Sepsis is a potentially life-threatening condition, in which your immune system's reaction to an infection may injure body tissues far from the original infection.

As sepsis progresses, it begins to affect organ function and eventually can lead to septic shock — a sometimes fatal drop in blood pressure.

People who are most at risk of developing sepsis include:

• The very young and the very old
• Individuals with compromised immune systems
• Very sick people in the hospital
• Those who have invasive devices, such as urinary catheters or breathing tubes

Early treatment, usually with large amounts of intravenous fluids and antibiotics, improves chances for survival.

Many doctors view sepsis as a three-stage syndrome, starting with sepsis and progressing through severe sepsis to septic shock. The goal is to treat sepsis during its mild stage, before it becomes more dangerous.

Sepsis
To be diagnosed with sepsis, you must exhibit at least two of the following symptoms:

• Fever above 101.3 F (38.5 C) or below 95 F (35 C)
• Heart rate higher than 90 beats a minute
• Respiratory rate higher than 20 breaths a minute
• Probable or confirmed infection

Severe sepsis
Your diagnosis will be upgraded to severe sepsis if you also exhibit at least one of the following signs and symptoms, which indicate organ dysfunction:

• Areas of mottled skin
• Significantly decreased urine output
• Abrupt change in mental status
• Decrease in platelet count
• Difficulty breathing
• Abnormal heart function

Septic shock
To be diagnosed with septic shock, you must have the signs and symptoms of severe sepsis — plus extremely low blood pressure.

When to see a doctor
Most often sepsis occurs in people who are hospitalized. People in the intensive care unit (ICU) are especially vulnerable to developing infections, which can then lead to sepsis. If you get an infection, or if you develop signs and symptoms of sepsis after surgery, hospitalization or an infection, seek medical care promptly.

Inflammation is one of the weapons your immune system uses to fight infections. Normally, a delicate balance of chemical signals starts and then stops the inflammatory process. In sepsis, however, the process becomes exaggerated. Inflammation extends beyond the infection site and affects your whole body.

This widespread inflammation prompts the formation of microscopic clots in tiny blood vessels throughout the body. At the same time, the overactive inflammatory response interferes with your body's natural ability to break down blood clots.

As a result, even as the heart works harder to pump blood, the clots prevent enough oxygen from reaching your organs — causing them to fail.

Sepsis can occur in anyone with an infection, but certain factors increase your risk.

Age
Sepsis occurs more often in people over the age of 65 and in infants.

Race
Black people are more likely than are white people to get sepsis, and black men face the highest risk.

Compromised immune system
Your risk of sepsis increases if your immune system has been weakened by:

• Cancer or cancer treatment
• HIV or AIDS
• Anti-rejection drugs taken after organ transplants
• Kidney or liver failure

Hospitalization
People who are in the hospital, particularly those in intensive care units, are at higher risk of developing sepsis.

Invasive medical devices
Your risk of sepsis is higher if you have:

• A urinary catheter
• A breathing tube
• Artificial joints

Medical conditions
Medical conditions that can increase your risk of sepsis include:

• Bacteremia, a bacterial infection in your blood
• Pneumonia
• Diabetes
• Severe injuries, such as bullet wounds or large burns

Genetics
Some people appear to have a genetic tendency toward developing sepsis.

Sepsis ranges from less to more severe. As sepsis worsens, blood flow to vital organs, such as your brain, heart and kidneys, becomes impaired. Sepsis can also cause blood clots to form in your organs and in your arms, legs, fingers and toes, leading to varying degrees of organ failure and tissue death (gangrene).

Most people recover from mild sepsis, but about 15 percent die. Some studies indicate that the mortality rate for severe sepsis or septic shock is close to 50 percent.

Diagnosing sepsis can be difficult because its signs and symptoms can be caused by other disorders. Doctors often order a battery of tests to try to pinpoint the underlying infection.

Blood tests
A sample of your blood can be tested for:

• Evidence of infection
• Clotting problems
• Abnormal liver or kidney function
• Impaired oxygen availability
• Electrolyte imbalances

Other laboratory tests
Depending on your symptoms, your doctor may also want to run tests on one or more of the following bodily fluids:

• Urine. If your doctor suspects that you have a urinary tract infection, he or she may want your urine checked for signs of bacteria.
• Wound secretions. If you have an open wound that appears infected, testing a sample of the wound's secretions can help show what type of antibiotic might work best.
• Cerebrospinal fluid. A spinal tap (lumbar puncture) involves inserting a needle between the bones of your spine, to draw off a sample of the fluid that bathes and cushions your brain and spinal cord. This fluid can be checked for infections, such as meningitis.

Imaging scans
If you have no obvious infection, your doctor may order imaging tests to try to find a source of infection.

• X-ray. Using low levels of radiation, X-rays are a good tool to visualize problems in the lungs. X-rays are painless and take only a few minutes to complete.
• Computerized tomography (CT). Infections in the appendix, pancreas or bowels are easier to see on CT scans. This technology takes X-rays from a variety of angles and combines them to depict cross-sectional slices of your body's internal structures. The test is painless and usually takes less than 20 minutes.
• Ultrasound. This technology uses sound waves to produce real-time images on a video monitor. Ultrasound may be particularly useful to check for infections in your gallbladder or ovaries.
• Magnetic resonance imaging (MRI). MRIs may be helpful in identifying soft tissue infections, such as abscesses within the spine. This technology uses radio waves and a strong magnet to produce cross-sectional images of your internal structures.

Early, aggressive treatment boosts your chances of surviving sepsis. People with severe sepsis require close monitoring and treatment in a hospital intensive care unit. If you have severe sepsis or septic shock, lifesaving measures may be needed to stabilize breathing and heart function.

Medications
A number of different types of medications are used in treating sepsis. They include:

• Antibiotics. Treatment with antibiotics begins immediately — even before the infectious agent is identified. Initially you'll receive broad-spectrum antibiotics, which are effective against a variety of bacteria. The antibiotics are administered intravenously (IV). After learning the results of blood tests, your doctor may switch to a different antibiotic that's more appropriate against the particular bacteria causing the infection.
• Vasopressors. If your blood pressure remains too low even after receiving intravenous fluids, you may be given a vasopressor medication, which constricts blood vessels and helps to increase blood pressure.
• Others. Other medications you may receive include low doses of corticosteroids, insulin to help maintain stable blood sugar levels, drugs that modify the immune system responses, and painkillers or sedatives.

Therapy
People with severe sepsis usually receive supportive care including intravenous fluids and oxygen. Depending on your condition, you may need to have a machine help you breathe or dialysis for kidney failure.

Surgery
Surgery may be needed to remove sources of infection, such as:

• Medical devices
• Intravenous lines
• Drainage tubes
• Collections of pus (abscesses)