Sepsis

Definition

Sepsis is a severe illness in which the bloodstream is overwhelmed by bacteria.

Alternative Names

Systemic inflammatory response syndrome (SIRS)

Causes, incidence, and risk factors

Sepsis is caused by a bacterial infection that can begin anywhere in the body. Common places where an infection might start include:

• The bowel (usually seen with peritonitis)
• The kidneys (upper urinary tract infection)
  • The liver or the gall bladder
• The lungs (bacterial pneumonia)
• The skin (cellulitis)

Sepsis may also accompany meningitis. In children, sepsis may accompany infection of the bone (osteomyelitis). In hospitalized patients, common sites of infection include intravenous lines, surgical wounds, surgical drains, and sites of skin breakdown known as bedsores (decubitus ulcers).

The infection is often confirmed by a blood test. But, a blood test may not reveal infection in people who have been receiving antibiotics.

In sepsis, blood pressure drops, resulting in shock. Major organs and systems, including the kidneys, liver, lungs, and central nervous system, stop functioning normally.

A change in mental status and hyperventilation may be the earliest signs of sepsis coming on.

Sepsis is often life-threatening, especially in people with a weakened immune system or with other illness.

Symptoms

• Chills
• Confusion or delirium
• Decreased urine output
• Fever or low body temperature (hypothermia)
• Hyperventilation
• Lightheadedness
• Rapid heart beat
• Shaking
• Skin rash
• Warm skin

Signs and tests

The following may indicate sepsis:

• Blood culture that reveals bacteria
• Blood gases that reveal acidosis
• Kidney function tests that are abnormal (early in the course of disease)
• Platelet count that is lower than normal
• White blood cell count that is lower or higher than normal

This disease may also change the normal results of the following tests:

• Blood differential -- showing immature white blood cells
• Fibrin degradation products -- often higher than normal, a condition that may be associated with a tendency to bleed
• Peripheral smear -- may show a low platelet count and destruction of red blood cells

Treatment

People with sepsis usually need to be in an intensive care unit (ICU). As soon as sepsis is suspected, "broad spectrum" (able to destroy a wide array of bacteria) intravenous (directly in the vein) antibiotic therapy is begun.

The number of antibiotics may be decreased when blood tests reveal which particular bacteria are causing the infection. The source of the infection should be discovered, if possible. This could mean more testing. Infected intravenous lines or surgical drains should be removed, and any abscesses should be surgically drained.

Oxygen, intravenous fluids, and medications that increase blood pressure may be needed. Dialysis may be necessary if there is kidney failure, and a breathing machine (mechanical ventilation) if there is respiratory failure.

Expectations (prognosis)

The death rate can be as high as 60% for people with underlying medical problems. The death rate is somewhat lower in those without other medical problems.

Complications

• Death
• Disseminated intravascular coagulation
• Impaired blood flow to vital organs (brain, heart, kidneys)
• Septic shock

Prevention

References

Enrione MA, Powell KR. Sepsis, septic shock, and systemic inflammatory response syndrome. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th Ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 176.

Shapiro NI, Zimmer GD, Barkin AZ. Sepsis syndrome. In: Marx, JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. Philadelphia, Pa: Mosby Elsevier; 2006: chap 136.