Systemic Effects of Inflammation PDF

Systemic Effects of Inflammation The systemic effects of inflammation, collectively called the acute-phase reaction, or the systemic inflammatory response syndrome The cytokines TNF, IL-1, and IL-6 are the most important mediators of the acute-phase reaction The acute-phase response consists of s...

Systemic Effects of Inflammation The systemic effects of inflammation, collectively called the acute-phase reaction, or the systemic inflammatory response syndrome The cytokines TNF, IL-1, and IL-6 are the most important mediators of the acute-phase reaction The acute-phase response consists of several clinical and pathologic changes:  Fever: characterized by an elevation of body temperature, the most prominent manifestations of the acute-phase response  Fever is produced in response to pyrogens that act by stimulating prostaglandin synthesis in the hypothalamus  Bacterial products, stimulate leukocytes to release cytokines (IL-1 and TNF) which increase the levels of cyclooxygenases that convert AA into prostaglandins  In the hypothalamus the prostaglandins, especially PGE2, stimulate the production of neurotransmitters, which function to reset the temperature set point at a higher level  Elevated plasma levels of acute-phase proteins: mostly synthesized in the liver  Three of the best known of these proteins are C- reactive protein (CRP), Fibrinogen, and Serum Amyloid A (SAA)  Synthesis of these molecules by hepatocytes is stimulated by cytokines, especially IL-6  Serial measurements of CRP are used to assess therapeutic responses in patients with inflammatory disorders such as rheumatoid arthritis  Elevated serum levels of CRP are now used as a marker for increased risk of myocardial infarction or stroke in patients with atherosclerotic vascular disease  Leukocytosis is a common feature of inflammatory reactions, especially those induced by bacterial infection  The leukocyte count usually climbs to 15,000 to 20,000 cells/mL  Neutrophilia most bacterial infections induce an increase in the blood neutrophil count  Lymphocytosis in viral infections, (infectious mononucleosis, mumps), are associated with increased numbers of lymphocytes  Eosinophilia (Bronchial asthma, and parasite infestations) involve an increase in the absolute number of eosinophils  Leukopenia (typhoid fever and infections by some viruses, and certain protozoa) are associated with a decreased number of circulating white cells  Other manifestations include increased heart rate, and blood pressure and decreased sweating  TNF can cause disseminated intravascular coagulation (DIC), metabolic disturbances including acidosis, and hypotensive shock  This clinical triad is described as septic shock