrome

VIVAX
- Dormant liver hypnozooites- can reactivate if not eradicated
- Splenic rupture

OVALE
KNOWLESI

Question 3

Malaria (Plasmodium): Investigations

Answer 3

Thick & thin film
- Repeat x1, 12 hours apart
- Must have THREE negative to exclude malaria
Rapid antigen test

FBC
- Anaemia (normo)
- Thrombocytopaenia

HAEMOLYSIS SCREEN
- Bili, ALP, haptoglobin, LDH, retics, film

UEC, LFT, Coags, BSL, VBG
- Organ dysfunction

DDx EXCLUSION

Question 4

Malaria (Plasmodium): Treatment

Answer 4

Admit & ID consult
Notifiable disease

Severe, falciparum:
- IV ARTESUNATE 2.4mg/kg @ 0, 12, 24 hours
Alternative: IV Quinine 20mg/kg

PO if non-severe. Artemether + Lumefantrine

Question 5

Risk factors for severe malaria:

Answer 5

Pregnant
Splenectomy
Immune compromise
Extremes of age
Traveller (immunologically naive)

Question 6

Criteria for SEVERE malaria:

Answer 6

• > 5% RBCs infected
• Cerebral malaria (ALOC, psychosis, seizure)
• ARDS
• Severe haemolytic anaemia
• Renal failure
• Haemoglobinuria (“blackwater”)
• DIC
• Metabolic acidosis
• Hypoglycaemia

Question 7

Dengue:

Answer 7

Aedes mosquito

Incubation usually 1, up to 2 weeks

Most are asymptomatic.

Some get ‘Dengue fever’: (‘break bone fever)
- Fever
- Measle-like rash
- Severe myalgia

Those with subsequent infection, once initial fever subsides, may develop severe ‘Dengue Haemorrhagic Fever’:
- Thrombocytopaenia
- Mucocutaneous bleeding
- Third-spacing and hypovolaemia

DX
- PCR or serology
- Positive tourniquet test

MX
- Supportive
- Avoid subsequent infection!!

Question 8

Viral Haemorrhagic Fever:

Answer 8

Fever + DIC

Syndrome caused by a group of exotic viruses.
Lassavirus
Crimean-Congo
Ebola
(Dengue, Yellow Fever)

High mortality, very infectious
Supportive only

Question 9

Typhoid Fever

Answer 9

AKA Enteric Fever

Salmonella Typhi (S. Paratyphi causes similar, less severe syndrome)

Fecal-oral. Often contaminated food.

Fever for 2 weeks with relative bradycardia
Then
Prostration
Rose spots (pink papules)
Severe diarrhoea and abdo pain

Give CEFTRIAXONE.

Question 10

Yellow Fever (virus)

Answer 10

Incubation 3 days
Then, 3 days of symptoms

Flu-like for most
15% get jaundice,haemorrhage (thrombocytopaenia), liver dysfunction + renal failure
–> Mortality with this is 50%.

Vaccination exists.

Question 11

DDx for FEVER in returned traveller:

Answer 11

Parasitic: Malaria
Viral: Dengue, Yellow Fever, Viral haemorrhagic fever, Hepatitis, Zika
Bacterial: Typhoid, ‘travellers diarrhoea’

+ Non-travel causes.

Question 12

DDx for RASH in returned traveller:

Answer 12

Dengue (morbilliform)
Typhoid (Rose spots)
HIV seroconversion

Sunburn, tinea from swimming, contact dermatitis from hotel sheets, scabies, photosensitivity from malaria PrEP etc.

Scrub fever (black scab, tick)
Leishmaniasis (ulcer, sandfly)

+ non-travel related

Question 13

DDx for CNS symptoms in returned traveller:

Answer 13

Cerebral malaria
Dengue or Viral haemorrhagic fever with ICH
Typhoid fever
African tryptosomiasis (sleeping disease)
Methanol
…

+ non-travel related

Question 14

Treatment of ‘traveller’s diarrhoea’:

Answer 14

AZITHROMYCIN 1g IV single dose.

Only if moderate to severe.

Usually self-resolves within a 3-7 days, even if bacterial. Antis reduces duration by a very small amount.

If prolonged and parasitic suspected: METRONIDAZOLE.

Question 15

Where is P. FALCIPARUM found?

Answer 15

Sub-saharan Africa mostly

Asian more commonly non-falciparum

Question 16

Incubation periods for main returned traveller fever DDx:

Answer 16

3 days: Yellow Fever, travellers diarrhoea
1 week: Dengue
1-2 weeks: Typhoid, haemorrhagic fever
1-6 weeks (up to 12 months!): Malaria
—> Falciparum <3 weeks, Malariae long, Vivax can be months++
—> 98% manifest within 3 months
1-2 months: Hep B
Months: Schistosomiasis

Question 17

Schistosomiasis:

Answer 17

AKA Bilharzia

Freshwater snails

Parasitic worms get through skin + lay eggs in any body tissue. Partic:
–> Intestinal (incl. portal HTN, ascites, obstruction, stricture)*
–> Bladder
–> Liver

Body’s reaction to the eggs is the problem.

Itchy rash first few days
After months, flu-like + organ/tissue effects.

TEST
- Stool, urine

TREAT
- Praziquantel