Treatment of malaria | Infectious diseases | NCLEX-RN | Khan Academy

– [Voiceover] So, once
Malaria has been confirmed by lab or by biochemical
diagnosis treatment kind of has to start right away to give the
person the best chance of survival, right, with as few
complications as possible. So, let’s say we’re gonna use
antimalarial drugs to treat the disease, right. So, to make sure we’re using
the right drugs we’ll need to know a few things. So, we need to know
what type of plasmodium is causing the infection,
because some subtypes will just respond to drugs
that others might not. We’ll need to know how the
patient’s doing, right? Is this an uncomplicated
Malaria, right, with, you know, flu-y symptoms, fevers, and
chills that kind of stuff? Or is this severe Malaria
with systemic life threatening symptoms? We’ll need to know what
we’re dealing with. We’ll also need to know if
these parasites that are causing the infection, we need to
know if they’re resistant to any of our treatment. Maybe the infection was
picked up in, you know, a part of the world known
to have treatment resistant Malaria. So, there’s a couple
things we need to know right off the bat before
we start treatment. So, let’s say our patient
over here he has uncomplicated Malaria, and let’s remind
ourselves that uncomplicated is still very serious,
it can still be fatal. And, our patient over here,
let’s say he has severe Malaria. Notice that this guy,
uncomplicated guy is just hanging out at home, right, he’s still
really exhausted and flu-y feeling, but he’s at home. But, severe Malaria guy over
here he’s in a hospital bed and he’s got an IV in
and he’s being monitored, he’s being totally looked
after by the hospital staff. And, that’s because for
uncomplicated guy over here he can take his antimalarial
drugs in pill form. He can just take them at home. But, severe guy, remember
he’s having systemic symptoms, maybe his blood pressure
is dangerously low or maybe he’s severely anemic, or
maybe he has brain symptoms, cerebral Malaria where he’s
having seizures or maybe his brain just isn’t controlling
his breathing properly, or maybe he’s gone into a coma. So, he’s in a hospital
because in addition to getting antimalarials, which he’ll
get through this IV line here, he won’t get them in pill
form like this guy over here he’ll need constant medical
care to make sure that he survives, and with as few
permanent complications as possible. So, let’s talk about the types
of medicines that can cure a Malaria infection. So, remember that there’s
essentially two stages of infection with Malaria. There’s a liver phase
where sporozorites infect your liver cells and multiply
into thousands of merozoites. And then, there’s a red
blood cell phase where these little merozoites break
out of your liver cells and infect your red blood cells. And, once they’re inside
your red blood cells they turn into what are
called trophozoites. They hang out for a while
and then they multiply into thousands more merozoites again. So, we have medications that
can destroy these parasites at any of these stages, which is good. So, for uncomplicated Malaria
the person usually gets treated with combination
therapy which means that they take a few different drugs
to treat their Malaria. So, they take usually two to three drugs because if you just use
one drug to treat a Malaria infection well pretty quickly
the parasites are gonna figure out how to become resistant,
right, how to avoid being killed by that one drug. And, in fact, this is
already a huge problem, there’s already a lot of drug
resistance that’s cropped up in different parts of the world. So, that’s why it’s super
important to use combination therapies to make sure
that no potentially mutated parasites survive after treatment. Otherwise one day we just
won’t have any drugs left that work. So, the recommended combination
for treating uncomplicated Malaria is called ACT: artemisinin combination therapy. And, artemisinin here is
actually the name of a plant that we get this main
drug in this combo from. The drug is called
Artesunate and we get it from the artemisinin plant. So, Artesunate does a few
things, it creates a really toxic environment in the
parasites that can kill them. And, it interferes with some
pretty important proteins on the plasmodium surface
that allow them to get their nutrients. So, that makes it hard for
them to stay alive too. And, the reason that ACT is
built around this Artesunate drug here is because Artesunate
is really, really effective against all the types of plasmodium. And, because there’s not
