Rigors And Bacteremia - Overview



• Rigors are a response to the release of cytokines and prostaglandins as part of the inflammatory response to a pathogen (e.g., bacteria).

• Increase the temperature set point for the hypothalamus → fever



Indicators (source: ncbi.nlm.nih.gov/pubmed/22851117):

	• Shaking chills were helpful in identifying bacteremia

	• Chills in febrile patients were more useful than chills alone

	• Temperature alone was not particularly helpful



Most Significant Predictor of Bacteremia (source: ncbi.nlm.nih.gov/pubmed/22463870):

	• Rigors

	• Chills

	• Thrombocytopenia



Shaking Chills (or Rigors) showed a specificity of 90.3% and positive likelihood ratio of 4.65 for bacteremia!



PATHOPHYSIOLOGY:

→ Exogenous Pyrogen:

	• Bacteria: Lipopolysaccharide components, Peptidoglycans and muramyl peptide derivatives, Toxins

	• Virus: Double-stranded RNA

	• Fungi: Mannan and glucan components

→ Stimulate immune cells: Neutrophils, Monocytes/Macrophages

→ Synthesis of pro-inflammatroy mediators (Endogenous Pyrogen)

→ Endogenous Pyrogen (TNF, IL-1, IFN, IL-6):

Transport to brain vasculature via:

	• Active transport across blood-brain barrier

	• Passive transport through fenestrated capillaries in the circumventricular organs

CNS: Endogenous pyrogen induces synthesis of Prostaglandins (PGE2)

→ PGE2 stimulates cAMP in the hypothalamus

→ Elevates thermoregulatory set point

→ RIGORS



#Rigors #Bacteremia #Pathophysiology #InfectiousDiseases #Diagnosis