What is Endocarditis?

Endocarditis is a serious and potentially life-threatening infection of the inner lining of the heart chambers and valves, known as the endocardium. It typically occurs when bacteria or other pathogens enter the bloodstream and attach to damaged areas of the heart.

Infectious agents

The most common triggers are microorganisms such as:

  • Bacteria: Especially Streptococcus and Staphylococcus species

  • Fungi: Candida and Aspergillus (more common in immunocompromised patients)

  • Other pathogens: Rarely, viruses and other microbes

How pathogens enter the body

Microorganisms can access the bloodstream through:

  • Dental procedures or poor oral hygiene

  • Catheters or IV drug use

  • Skin infections or open wounds

  • Urinary tract or gastrointestinal procedures

Once in the bloodstream, they can lodge in heart tissue, especially where there’s prior damage.

Heart valve damage

One of the strongest risk factors is pre-existing damage to heart valves. Common conditions include:

  • Rheumatic heart disease

  • Congenital heart defects

  • History of heart valve surgery

  • Degenerative valve disease in older adults

Prosthetic heart valves

People with artificial heart valves are at much higher risk. Bacteria tend to adhere more easily to foreign materials in the heart.

Injection drug use

IV drug use is a major contributor to endocarditis. Contaminated needles introduce bacteria directly into the bloodstream, often leading to infection of the right side of the heart (tricuspid valve).

Poor dental hygiene

Poor oral health increases the risk of endocarditis. Everyday activities like brushing or flossing inflamed gums can allow bacteria to enter the blood.

Medical procedures

Certain procedures that involve mucous membranes or infected tissues can introduce pathogens:

  • Dental extractions

  • Endoscopy

  • Surgery on infected skin

  • Urinary catheterization

Antibiotic prophylaxis is often used in high-risk individuals undergoing such procedures.

Weakened immune system

People with compromised immunity—due to chemotherapy, HIV/AIDS, diabetes, or autoimmune diseases—are more vulnerable to infections like endocarditis.

Hospital-acquired infections

Nosocomial (hospital-acquired) endocarditis is increasingly common, especially among ICU patients with:

  • Central lines

  • Pacemakers

  • Frequent vascular access

Chronic conditions

Patients with diabetes, cancer, or chronic kidney disease face elevated risks due to:

  • Frequent hospital visits

  • Immunosuppression

  • Need for invasive treatments or dialysis

Congenital heart defects

Even minor congenital defects like ventricular septal defect (VSD) can increase the risk by creating turbulent blood flow that damages the endocardium, making it easier for bacteria to settle.

Gender and age

Men are more commonly affected than women. Most cases occur in adults over age 60, particularly those with degenerative heart conditions or prosthetic valves.

Cancer treatments

Chemotherapy and radiation weaken the immune system, increasing the chances of opportunistic infections like fungal endocarditis, especially in patients with indwelling catheters.

Genetic and rare disorders

Although rare, certain genetic syndromes or blood disorders may predispose individuals to bacterial infections or abnormal heart structures, indirectly raising endocarditis risk.

Multiple risk factors

Often, endocarditis results from a combination of triggers. For example, an elderly person with a prosthetic valve and diabetes undergoing dental surgery would be at especially high risk.

How to reduce your risk

Prevention focuses on:

  • Maintaining good oral hygiene

  • Avoiding IV drug use

  • Managing chronic diseases

  • Informing healthcare providers if you have heart valve issues

  • Using antibiotics prophylactically when recommended

When to seek help

Warning signs include:

  • Persistent fever

  • Fatigue

  • Unexplained weight loss

  • Night sweats

  • New or changing heart murmurs

Early diagnosis and treatment are critical to prevent complications like valve damage, stroke, or death.

Conclusion

Understanding what causes endocarditis helps in identifying and minimizing your risk. While not all cases are preventable, being aware of the triggers and seeking early medical care can save lives.