Wednesday, April 30, 2014

SIRS: The End of a Deadly Disease Spectrum


When an infant or child falls very ill, one of the most feared complications is systemic inflammatory response syndrome (SIRS). 



SIRS is a deadly ending to a spectrum of bloodstream infection which begins when a bacteria or virus enters the bloodstream (bacteremia). In most cases, young bodies can successfully fight off the organism before it causes any serious problems. Unfortunately, this is not always the case. Sometimes, the immune system goes a bit too far and decides to put all of its cards on the table. It releases everything it has, including white blood cells, pro-inflammatory molecules and blood-clotting proteins. This most often leads to the loss of fluids in our blood vessels and the collapse of our circulatory system. Inside the body, the organs (heart, lungs, kidneys, brain) lose vital oxygen and nutrients and begin to shut down. Outside the body, doctors notice signs of shock, which include fever and changes in breathing, heart rate, mental status, blood pressure and temperature regulation. If caught very early, doctors can typically keep the patient alive. In many cases, however, nothing the physician does will save the patient from the downward spiral.



The inci­dence of SIRS is highest in infants (5.16 per 1000), occurring in 20% of low birthweight neonates and resulting in death in over 10% of cases. Studies show that 37% of infections leading to SIRS arise from the respiratory tract, while 25% are primary bloodstream infections (BSIs). 

The management of SIRS is performed in a neonatal intensive care unit (NICU) or pediatric intensive care unit (PICU). Doctors will culture the blood and monitor vital organs while ensuring the body is receiving adequate oxygen. A broad spectrum antibiotic (fights many different infections) is started until a culture comes back from the lab showing what specific organism is causing all the trouble. The antibiotic is then switched to one specifically formulated to kill that bug. One of the most frightening scenarios for a physician is when the culture comes back showing a bacteria that is resistant to all the drugs we have available. This is becoming the case with some gram negative bacteria (Klebsiella and E. coli) that release something called endotoxin and are resistant to our last line of antibiotic defense against them, carbapenems.

Scientists and physicians continue to conduct studies in order to discover ways to prevent SIRS from occurring. Though many different types of treatments have been attempted, the most effective of them continues to be early detection with  prompt antibiotic administration and fluid resuscitation.

  • Occasionally, other conditions can trigger SIRS (trauma, ARDS, neoplasm, burn injury, pancreatitis)
  • In order to reduce your child's risk, always ensure they are up to date on their vaccinations and be sure to keep them away from undercooked meat, especially beef and chicken.

References

Principles and Practice of Pediatric Infectious DiseasesJudith A. Guzman-Cottrill, Beth Cheesebrough, Simon Nadel, and Brahm Goldstein. Part II, Section A, 11: The Systemic Inflammatory Response Syndrome (SIRS), Sepsis, and Septic Shock. Pg 97-104.