Infective Endocarditis

exp date isn't null, but text field is

This is an infection of the heart valves and lining of the heart chambers by microorganisms.

Causes

It is classified into 3 types:

  • Sub-acute endocarditis: caused by low virulence organisms such as Streptococcus viridans and enterococcus; occurs on damaged heart valves
  • Acute endocarditis: caused by common pyogenic organisms such as Staphylococcus aureus; occurs usually normal heart valves.
  • Post-operative endocarditis: following cardiac surgery and prosthetic heart valve placement. The most common organism involved is Staphylococcus aureus

Risk Factors

  • Rheumatic heart disease
  • Congenital heart disease
  • Prosthetic valve
  • Invasive dental/diagnostic/surgical procedures (including cardiac catheterization)
  • Immunosuppression
  • Intravenous drug abuse

Signs and symptoms

  • Acute:
  • High fever with rigors
  • Delirium
  • Shock
  • Development of new murmurs
  • Severe cardiac failure
  • Abscesses may form in many parts of the body (e.g. brain)

Subacute:

  • Low-grade fever
  • Signs of carditis
  • Finger clubbing
  • Arthralgia
  • Splenonegaly
  • Osler's nodules
  • Janeway lesions
  • Roth spots
  • Fatigue
  • Weight loss

Complications

  • Cardiac failure
  • Myocardial abscess
  • Solid organ damage from emboli
  • Septi
  • Glomerulonephritis

Differential diagnosis

  • Myocarditis
  • Rheumatic heart disease

Investigation

  • Full blood count and differentials
  • ESR
  • Urinalysis and microscopy
  • Blood cultures X 3 (the yield is higher if blood is taken at the time of pyrexia)
  • Echocardiography

Treatment objectives

  • Stop the infection
  • Treat cardiac failure
  • Prevent coagulation disorders 

Non-pharmacological treatment

  • Bed rest
  • Low salt diet

Pharmacological treatment

Benzylpenicillin 7.2 g daily by slow IV injection or IV infusion in 6 divided doses for 4-6 weeks; may be increased up to 14.4 g daily if necessary

PLUS

Gentamicin 60-80mg intravenously or intramuscularly every 8 hours for 2 weeks

Following bacteriological confirmation institute appropriate antimicrobial therapy

Staphylococci:

Flucloxacillin IV

250 mg-2 g intravenously every 6 hours for 4-6 weeks

Vancomycin IV

1 gm intravenously every 12 hours

Gentamicin IV

60-80 mg intravenously every 12 hours for 2 weeks

Enterococci:

Amoxicillin IV

2 gm intravenously every 4 hours

Gentamicin IV

60-80 mg intravenously every 12 hours

Candida: Systemic antifungals

Prevention

Prophylactic antibiotics for patients at risk who are undergoing:

  • Dental procedures
  • Genito-urinary tract manipulation
  • Obstetric, gynaecological, and gastrointestinal procedures