Sepsis to Shock: What Happens When Bacteria Invade the Body

Sepsis, the leading cause of death in hospitals in the United States, kills more than 200,000 people every year, and the number is growing.


Severe sepsis is a common but deadly condition. It is usually caused by a bacterial infection that sets off a body-wide inflammatory response. It can show up in a number of ways. A patient might appear in the ER with an altered body temperature -- typically higher than 100.4° F (38° C) or lower than 96.8° F (38° C), rapid heartbeat, rapid breathing, or lab tests showing signs of an infection (lots of white blood cells) or unusually few white cells.

The leading cause of death in hospitals in the United States, severe sepsis is associated with an estimated in-hospital mortality risk between 25 and 30 percent. In the U.S. alone, more than 500,000 adult patients are admitted to hospitals every year with evidence of sepsis and organ dysfunction. Each year in the U.S. there are approximately 750,000 cases of severe sepsis, which result in 215,000 deaths.

Even more disturbing is the fact that the volume of patients presenting to hospitals with sepsis appears to be increasing, making it increasingly difficult for doctors to quickly identify these patients and determine how severe their sepsis is.

Some relatively new techniques have shown a lot of promise in the treatment of severe sepsis. For example, Early Goal Directed Therapy (EGDT), which involves intense monitoring of oxygen delivery to the patient, can resuscitate patients and reduce the risk of mortality in people with dysfunctions of the heart or other organs. The benefit of these newer methods decreases, however, if there is any delay in beginning them, which makes it essential for doctors to determine which patients are at the highest risk and for patients and families to be alert to the symptoms.


A person can develop sepsis when the body -- in particular, the bloodstream -- is overwhelmed with bacteria. The infection can begin anywhere in the body, but common places are the intestines, kidneys, lungs (as in pneumonia), or the linings around the brain (as in meningitis).

If a patient is hospitalized for any reason, sepsis can develop from an IV line or at a surgical incision if he or she has had surgery.

Symptoms of severe infection typically include chills, fever, confusion, rash, and shaking. The most dangerous symptom of sepsis is a rapid drop in blood pressure, which can cause a patient to go into shock, which is life-threatening since the organs, including the brain, are deprived of oxygen. Treatment involves giving antibiotics through an IV, and administering fluids, oxygen, and medications to bring blood pressure back up. Sometimes a breathing machine or dialysis may be needed if the lungs or kidneys are affected.


Because of the seriousness of sepsis and the possibility of shock, it is critical for doctors to determine each patient's risk level, so that he or she may be treated quickly and appropriately. More than 50 percent of patients with severe sepsis receive some part of their care in an intensive care unit (ICU), and sepsis is the most common cause of ICU admissions (other than surgery) in the U.S.

Treating severe sepsis contributes significantly to the overcrowding of ICUs, and adds to the more than $16 billion annual cost of caring for this syndrome in the U.S. As our population ages, the number of severe sepsis cases will inevitably increase. Accurate methods to determine a person's risk could focus our limited health care dollars on seriously ill patients who are most likely to benefit, and at the same time decrease the use of invasive procedures on patients who have lower risk. Here, we'll outline some of the newer techniques that doctors use to figure out who's at greater risk for sepsis and who is not.

Organ Dysfunction

Sepsis can affect one or many organs of the body, depending on the extent of the infection. Doctors determine whether organs are failing using basic clinical evidence that is fairly clear-cut, and doing so can tell them who is at risk for death in the short term. However, patients with severe sepsis can range from having several failing organs to more mild organ "malfunctions." Therefore, there are limits to what organ function -- or organ failing -- can tell us about the health status of the patient in question. For this reason, doctors have to use additional techniques that help them flesh out the picture when a patient develops sepsis.

Tests, Tests, and More Tests

There are a number of tests, some newer than others that are used to determine whether sepsis is present and, if it is, the degree to which it is present.

The Acute Physiology and Chronic Health Evaluation (APACHE) tests were the earliest ways to determine risk for septic patients in the ICU. But they are complex, and can often require information that's not typically available early on in treatment such as data on the oxygen pressure in arterial blood. The Mortality in Emergency Department Sepsis (MEDS) score is used for adult patients who come into the emergency department with a suspected infection. This tool was developed specifically for determining risk quickly, using basic factors, which makes it very useful for measuring risk in the early stages and in many different types of patients. Unfortunately, its accuracy is not always so high in patients with severe sepsis, so it may need to be used with other tests.

Presented by

Jeffrey P. Green is a clinical research fellow in the department of emergency medicine at the University of California, Davis, School of Medicine.

Saving the Bees

Honeybees contribute more than $15 billion to the U.S. economy. A short documentary considers how desperate beekeepers are trying to keep their hives alive.

Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register.

blog comments powered by Disqus


How to Cook Spaghetti Squash (and Why)

Cooking for yourself is one of the surest ways to eat well.


Before Tinder, a Tree

Looking for your soulmate? Write a letter to the "Bridegroom's Oak" in Germany.


The Health Benefits of Going Outside

People spend too much time indoors. One solution: ecotherapy.


Where High Tech Meets the 1950s

Why did Green Bank, West Virginia, ban wireless signals? For science.


Yes, Quidditch Is Real

How J.K. Rowling's magical sport spread from Hogwarts to college campuses


Would You Live in a Treehouse?

A treehouse can be an ideal office space, vacation rental, and way of reconnecting with your youth.

More in Health

Just In