Sepsis Pathophysiology

Sepsis Patho

What is Sepsis?

Sepsis is an inflammatory response as a result of the presence of infectious agents or their products in the bloodstream.

A pathogen enters the bloodsteram triggering an immune response.  This can cause changes in capillary membranes and vascular tone.

The pathogen stimulates macrophages to release cytokines, triggering inflammatory response causing vasodilation, capillary leak and blood clotting.

Toxins in the pathogen cause capillaries to become leaky, causing fluid (albumin, water and electrolytes) to move from capillaries to surrounding tissues, causing tissue oedema.  This causes a low platelet count, causing blood to be unable to clot properlly.

Capillary leak causing fluids to enter tissues makes it harder for oxygen to reach cells, leading to cellular hypoxia.  Excessive inflammation causes blood to clot within vessels, blocking blood flow and starving tissues of oxygen.

Fluids leak into the alveoli leading to inflammation and making it harder to breathe.  This increases work of breathing.

Fluid leaking reduces circulation volume and cardiac output.

Capillaries flowing below the alveoli have reduced circulation, impairing oxygen exchange.  This leads to a build-up of carbon dioxide, and a lack of oxygen in the blood, resulting in low saturations.

Receptors in the…