really much resistance to it right now, which is great. So, the standard combo is
Artesunate, plus some other drug with a different mechanism of action. So, for example one
that’s commonly used is Mefloquine. Mefloquine here, which
disrupts the acid base balance in the parasite
and that’s often lethal to the parasite. Or, sometimes you’ll get a
combo of two synergistic drugs Sulfadoxin and Pyrimethamine,
which stops the Malaria from being able to
replicate its DNA properly which means it can’t
really reporoduce very well in our bodies. These are just examples,
there’s other possibilites as well, though. So, what I just told you
all this ACT stuff, that’s the standard treatment
of uncomplicated Malaria caused specifically by
a plasmodium falciparum. ACT is really good at clearing
a falciparum infection from the bloodstream. Plasmodium vivax, on the
other hand, that has to be treated in a different way. So, for the blood stage
you could still use ACT just like with falciparum, or
often a drug called Chloroquin is used, but there’s a
fair amount of resistance to Choloroquin amongst Malaria parasites nowadays, mostly in south east Asia. But, how does Choloroquin work? Well, Malaria parasites feed
on blood, they actually like the hemoglobin component
of red blood cells, that’s why they have such
a blast in our bloodstream. But, when they’re busy
digesting the hemoglobin from a red blood cell
they release the heme part of the hemoglobin molecule, right. So, they’re just kind floating
around because they don’t wanna eat it, they just
eat the globin part. And, free heme floating
around here is actually toxic to both them, the
parasites, and to the red blood cell that they’re hanging around in. So, because they wanna
stick around in the red cell for a while and, you know of
course, because they wanna live the parasites convert this
heme into crystals of hemozoin, which is not toxic to the cell or to them. So, Cholorquin and actually
Mefloquin does this as well, these drugs prevent the
parasites from converting the toxic heme into nontoxic
hemozoin crystals, right? So, all of the resulting heme
it builds up and it just makes the environment really
toxic and then the parasites end up dying, which is great. So, that’s the blood stage
with plasmodium vivax but vivax is interesting
though, it likes to hang out in the liver as well in a
dormant phase, unlike falciparum. Falciparum sort of gets on
with it and causes super severe infections pretty
quickly, where as vivax, right, while it can still be
really severe it takes it a bit slower so it likes to
transform into what are called hypnozoites. And then, these hypnozoites
take naps in the liver cells for extended periods of time. So, it’s kinda like having
a chronic Malaria infection with vivax. So, you have to kill the liver
parasites, and you can do that with Primaquine which
is actually effective against all types of Malaria,
but we especially like it for how it deals with
the vivax hypnozoites. Anyway, the Primaquine
works by blocking oxidative metabalism in these
hypnozoites in the liver. So, it stops them from being
able to make enough energy to survive, so they die. Now, those are just the
basic ideas of how you treat uncomplicated falciparum and vivax. You can see that there’s
quite a few different things to think about. But, if someone has severe
malaria, right this guy over here, there’s pretty much
one thing that you always do. You stick in an IV, an
intravenous line, right? And, you give the person
Artesunate, remember that main drug in the ACT combo therapy. And, they can’t take it in
pill form, they need it to go straight into their bloodstream
because there’s not really any time to fiddle around
with pills and all that. So, besides the IV Artesunate
the person willl need supportive treatment,
remember in severe Malaria the person might be having
seizures, or they might be in a coma, or they might
not be able to breathe on their own. So, they’re gonna need
respiratory support, and they’ll probably also be really
dehydrated so they’ll need fluids and electrolytes as well. So, what sort of prognosis can you expect with Malaria treatment? Well, if you get proper
treatment then usually you can expect a full recovery,
especially with uncomplicated Malaria. And, this is all usually
true with severe Malaria too, but it’s important to keep
in mind that severe Malaria can progress really quickly
and it can also be a bit unpredictable. So, even with treatment and intensive care it still often still leads to death.


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