Every year, some 750,000 Americans develop sepsis, an extreme immune system response to infection. It kills a quarter to half of them, more than the combined number of people who die of prostate and breast cancer and AIDS, according to the National Institutes of Health.
Health care providers have a limited amount of time to treat sepsis, which appears to be on the rise, possibly because of the longevity of people with chronic diseases and spread of antibiotic-resistant organisms.
Dr. Dean W. Meadows, assistant director of the adult intensive care unit at St. Agnes Hospital, explains sepsis and how it's treated.
What is sepsis and what causes it?
Sepsis is a life-threatening medical condition characterized by a syndrome of systemic inflammation caused by the body's response to infection. There are several common sources of infection, which include the lungs, urinary tract, and skin. Infections may also occur in or around specific organs such as the brain, intestines, kidneys, gallbladder or pancreas. It is the body's response to this infection that starts a cascade of acute inflammation. This is seen clinically by high respiratory rate, elevated heart rate, abnormal (high or low) body temperature, and abnormal (high or low) white blood cell count. The Systemic Inflammatory Response Syndrome, also known as SIRS, can be diagnosed when two of these signs are present. SIRS can also be related to other noninfectious conditions such as trauma, burns and pancreatitis. When SIRS is caused by infection it is called sepsis. Most commonly the type of infection is bacterial, but sepsis can also be caused by viral and fungal infections. If a patient has sepsis and then develops organ dysfunction (i.e., kidney or respiratory failure) or low blood pressure, the patient is then diagnosed with severe sepsis. If organ failure or low blood pressure persists despite adequate fluid resuscitation, this is called septic shock. The mortality rate of severe sepsis and septic shock is frequently quoted as anywhere from 20 percent to 50 percent.
Are some people more at risk than others?
People that have weakened immune systems or chronic medical conditions such as diabetes or chronic kidney failure are at higher risk for sepsis. Age is also a risk factor most commonly affecting the very old and very young. In addition, patients who have frequent hospitalization or those that reside in nursing facilities are at higher risk. Epidemiologic studies have suggested that sepsis is more common among men than among women. Research has also suggested that sepsis is more common among nonwhite persons than among white persons. More recent studies have shown multiple genetic predisposing factors. For example, the proteins involved in the recognition of bacterial pathogens in the body as well the proteins directly involved in the inflammatory cascade, may differ from one person to another.
Is there any special technology to diagnose sepsis?
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As discussed above, the first step in diagnosing sepsis is to recognize the components of the systemic inflammatory response syndrome. Once two out of four criteria are met, the source of infection needs to be determined. Typical diagnostic testing includes blood, urine, and sputum cultures. If the patient has developed a skin infection, then the skin may be cultured as well. If meningitis is suspected, a lumbar puncture is performed. Imaging tests including a chest X-ray, or CT scan may be done to assess the brain, lungs, abdomen, or extremities. There is no gold standard lab test to diagnose sepsis.
How quickly does it need to be treated?
A heightened level of suspicion is necessary for the medical team to quickly diagnose sepsis. Early aggressive treatment is necessary to stop the natural progression of sepsis to septic shock. Early appropriate antibiotic therapy should be started as early as possible and always within the first hour of recognizing severe sepsis. Patients with organ dysfunction or low blood pressure will also require intravenous fluids initiated as soon as possible to minimize the risk of multiple system organ failure. While antibiotics are started and intravenous fluids are being administered, attempts are made to quickly identify the source of the infection. There are occasions where the infection cannot be treated with antibiotics alone. If an abscess is present, it should be drained, and the patient may require more extensive surgical intervention.
How can you tell if treatment isn't working and are there alternatives?
If a patient develops ongoing organ failure or has persistently low blood pressure, then additional support is necessary. The patient may need to be placed on mechanical ventilation for respiratory failure. Dialysis may be initiated for kidney failure. A catheter may be placed in the jugular or subclavian veins to measure pressure of blood filling the heart or to sample the blood frequently for laboratory testing. If treatment is not working, medications called vasopressors are added to maintain arterial blood pressure and perfusion to the vital organs of the body. Medications are used to treat both the infection as well as the acute inflammation in the body. These interventions are initiated in the emergency room and transitioned to the intensive care unit under the direction of a specialized critical care team.