Septic Shock

[liveonearth]

--can occur dt gram pos or neg infx
--was the #1 cause of death in intensive care units
--was the 13th most common cause of death in US in 1990
--wonder if these are still close to true
--mortality rate is very high, up to 40% of pts die even with intensive care and antibiotics
--in 1/3 of cases the original site of infection is not identified
--10-15% increase in mortality if antibiotic tx is delayed
--Sx: alteration in body temp (usu up but can go down), incr WBCs, HR and RR
--TX: ABX, fluids to support BP (isotonic saline), drugs to support BP (epi, norepi), hydrocortisone
--NSAIDS don't help
--bacteremia = bacteria in the blood, occurs after tooth brushing transiently
--sepsis = systemic immune response to bacteremia
septic shock = drop in blood pressure and organ dysfx from systemic infection, aka endotoxic shock
but can also be triggered by gram + and fungi so septic shock more appropriate term

HOW INFECTION KILLS
local infection-->orgs release endo or exo toxin that circs in blood-->immune system activated
local may-->systemic
immune cells release cytokines = endogenous mediators of sepsis
most imp cytokine: TNF aka tissue necrosis factor aka cachectin bcs released from tumors)
TNF-->wasting, hypotension, death, also triggers IL-1 from macrophages
TNF-->IL-->more cytokines & prostaglandins-->vasodilation, hypotensions, lung problems
if kidneys fail add 15-20% to mortality rate

ENDOTOXIN
= lipid A
in outer membrane LPS of gram negative bacteria
LPS = lipopolysaccharide
LISTERIA is the only gram + bacteria that has endotoxin
released when bact lyses
shed from living bact steadily
treatment can cause shock if it kills a lot of bacteria all at once
not same as exotoxin

EXOTOXIN
mb neurotoxin (tetanus, botulinum) or enterotoxin (osmotic D dt inhib NaCl in, active NaCl out)
mb pyrogenic (staph, strep) or tissue invasive or other
from all gram + except listeria which makes endotox
also from Vibrio, E.Coli, Campy, Shig in diarrhea
Staph a and Strep p in fever/rash/TSS

SOME BUGS WITH ENDOTOXIN ??? this list incomplete
Listeria
Vibrio cholerae (choleragen-->death by dehydration)
E.coli (heat labile toxin sim to choleragen)
Campylobacter jejuni (same as e.coli)
Bacillus cereus (same as campy)
Shigella dysenteriae (shiga toxin-->bloody D, mb HUS)