Introduction
Infective endocarditis is an infection of the heart’s inner lining (endocardium), most often involving one or more heart valves. Bacteria—or less often fungi or other microbes—enter the bloodstream, stick to damaged or abnormal valve surfaces, and form vegetations made of platelets, fibrin, and organisms.
Anyone can develop it, but risk is higher with pre-existing valve disease, congenital heart defects, prosthetic valves, prior endocarditis, intravenous drug use, or weakened immunity. Vegetations can impair valve function, seed emboli to the brain or other organs, and cause life-threatening complications.
Symptoms may start gradually or suddenly—fever, chills, fatigue, and new heart-related signs are common. Prompt diagnosis with blood cultures and echocardiography, followed by prolonged antibiotics and sometimes surgery, is essential.
This page covers causes, risk factors, symptoms, tests, treatment, prevention, and when to seek urgent care. It is general education—not personal cardiac advice.
Overview
Endocarditis is a true infection of heart tissue, not simply “heart inflammation” in the nonspecific sense. It must be distinguished from myocarditis (muscle), pericarditis (sac around the heart), and non-infectious febrile illnesses.
Prognosis depends heavily on how quickly treatment starts, which organism is involved, and whether valves are already damaged. With timely care many people recover; delayed care raises the chance of heart failure, stroke, and multi-organ infection.
Treatment usually means weeks of intravenous antibiotics matched to culture results. Valve repair or replacement may be needed when destruction, large vegetations, uncontrolled infection, or high embolic risk is present.
- Infection of endocardium/valves with vegetation formation
- Usually bacterial (Staphylococcus, viridans streptococci, enterococci); fungi less common
- Higher risk with valve disease, prostheses, congenital defects, IV drug use
- Key tests: serial blood cultures and echocardiography
- Core treatment: prolonged IV antibiotics ± valve surgery
- Prevention: oral hygiene; antibiotic prophylaxis only for selected high-risk patients
What happens in the body
Microbes reach the blood through skin breaks, dental procedures or poor oral hygiene, gastrointestinal or genitourinary procedures, or injected drug use. They adhere to abnormal endothelium or prosthetic material and grow within a protective vegetation.
Valve leaflets may leak or obstruct; fragments can embolise. Immune complexes and septic emboli explain some skin and kidney findings. Without clearance of the organism, heart failure and distant abscesses can follow.
- Bacteraemia + abnormal valve surface → vegetation
- Common organisms: S. aureus, viridans group streptococci, enterococci
- Emboli can cause stroke or organ infarcts/abscesses
- Valve destruction drives acute heart failure
Signs and symptoms
Features vary and may develop slowly or abruptly. Common symptoms include:
- Persistent fever
- Chills and night sweats
- Fatigue and weakness
- Muscle and joint pain
- Shortness of breath
- Swelling of legs, feet, or abdomen
- New or changing heart murmur (found on exam)
- Petechiae, Janeway lesions, or other skin signs in some cases
- Warning features: severe chest pain, sudden confusion or speech difficulty, rapid heartbeat, new rashes or lesions
Causes and risk factors
Infection is required, but several factors raise the chance that circulating microbes will settle on the heart:
- Staphylococcus aureus from skin or invasive procedures
- Viridans streptococci from the mouth (dental disease or procedures)
- Enterococci from intestinal or urinary sources
- Fungal endocarditis in selected immunocompromised or device-related settings
- Intravenous drug use and shared needles
- Poor dental hygiene and untreated oral infection
- Pre-existing valve disease, congenital heart defects, prior valve surgery, or prior endocarditis
- Older age, male sex, uncontrolled diabetes, and autoimmune disease affecting the heart as contributing risks
Diagnosis and evaluation
Diagnosis rests on clinical criteria plus microbiology and imaging—not a single symptom:
- Detailed history of fever, procedures, dental health, drug use, and heart disease
- Exam for murmur, embolic skin signs, and heart-failure findings
- Multiple blood cultures before antibiotics whenever safely possible
- Echocardiogram (transthoracic and/or transoesophageal) to look for vegetations and valve damage
- ECG for conduction changes; chest X-ray for congestion or other clues
