Sepsis occurs when bacteria from an existing infection cause a systemic inflammatory response in the body. The body’s immune system reacts in an attempt to fight the disease, which creates a host of additional problems. The infection itself can cause damage to the body, such as histones in the blood which have been shown to cause heart damage and injury to the cardiovascular system.

Two of the main causes of death from sepsis are multiple organ failure and hypotension, a significant continued decrease in blood pressure. Blood clots resulting from sepsis may contribute to multi-organ failure and tissue death. Sepsis can begin in any body location from a number of possible bacteria. Any infected part of the body, from skin to kidneys to teeth, can spread into the bloodstream without proper medical care. Individuals who have a compromised immune system, such as those with kidney disease, cancer, or HIV have elevated risk of developing sepsis when they have a simple infection.


How sepsis affects the body

Sepsis is fairly common and highly treatable in mild stages. Sepsis occurs when a localized bacterial infection causes a systemic inflammatory reaction in the body. As a method of fighting the infection, the body releases cytokines and other mediators, proteins that help fight bacteria. These cytokines cause blood vessels to dilate, lowering blood pressure and causing systemic inflammation.

Treated with antibiotics and possibly fluids (either orally or through IV), sepsis in may be mild and easy to cure. However, if left untreated or if the body does not respond properly to treatment, the inflammation may cause a dangerous drop in blood pressure or multi-organ failure by depriving the organ systems of the blood flow they need, a state known as septic shock. Once a patient reaches septic shock, mortality rates increase to 40-50%.


How sepsis affects the heart

In cases of severe sepsis, low blood pressure and organ failure lead to mortality in up to 40% of patients. As severe sepsis usually involves infection of the bloodstream, the heart is one of the first affected organs.

Researchers have long understood a correlation between sepsis and heart damage, but it was only a few years ago that a team of researchers uncovered nuclear proteins, histones, which are released in septic patients and damage the heart muscle.

We may now predict which sepsis patients are at a higher risk of developing heart damage during sepsis by measuring the level of levels of histones in the blood. The findings were published in Critical Care Medicine in 2015 and have implications for the future treatment of sepsis and heart damage due to sepsis.