L19 - Bloodstream Infections & Serious Sepsis Flashcards
Define sepsis
A systemic inflammatory response to inflammation caused by microbial invasion of normally sterile parts of the body
What is the clinical definition of sepsis?
Clinical suspicion/evidence of infection + evidence of a systemic response - 2 or more of: Temp >38 OR <36 HR >90 RR >20 OR pCO2 <4.2kPa WBC >12*10^9/L OR <4*10^9/L
What are the systemic symptoms that may suggest sepsis?
Temp >38 OR <36
HR >90
RR >20 OR pCO2 <4.2kPa
WBC >1210^9/L OR <410^9/L
Define severe sepsis
Sepsis with organ dysfunction Hypotension (Sys <90mmHg) Lactic acidosis Oliguria Confusion Liver dysfunction
What is the mortality of severe sepsis?
30-50%
Define septic shock
Severe sepsis w/ hypotension despite adequate fluid resuscitation
What is the mortality of septic shock?
50-60%
Define bacteraemia
Presence of micro-organisms in bloodstream
Define septicaemia
Bacteraemia AND sepsis
Describe the pathogenesis of sepsis
Bacteria release endotoxins (G-) or exotoxins (G+)
Activates macrophages
Release of inflammatory mediators
Endothelial damage - Extravasation of fluid, decreased BV/albumin, DIC
Poor tissue perfusion + poor lung function
Define SIRS
Systemic Inflammatory Response Syndrome
What non-infective causes are there of SIRS?
Trauma Burns Haemorrhage Pancreatitis Toxins (Cytokine release key)
What are the principle pathogens causing Sepsis? - Community
Escherichia coli Strep. pneumoniae Staph. aureus Neisseria. meningitidis Streptococci, Gram- bacilli
What are the principle pathogens causing Sepsis? - Hospital
S. aureus E. coli Klebsiella spp. Coag- staph Pseudomonas aeruginosa Candida spp.
What are the common syndromes leading to Community-acquired Sepsis?
UTI/Pyelonephritis Pneumonia Meningitis Skin/soft tissue infections Intra-abdominal sepsis Infective endocarditis Bone/Joint infection
Describe infective endocarditis
Infection of the cardiac endothelium (valves)
High morbidity/mortality
What are the risk factors for endocarditis?
Damage to heart tissue: Valvular heart disease i.v. drug use Central venous lines Prosthetic heart valves Implantable cardiac devices
What are the causative organisms of endocarditis?
S. aureus Viridans streptococci Enterococci HACEK organisms Coag- staph (PVE)
How does infective endocarditis present?
Typically w/ new murmur and febrile illness
Echogardiography shows vegetations
How is infective endocarditis diagnosed?
Multiple blood cultures
IE causes continuous bacteraemia
What is the treatment for infective endocarditis?
High dose, targeted i.v. antibiotics
Surgery
What are the main sources of Hospital Acquired Sepsis?
Lines (peripheral/central) Urinary catheters LRTIs Wound infections Abdominal sepsis Instrumentation (ERCP/TURP)
What are the clinical signs for diagnosis of sepsis?
Temp >38 or <36 Rigors Tachycardia Hypotension (early in Gram-) Hypoxia, Oliguria (later) Physical signs of source/organism
What laboratory tests should be performed when diagnosing sepsis?
FBC
Clotting tests
CRP (inflammation)
Lactate (>4 suggests poor prognosis)
What microbiology tests should be performed when diagnosing sepsis?
2 Blood cultures Urine Samples from specific sites: Pus CSF Joint Aspirate Sputum
What is the management of Sepsis?
ABC - Oxygen/Fluid resuscitation Mechanical ventilation, vasopressors Monitor hourly urine output (AKI) Antibiotic to cover likely organisms (w/i 1 hour admission) Source control
What is a good starting antibiotic for sepsis?
Tazocin (Piperacillin/Tazobactam)
What guides antibiotic therapy in treating Sepsis?
Likely source Previous microbiology Sensitivity results Severity Underlying disease/immunity
What are the risk factors for resistant organisms?
Prev. isolation of organism Frequent admissions Prolonged stay on ICU Hospital stay overseas Nursing home resident Prev. antibiotic use
What treatment should be given when treating resistant bacterial strains?
i.v. Vancomycin
What steps should be taken when following up after sepsis?
Review to determine source Potential for recurrence Consideration of endovascular focus (continuous bacteraemia) Review CRP/ESR response Monitor renal/liver function
