Malaria Flashcards
What are the 5 types of malaria?
- Plasmodium falciparum
(“Non-falciparum malaria”)
- P.vivax
- P.ovale
- P.malariae
- P.knowlesi
What is the initial management of patients with falciparum malaria?
Hospital admission initially due to risk of rapid deterioration even after starting treatment
*if the infective species is not known or the infection is mixed and includes falciparum, initial treatment should be as for falciparum malaria
What is the treatment of choice for uncomplicated P.falciparum malaria?
“Artemisinin combination therapy”
FIRST LINE:
- artemether with lumefantrine
SECOND LINE:
- artenimol with piperaquine phosphate
THIRD LINE:
- oral quinine
- atovaquone with proguanil hydrochloride
**quinine is highly effective but poorly tolerated in prolonged treatment and should be used in combination with an additional drug, usually oral doxycycline or clindamycin in pregnant women and young children
What are the main contraindications to using artemether with lumefantrine? (5)
(Risk factors for cardiotoxicity)
- Family history of congenital QT interval prolongation
- Family history of sudden death
- History of arrhythmias
- History of clinically relevant bradycardia
- History of congestive heart failure accompanied by reduced LVEF
What are the main contraindications to using artenimol with piperaquine phosphate? (10)
(Risk factors for cardiotoxicity, torsades de pointes)
- Acute MI
- Bradycardia
- Congenital long QT syndrome
- Electrolyte disturbances
- Family history of sudden death
- Heart failure with reduced LVEF
- History of symptomatic arrhythmias
- LVH
- Risk factors for QT interval prolongation
- Severe hypertension
What are the main contraindications to chloroquine use? (4)
- Hemoglobinuria
- Myasthenia gravis
- Optic neuritis
- Tinnitus
(Caution used in patients with risk factors for cardiac toxicity eg Afib, cardiac disease, conduction defects, heart block, etc. as well as first trimester pregnancy and G6PD deficiency)
What are the key features of quinine overdose? (2)
Quinine is very toxic in overdose
- Life-threatening arrhythmias (can be very rapid onset)
- Convulsions (can be intractable)
What are the main side effects of quinine? (7)
- Tinnitus (may be permanent)
- Deafness (may be permanent)
- Blindness (may be permanent)
- GI upset
- Prolongs QT interval, may cause arrhythmias
- Hypoglycemia
- Leg cramps
Quinine should be prescribed with caution in which patients? (3)
- Existing hearing or visual loss
- First trimester pregnancies (teratogenic)
- G6PD deficiency
What are the main contraindications to the use of atovaquone with proguanil hydrochloride?
None
Caution used if diarrhea or vomiting (reduced absorption)
What are the neuro-psychiatric side effects of some antimalarial drugs?
Neuro:
- movement disorders
- neuromyopathy
- seizure
Psychiatric:
- hallucinations
- psychotic disorder
- personality change
- insomnia
- anxiety
- confusion
**particularly with chloroquine and mefloquine; frequency rare or not known
What is the treatment of choice for severe or complicated falciparum malaria?
Should be managed in a high dependency unit or intensive care setting
FIRST LINE:
- IV artesunate min 24 hours followed by a full course of oral artemisinin combination therapy
SECOND LINE:
- IV artesunate min 24 hours followed by a full course of oral quinine with doxycycline (or clindamycin) OR atovaquone with proguanil
How should patients with severe or complicated falciparum malaria be managed in the absence of artesunate therapy?
Do not delay treatment if artesunate is not immediately available; quinine by IV infusion should be given until the patient can take oral quinine to complete a full course
What is meant by “Artemisinin combination therapy?”
Artemisinin derivatives include artesunate, artenimol, and artemether. These drugs are combined with a second drug to increase efficacy against malaria
FIRST LINE:
- artemether with lumefantrine
SECOND LINE:
- artenimol with piperaquine phosphate
Why are chloroquine and mefloquine avoided in treatment of malaria?
P.falciparum is now resistant to chloroquine in most parts of the world
Mefloquine is no longer recommended use to severe adverse effects leading to non-completion of drug courses (ie neuropsychiatric symptoms)
What is the main concern regarding falciparum malaria in pregnancy?
Falciparum malaria in pregnancy carries a higher risk of severe disease, requiring prompt treatment by specialists in hospital and close observation
What is the treatment of choice for uncomplicated falciparum malaria in pregnancy?
Second and third trimesters:
FIRST LINE: Artemether with lumefantrine
All trimesters:
FIRST LINE: Quinine with clindamycin
**NB: quinine can increase the risk of uterine contractions and hypoglycemia
What are the main concerns regarding quinine use during pregnancy?
Quinine can increase the risk of uterine contractions and hypoglycemia
What is the treatment of choice for severe or complicated falciparum malaria during pregnancy?
FIRST LINE:
- IV artesunate in any trimester
SECOND LINE:
- IV quinine with clindamycin
What is the treatment of choice for non-falciparum malaria?
FIRST LINE:
- artemisinin combination therapy
- chloroquine
*artemisinin combination therapy may be preferred in Indonesia, Malaysia, and eastward of Southern Vietnam due to reported chloroquine resistance, but either can be used with appropriate follow-up
What additional measures may be taken in cases of P.vivax and ovale infection?
