Causes of Endocarditis
The causes of endocarditis centre on how infectious organisms—usually bacteria—enter the bloodstream and infect the heart. Endocarditis typically occurs when these bacteria attach to areas of the heart lining or valves that are already damaged or abnormal.
Common Entry Points for Bacteria
Dental procedures or poor oral hygiene, which allow mouth bacteria to enter the blood
Infected skin wounds or pressure sores
Use of intravenous drugs, which introduces unsterile substances directly into veins
Catheters, intravenous lines, or implanted medical devices
Urinary tract infections or surgical procedures involving the bladder or intestines
Unsterile medical equipment in settings with poor infection control
Once in the bloodstream, bacteria such as Staphylococcus aureus, Streptococcus viridans, or Enterococcus species may reach the heart. They can settle on heart valves, especially if the valves are already scarred or prosthetic. These bacteria then form vegetations—clumps of germs and damaged tissue—that interfere with normal valve function and may break off and travel to other organs.
Risk Factors
People at highest risk for endocarditis include:
Those with artificial heart valves
People with congenital heart defects
Individuals with a previous history of endocarditis
People with rheumatic heart disease, which remains a concern in South Africa
Patients undergoing hemodialysis
People who inject drugs
Individuals with HIV, especially if immunity is compromised
Causes of Endocarditis
Fungal endocarditis, although less common, can occur in immunocompromised individuals or after long-term antibiotic use. It is more difficult to treat and often requires surgery.
In South Africa, the burden of untreated dental infections, poor access to safe medical equipment, and high rates of HIV and rheumatic fever contribute to a greater risk of endocarditis in rural and underserved populations.
Understanding the causes of endocarditis helps identify who needs preventive care and allows for early intervention when symptoms arise. Prevention strategies include good oral hygiene, sterile medical procedures, and targeted antibiotic use before certain surgeries.
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