malaria + infectious diseases Flashcards
how many at risk
85 countries
half world pop
225 mill annual infections
it is a notifiable disease!
children under 5 usually die.
what causes the disease
eukaryotic single celed parasite of the genus plasmodium
complex life cycle involving female mosquito
life cycle of malaria
mosquito- gamete- zygote-ookinete– salivary gland
—> into human —>
sporozoites–>
go to liver (can be dormant or active)
merozoites in the blood
then turn to gametocytes- eaten by the mosquito again
drop in temp in the mosquito causes activation of gametocytes where they reproduce sexually.
what is the important malaria strain,
what do they look like on blood slides, what do you use to stain it
P falciparum- is the main killer caues most of the deaths.
P vivax is 2nd important and can be dormant for long times.
giezma stain is used.
they digest the haem which leads to the schizont
16 can live in each erythrocite!
diagnosis of malaria
FBC, LFTs, Urine analysis
Microscopy
Requires skilled operative
Thick and thin smears, stained with Giemsa
Thick smear => drop of blood plated down on
Thin smear => monolayer of RBCs, which then stains, you can look at individual RBCs and do speciation
Allows speciation => except for P. Knowlesi
Gold standard in the UK. You need to do this for confirmed diagnosis
Rapid Diagnostic Tests => preferred now, is the gold standard
Simple to perform
Detects specific parasite antigens with lateral flow devises
signs and symptoms of malaria
Uncomplicated:
Fever + any of the following
Headache
Body and joint pains
Feeling cold and sometimes shivering
Loss of appetites and abdo pain
Diarrhoea, nausea, vomiting
Splenomegaly
Complicated
Fever + any of the above + any of the following
Impaired consciousness
Anxiety, palpitations and sweating
Convulsions/ fits
Tachypnoea
Dyspnoea
Pale hands, tongue, inner eyelines
Body weakness
Dehydration
Jaundice
Severe malnutrition
Dark urine/ no urine
how does malaria cause symptoms
reproduction (Asexual) in the red blood cells causes them to burst, and spread to other RBC.
this bursting also caues sytokine relase adhesion etc. - get symptoms due to the bursting rbc
in complicated disease:
microvascular obstruction by infected RBC.
(haemozyn is digested haemoglobin and its sticky)
many proteins are shifted to the outside of the cell. PfEMP-1 is important protein, it can adhere to many receptors on epithelial cells- pulling RBC out of circ and blocks circulation.
how to manage and treat malaria
vector control- think nets prophylaxis etc.
getting some drug resistance problems.
Artemisinin based combination therapy (ACT)
Coartem (artemether 20mg/ lumefantrine 120mg)- dose by weight- give approrpate blister pack for the weight
In the 1st trimester of pregnancy => don’t use artemisinin, give 7 days of quinine + clindamycin
p vivax isnt as resistive so can use choloroquine
quinines are japanease drugs, choloquine is american
if severe give thiamine as can be low.
primaquine is a ‘radical cure’ but its pretty heavy handed/ unpleasent drug.- 14/7 course (this is for dormant
what is follow up for malaria
if drug failst investigate absorbtion causes rather than resistances
generally then treat with quinine and doxy
overview of pyrexia of unknown disease
a prolongued fever which persists even after you have done routine investigations and there is no obvious cause. classically longer than 3 weks or more than 1 week of hospital investigaitons
what is the minimum diagnostic examination required to qualify as a Pyrexia of unknown origin
comprehensive history (contact, travel etc etc)
repeated physical examination
complete blood count inc differential and platelets
routine blood chemistry (lactate, bilirubin, liver enzymes)
urineanalysis, microscopic examination
CXR
ESR, ANA, RF, angiotensin converting enzyme
routine blood cultures whilst NOT recieving abx
CMV IgM
heterophile detection in young adults + kids
abdo CT
HIV antibodies
suggested further ix includes
echo, CT CAP, Bone marrow biopsy, liver biopsy, PET/ white cell scan
commoner + less commmon causes of PUO
infection (TB, abcess, osteomyelitis, endocarditis)
connective tissue disorder - adult onset stills, giant cell artetiris, polyarteritis nodosa
maligancy (lymph, leukae, renal, hepatocellular)
Drugs can cause fevers
factitious fevers- anxiety etc
get lots of opinions on it
