Sepsis (Blood Infection): Causes, Signs, Symptoms, Treatment & More

Causes of Blood Infection

Bacterial infection is the most frequent cause of blood infection. However, fungal & viral infections can also result in the same signs. A breach in the body’s protective mechanisms allows organisms to spread around the body, spreading toxic substances which are responsible for the diverse symptoms of blood infection. 

The causative agent may be introduced through:

• A wound that hasn’t been tended to properly
• The use of a catheter or breathing tube
• Poor hygiene

Blood infections commonly begin in:

• Lungs
• Bones (Osteomyelitis)
• Gastrointestinal Tract
• Urinary Tract
• Skin

Stages of Blood Infection

Without blood infection treatment, a patient’s condition worsens. Blood infection can progress through the following stages:

• Mild sepsis
• Severe sepsis
• Septic shock

From its onset, the signs of blood infection vary with each stage of the condition.

Mild Sepsis

Mild sepsis is the initial stage of blood infection. The symptoms experienced at this stage are mostly fever, weakness, increased heart rate & respiration. Patients experiencing these signs of blood infection require blood infection treatment at this stage to increase the chances of survival without severe complications.

Severe Sepsis

Since the mild sepsis stage may be overlooked, blood infection might progress to the second stage, which is known as severe sepsis, before it is treated medically. This stage is characterized by decreased blood supply to organs, usually due to clotting, as well as a drop in blood pressure. The signs of blood infection in severe sepsis can include breathing difficulty, abdominal pain, diarrhea, decreased urine production, & increased heart rate.

Septic Shock

Without blood infection treatment, blood infection progresses to its most critical stage. Septic shock is marked by life threateningly low blood pressure. 

Initially the body’s neural & hormonal systems may temporarily maintain the blood pressure, which may manifest through a decrease in urine output & increased heart rate. Eventually, the decreased blood pressure severely affects the delivery of oxygen & other requirements. This results in increased levels of lactic acid as the cells try to function without adequate oxygen. Blood glucose levels may also be elevated in such severe blood infection due to the release of stress hormones.

As a result, blood infection causes multi-organ dysfunction. Even though emergency treatment may prove successful in certain cases, a high mortality rate is associated with septic shock.

Risk factors for Blood Infection

Normally infections are self-limiting or require basic treatment. However, certain individuals may be at greater risk of progressive blood infection with concerning signs & complications. Blood infections are a problem for:

• Aged individuals
• Premature infants or infants aged 3 months or younger
• Individuals with HIV
• Individuals using immunosuppressants to avoid tissue rejection after transplants or for autoimmune diseases
• Individuals with chronic diseases such as diabetes
• Pregnant women
• Frequent antibiotic users
• Hospitalized patients in the ICU or those using catheters or breathing tubes