Systemic Inflammatory Response Syndrome (SIRS)

Question 1

Define and contrast endotoxemia and systemic inflammatory response syndrome (SIRS).

Answer 1

Endotoxemia - the presence of endotoxin in systemic circulation

Systemic inflammatory response syndrome (SIRS) - a non-specific common pathway of systemic inflammation that occurs when the inflammatory response to tissue damage extends beyond local tissues generating a clinical syndrome (SIRS). NOT a primary condition.

Question 2

Describe the clinical examination and clinicopathological findings consistent with SIRS in a horse and explain the pathophysiology of these abnormalities.

Question 3

List common conditions that lead to SIRS and endotoxemia in horses.

Answer 3

SIRS:
Endotoxemia
Severe infection (localized or bacteremia)
Trauma / large tissue injury
Hypoxia / ischemia
Burns, neoplasia, multiple blood transfusions, snake envenomation, etc.

Endotoxemia:
Conditions affecting the mucosa of the large intestine (colitis, colon torsion, ileus)
Retained placenta
Pleuropneumonia
Peritonitis
Any gram negative infection

Question 4

Develop a treatment plan for a horse with endotoxemia secondary to a strangulating obstruction of the small intestine or colitis.

Answer 4

Treat underlying disease process - remove obstruction

Fluid therapy - resuscitation and maintenance

Block/neutralize endotoxin - Polymyxin B 2 doses after fluids (abx binds circulating LPS); BioSponge NGT (binds endotoxin in GIT)

Inhibit inflammation and inflammatory mediators - Flunixin maglumine (NSAID) 0.25 mg/kg IV q 6h

Supportive care