Blood Infection or Sepsis – Causes, Symptoms, Signs, Treatment

What Is Sepsis?

Sepsis (Greek sepsis= putrefaction, decay) is an exaggerated response of body’s immune system to an infection, like severe pneumonia or cellulitis, which has spread to the blood; it is also called blood infection. If treatment does not start promptly, sepsis may be deadly.

NOTE: Bacteremia, viremia, fungemia or parasitemia refer only to a presence of microbes in the blood, which by themselves rarely causes any symptoms, while sepsis is always a serious condition with detectable inflammation in the blood and obvious symptoms. Check what septic means.

Usually, the body’s response to an infection is limited to the affected organ, while in sepsis it spreads through the whole body and is called Systemic Inflammatory Response Syndrome (SIRS). In SIRS, toxins released by microbes, and cytokines released by immune cells, cause widening (dilation) of arteries, resulting in marked drop in blood pressure, leading to insufficient blood supply to vital organs, like the brain and kidneys (1).

Sepsis has three stages: 1. sepsis, 2. severe sepsis and 3. septic shock (2).

1. Sepsis

To be diagnosed with sepsis, you have to have at least two of the following:

  • Body temperature above 101.3 °F (38.5 °C) or below 95 °F (35 °C), with or without shaking chills
  • Rapid breathing (> 20/min)
  • Rapid heartbeat (>90 beats per minute)
  • Confirmed or suspected infection

2. Severe Sepsis

In severe sepsis, at least two additional symptoms, which suggest dysfunction of the vital organs, appear:

  • Confusion or decreased consciousness
  • Difficulty breathing
  • Mottled skin or small red dots (petechia) due to bleeding into the skin
  • Decreased urination
  • Decreased blood platelets
  • Blood white blood cells > 12,000 mL or < 4,000 mL
  • Abnormal heart function (detected by ECG)

3. Septic Shock

Diagnosis of septic shock is given, when you have symptoms and signs of severe sepsis and extremely low blood pressure.

Who Is at Risk to Develop Sepsis?

Anyone can develop sepsis during an infection, however, the risk of sepsis is greatly increased in:

  • Severely ill patients in an intensive care unit
  • Patients with severe infection, like pneumonia, urinary tract infection, meningitis, osteomyelitis (infection of the bone), cellulitis (MRSA-related sepsis), bowel abscesses in Crohn’s disease, infected surgical wounds, bullet wounds, extensive burns or bed sores
  • Infants and old people with chronic diseases, like diabetes
  • Persons with lowered immunity due to AIDS, chemotherapy, corticosteroids, immunosuppressive drugs, etc.
  • Persons who have no spleen

When to Visit a Doctor?

When you have two or more of above mentioned symptoms, call emergency room (911 in US) right away.

Tests to Expect in Sepsis

Tests and treatment of sepsis are usually performed in an intensive care unit in a hospital. X-ray or CT may reveal pneumonia or abdominal infection. Blood sample is taken to grow a blood culture from which causative microbes can be identified; samples of urine, spinal fluid or sputum may also be required.


Treatment includes maintaining adequate blood pressure with intravenous fluids and fighting an infection with antibiotics. An urgent surgery may be required to remove a source of infection, like abdominal abscess.


Patients who were severely ill before developing sepsis, especially old ones, those infected with aggressive microbes and those in whom treatment has started late, have bad prognosis. Sepsis still has a high mortality rate – a prompt start of treatment increases chances of survival.

Related Articles:


  1. Pathophysiology of sepsis
  2. Symptoms of sepsis
About Jan Modric (209 Articles)
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