Endocarditis: Causes

Pathogenesis (development of disease)

The following forms of endocarditis can be distinguished:

  • Abacterial endocarditis – caused by antibody reactions; e.g., endocarditis rheumatica.
  • Infective endocarditis – endocarditis caused by bacteria, viruses, fungi:
    • Acute endocarditis: mainly Staphylococcus aureus (about 45-65% of cases), streptococci (about 30% of cases) and enterococci (gram-negative bacteria from the HACEK group (H – Haemophilus aphrophilus and Haemophilus paraphrophilus, A – Aggregatibacter actinomycetemcomitans (prev. Actinobacillus actinomycetemcomitans), C – Cardiobacterium hominis, E – Eikenella corrodens, K – Kingella kingae), < 10% of cases; the pathogens are highly pathogenic and can also affect intact heart valves).
    • Subacute endocarditis (most common pathogen: Streptococcus viridans; the pathogen is weakly pathogenic, therefore usually affects only pre-damaged heart valves or prosthetic heart valves = subacute endocarditis lenta)
  • Mixed forms – in this case, an infective endocarditis grafted onto an abacterial infection.

In patients with infective endocarditis, infections with staphylococci (44% and enterococci (16% are most common; infections with orally transmitted streptococci (12%) are less common. Natural heart valves (57%) are more commonly affected than prosthetic heart valves (30%).

Bacterial endocarditis usually occurs in pre-damaged hearts. Bacteria circulating in the blood can lodge in the area of damaged endocardium and lead to infection.

Risk factors for bacterial endocarditis include:

Etiology (causes)

Disease-related causes

Cardiovascular system (I00-I99)

  • Endocarditis rheumatica
  • Endocarditis Libman-Sacks – form of endocarditis (endocarditis) occurring in visceral lupus erythematosus.
  • Endocarditis Löffler (endocarditis parietalis fibroplastica) – acute form of endocarditis (endocarditis), which affects mainly the right ventricle (heart chamber).
  • Endocardial myocardial fibrosis

Infectious and parasitic diseases (A00-B99).

Surgeries/invasive procedures

  • Bronchoscopy (pulmonary endoscopy) and blood transfusion: 5-fold increased relative risk (RR) of developing endocarditis in the next 12 weeks (relative risk, RR: 5.00 and 5.50, respectively). In the case of a
  • Bone marrow examination: increased 4-fold (RR: 4.33).
  • Coronary angiography (radiologic procedure that uses contrast agents to visualize the lumen (interior) of the coronary arteries (arteries that surround the heart in a wreath shape and supply blood to the heart muscle)) (RR: 4.75)
  • Dialysis (blood washing) (RR: 4.33)
  • Hemodiafiltration (extracorporeal blood purification procedure a combination of hemodialysis and hemofiltration) (RR: 4.00)

Other causes

  • I.v. drug addiction