INF2 - A. MALARIA-COVERED Flashcards

1
Q

where is malaria mainly found

A

tropical regions
- Africa and Asia
- central and south America
- Haiti and Dominican Republic
- Middle East
- some pacific islands

not found in UK (only returning travellers)

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2
Q

what factors affect travellers’ exposure to malaria

A
  • high humidity and 20-30 degrees Celsius
  • transmission doesn’t occur where temp is below 16 degrees Celsius isotherm
  • parasite maturation in mosquito can’t take place >2000m above sea level
  • seasonal rainfall increases mosquito breeding (monsoons)
  • rural location (swampy)
  • backpackers: cheap accommodation, open windows
  • outdoors between dusk and dawn when Anopheles mosquitos bite
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3
Q

prophylaxis of malaria

A

ABCD
- Awareness of risk: are you at risk: where, what, how long
- Bite prevention: insect repellent, cover arms and legs, insecticide-treated mosquito net, inside between dusk and dawn
- Check if need malaria prevention tablets
- Diagnosis: immediate medical advice if develop malaria symptoms, up to a year after travelling

Consult a HC professional if going somewhere where malaria is a risk

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4
Q

how to prevent getting bitten

A
  • air conditioning and screening on doors and windows
  • close windows and doors
  • sleep under an intact mosquito net treated with insecticide
  • long lasting impregnated nets
  • insect repellent on skin and when sleeping. Need at least 50% DEET
  • loose-fitting trousers and long sleeves: esp at night when they prefer to feed
  • homeopathic remedies don’t offer any protection
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5
Q

what are the 2 types of chemoprophylaxis

A
  1. casual prophylaxis
    - targets liver stage
    - takes 7 days to develop (liver stage)
    - continue for 7 days after leaving malarious zone
  2. suppressive prophylaxis
    - targets erythrocytic stage
    - continue for 4 weeks after leaving malarious zone

no prophylactic drugs for hypnozoites - P. oval and P. vivax

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6
Q

Atovaquone plus proguanil (Malarone) chemoprophylaxis (POM)

A
  • 1st choice
  • prevents development of liver schizonts (casual)
  • take 1-2 days before entering malarial zone, when there and for a week after leave
  • 1 tablet every day
  • works on erythrocytic stages so used for treatment aswell
  • 90% efficacy against P. falciparum and also against P. vivax
  • side effects: headache, GI upset, skin rash, mouth ulcers
  • NOT taken by pregnant or breastfeeding women or those with severe kidney problems
  • more expensive
  • licensing: 12 weeks
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7
Q

Mefloquine (Larium) prophylaxis (POM)

A
  • a quinoline
  • suppressive?
  • take a week before, when there for 4 weeks after leave
  • one tablet weekly
  • 90% efficacy against P. falciparum
  • NOT for those with epilepsy, seizures, depression, mental health problems, if close relative has these, severe heart or liver problem
  • side effects: dizziness, headache, sleep disturbances, psychiatric reactions (anxiety, depression, panic attacks, hallucinations)
  • 3-week trial recommended
  • licensing: 12 months
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8
Q

doxycycline (vibramycin-D) prophylaxis (POM)

A
  • suppressive: prevents development of erythrocytic stages
  • take a week before, when there for 4 weeks after leave
  • 1 tablet every day
  • NOT taken by pregnant or breastfeeding women, under 12 (risk of permanent tooth discolouration), sensitive to tetracycline antibiotics or people with liver problems, on warfarin
  • side effects: sunburn due to light sensitivity, stomach upset, heartburn, thrush
  • take with food, standing or sitting
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9
Q

chloroquine and proguanil prophylaxis (P)

A
  • 2 separate tablets
  • chloroquine: once weekly, proguanil: everyday
  • suppressive
  • take a week before, when there for 4 weeks after leave
  • rarely used as largely ineffective against P. falciparum
  • india and Sri Lanka: P. falciparum less common
  • same side effects as mefloquine
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10
Q

what is the most common cause of malaria

A

P. falciparum, where chloroquine-resistant P. falciparum is endemic

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11
Q

what is the incubation period for P. falciparum, vivax, oval

A

8-12 days

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12
Q

what is the incubation period for P. malariae

A

18 days - 6 weeks

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13
Q

prodromal symptoms

A

headache
muscular aches and pains
malaise
nausea
vomiting
- 2nd week after exposure
- incubation period can be delayed for months

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14
Q

what can confirm diagnosis

A
  • history of travel to an endemic area
  • typical paroxysmal episode of chills and fever
  • thrombocytopenia
  • jaundice
  • +ve identification of parasites in blood (blood film)
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15
Q

what are the 3 stages of malarial febrile paroxysms

A
  1. cold stage: marked vasoconstriction
    - lasts 30-60 minutes
    - intensely cold and shivering
    - temp rises rapidly - 41 degrees Celsius
    - can have seizures
  2. hot stage:
    - lasts for 2-6 hours
    - intensely hot
    - delirium esp if dehydrated
  3. sweating stage:
    - bedclothes drenched
    - fatigued and exhausted
    - sleeps

*fever every other day with P vivax and ovale
*P. falciparum - develops in RBCs, RBCs develop knobs and stick to endothelium - organ damage to kidneys, liver, brain, GI tract
*severe fever and prodrome has no pattern

need to be in intensive care
paracetamol
fluids
oxygen
treatment

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16
Q

how does cerebral malaria and blackwater fever occur

A
  • not treated promptly enough
  • > 2% RBCs infected
17
Q

symptoms of cerebral malaria

A
  • increase in body temp
  • rapid deterioration in consciousness
  • convulsions
  • coma and death
18
Q

symptoms of blackwater fever

A
  • dark brown urine from intravascular haemolysis
  • only P. falciparum
  • acute renal failure so dialysis needed
  • splenic rupture
  • jaundice
  • diarrhoea
  • severe anaemia
  • hypoglycaemia
  • acidosis
  • pulmonary oedema
  • if pregnant: high maternal mortality and and increased risk of LBW and infant mortality
19
Q

what is tropical splenomegaly syndrome

A
  • inflamed spleen
  • where malaria is hyper endemic
20
Q

treatment for severe falciparum malaria (IV)

A
  • UK, artesunate or quinine dihydrochloride infusion

IV artesunate not licensed in UK, so has to be given on a named-patient basis but quinine is 2nd choice as not as well-tolerated or effective

use unlicensed artesunate if quinine unsuccessful, quinine resistance (for named patient and specially imported)

  • haemodialysis, response support, glucose, blood transfusions, BZDs in children
21
Q

treatment for uncomplicated falciparum malaria (ORAL)

A
  1. artemisinin combo therapy: artemether-lumefantrin or dihydroartemisinin-piperaquine for 3 days
  2. oral atovaquone-proguanil for 3 days
  3. oral quinine plus doxycycline for 7 days
22
Q

treatment for non-falciparum malaria (vivax/ovale)

A

oral chloroquine or artemether-lumefantrin 3 days then primaquine 14 days

23
Q

what are the emergency treatments

A

Malarone
artemether with lumefantrine = Riamet
quinine with doxycycline

24
Q

determinants of malaria

A
  • host: SCD, no Duffy blood factor - more resistant to malaria
  • parasite: falciparum is more virulent and resistant
  • tropical warms areas, heavy rainfall, high humidity, still water
  • swamp draining, air conditioning etc
25
Q

burden of malaria

A
  • anaemia and LBW babies
  • malaise, fatigue for life
  • neurological defects for children that survive cerebral malaria
  • persistent language deficits, epilepsy, decreased life expectancy
26
Q

what is the malaria initiative

A

Roll back malaria initiative (global partnership)