Sepsis and Infective Endocarditis Flashcards
What can presence or growth of a pathogen within the blood lead to?
Bacteraemia
Parasitaemia
Viraemia
Fungaemia
How do pathogens cause sepsis?
Access is via medical or dental procedures or through infection of tissues from stabbing, bites and lungs - Extravascular infection
Ultimate outcome may be sepsis and death from intravascular infection
How can Streptococci cause bacteraemia?
After dental work, oral streptococci can enter the blood as an occult bacteraemia and set up infection in damaged heart valves, resulting in endocarditis
How can Streptococcus pneumoniae cause bacteraemia?
Streptococcus pneumoniae causes bacterial pneumonia, which can result in transient bacteraemia.
A microbial liver abscess, resulting from a source such as the appendix abscess may result in bacteraemia.
An appendix abscess can result in bowel organisms entering the portal vein and can cause a liver abcess
How can group A streptococcus cause bacteraemia?
Group A streptococcus causes cellulitis which can give rise to bacteraemia
Group A streptococci can also cause necrotising fasciitis which can give rise to bacteraemia
How can Neisseria meninigitidis cause bacteraemia?
Neisseria meninigitidis colonises the oropharynx of many individuals.
In certain cases can invade the blood causing sepsis and then invades the meninges to cause meningitis
How can Coagulase-negative staphylococci cause bacteraemia?
Coagulase-negative staphylococci can colonise long-term plastic central-lines giving rise to bacteraemia.
Coagulase-negative staphylococci can also infect heart valves in bacterial endocarditis, giving rise to continuous bacteraemia
How can E. coli cause bacteraemia?
E. coli can cause nephritis. The bacteria can then enter the blood to produce a transient bacteraemia and septic shock may be initiated
What are intravascular infections?
Damage to the cardiovascular system results from infection of the blood.
Give example of intravascular infections
Thrombophlebitis - infection in the veins
Endoarteritis - infection of the arteries
Endocarditis (infectious endocarditis) - infection of the heart particularly the valves
All conditions cause shedding of organisms into the blood
What are the symptoms of intravascular infections?
Persistent low grade fevers are characteristic
Can be fatal if untreated
What are the predisposing factors for sepsis?
Hospitalisation Splenectomy Age and Sex Cancers – haematological and solid tumours Diabetes Pulmonary disease Renal disease – any catheterisation Neutropenia
What are the most common bacteria to cause sepsis (90% of cases)?
Haemophilus influenzae type B Neisseria meningitidis Streptococcus pneumoniae Brucella Salmonella enterica serovar Typhi Listeria
What conditions are caused by presence of pathogens or products of pathogens in the blood or tissues?
Sepsis
Septic shock
Toxic shock
