Overview
Endocarditis is inflammation or a serious infection of the inner lining of the heart chambers and heart valves, known as the endocardium. It typically occurs when bacteria or other germs enter the bloodstream and attach to damaged areas of the heart. Though relatively rare, endocarditis can cause life-threatening complications if not treated promptly. It most often affects people with preexisting heart conditions or artificial heart valves.

Why It’s Important
Endocarditis can lead to heart valve damage, stroke, heart failure, or the spread of infection to other organs. Because the symptoms may appear gradually or mimic other illnesses, it can be easily overlooked, delaying diagnosis and increasing risk. Early detection and treatment are critical to avoid permanent heart damage or death.

Quick Facts

• Can affect all age groups, but higher risk in those with heart defects, prosthetic valves, or intravenous drug use

• Estimated incidence: 3–10 cases per 100,000 people per year

• Typically acute (sudden onset) or subacute (slower onset)

• Caused mostly by bacteria (especially Staphylococcus and Streptococcus), but fungi and other organisms can also be responsible

• Forms:

  • Native valve endocarditis

  • Prosthetic valve endocarditis

  • Intravenous drug use-related endocarditis

What Happens in the Body
When harmful bacteria or fungi enter the bloodstream—through dental procedures, surgeries, IV drug use, or infections—they can lodge in the heart, especially if there is existing damage or a foreign object (like a valve). This triggers inflammation and the formation of vegetations (clumps of organisms and immune cells) on heart valves, disrupting blood flow and potentially spreading infection or causing clots to break off and travel to other organs.

Common Signs and Symptoms

• Fever and chills

• Fatigue and weakness

• Heart murmur (new or changed)

• Shortness of breath

• Night sweats

• Swelling in feet, legs, or abdomen

• Tiny red or purple spots under nails or on the skin (petechiae)

• Painful red nodules on fingers or toes (Osler nodes)

• Painless spots on palms or soles (Janeway lesions)

Diagnosis

• Blood cultures to identify the organism

• Echocardiogram (especially transesophageal) to detect vegetations on valves

• Blood tests (inflammatory markers, anemia)

• Electrocardiogram (EKG) or chest X-ray as supporting tests

• See a doctor immediately if you have:

  • Persistent fever with heart problems or IV drug use

  • Sudden heart murmur or worsening shortness of breath

  • Signs of stroke or embolism (e.g., vision loss, pain in limbs, confusion)

Treatment and Management

• Hospitalization is often required

• High-dose IV antibiotics for 4–6 weeks

• Antifungals if caused by fungi

• Surgery may be needed to repair or replace damaged heart valves

• Good dental hygiene and antibiotic prophylaxis before certain procedures are important for prevention in high-risk individuals

• Recovery depends on how quickly it’s caught and the presence of complications

Risks and Complications

• Heart failure due to valve damage

• Stroke or other embolic events

• Abscesses in the heart or other organs

• Death, especially if untreated or in high-risk individuals

• Recurrent infections in people with ongoing risk factors

Who Is at Risk

• People with damaged or artificial heart valves

• Those with congenital heart defects

• IV drug users

• People with a history of endocarditis

• Individuals on long-term hemodialysis

• Recent dental or surgical procedures without appropriate precautions

Related Conditions

• Heart valve disease

• Congenital heart defects

• Sepsis

• Stroke

• Rheumatic heart disease

When to See a Doctor

• Unexplained fever lasting more than a few days, especially with a heart condition

• New or changed heart murmur

• Symptoms of infection, stroke, or heart failure

• History of heart valve disease or surgery and signs of illness

Last Updated: June 22, 2025