Sepsis is the 10th leading cause of death in the U.S. Septic shock is a type of severe sepsis in which the blood pressure falls to dangerously low levels. It starts with an infection, but the major damage is done by the immune response. Severe sepsis includes damage to major organs. Time is critical in treating sepsis since there is no definitive cure.
The innate immune response is our first line of defense against infection. This depends strongly on inflammation to start killing invaders immediately. The adaptive immune response is based on antibodies and takes some time to develop. We get vaccinations to enhance our adaptive immunity. But for many infections, our survival depends on a well-controlled innate immune response. Ideally, the inflammation clears out the pathogens and then stops before it does too much damage to our tissue.
People at risk for sepsis include:
1. Elderly patients and young children. In the U.S., sepsis accounts for 4,500 childhood deaths annually.
2. Immune-compromised patients.
3. Patients undergoing invasive procedures.
Children who die from sepsis have lower levels of zinc than those who survive, indicating that nutrition is a factor.
Sepsis treatments have had a remarkably low success rate in clinical trials. Early goal-directed therapy, or EGDT, may be the best so far. This approach emphasizes early, aggressive treatment for the symptoms, especially low blood pressure. Powerful anti-inflammatory drugs, including corticosteroids and tumor necrosis factor inhibitors, have demonstrated limited benefits.
Sepsis is a challenge for critical care physicians because patients with similar cases can have very different outcomes from the same treatment. Researchers in Cincinnati report that the one size fits all model is the problem. Patients have genetic differences in the complicated processes of innate immunity. For some, the pro-inflammatory phase causes multiple organ dysfunction and death; for others, the anti-inflammatory phase causes immune paralysis and allows the original infection to overwhelm the weakened host. In addition, innate immunity is tied to coagulation and to the central nervous system.
Sepsis is one of the most active areas of medical research. There are 562 clinical trials currently listed on the U.S. National Institutes of Health directory, at Clinicaltrials.gov.
Sources:
Shimaoka M et al, “Advances in understanding sepsis”, Eur J Anaesthesiol Suppl. 2008; 42: 146-53.
Wheeler DS et al, “Novel pharmacologic approaches to the management of sepsis: Targeting the host inflammatory response”, Recent Pat Inflamm Allergy Drug Discov. 2009; 3(2): 96-112.
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.