infection - travel related infections: malaria Flashcards
why is travel history important?
- recognise imported diseases
- different strains of pathogen (antigenically different, impacts on protection / detection, antibiotic resistance)
- infection prevention (in ward & lab)
what are the key aspects of travel history?
any unwell travel companions / contacts?
pre-travel vaccinations / preventative measures?
recreational activities? e.g. caving
healthcare exposures? e.g. hospital admission?
what would a patient with malaria present like on examination?
high temp, LOW BP, tachycardia, low sats (low BP) - (haemolysis of RBC, liver can’t make proteins (low BV))
unwell, slightly confused
moderate jaundice - hepatic stage of malaria
multiple bite marks
hepatosplenomegaly
what are the investigations you would carry out in a patient suspected with malaria?
FBC - Hb, platelets (malaria blood borne stage)
biochemistry: U&E, bilirubin (hepatic stage), other LFTs, CRP
what are the main species of plasmodium?
falciparum (most dangerous, majority), vivax, ovale (mostly India), malariae
how does malaria spread?
vector - pregnant female anopheles mosquito
no case-to-case spread
what is the incubation period, history and examination of malaria?
minimum 6 days
falciparum (up to 6months), vivax/ovale: up to 1+ year
history: fever, chills & sweat - cycle 3/4 days
examination: hepatosplenomegaly
what are consequences of severe falciparum malaria (parasites >2%)?
CVS: tachycardia, hypotension, arrhythmia (early-after depolarisation)
resp: ARDS (sepsis, malaria) - V/Q mismatch, low BP
renal: AKI
CNS: confusion, cerebral malaria
GIT: diarrhoea, bilirubin (Haemolysis)
blood: DIC
metabolic acidosis (lactate, anaerobic resp), hypoglycaeima
secondary infection
what are the stages of malaria life cycle?
mosquito vector: salivary glands, gut
liver (host): exo-erythrocytic stage
blood (host): erythrocytic stage
what are the investigations for malaria?
blood smear x 3 - (doesn’t come up on first blood smear, important to exclude malaria)
FBC, U&E, LFT, glucose (hypoglycaemic - infection), platelets (coagulation)
head CT if CNS symptoms (CSF)
CXR - trouble breathing
what are the treatments for malaria?
P. falciparum: artesunate, quinine + doxycycline
P. vivax, ovale, malariae: chloroquine + primaquine, hypnozoites (liver stage)
can recur months-years later
(chloroquine = quinolone, prevent nucleic acid synthesis)
what are the stages to prevention of malaria?
ABC:
Assess risk: knowledge of risk areas (regular / returning travellers)
Bite prevention: repellant, clothing, nets
Chemoprophylaxis: before travel, specific region, continue after return (4 weeks)
what are the other differential diagnosis aside form malaria?
typhoid (fever)
dengue (fever)
rickettsial infection
non-travel related infection (Meningococcal septicaemia)
