Sepsis is a serious medical condition caused by an overwhelming immune response to infection. Chemicals released into the blood to fight infection trigger widespread inflammation.
Inflammation may result in organ damage. Blood clotting during sepsis reduces blood flow to limbs and internal organs, depriving them of nutrients and oxygen. In severe cases, one or more organs fail. In the worst cases, infection leads to a life-threatening drop in blood pressure, called septic shock. This can quickly lead to the failure of several organs — lungs, kidneys, and liver — causing death.
Sepsis occurs in 1% to 2% of all hospitalizations in the U.S. It affects at least 750,000 people each year.
The term sepsis is often used interchangeably with septicemia, a serious, life-threatening infection that gets worse very quickly and is often fatal.
Sepsis Causes and Risk Factors
Bacterial infections are the most common cause of sepsis. However, sepsis can also be caused by other infections. The infection can begin anywhere bacteria or other infectious agents can enter the body. It can result from something as seemingly harmless as a scraped knee or nicked cuticle or from a more serious medical problem such as appendicitis, pneumonia, meningitis, or a urinary tract infection.
Sepsis may accompany infection of the bone, called osteomyelitis. In hospitalized patients, common sites of initial infection include IV lines, surgical incisions, urinary catheters, and bed sores.
Although anyone can get sepsis, certain groups of people are at greater risk. They include:
- People whose immune systems are not functioning well due to illnesses such as HIV/AIDS or cancer or use of drugs that suppress the immune system, such as those to prevent rejection of transplanted organs.
- Very young babies.
- The elderly, particularly if they have other health problems.
- People who have recently been hospitalized and/or had invasive medical procedures.
- People with diabetes.
Because sepsis can begin in different parts of the body, it can have many different symptoms. Rapid breathing and a change in mental status, such as reduced alertness or confusion, may be the first signs that sepsis is starting. Other common symptoms include:
- fever and shaking chills or, alternatively, a very low body temperature
- decreased urination
- rapid pulse
- rapid breathing
- nausea and vomiting
The first step to successful treatment for sepsis is quick diagnosis. If sepsis is suspected, the doctor will perform an exam and run tests to look for:
- Bacteria in the blood or other body fluids
- Source of the infection, using radiologic imaging such as X-ray, CT scan, or ultrasound
- A high or low white blood cell count
- A low platelet count
- Low blood pressure
- Too much acid in the blood (acidosis)
- Altered kidney or liver function
Other tests of bodily fluids and radiologic tests, such as X-ray or CT scan, can help in diagnosing the cause of the infection. People diagnosed with severe sepsis are usually placed in the intensive care unit (ICU), where doctors try to stop the infection, keep vital organs functioning, and regulate blood pressure.