Endovascular infection of cardiovascular structures, usually involving the cardiac valves

Aetiology

• Usually the consequence of two factors: the presence of organisms in the bloodstream, and abnormal cardiac endothelium that facilitates their adherence and growth

Risk factors

• Abnormal cardiac endothelium:
  • Previous rheumatic heart disease
  • Congenital heart disease
  • Age related valvular degeneration
  • Prosthetic heart valve
• Organisms in the bloodstream:
  • PWID
  • ICED
  • Intravascular lines
  • Septicaemia
  • Poor dentition and dental infections
• Others:
  • Age > 60 years
  • Male sex

Causative organisms

• Staph. aureus is the most common cause of acute IE for all groups
• Strep. viridans is the most common cause of subacute IE, especially in pre-damaged native valves
• Staph. epidermidis commonly causes IE in patients with prosthetic valves
  • Infection can be early (at time of valve insertion) or late (up to many years after valve insertion, due to co-incidental bacteraemia, many causative organisms)
• Candida and Staph. aureus common in PWID
  • Right sided valves usually affected, especially tricuspid
• Atypicals:
  • Coxiella burneti - farming, aortic valve, lifelong antibiotic therapy may be required
  • HACEK bacteria - associated with poor dental hygiene
  • Brucella - goats
  • Fungi - immune-compromised, PWID, IV lines

Clinical features

Acute

• Overwhelming sepsis and failure
• Usually due to aggressive organisms e.g. Staph. aureus

Subacute

Symptoms

• Fever