What is Sepsis

What is Sepsis?
Sepsis is the term used to describe the body’s response to an infection. It is characterized by a host systemic inflammatory response syndrome (SIRS) to an invading microorganism consisting of fever, tachycardia (increased heart rate), tachypnea (rapid breathing), and an elevated white blood cell count. Among patients presenting to the hospital from the community, the most frequent sites of infection leading to sepsis are the lung (pneumonia), urinary tract (bladder or kidney infection), and abdomen (ruptured appendix or other abdominal organs, abdominal abscess, gallbladder infection, or bowel obstruction). In hospitalized patients, sepsis is a frequent and troublesome complication which often prolongs the duration of hospital stay and increases health care cost. Hospitalized patients are at high risk for developing infection because they are already sick, often have underlying chronic disease, and frequent have indwelling devices and/or undergo invasive diagnostic and therapeutic procedures which place them at risk for acquiring infection. Among hospitalized patients, pneumonia, urinary tract infection, line infection, and skin and soft tissue infections are common. Regardless of whether an infection originates in the community or hospital setting, sepsis is the number one cause of ARDS (Acute Respiratory Distress Syndrome) and MODS (Multiple Organ Dysfunction Syndrome). In severe cases of sepsis, patients are admitted to the intensive care unit because they frequently develop shock (low blood pressure), respiratory failure (require a breathing machine), or other organ failures. The greater the number of individual organs that become dysfunctional as a consequence of the septic process, the greater the risk of death, permanent organ dysfunction (kidney, lung, brain), and the higher the mortality rate.

Approximately 500,000 episodes of sepsis occur in the USA annually. Sepsis affects individuals of all age groups; however, at greatest risk are those at extremes of age, alcohol and drug abusers, those with burns or wounds, chronic lung or cardiovascular disease patients, diabetics, hepatic or renal failure patients, HIV-positive individuals, those receiving immunosuppressive drugs, individuals with indwelling urinary or intravascular catheters and devices, patients with malignancy, malnutrition, organ transplant recipients, and those suffering from trauma. In recent years, the incidence of severe sepsis has increased from 74 cases per 100,000 people -in 1979-to 176 cases per-100,000 people in 1987.

Sepsis is the number one cause of mortality in today’s intensive care units. The overall mortality rate of severe sepsis is estimated to be 40-70%. It is estimated that between 200,000-300,000 Americans die each year as a consequence of this disease – about 1,500 in the Memphis metropolitan area. Despite progress in critical care and in antibiotic and vasopressor therapy the mortality rate from sepsis has not significantly improved. Furthermore, when shock, ARDS, or MODS complicates sepsis the mortality rate is much higher (60-100%). Sepsis has a significant impact on public health and accounts for 5 to 10 billion dollars in medical care cost each year. The cost of a single day of intensive care unit stay for a patient with sepsis ranges from 1,000 to 6,000 dollars and the hospital cost may exceed 100,000 dollars depending on the intensity of required supportive care.

Why do Patients with Sepsis Die?
Over the past 10 years we have learned by measuring blood cytokine levels over time in patients with sepsis that death is caused by an exaggerated (self-destroying) host defense response. We have found that nonsurvivors have significantly higher levels of inflammatory cytokines in the circulation at the onset and during the course of sepsis while survivors have a milder degree of inflammation (lower cytokine levels) that subsides spontaneously in a few days. Although infection is usually easily eradicated with antibiotic and surgical therapy, we have found that it is the inability to shut down or downregulate the exaggerated host inflammatory response to infection which leads to complications such as shock, SIRS, ARDS, MODS, and ultimately death. While an appropriate inflammatory response is crucial to the eradication of infection and the repair of damaged tissue, an exaggerated inflammatory response (“too much of a good thing”) may harm more than help the patient.

Although most patients who survive sepsis return to their prior quality of life within a few weeks or months following hospital discharge, many develop a debilitating psychiatric condition called post-traumatic stress syndrome. In patients with septic shock randomized to glucocorticoid treatment, a German group reported a measurable reduction in the development of post-traumatic stress syndrome. Survivors of septic shock are also at increased risk for premature death for a period of 5 years following discharge from the hospital. The effect of steroids on long term outcome and quality of life in patients with ARDS and sepsis treated with glucocorticoids is being investigated, as part of the project supported by the Baptist Memorial Health Care Foundation.

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