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
