Returning traveller - malaria Flashcards

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1
Q

Suspect malaria in patient with fever, and travel history

Incubation is usually 6 days - 3 months. But 10% can present up to 1 year after exposure.

Prophylaxis provides 95% protection.

What are initial tests required?

A

FBC/U+E/LFT/CRP/Coag

Blood culture
Urinalysis
CXR

Malaria specific -
Malaria Ag
Blood film - thick/ thin with parasite count
ABG - acidosis/ hypoglycaemia

If positive for malaria, presume it is falciparum until proven otherwise

If patient presenting as outpatient for assessment, blood film needs to be done before discharging home

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2
Q

How many cases of malaria per year in UK?

What is case fatality rate?

A

2000/ year

1.2% case fatality

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3
Q

What are issues with malaria rapid antigen test?

A

Lower sensitivity

Detects antigen rather than live parasite, so can remain positive for weeks after treatment

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4
Q

Patient seen in A&E, plasmodium falciparum seen on blood film.
Patient well, no severe markers

What is management?

A

Admit for at least 24 hours of treatment

falciparum can deteriorate rapidly

if on chemoprophylaxis, stop. As clearly not working, and can reduce parasitaemia to make diagnosis more difficult

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5
Q

What are markers of severe malaria?

Any of these indicators means should be admitted, and given IV treatment
Escalate to ITU early

A

Parasitaemia >2%

Reduced GCS/ seizures

AKI - Cr >265

Pulmonary oedema

Hypoglycaemia

Anaemia - Hb <8 may need transfusion

Metabolic acidosis

Hypovoloaemia/ shock

jaundice - bilirubin >50

prostration

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6
Q

Why does hypoglycaemia occur in malaria?

A

increased glucose use in unwell patient

quinine stimulates insulin release

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7
Q

What is drug treatment of severe falciparum malaria?

This is a medical emergency

A

Artesunate

If artesunate no rapidly available, give IV quinine loading dose

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8
Q

Artesunate better than quinine, and has fewer side effects, and does not cause hypoglycaemia

What is dosage of artesunate?

When switch to oral?

A

2.4mg/kg IV bolus

Given at 0/ 12/ 24 hours, then daily afterwards

continue IV until can tolerate oral, patient improving, parasite count improving

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9
Q

After artesunate given for severe malaria, oral step down options preferred is coartem/ riamet

What is dosage?

What is duration of therapy?

A

Coartem/Riamet - artmether 20mg/ lumefantrine 120mg

4 tablets taken at 8 /24/ 36/ 48/ 60 hours

give with milk/ fatty foods as aids absorption

normally 48 hours IV artesunate, and 3 days oral is sufficient for cure

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10
Q

If co-artem/riamet oral options are not available, what other oral options are available for malaria?

Which option is suitable for pregnancy?

A

Atovaquone-proguanil OD 3 days

Doxycycline 200mg OD 7 days

Clindamicin 450mg TDS 7 days - suitable for pregnancy

These options are particularly helpful if artesunate/ coartem/ riamet not available.
IV quinine until stable - then oral quinine or the options above. Particularly helpful if has side effects to quinine

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11
Q

Patient with severe falciparum malaria. No artesunate available.

What is dose of quinine?

What is duration of therapy?

A
  • 20mg/kg loading dose, given over 4 hours
  • unless received mefloquine the previous day, when 10mg/kg should be used
  • maintenance 10mg/ kg TDS
  • switch IV to oral quinine once improving/ able to tolerate oral, for total of 7 days
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12
Q

What are side effects of quinine?

What tests need to be done before starting treatment?

Cinchonism is pathological condition caused by excess quinine or its natural source, cinchona bark

A

tinnitus - this is reversible, and not an indication for stopping quinine

QT prolongation - class 1 anti-arrhythmic. Can lead to Torsades de Pointes. Needs ECG before starting treatment

hypoglycaemia - promotes insulin secretion. Requires BM every 2-4 hours

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13
Q

Patient successfully treated for falciparum malaria with artesunate/ coartem/ riamet, and discharged home.

What follow up is required?

A

Increasing evidence of haemolytic anaemia, occurring 2-4 weeks after artesunate treatment

recommend weekly FBC for all patients who have received IV artesunate

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14
Q

Why are pregnant patients more likely to have severe malaria?

A

parasite count can be higher than suggested in peripheral blood film, due to placental sequestration

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15
Q

What are treatment options for malaria in pregnancy?

A

Artesunate/ quinine both safe pregnancy

quinine and pregnancy can both cause hypoglycaemia, so requires close monitoring

clindamicin is another oral step-down options

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16
Q

Uncomplicated falciparum malaria treatment

What are options?

A
  • All falciparum cases, even if well, should be admitted for 24 hours
  • do not use any drugs for treatment, if patient was previously using for prophylaxis e.g atovaquone-proguanil

Co-artem/ riamet 8/ 24/ 36/ 48/ 60
Quinine plus doxycyline 7 days
Quinine plus clindamicin 7 days
Atovaquone/ proguanil 3 days

17
Q

Non-falciparum malaria - vivax/ ovale/ malariae

What are treatment options?

A

Admit if unwell, but can often be managed as outpatient

Riamet/ coartem

Chloroquine

18
Q

Patient with vivax/ ovale malaria is initially treated with riamet/ coartem/ chloroquine, and improves.

What can be given to prevent relapse prevention?

A

Check G6PD level as risk haemolysis

Primaquine 15mg OD 14 days

19
Q

Pregnant patient with vivax/ ovale improves on initial treatment.

What can be given to prevent relapse from hypnozoites?

A

primaquine contraindicated in pregnancy

chloroquine once a week for duration pregnancy/ breast feeding

once stops breast feeding, give primaquine 15mg OD 14 days

20
Q

Patient treated for malaria, being discharged home.

What advice should you give about further travel?

A

Does not provide immunity

Bed nets/ insect spray

Chemoprophylaxis

be alert for symptoms in other family members who may be incubating

21
Q

Plasmodium transmitted by female anopheles mosquito

Which species can cause severe malaria?

A

Falciparum
Vivax
Knowlesi

22
Q

What is mechanism of action of artesunate?

A

Artesunate has endoperoxide bridge, with reacts with heme iron in malarial pigment

This generates free radicals, which inhibits protein synthesis or plasmodium parasite