L8 - Heart & Circulatory system Flashcards
Definition of Bacteraemia?
mere PRESENCE of bacteria in the blood
Definition of Septicaemia?
Presence of bacteria in the blood that causes CLINICAL SYMPTOMS
What were the main causative bacteria of Septicaemia before WWII?
pyogenic cocci - strep, staph
What were the main causative bacteria of septicaemia after introducing antibiotics?
Gram-neg rods
What are the main causative bacteria of septicaemia today?
Gram-pos, Gram-neg
Candida albicans
Why is it that streptocci do not cause septicaemia as much but staphylocci still do?
Strep are susceptible to antibiotics still
How can septicaemia occur?
haemotogenous spread - infection at other site
intraluminal spread - through CVC
extraluminal spread - break in skin
What is the Plague caused by?
Yersinia pestis
gram-neg bacillus
How is the Plague transmitted?
Droplets
contact
faecal-oral
vector
BLACK RATS
2 diff. types of plagye?
bubonic
pneumonic
What bacteria are newborn babies vulnerable to that can cause septicaemia?
L. monocytogenes
Group b streptococcus
What bacteria are immunosuppressed people vulnerable to that can cause septicaemia?
P. aeruginose
Stenotrophomonas maltophilia
Acinetobacter spp.
What is endotoxic shock?
Lipid A - vasodilation - hypotension ‘warm shock’
vessels constrict - ‘cold shock’
disseminated intravascular coagulation (DIC)
What bacteria is endotoxic shock caused by?
Gram-neg bacteria that cause septicaemia
what is toxic shock syndrome caused by?
TSST-1 toxin of S.aureus
What happens during TSS?
non-specific binding of MHC II with T cell receptors for TSST-1
cytokine storm
How is septicaemia diagnosed in the lab?
BacT/ALERT system
blood cultures - 3 draws from diff. sites
colourimetric detection
what is the antimicrobial treatment of septicaemia?
empirical therapy - aminoglycoside * B-lactam + metronidazole
What is infective endocarditis?
infection of endocardial surface of the heart
golden ‘vegetation’ lumps
What are vegetations (endocarditis)?
damaged valves = disturbance in blood flow
microcolonies deposit fibrin
growing vegetations = friable - break off and block other vessels
What is ‘early’ prosthetic valve endocarditis?
<1 after valve replacement
contamination
S. aureus
diptheroids
coag-neg staph
What is ‘late’ prosthetic valve endocarditis?
> 1 after valve replacement
endogenous infections
‘viridans streptococci’
Enterococci
coag-neg staph
What is native valve endocarditis?
rare
seen in i.v. drug users
tricuspid valve infected
How is endocarditis diagnosed?
Modified Duke critera
What are the ‘major’ requirements for the Duke criteria?
2x blood cultures positive for organisms known to cause IE
Echocardiogram positive for IE
What are the ‘minor’ requirements for the Duke criteria?
predisposing factors
fever
vascular phenomena (Janeway lesions)
immunologic phenomena (Roth’s spots)
microbial evidence
What are the 3 allowed criteria for the Duke criteria?
2 major
1 major, 3 minor
5 minor
What is a mycotic aneurysm?
damage of arterial wall
bulging
What is suppurative thrombophlebitis?
inflammation of vein wall
clots
common with IV catheter