P.vivax and ovale undergo a dormant hypnozoite stage in the host liver. Thus, with chloroquine treatment alone, hypnozoites are not killed and the individual is vulnerable to relapse. To provide “radical cure” in these patients, primaquine should be given along with chloroquine treatment
*whereas chloroquine therapy alone is adequate for P.malariae and knowlesi infection
What should be done before initiation of primaquine treatment?
Screening for G6PD deficiency; may cause hemolysis in individuals with G6PD deficiency
What is the treatment of choice for severe or complicated non-falciparum malaria?
Same as treatment of severe or complicated falciparum malaria
FIRST LINE:
- IV artesunate
SECOND LINE:
- IV quinine
What is the treatment of non-falciparum malaria during pregnancy?
Chloroquine can be given throughout pregnancy
Artemisinin combination therapy can be used in the second and third trimester with quinine used in the first trimester if there is concern about chloroquine-resistant P.vivax
**in cases of P.vivax or ovale infection, radical cure with primaquine should be postponed until pregnancy and breastfeeding are over due to risk of neonatal hemolysis and methemoglobinemia in the third trimester in G6PD-deficient infants
Can artemisinin combination therapy be used in the first trimester of pregnancy?
Toxicity in animal studies with artemether; manufacturer advises use only if potential benefits outweigh risks
How is radical cure attained in pregnant patients?
Radical cure with primaquine should be postponed until the pregnancy and breast-feeding are over
Instead, weekly chloroquine prophylaxis should be continued until delivery or completion of breastfeeding
Which anti-malarials are avoided during the first trimester of pregnancy? (4)
All should be avoided unless benefit of use outweighs risk…
- Primaquine (risk of hemolysis)
- Artemether (toxicity in animals)
- Artenimol (teratogenic in animals, not to be used as first line)
- Quinine (teratogenic at high doses, benefits may outweigh risks)
(Proguanil may be used along with adequate folate supplementation in the mother)
When considering malaria prophylaxis, what factors should be taken into account? (5)
- Risk of exposure to malaria
- Extent of drug resistance
- Efficacy of the recommended drugs
- Side-effects of the drugs
- Patient-related factors eg. age, pregnancy, renal, hepatic impairment, compliance
In addition to antimalarial prophylaxis medication, what measures should be taken to avoid infection? (3)
- Use of mosquito nets, particularly those impregnated with insecticide
- Vaporised insecticide
- Long sleeves and trousers worn after dusk
When should prophylaxis be started?
Generally, before travel to an endemic area…
1-2 days before travel:
- atovaquone + proguanil or doxycycline
1 week before travel:
- Chloroquin
- proguanil
2-3 weeks before travel:
- mefloquine
How long should prophylaxis be continued?
Continued until 4 weeks after leaving the area EXCEPT atovaquone with proguanil which should be stopped 1 week after leaving
What drugs may be offered in those requiring long-term prophylaxis? (5)
- Chloroquine
- Proguanil
- Mefloquine (licensed up to 1 year)
- Doxycycline (up to 2 years)
- Atovaquone with proguanil (up to 1 year)
During what window of time should malaria be considered in returning travelers?
It is important to consider that any illness that occurs within 1 year and especially within 3 months of return might be malaria even if all recommended precautions against malaria were taken
Which drugs are unsuitable for malaria prophylaxis in individuals with a history of epilepsy? (2)
- Chloroquine
- Mefloquine
*offer doxycycline or atovaquone with proguanil instead; however doxycycline may interact with some antiepileptics so its dose may need to be adjusted
In which patient population should additional anti-malaria prophylaxis measures be taken to avoid severe disease?
Asplenic patients or those with severe splenic dysfunction
How should malaria prophylaxis be managed in pregnant women?
Travel to malarious areas should be avoided during pregnancy; if travel is unavoidable, pregnant individuals must be informed about the risks and benefits of effective prophylaxis.
Drug choices: (depends on region)
FIRST LINE in sensitive areas
- chloroquine (safe in pregnancy)
- proguanil (give with folic acid)
In high risk areas or in cases of resistance:
- mefloquine (during second or third trimester; in first trimester if benefits outweigh risks)
- doxycycline (only if other regimens are unsuitable)
- atovaquone with proguanil + folate (only if no suitable alternative)
Is prophylaxis required in breast-fed infants?
Yes; antimalarials are present in breast milk but amounts are too variable to give reliable protection
How is malaria prophylaxis managed in patients taking warfarin?
Travelers should begin chemoprophylaxis 2-3 weeks before departure and INR should be stable before departure
*INR should be measured before starting prophylaxis, 7 days after starting, and after completing the course. For prolonged stays, the INR should be checked at regular intervals
For patients already taking hydroxychloroquine, does this medication need to be stopped prior to initiation of chloroquine therapy?
No, can remain on hydroxychloroquine
Does acquired immunity to malaria remain after emigrating from an endemic region?
Settled immigrants (or long-term visitors) to the UK may be unaware that any immunity they may have acquired while living in malarious areas is lost rapidly after migration to the UK
Where can you find a list of countries where malaria is endemic?
BNF Treatment Summaries: Malaria, prophylaxis
