What is sepsis?

Definition

Sepsis is a systemic inflammatory response to infection. In the United States, as of 2008, more than 1.1 million persons develop sepsis each year, and between one-quarter and half of those with sepsis die from the infection, according to the US Centers for Disease Control and Prevention. The number of cases has been rising, due to an aging population, to higher rates of illness and medical procedures, and to improved diagnostics and reporting. In the past, the term “septicemia” (or “blood poisoning”) was often used interchangeably with sepsis, but that practice has fallen out of favor because the disease description, “blood poisoning,” is considered imprecise.

Causes

Sepsis often begins when there is an infection in the body, whether bacterial, viral, fungal, or parasitic. In this situation, the body frequently has trouble delivering oxygen to all the organs and cells that need it. The lungs, abdomen, urinary tract, skin, brain, and bone are common starting points for sepsis. Sepsis can also affect the intestine, where bacteria thrive, and already-infected areas after surgery. A foreign object (such as a catheter or drainage tube) inserted into the body also can cause sepsis.

Risk Factors

Sepsis has become more common, especially among hospitalized persons. People at risk include the elderly, neonatal patients, immunocompromised persons, and persons who use injectable drugs. The widespread use of antibiotics encourages the growth of drug-resistant microorganisms. There is a higher incidence of sepsis when a person is already weakened by a condition such as malnutrition, alcoholism, liver disease, diabetes, a malignant neoplasm (cancer), organ transplantation, bone marrow transplantation, or human immunodeficiency virus (HIV) infection.

Of persons with end-stage renal disease, 75 percent will die of sepsis. Sepsis also causes high rates of mortality in persons undergoing dialysis and in renal transplant recipients. Systemic inflammatory response syndrome and acute respiratory distress syndrome are closely related to sepsis.

Men are more susceptible than women to developing sepsis. Minorities appear to be at greater risk of developing sepsis as well. Among persons who already have sepsis, blacks are more likely to die than are whites. Preliminary studies have identified socioeconomic status, educational level, genetics, the number of other chronic diseases a person has, tobacco or alcohol use, nutritional status, and when and where a patient develops sepsis (i.e., before, during, or after hospitalization) as areas for further research into what effect race has on the disease progression and mortality of people with sepsis. Similar factors may affect risk by gender as well.

Symptoms

Symptoms of sepsis include shaking, chills, fever, weakness, rapid heart rate, rapid breathing, low blood pressure, decreased urine output, nausea, vomiting, and diarrhea. Sepsis can cause infections that attack crucial body systems, such as the lining of the brain, the sac around the heart, the bones, or the large joints. Sepsis can also bring about impaired intestinal function.

Sepsis can attack the endothelium, the thin layer of cells within the blood
vessels, which affects the circulation, the heart, and, ultimately, the organs of
the body. Multiple organ failure is a common effect of sepsis. Apoptosis, also known as suicide of the cells, is closely linked to multiple
organ failure and sepsis.

Screening and Diagnosis

Because sepsis is so lethal, early diagnosis is crucial. Some of the signs are
a temperature above 101° or below 96° Fahrenheit, a heart rate above ninety beats
per minute, or a breathing rate faster than twenty beats per minute. Additional
signs include having a white blood cell count greater than 12,000 cubic
millimeters or having pus-forming or other pathogenic organisms. Blood cultures
are drawn to determine the source of the infection. Diagnostic tests may also be
performed on wound secretions or on cerebrospinal fluid. Imaging scans may
be done too.

A number of factors can complicate diagnosis. Doctors often do not see persons with sepsis until those persons are in the later stages of illness and who tend to have several complex diseases. Sepsis may be one component of a larger disease process, such as systemic inflammatory response syndrome or multiple organ dysfunction syndrome.

If there is damage to vital organs, the diagnosis becomes severe sepsis. The most serious form of sepsis is septic shock, with the complication of low blood pressure (hypotension) that does not respond to standard treatment.

Treatment and Therapy

Because sepsis spreads so quickly, treatment may start before the results of blood cultures are available. More potent antibiotics are available, covering a broader spectrum, and antifungal agents may be used if the infection is thought to be fungal, rather than bacterial, in origin. Immunosuppressive agents may also be used. Other treatments include insulin, painkillers, sedatives, and surgery. One strategy is to attempt invasive treatment of inflammatory, infectious, and neoplastic diseases. A 2015 Cochrane Review meta-analysis of clinical trials also shows that low-dose corticosteroids given over an extended period appear to reduce mortality and to improve the odds of recovery from septic shock.

Respiratory failure is treated with gas exchange and oxygen. To treat liver failure, therapy involves stimulating beta 2 receptors. For cardiac dysfunction, the patient is treated with volume therapy and vasoactive drugs. Ventilator support is used for neurological problems.

Prevention and Outcomes

The best protection against sepsis is frequent handwashing, staying current on immunizations, and seeking prompt care for infections. Skin that has redness, swelling, or pus should be examined by a doctor. In hospitals, the best prevention is identifying sepsis early and treating it with the correct antibiotic, a protocol that will help to reduce organ dysfunction. In many cases, however, sepsis strikes persons who are already vulnerable.

Those who survive sepsis or septic shock may experience temporary depression, anxiety, confusion, loss of appetite, aches and pains, fatigue, weight loss, insomnia, or shortness of breath. Most survivors of sepsis regain renal function over time; however, those with pre-existing renal problems may need ongoing dialysis. More rarely, survivors experience long-term neurocognitive impairments, struggle with insomnia, have ongoing organ dysfunction, or require amputation of a limb.

Bibliography

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