What is Sepsis?  Gut Origin Theory

The body is protected from the external environment by two separate surfaces, one external (the skin) and the other internal (the gut). Moreover, the internal surface protects us from a multitude of potentially pathogenic bacteria, which reside, symbiotically, in the gut lumen. It is believed that disruption of the gut mucosa may open the gates to bacterial penetration of the body via the bloodstream (17;20) .

The intenstinal mucosa is a metabolically active area: it’s purpose is to absorb nutrients broken down in the gut lumen. This is driven by an energy hungry countercurrent multiplier, active transport process. This is similar to what goes on in the renal nephron, and like the kidney, blood flow to the gut mucosa appears to be autoregulated. The mucosa receives its nutrition, like the luminal bacteria, directly from foodstuffs in the gut.

Following any acute injury, there is large increase in circulating epinephrine. As this is designed as a “fight or flight” response, blood is redistributed to essential organs, the heart, the brain (an, to an extent, the muscles). The gut is a non-essential organ, and as one is unlikely to eat while doing battle (or bleeding to death), splanchnic blood flow is cut off, until the situation changes. In sepsis, the flow of blood to the gut may be shut off for hours or days, depending on the quality of fluid resuscitation and the restoration of perfusion pressure. This, and the simultaneous loss of tropic nutrients in the gut lumen (if the patient is not being fed), serves to starve the mucosa of food and nutrients, and it gradually atrophies and breaks down. Simultaneously, the gut bacteria become hungry, and go looking for food. With loss of the mucosal barrier, these bacteria are able to translocate into the portal circulation, where they make their way to the liver, to amplify the systemic inflammatory response.

Loss of splanchnic blood flow, starvation and bacterial translocation may well be the motor which drives the systemic inflammatory response (17;21) . Modern management strategies involve aggressive splanchnic resuscitation (17;22) (e.g. with dobutamine), and early enteral nutrition.

CLICK HERE OR ON THUMBNAIL TO VIEW PICTURE GALLERY

References

CLICK HERE FOR REFERENCES

THIS TUTORIAL BY PATRICK NELIGAN MD, UNIVERSITY OF PENNSYLVANIA

Please note: these tutorials are for personal study purposes only.  They are not currently peer reviewed, and no responsibility will be taken for mistakes or inaccuracies. Reproduction of information is forbidden. All material is copyrighted by the GasWorks Group.