Hello and welcome to the Zero to Finals podcast.

My name is Tom and in this episode I'm going to be going through sepsis.

And you can find written notes on this topic at zero to finals.com slash sepsis

or in the Infectious Diseases section of the second edition of the zero to finals medicine book.

So let's get straight into it.

Sepsis is where the body launches a large immune response to an infection

causing systemic inflammation and organ dysfunction.

Let's start with the pathophysiology.

Macrophages, lymphocytes and mass cells are cells of the immune system that recognize pathogens.

These cells release large amounts of cytokines, as interleukins and tumour necrosis

factor which activate the entire immune system.

This immune system activation leads to systemic inflammation or inflammation throughout the body

and the release of other chemicals such as nitrous oxide, which causes vasodilation,

or dilating of blood vessels. Many of these cytokines cause the endothelial lining of blood vessels

or the inner lining of blood vessels to become more permeable. A permeable endothelial lining allows fluid to leak out of the blood

and into the extracellular space. This results in edema and reduced intravascular volume,

the amount of fluid inside the blood vessels, because it's leaking out into the

extracellular space.

Adema creates a gap between the blood and the tissues, reducing the amount of oxygen that

reaches the tissues.

Activation of the coagulation system, or the clottingting system leads to the deposition of fibrin

and the formation of blood clots or thrombi throughout the circulation. This further compromises organ and tissue perfusion with blood.

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