Sepsis is a condition in which the body is fighting a severe infection that has spread via the bloodstream. If a patient becomes "septic", they will likely have low blood pressureleading to poor circulation and lack of perfusion of vital tissues and organs. This condition is termed "shock". This condition can develop either as a result of the body's own defense system or from toxic substances made by the infecting agent (such as a bacteria, virus, orfungus).
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 Enterococcusspecies; 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.
In almost every case of sepsis, patients need to be hospitalized, treated with appropriate intravenous antibiotics, and given therapy to support any organ dysfunction. Sepsis can quickly cause organ damage and death; therapy should not be delayed as statistics suggest as high as a 7% mortality increase per hour if antibiotics are delayed in severe sepsis. Most cases of sepsis are treated in an intensive care unit (ICU) of the hospital.
Appropriate antibiotics to treat sepsis are combinations of two or three antibiotics given at the same time; most combinations usually include vancomycin to treat many MRSA infections. However, once the infecting organism is isolated, labs can determine which antibiotics are most effective against the organisms, and those antibiotics should be used to treat the patient. In addition to antibiotics, two other major therapeutic interventions, organ-system support and surgery, may be needed.
First, if an organ system needs support, the intensive care unit can often provide it (for example, intubation to support lung function or dialysis to support kidney function). Secondly, surgery may be needed to drain or remove the source of infection. Amputation of extremities has been done to save some patients' lives.
A recent research report may alter a common treatment for septic shock. Because of the low blood pressure seen with septic shock, IV fluid boluses have been used to support the patient's blood pressure. However, a 2011 study in over 3,000 children in Africa with impaired perfusion (shock) the fluid bolus treatments actually increased mortality in the children.
This surprising result has raised questions about how clinicians can best manage septic shock in the future. For example, in 2004, guidelines were published that "bundled" therapeutic methods (for example, blood cultures, antibiotic therapy, and fluid therapy) to treat sepsis in an initial six-hour period that included fluid boluses. This septic treatment bundle of techniques may need revision or reexamination.