Micro U2 L1. Flashcards
What is the leading cause of death in patients admitted to non coronary intensive care units
blood stream infections
What is the incidence of severe sepsis in America?
300/100,000 people
What is the mortality rate of severe sepsis? In the ICU specifically?
28-50%; 80% in the ICU
Infection
presence of microorganisms in a normally sterile site
Bacteremia
cultivatable bacteria in blood stream (may be transient and inconsequential; inconsistent correlation with severe sepsis)
Systemic inflammatory response syndrome (SIRS)
systemic response to a stress. includes two of the following: 1. temp >38, 90; 3. RR >20 or PaC02 12,000 cells/mm3 or 10% immature band forms
Sepsis
systemic response to infection. in US: if you have proven or clinically suspected infection, SIRS becomes sepsis
Hypotension
systolic 40 from baseline (must have no other cause to be septic related)
Severe sepsis
sepsis with associated dysfunction of organs distant from site of infection, hypoperfusion, or hypotension
Septic shock
sepsis with hypotension despite adequate fluid resuscitation requires vasopressor therapy - perfusion abnormalities that may include lactic acidosis, oliguria, altered mental status, acute lung injury
Is SIRS a normal response by the body?
NO - an ABNORMAL generalized inflammatory reaction in organs remote from the initial insult
TLR4
plays a critical role in mediating SIRS and its severity - transmits the LPS recognition signal to the interior of the cell which then lead to signal transduction - promote production and secretion of molecules mediating the inflammatory response
LPS
major component of cell wall of gram-negative bacteria - recognized by TLR4
What recognizes gram + cells?
TLR2
How can signaling through TLR4 be altered?
variation in # of alkyl chains in lipid A (reduced # = inhibitor of immune activation by gram - ) - bacteria can change # acyl chains in response to environment
What are indicators of septic shock?
APC (modulator of coagulation and inflammation - interferes with plasminogen activation) and Antithrombin
When does septic shock occur?
in the presence of both SIRS and infection (SIRS can occur without infection due to trauma, burns, pancreatitis, etc)
Transient bacteremia
comes from tooth brushing, biopsy (comes quick and then is cleared)
Intermittent bacteremia
comes from abscess, UTI, pneumonia - MOST COMMON for septic patients!! - clearance and recurrence cycle
Persistent/sustained bacteremia
intravascular
Infective endocarditis pathogenesis
damage to cardia endothelium -> deposition of platelets and fibrin -> organisms gain access to bloodstream and stick = colonization -> protective layer of fibrin and platelets matrix -> bacterial multiplication -> vegetation formation
What are organisms associated with endocarditis?
staph aureus, followed by strep, then coagulase negative staph
Who is at a high risk of developing IE?
IV drug abusers
Mycotic aneurysm
result from damage to endothelial cells lining the arteries (aneurysm due to an infectious agent)
Supprative thrombophlebitis
venous thrombosis associated with inflammation in the setting of bacteremia (need to remove intravenous catheters every 3 days to avoid this happening)
Catheter associated bloodstream infections
indwelling catheter becomes colonized with bacteria - associated with staph and candida species
What is a primary BSI? What are the primary BSIs?
primary BSI: BSI without a documented primary source of infection and source is from an intravascular site. Includes: infective endocarditis, myotic aneurysm, supprative thrombophlebitis, catheter associated bloodstream infections
What is a secondary BSI? What are the secondary BSIs?
there is a documented portal of entry and/or a known associated site of infection. Includes UTIs, bacterial pneumonias, post surgical wound infections
How is bacteremia detected?
culturing of blood
What are consideration for blood cultures?
need 3 blood cultures sets over 24 hours - 20 mL total to be take (10 mL in aerobic bottle and 10 for anaerobic bottle) - usually takes 48 hours to detect - some weird ones can take 5 days
What test can differentiate between infectious SIRS from noninfectious SIRS?
high procalcitonin level (>2 ng/mL)
