Definition

Blood poisoning is an illness due to an infection or its toxin spreading through the bloodstream. The presence of bacteria in the blood is called bacteremia.

Short bursts of low levels of bacteria in the blood usually do not cause problems. Mild bacteremia typically occurs during a dental cleaning or when brushing your teeth [2]. Your body's immune [3] system fights off these bacteria.

If bacteria persist in the blood they may cause sepsis. This is a serious, life-threatening condition.

Causes

Sepsis occurs when large numbers of infectious agents exist in the blood. Bacteria usually enter the blood from an infection somewhere in the body. Infections with fungi and parasites may lead to sepsis as well. The initial infection could be from any source, but often comes from:

• A burn, ulcer, or other open wound
• Pneumonia [4]
• Urinary tract infection [5]

Sometimes, bacteria may enter the bloodstream directly from an outside source. A dirty needle used by an intravenous (IV) drug user can cause this type of infection. In some cases, the source of the infection is unknown.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

• Recent illness or hospital care
• Frail health [6] due to extreme age
• Poorly working immune [3] system due to:
  
  • Cancer or chemotherapy [7] for treatment of cancer [8]
  • Diabetes [9]
  • AIDS [10] or another immunosuppressive condition such as an autoimmune disease or an immune [3] deficiency
  • Immunosuppressive medications needed after a transplant
• Medical treatment with an invasive device
• IV drug abuse

Symptoms

Initial symptoms depend on the site of the infection. For example, with pneumonia you would probably have a cough and shortness of breath. With a urinary tract infection, you would probably have frequent urination and a burning sensation.

As the condition progresses to sepsis, symptoms include:

• Fever and chills
• Low temperature
• Paleness of skin color
• Listlessness
• Changes in mental [11] status
• Rapid breathing
• Increased heart [12] rate
• Decreased urine output
• Low blood pressure
• Shock
• Problems with bleeding or clotting

Diagnosis

The doctor will ask about your symptoms and medical [13] history, and perform a physical exam. If sepsis is suspected, the doctor will try to find the source of the infection.

Tests include:

• Several blood cultures to confirm the diagnosis of sepsis
• Urine and other blood tests to check for signs of infection
• Cultures of urine, sputum, stool, and other secretions to check for bacteria or other infectious agents
• X-rays [14] —a test that uses radiation to take a picture of structures inside the body
• CT scan [15] —a type of x-ray that uses a computer to make pictures of structures inside of the body
• MRI scan [16] —a test that uses magnetic waves to make pictures of structures inside of the body
• Other specialized tests depending on the source of the infection

Treatment

Sepsis needs aggressive treatment. Treatment is directed at the cause of the initial infection, if this is identified.

Early treatment improves the chance of survival. Life-saving measures may be needed to stabilize breathing and heart [12] function. Patients usually need monitoring in an intensive care unit.

Prevention

It is not always possible to prevent blood poisoning. Avoiding IV drug abuse decreases your chance of sepsis and other serious infections (hepatitis and AIDS). Healthcare professionals must also take steps to stop the spread of these infections. Getting prompt medical [13] care for infections can reduce your risk of sepsis.