Recognizing the clinical presentation of malaria

In this video, we'll look at why malaria symptoms tend to be cyclical, but why that's not always the case.

John F. Fisher, MD MACP FIDSA
John F. Fisher, MD MACP FIDSA
23rd Jun 2020 • 4m read

The presentation of malaria tends to be cyclical in nature, and understanding this cycle is important when treating your malaria patient. In this video, from our Malaria Mini: The Basics course, we connect the cyclical nature of malaria symptoms to the parasite's life cycle and take a look at why this cyclical pattern isn't always present.

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Video transcript

Remember that right after infection, the sporozoite is transported to the liver, where it passes through a clip for cell into an hepatocyte. The parasite then divides within a liver cell to form a liver schism, until the cell eventually bursts, releasing mera ZooLights into the bloodstream. The cycle continues in red blood cells with the release of merozoites in a cyclic fashion.

But along with those merozoites, some malaria pigment, and DNA from these broken malaria parasites will also be released. These components are picked up by the immune system, activating the production of the pro inflammatory cytokine TNF alpha, which targets the hypothalamus resetting your central thermostat to high.

This process from initial infection to the clinical manifestations is known as the incubation period and takes approximately six weeks. So once your thermostat is reset to say 39 degrees Celsius, your body says, Wait a minute, I'm not hot enough. So I've got to shiver to make myself reach that temperature that was set in the hypothalamus.

This represents the cold stage of malaria, where the patient will exhibit bed shaking bone rattling chills, and fever, which typically last from 15 minutes to one hour. Eventually, the Shivering will help the body reach that threshold of high fever. So the chills and shaking are gone. But this is the hot stage.

And like any other fever, it's often accompanied by muscle aches and other symptoms that generally make the patient feel horrible. Unfortunately, this stage may last from six to 10 hours. After a while as the thermostat begins to reset, the body will seek to cool itself and the patient will begin to sweat.

This is known as the effervescence phase in which patients will generally experience drenching sweats, which rapidly reduce the body temperature. And after differ vestments patient may have no symptoms at all. And that's where we get this idea of cyclic fevers and chills. So there may be times when patients theoretically have no symptoms at all.

But every time a red cell bursts and releases merozoites, the immune system will be activated, and this cycle will start over. So let's talk about the cycles. These are based on the time it typically takes between when the parasite invades the red cell, and when the resulting schism bursts to release merozoites into the bloodstream.

And it's different for different types of malaria. The most common types Plasmodium falciparum vive X and O Valley cycle approximately every 48 hours. So that would be fever on day one, no fever on day two, fever again on day three, so called tertian malaria, Plasmodium malaria cycles at 72 hours before the red cells burst.

So that would be fever on day one, no fever on days two and three, then fever again on day four or quartan malaria and contrast, Plasmodium nosey malaria cycles daily. So you would see all of these stages in a 24 hour period. You can imagine if you only got bitten by one mosquito, you might cycle like that.

But if you're in a malarious area, you may be bitten by different mosquitoes on different days, even carrying a different type of malaria. So if you're looking for Pure Cycles, look again, you may not really have the Pure Cycles because the stages may end up overlapping. It just may not be as regular as the textbooks would have you believe.

But the bottom line is if you see a patient with fever and chills, especially if it seems to come and go even remotely, you should consider malaria, and obtaining a detailed travel history, especially for the past six or more weeks. This is a must.

So I hope you liked this video. absolutely make sure to check out the course this video was taken from and to register for a free trial account which will give you access to select the chapters of the course. If you want to learn how Medmastery can help you become a great clinician, make sure to watch the abutment mastery video. So thanks for watching, and I hope to see you again soon.