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Medical Author:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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In this Article

• Sepsis (blood poisoning) facts
• What is blood poisoning?
• What is sepsis?
• Why are there so many diseases with "sepsis," "septic," "septicemia," or "blood poisoning" in their name?
• What are the signs or symptoms of sepsis (blood poisoning)?
• What causes sepsis?
• How is sepsis diagnosed?
• How is sepsis treated?
• What is the prognosis (outcome) with sepsis?
• How can sepsis be prevented?
• What are some additional sources for information on sepsis?
• Patient Comments: Sepsis - Treatment
• Patient Comments: Sepsis - Symptoms
• Sepsis Index

The majority of cases of sepsis are due to bacterial infections, some are due to fungal infections, and very few are due to other causes of infection or agents that may cause SIRS. The infectious agents, usually bacteria, begin infecting almost any organ location or implanted device (for example, skin, lung, gastrointestinal tract, surgical site, intravenous catheter, etc.). The infecting agents or their toxins (or both) then spread directly or indirectly into the bloodstream. This allows them to spread to almost any other organ system. SIRS criteria result as the body tries to counteract the damage done by these blood-borne agents.

Common bacterial causes of sepsis are gram-negative bacilli (for example, E. coli, P. aeruginosa, E. corrodens and Haemophilus influenzae in neonates), S. aureus, Streptococcus species and Enterococcus species; however, there are a large number of bacterial genera that have been known to cause sepsis. Candida species are some of the most frequent fungi that cause sepsis. In general, a person with sepsis can be contagious, so precautions such as hand washing, sterile gloves, masks, and clothing coverage should be considered depending on the patient's infection source.

Clinically, the patient needs to fit at least two of the SIRS criteria listed above and have a suspected or proven infection. Definitive diagnosis depends on a positive blood culture for an infectious agent and at least two of the SIRS criteria. However, two subsets of the four criteria depend on lab analysis; white blood cell examinations and PaCO2. These subset criteria, like blood cultures, are measured in clinical laboratories.

There are other diagnoses that indicate the severity of the patient's sepsis. Severe sepsis is diagnosed when the septic patient has organ dysfunction (for example, low or no urine flow, altered mental status). Severe sepsis can also include sepsis-induced hypotension (also termed septic shock) when the patient's blood pressure falls.