Pathogenesis of Sepsis and antibiotics Flashcards
What is septic shock?
Sepsis with acute or refractory hypotension or tissue hypoperfusion despite fluid resuscitation
SIRS temperature?
> 38 or <36
SIRS RR?
or SIRS PaCO2?
> or equal to 20/min
or < 32 mmHg (normal: 38-42)
SIRS WBC?
12,000/ul or over
or 4,000/ul or under
or >10% immature forms
What is sepsis?
At least two SIRS criteria caused by an infection (known or suspected)
What is LPS?
An endotoxin secreted by gram negative bacteria
What is the most common cause of shock from gram negatives?
LPS
What is the most common cause of shock from gram positives?
Lipoteichoic acid
Direct cause of shock by microbe?
Interaction with the vascular endothelium
Common producers of super antigens?
S. aureus Streptococcus pyrogenese (group A strep)
What does a superantigen do?
Directly attach to MHC class II and TCR causing faster and prolonged response
What effect of sepsis causes tissue hypo-perfusion
Increased coagulation, loss of red cell deformability, decrease in BP (leaky vessels)
G -ve causes of shock?
E. coli
Meningococci
Pseudomonas
Haemophilus
G +ve causes of shock?
Staph aureus
Group A streptococci
Strep pneumoniae
Clostridium spp.
Causes of neonatal shock?
Group B streptococci
Listeria
E. coli
What does strep pneumoniae cause?
Pneumonia and meningitis
What fungus is common in the immunosuppressed?
Aspergilus
Common bacteraemias:
S. aureus (+)
Enterococcus (+)
Strep pneumoniae (+)
E. coli (-)
Klebsiella (-)
Pseudomonas (-)
Most common cause of g -ve septicaemia in hospital?
UTI with pyelonephritis
Hospital cause of septicaemia?
IV catheters and devices
Differentials for septic shock
Burns or trauma Pancreatitis PE (resembles pneumonia) Ruptured AAA, bleed, MI, tamponade Overdose Adrenal insufficiency Anaphylaxis
Management of sepsis?
Fluids Dopamine Transfusion (ICU) Solve precipitating problem Anti-biotics
Monitor what in sepsis?
ABG Renal function (U+E's) CNS Glasgow coma score (GCS) LFTs Myocardial function
Sepsis 6:
1: Administer high flow O2
2: Blood cultures
3: Broad spectrum anti-biotics
4: IV fluid challenges
5: Measure serum lactate and Hb
6: Measure hourly urine output
When do should IV abx have begun?
Within the first hour of admission
Consider what in neutropenic patients?
Combination empiric therapy
What is de-escalation?
Going from broad spectrum antibiotics to narrow
Carry out once cultures come back
Examples of beta-lactams:
Penicillins, cephalosporins and carbapenems (ertapenem, meropenem)
Glycopeptide Abx:
Vancomycin
Teicoplanin
What are glycopeptide Abx used for?
G +ve
MRSA
Coagulase -ve staphylococcus
Bactericidal vs bacteriostatic:
Kill vs stop growth
-mycin =
Macrolide (bacteriostatic)
When might a macrolide be used?
Penicillin allergy against staph and strep e.g. skin/throat
Atypical pneumonia
-cycline
Tetracycline (bacteriostatic, broad spec)
When might a tetracycline be used?
Respiratory and soft tissue atypicals e.g. legionella and mycoplasma
Tigecycline is effective against?
G +ve
G -ve
Anaerobes
Aminoglycosides are used for what?
G -ve
Synergy with penicillins against strep and others
Used for serious sepsis
Potential complication of macrolide use? (except tobramycin)
Nephrotoxicity
CN VII toxicity
Penicillins ordered from broad (top) to specific (bottom):
Tazobactam Co-amoxicillin Amoxicillin Penicillin V PO
Function of quinolones?
Prevents DNA synthesis
-oxacin
Quinolone
Examples of quinolones:
Ciprofloxacin
Levofloxacin
Maxifloxacin
Use for trimethoprim?
UTI
Potential complications of trimethoprim and co-trimoxazole?
Interfere with folate G +ve side effects G -ve side effects Stevens-Johnson syndrome Bone marrow suppression/aplasia
In which situations do abx not help the patient get better quicker?
Comylobacter
Acute bacterial sinusitis
Treatment for:
CAI and shock
Origin unknown/gut/renal/biliary
Co-amoxiclav + gentamicin (+vancomycin if MRSA)
or cefuroxime + metronidazole + gentamicin
or ciprofloxacin + metronidazole + gentamicin
Treatment for:
CAI and shock
Origin skin/soft tissue
Flucoxacillin + penicillin/amoxicillin +/- gentamicin
consider adding clyndamicin if group A strep or staph. aureus - risk of toxic shock
Treatment for:
CAI and shock
Pneumonia
co-amoxiclav + doxycycline
or cefuroxime + erythromycin
Treatment for:
CAI and shock
Meningococcal disease
Penicillin or ceftriaxone
Treatment for:
CAI and shock
Malaria
Quinine
Penicillin allergy (rash only)
Consider using penicillin or cephalosporin depending on the allergy
Penicillin allergy (severe i.e. anaphylaxis)
Ciprofloxacin, vancomycin, eryhthromycin (get advice)
No beta-lactams at all
HAI vs CAI
For HAI you have to go more broad spectrum
Early HAI abx
Same as CAI
Late HAI abx
Broad
Gentamicin + Tazocin
(maybe meropenem or colistin as resistance that bad)
MRSA abx:
Vancomycin
VRE
Linezolid