- Differential includes myocarditis, pericarditis, pneumonia, and other febrile illnesses
Treatment and management
Care is specialist-led. Antibiotic choice depends on the organism and susceptibilities:
- Prolonged intravenous antibiotics (often 4–6 weeks), sometimes combining agents for synergy
- Examples of drug classes used (by organism): penicillins for many streptococci; vancomycin for resistant staphylococci; gentamicin in selected combinations
- Valve repair or replacement when severe regurgitation, large vegetations, abscess, persistent infection, or high embolic risk is present
- Supportive care for heart failure and complications
- Tailored plans for children and older adults with multiple comorbidities
- Substance-use treatment support when IV drug use is a driver of infection
Prevention, self-care, and lifestyle
Not every condition is fully preventable, but the steps below may lower risk or recurrence:
- Maintain excellent oral hygiene and regular dental care
- Ask about antibiotic prophylaxis before dental or certain invasive procedures if you have high-risk heart conditions—only when guidelines recommend it
- Avoid intravenous drug use; seek help for substance use disorders
- Keep chronic conditions (diabetes, heart disease) well controlled
- Stay current with vaccines that reduce infection risk overall
- Do not ignore unexplained prolonged fever if you have a prosthetic valve or known valve disease
Possible complications
Delay, missed care, or unsafe self-medication can raise the chance of complications in some cases:
- Heart failure from valve destruction
- Stroke or other embolic events from vegetation fragments
- Abscesses in the heart or distant organs; systemic infection
- Acute short-term crises such as septicemia or sudden pump failure
- Long-term need for valve surgery, chronic heart issues, or prolonged antimicrobial courses
When to see a doctor or seek emergency care
Seek prompt medical advice or emergency care if any of the following apply—it is safer not to wait and see:
- Persistent fever, chills, or unexplained fatigue—especially with known heart valve disease or IV drug use
- New shortness of breath, swelling, or reduced exercise tolerance
- Severe chest pain or pressure
- Sudden confusion, weakness, or difficulty speaking
- Rapid heartbeat or new concerning skin lesions with fever
- Any suspicion of endocarditis after recent dental work, invasive procedures, or bloodstream infection
Living with the condition
Recovery often includes weeks of IV antibiotics, sometimes via outpatient parenteral therapy when stable. Follow activity limits if heart function is impaired, and attend all cardiology and infectious-disease follow-ups.
Dental care remains lifelong prevention. Carry a summary of your valve status and any prophylaxis recommendations for dentists and surgeons.
Report new fever promptly after treatment—recurrence and residual valve problems need early review.
Frequently asked questions
What are early signs of infective endocarditis?
Persistent fever, chills, fatigue, and unexplained muscle or joint pain are common early clues—especially if you have heart-valve risk factors. Seek medical review rather than waiting for classic late signs.
How is it diagnosed?
Doctors combine history and exam with blood cultures to identify the organism and echocardiography to look for vegetations and valve damage. Other imaging and ECG support the work-up.
How long does treatment last?
Antibiotic courses commonly last about 4 to 6 weeks, depending on the organism, valve type, and complications. Surgery may add recovery time.
Is infective endocarditis contagious?
No. It is not spread like a cold. It occurs when microbes enter the bloodstream and infect the heart, often via procedures, oral bacteria, or injected drug use.
Can it be prevented?
Risk can be reduced with good dental hygiene, avoiding IV drug use, managing heart disease, vaccinations as advised, and—for selected high-risk patients—prophylactic antibiotics before certain procedures.
What if it is left untreated?
Untreated endocarditis can cause heart failure, stroke, and damage to other organs. It is a medical emergency in practice—prompt care saves lives and valves.
Important caution
This information is for general education only and is not a substitute for personalised medical advice, diagnosis, or treatment.
Suspected endocarditis needs urgent specialist assessment—do not rely on home remedies or incomplete antibiotic courses.
If you have severe chest pain, sudden neurologic symptoms, or marked breathlessness with fever, seek emergency care immediately.