Blood infection: Causes, Symptoms, Risk Factors, Diagnosis and Treatment

What is blood poisoning or infection?

A blood infection is a severe issue. When the bacteria are in the bloodstream, invading and alter their structure.

However, the name sounds dangerous, and for good reasons. Sepsis is a severe, potentially fatal infection.

Blood poisoning can progress to sepsis quickly. Rapid diagnosis and treatment are essential to treat blood poisoning, but understanding your risk factors is the first step in preventing the condition.

What causes the infection of the blood?

Blood poisoning or infection occurs when the bacteria that cause the infection in another part of your body enter your bloodstream.

The presence of bacteria in the blood is known as bacteremia or Septicemia. The terms “septicemia” and “sepsis” are often used interchangeably, although technically, they are not precisely the same.

Septicemia is the state of having bacteria in the blood, leading to sepsis. In contrast, sepsis is a severe condition in which the tissues or organs begin to stop functioning and is often lethal from the infection if left untreated. However, any type of infection – bacterial, fungal, or viral – can cause sepsis.


Moreover, these infectious agents do not necessarily have to be in a person’s bloodstream to cause sepsis.

Such infections most commonly occur in the lungs, abdomen, and urinary tract. Sepsis occurs more often in hospitalized people, where the risk of infection is already higher.

Because blood poisoning occurs when bacteria enter the bloodstream in conjunction with another infection, sepsis will not develop without having an infection in the first place.

Some common causes of infections that can cause sepsis include:

  • Abdominal infection
  • An infected insect bite
  • Infection of the central line, such as a dialysis catheter or a chemotherapy catheter
  • Dental extractions or infected teeth
  • Exposure of a wounded bacterium during surgical recovery or not changing a surgical bandage
  • Exposure of any wound open to the environment
  • Infection by drug-resistant bacteria
  • Kidney or urinary tract infection
  • Pneumonia
  • Skin infection

Who is at risk for poisoning or blood infection?

Some people are more susceptible than others to sepsis. Those that are most at risk include:

  • People with weakened immune systems, such as those with HIV, AIDS, or leukemia
  • Small children
  • Older adults
  • People who use intravenous drugs like heroin
  • People with poor dental hygiene
  • Those who use a catheter
  • People who have had recent surgery or dental work
  • Those who work in an environment with high exposure to bacteria or viruses, such as in a hospital or outdoors

Recognize the symptoms of blood poisoning

Symptoms of blood poisoning include:

  • Cold
  • Moderate or high fever
  • Weakness
  • Fast breathing
  • Increased heart rate or palpitations
  • Paleness of the skin, especially on the face

Some of these symptoms are associated with flu or other diseases.

However, if you have recently had surgery or are recovering from a wound, you must call your doctor immediately after experiencing these possible signs of blood poisoning.

The advanced symptoms of blood poisoning can be deadly and include:

  • Confusion
  • Red spots on the skin that can grow larger and look like a giant, purple bruise
  • Shock
  • Little or no production of urine
  • Failure in some organ

Blood poisoning can lead to respiratory distress syndrome and septic shock. These complications can lead to death if the condition is not treated immediately.


It is difficult to diagnose the poisoning or infection of the blood because its symptoms are similar to those of other diseases.

The best way to determine if you have Septicemia is to see a doctor. First, your doctor will perform a physical examination, including checking your temperature and blood pressure.

If blood poisoning is suspected, your doctor will perform tests to detect signs of bacterial infection. Septicemia can be inferred with these tests:

  • Blood culture tests
  • Oxygen levels in the blood
  • Blood count
  • Coagulation factor
  • Urine tests, including urine culture
  • Chest x-ray
  • Tests of renal and electrolytic function

In addition, your doctor may see problems with liver or kidney function and imbalances in electrolyte levels. If you have a skin wound, your doctor may take a sample of any fluid leaking to detect bacteria.

As a precaution, your doctor may also request an imaging scan. These tests can help detect the infection in the organs of your body:

  • Bone scan
  • Computed tomography
  • Magnetic resonance
  • Ultrasound

If the bacteria are present, identifying the type of bacteria will help your doctor determine what antibiotic to prescribe to eliminate the infection.

Treatment Options

Immediate treatment of blood poisoning is essential because the infection can spread rapidly to the tissues or valves of the heart.

Once you are diagnosed with blood poisoning, you will likely receive treatment as an inpatient in a hospital.

If you show symptoms of shock, you will be admitted to the intensive care unit. The signs of shock include:

  • Pallor
  • Fast and weak pulse
  • Rapid and superficial breathing
  • Dizziness or unconsciousness
  • Low blood pressure

You can also receive oxygen and fluids intravenously to help maintain healthy blood pressure and eliminate the infection.

Blood clots are another concern in immobilized patients.

Sepsis is usually treated with hydration, often through an intravenous line and antibiotics that target the organism that causes the infection.

Sometimes medications may need to be used to withstand low blood pressure temporarily. These medications are called vasopressors.

If sepsis is severe enough to cause multiple organ dysfunction, the patient may have to be mechanically ventilated or may even need dialysis temporarily if their kidneys have failed.