Cerebral malaria Flashcards
What is the cause of malaria?
disease caused by Plasmodium protozoa which is spread by the female Anopheles mosquito
What are the 4 different species of Plasmodium protozoa which can cause malaria in humans?
- Plasmodium falciparum
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae
Which type of Plasmodium causes nearly all episodes of severe malaria?
Plasmodium falciparum
After Plasmodium falciparum, which type of Plasmodium is the most common cause of malaria?
Plasmodium vivax
What type of malaria is caused by Plasmodium vivax/ ovale/ malariae?
benign malaria
What is the most well-documented protective factor against malaria?
sickle-cell trait
What are 4 protective factors against malaria?
- Sickle cell trait
- G6PD deficiency
- HLA-B53
- Absence of Duffy antigens
Which is the commonest and mos severe type of malaria?
Falciparum malaria
What are 7 features of severe malaria?
- Schizonts on a blood film
- Parasitaemia >2%
- Hypoglycaemia
- Acidosis
- Temperature > 39
- Severe anaemia
- Complications (cerebral malaria, acute renal failure, ARDS, hypoglycaemia, DIC)
What are 5 complications of severe malaria?
- Cerebral malaria: seziures, coma
- Acute renal failure: blackwater fever, secondary to intravascular haemolysis, mechanisms unknown
- Acute respiratory distress syndrome (ARDS)
- Hypoglycaemia
- Disseminated intravascular coagulation (DIC)
What are 2 key features of cerebral malaria?
- Seizures
- Coma
What causes acute renal failure in Falciparum malaria?
may be renal or prerenal and may occur at the time of maximal parasitaemia or even when the parasites have been cleared
What is blackwater fever?
massive haemoglobinuria (urine becomes very dark, like coca cola) in context of malaria. urine is positive for blood on dipsticks but no red cells seen on microscopy
cause not completely known
What is the gold standard investigation for diagnosis of malaria?
high quality microscopy of peripheral blood film (if unavailable, RDTs - rapid diagnostic tests)
In what regions are strains of uncomplicated falciparum malaria resistant to chloroquine prevalent?
certain areas of Asia and Africa
What is the firts line therapy for uncomplicated falciparum malaria?
artemisinin-based combination therapies (ACTs)
What are 5 examples of artemisinin-based combination therapies used to treat malaria?
- artemether + lumefantrine
- artesunate + amodiaquine
- artesunate + mefloquine
- artesunate + sulfadoxine-pyrimethamine
- dihydroartemisinin + piperaquine
What is the treatment of severe falciparum malaria when there is a parasite count of >2%?
parenteral treatment, irrespective of clinical state
IV artesunate (now recommended over IV quinine)
What is the treatment of severe falciparum malaria?
IV artesunate
What treatment should be considered for severe falciparum malaria if the parasite count is >10%?
consider exchange transfusion
What may shock indicate in falciparum malaria?
coexistent bacterial sepsis (malaria rarely causes haemodynamic collapse)
In which regions is Plasmodium vivax malaria often found?
Central America and the Indian Subcontinent
In which regions is Plasmodium ovale malaria often found?
Africa
Where is Plasmodium knowlesi, another non-falciparum species of malaria, predominantly found?
South Eath Asia
What are 3 general features of non-falciparum malaria
same as general features of malaria
- fever
- headache
- splenomegaly
What is the typical nature of the fever of Plasmium vivax?
cyclical fever every 48h
What is the typical nature of the fever of Plasmium ovale?
cyclical fever every 48h
What is the typical nature of the fever of Plasmium malariae?
cyclical fever every 72 hours
What is an associated syndrome which may be seen with Plasmodium malariae?
nephrotic syndrome
Which 2 types of malaria have a hypnozoite stage and what does this mean clinically?
ovale and vivax
they relapse following treatment
What is the recommended treatment for non-falciparum malaria in areas which are known to be chloroquine sensitive?
either artemisin based combination therapy (ACT) or chloroquine
What is the recommended treatment for non-falciparum malaria in areas which are known to be chloroquine resistant?
artemisinin-based combination therapy should be used
In which patient group should artemisinin-based combination therapy (ACTs) be avoided?
pregnant women
What should patients with ovale or vivax malaria be given following acute treatment with chloroquine and why?
primaquine, to destroy liver hypnozoites and prevent relapse
What is the most important complication of falciparum malaria?
cerebral oedema
What is the treated mortality of cerebral malaria?
20% (i.e. high)
What is the definition of cerebral malaria?
unrousable coma in the presence of peripheral parasitaemia where other causes of encephalopathy have been excluded
What are 5 possible clinical features of cerebral malaria?
one or more of:
- diffuse cerebral dysfunction with coma
- generalised convulsations
- focal neurological signs
- brainstem signs such as abnormal doll’s eye or oculovestibular reflexes
- retinal haemorrhages
In what proportion of survivors of cerebral malaria are neurologicla sequelae seen?
5%
What are 5 possible neurological sequelae of cerebral malaria in survivors?
- hemiparesis
- cerebellar ataxia
- cortical blindness
- hypotonia
- mental retardation
When do most deaths in children from cerebral malaria occur?
within first 24h
What else can cause a reduced GCS in malaria, in addition to cerebral malaria?
hypoglycaemia
What is frequently seen in association with deep coma in cerebral malaria?
abnormalities of posture and muscle tone
What is used to grade coma in children with cerebral malaria?
Blantyre Coma Scale
