Bacteraemic infection
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- Created by: z
- Created on: 04-03-16 19:24
Bacteraemia
septicaemia/bacteraemia is not a diagnosis- must think of pathway to blood e.g.
- catheter (trauma to urethral vessels)
- IV or art lines
- Ventilation
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Aetiology of bacteraemic infection
- Precipitating agent, e.g.
- Endo toxin
- Toxic shock syndrome toxin (S. aureus)
- Erythrogenic toxin (group A strep)
- cell wall of gram +ve bacteria
- causes action in:
- activation of complement
- neutrophils, monocytes, cytokines (e.g. TNF, IL-1)
- endothelial cells
- which results in:
- capillary leak (albumin may leave vessels, thus H2O follows > oedema, esp pulm)
- fever
- DIC
- And ultimately
- Shock (AKI= early sign)
- Multiple organ failure
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Signs associated with bacteraemia
- Non blanching rash- DIC
- Ischaemia of peripheries
- Ascites
- +/- Grey-Turner’s sign
- In acute pancreatitis- bruising of flanks due to leakage of pancreatic secretions into paracolic gutters in
- +/- Cullen’s sign
- Bruising around umbilicus
- +/- Grey-Turner’s sign
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Transient bacteraemia
- Common after many events- not necessarily dangerous
- 30-80% of dental extractions commonly Streptococci, diphtheroids, S. epidermidis
- 40% of tonsillectomies – Streptococci, Haemophilus, diphtheroids
- 15% of bronchoscopies – streptococci, S. epidermidids, aerobic gram –ve rods
- 10% upper GI endoscopy – streptococci, s. epidermidis, diphtheroids, Neisseria
- 2-10% colonoscopy – aerobic gram –ve rods, streptococci, Bacteroides
- 10-36% urethral dilation – gram –ve rods, diphtheroids, streptococci
- 5% partutition – aerobic gram –ve rods, streptococci
- NB aerobic gram –ve bacilli= Pseudomonas (aeruginosa), B. pertussis, legionella, E.coli (coliform), Klebsiella pneumoniae (coliform)
- coliform= ferment lactose
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Bacteraemia: clinical
- Presentation
- Fever, rigors, shock
- Potentially w/ sympt from original source e.g. cough, sputum
- Diagnosis
- Isolate organisms form blood cultures
- Take multiple samples- greatly incr chance of isolating causal organism
- NB esp in infective endocarditis, many causes are also normal skin flora, thus difficult to differentiate b/w pathogen and contaminants from venepuncture
- VITAL- fluorescence reduced if: decr O2, incr CO2 or decr pH= signs that bacteria present
- Management
- Reverse shock w/ IV fluids
- IV high dose ab (broad spectrum if unknown)
- NO role for corticosteroids
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Aetiology of clinically significant bacteraemia
- E. coli: HA=CA – 29%
- S. aureus: HA >CA, 2:1 – 19% (ventilator)
- S. pneumoniae: CA>HA, 10:1 – 13% (pneumonia)
- Klebsiella: HA>CA, 3:1 – 7% (catheter/ventilator)
- Pseudomona aeruginosa: HA>CA, 10:1
- Viridans streptococci: CA>HA, 3:1
- Coagulase-negative staphyloccic: HA>CA, 20:1 (IV lines in neutropenic pts)
- Misc:19%
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Aetiology of infective endocarditis
- Native valve (e.g. bicuspid valve/RHF)
- A-haemolytic streptococci – 30%
- S. aureus – 30%
- Enterococci – 10%
- IVDU (normally easy to treat)
- S. aureus – 55%
- W/in 1 year of surgery (mainly SSIs)
- Coagulase –ve staphylococci – 55%
- > 1 yr post-surgery (basically the same as native valve b/c becomes endothelised)
- A-haemolytic streptococci – 30%
- S. aureus – 15%
- Enterococci – 10%
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Symptoms of infective endocarditis
- Fever – 90%
- Malaise – 60%
- Weight loss – 60%
- Anorexia – 50%
- Weakness – 50%
- Sweats – 30%
- Myalgia/arthralgia – 15%
- Back pain – 10%
- Confusion – 10%
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Signs of infective endocarditis
- Pyrexia – 90%
- Murmur – 85%
- Embolic event – 35%
- Splenomegaly – 25-50%
- Stroke – 20%
- Septic complications – 20%
- Retinal lesion – <5%
- Peripheral signs
- Petchiae – 25%
- Osler’s nodes – 10%
- Janeway lesions – 5-10%
NB FOU- if no history of travel, think IE
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Management of bacteraemia
- Supportive therapy
- Fluids (colloids, saline)
- Inotropes (e.g .dobutamine w. monitoring)
- Organ support (ventilation, haemofiltration)
- Removal of infective focus
- Abscess drainage
- Removal of infected catheter
- Wound debridement
- Antibiotics
- Initially IV and high dose
- Broad spectrum if unknown aetiology and focus not able to remove e.g. cefotaxime + metronidazole in intra-abdominal sepsis, meropenem
- Narrow spectrum if organism know e.g. fluclox for s.aureus
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