24: Infections of the cardiovascular system

Chapter 24 Infections of the cardiovascular system

In health, the cardiovascular system is sterile, but a few organisms may enter the blood stream (even in health) during routine procedures such as tooth-brushing, especially in the presence of periodontitis. However, these bacteria have only a transient existence as the efficient defences of the blood quickly destroy them.

Bacteraemia, septicaemia and sepsis syndrome

Septicaemia and sepsis syndrome

Aetiology

Some common predisposing factors and agents that cause septicaemia are shown in Table 24.1.

Table 24.1 Some common predisposing factors and agents of septicaemia

Predisposing factor Agent
Abdominal sepsis Enterobacteria
Bacteroides fragilis
Enterococcus faecalis
Infected wounds, burns Staphylococcus aureus
Streptococcus pyogenes
Enterobacteria
Osteomyelitis Staphylococcus aureus
Pneumonia Streptococcus pneumoniae
Intravascular devices Staphylococcus aureus
Staphylococcus epidermidis
Enterobacteria
Food poisoning Salmonella spp.
Campylobacter spp.
Meningitis Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae
Immunosuppressed patients Enterobacteria
Staphylococcus aureus, etc.

Infections of the heart

Important pathogens that cause pericarditis, myocarditis and endocarditis are shown in Figure 24.1. Of these, infective endocarditis is the most important disease of relevance to dentistry.

Infective endocarditis

Microbial aetiology

Bacteria are predominantly involved, although other organisms, such as fungi, rickettsiae and chlamydiae, may occasionally cause endocarditis (Table 24.2). More than 80% of infective endocarditis is caused by streptococci and staphylococci. The position held by the viridans group of organisms in the league table indicates the major role played by the oral commensals in causing this life-threatening disease. It is noteworthy that nearly all patients with viridans endocarditis have a previous heart lesion, and about a quarter give a history of a recent dental procedure as a precipitating factor.

Table 24.2 Causative microorganisms in infective endocarditis

Microorganisms Cases (%)
Total streptococci 60
Viridans group 35
Enterococcus faecalis 13
Microaerophilic streptococci 3
Anaerobic streptococci 2
Others 7
Total staphylococci 25
Staphylococcus aureus 20
Staphylococcus epidermidis 5
Miscellaneous 5
Culture-negative 10

(cumulative data from several sources)

Jan 4, 2015 | Posted by in General Dentistry | Comments Off on 24: Infections of the cardiovascular system
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