What Is Endocarditis? Learn Causes, Symptoms & Treatment

Overview of Endocarditis  

Endocarditis is a serious and potentially life-threatening inflammation of the inner lining of the heart valves and heart chambers called endocardium. It is an infectious disease and is also called bacterial endocarditis or infective endocarditis because it is usually caused by bacteria. However, less commonly, other organisms like fungi can also cause endocarditis. 

Importance of Recognizing Endocarditis

Early recognition of endocarditis is important because the condition can be fatal without timely and aggressive treatment. Left untreated, the vegetation (bacteria that have attached to the damaged heart valves) can continue multiplying and eventually destroy heart tissue. This can result in complications such as leaky heart valves, embolus formation (a small blood clot that can leave the heart and block small arteries), abnormal heart rhythm, abscess formation (pus collection near the heart), sepsis (spread of the infection throughout the body), and heart failure.

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Causes of Endocarditis  

What is the Main Cause of Endocarditis?

About 80-90% of infectious endocarditis is bacterial endocarditis caused by Gram-positive Streptococcus, Staphylococcus, and Enterococcus species. Specifically, a bacterium called Staphylococcus aureus accounts for around one-third of all cases. Other less common organisms include Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella (collectively called HACEK). Fungal endocarditis is rare (about 1% of cases).

How Bacteria and Other Pathogens Reach The Heart  

Bacteria and other pathogens can enter the bloodstream and travel to the heart in the following ways:

• During dental procedures such as tooth extractions.

• During other medical procedures like endoscopy.

• From the mouth to the bloodstream while eating, brushing teeth, or flossing.

• From the intestines while pooping.

• Through cuts and scrapes or a skin infection.

• Through intravenous drug use (people who inject drugs using contaminated equipment, for example).

What Are The Warning Signs of Endocarditis?

Common Symptoms of Endocarditis

• Flu-like symptoms (fever and chills)

• Night sweats

• Fatigue

• Skin rash 

• Draining skin sores

• Redness, pain, tenderness, and swelling

• Aching joints and muscles

• Cuts and wounds that won’t heal properly

• Scratchy throat, sore throat, pain with swallowing

• Dry or wet cough that persists for more than 2 days

• Nasal congestion

• Sinus drainage

• Headaches

• Tenderness along the cheekbones

• White patches on the tongue or mouth

• Shortness of breath.

• Chest pain with breathing

• Swelling in the feet, legs, or abdomen

• Nausea, vomiting, diarrhea, loss of appetite, weight loss

Less Common Symptoms of Endocarditis

Less commonly, endocarditis symptoms may include:

• Blood in urine

• Tenderness in the left chest area where the spleen is located

• Unexplained weight loss

• Janeway lesions (painless flat spots that are brown, red, or purple in color and located on the palms or soles)

• Osler nodes (painful dark or hyperpigmented bumps or patches that are red or purple in color and located on the fingertips or toes)

• Petechiae (tiny round spots that are red, purple, or brown in color and located on the skin, inside the mouth, or the whites of the eyes) 

Serious Endocarditis Symptoms Requiring Immediate Attention  

See your healthcare provider right away if you have any signs and symptoms of infective endocarditis, especially if you have a history of heart valve disease, artificial heart valves, or a congenital heart defect. This is a serious life-threatening condition, and endocarditis symptoms can resemble other less serious conditions. Only a healthcare provider can make a proper diagnosis and offer appropriate treatment.

What Are The 3 Stages of Endocarditis?

There are 3 types of infective endocarditis:

Acute Infective Endocarditis

Acute infective endocarditis begins suddenly and can become life-threatening within days. It is associated with severe symptoms of endocarditis and serious complications such as stroke, pulmonary embolism (blood clots in the lungs), sepsis, heart attacks, and heart failure. 

Subacute or Chronic Infective Endocarditis

Subacute infective endocarditis tends to develop slowly over several weeks to months. It causes nonspecific symptoms such as fever, chills, night sweats, trouble breathing, and muscle aches. Diagnosis of subacute endocarditis is often delayed due to the endocarditis symptoms being nonspecific. 

Prosthetic Valvular Infective Endocarditis

This is a type of infective endocarditis that develops within a year of heart valve replacement surgery.

Risk Factors For Endocarditis  

Groups Most Susceptible  

People who have valvular heart disease (for example, a leaky aortic valve or mitral valve prolapse) are the highest risk group for developing endocarditis because bacteria and other germs can attach more easily to defects on the surfaces of the damaged heart valves or diseased heart tissue. This is called native valve endocarditis. In addition, people with an artificial heart valve or congenital heart disease are also at risk of endocarditis. 

Note: People with a healthy heart rarely develop endocarditis because normal heart valves are resistant to infection. 

Medical Conditions Associated with Increased Risk  

Risk factors for developing endocarditis include:

• Valvular heart disease, for example, from rheumatic fever

• Previous episode of bacterial endocarditis

• Congenital heart defects

• Cardiothoracic surgery (valve surgery or heart transplant)

• Implanted cardiac devices such as a pacemaker or an implantable cardioverter defibrillator (ICD)

• Weakened immune system

• Poor dental hygiene or conditions affecting the teeth and gums

• Abuse of IV drugs 

• Hypertrophic cardiomyopathy (a condition in which the heart muscle becomes thickened and enlarged)

How is Infective Endocarditis Diagnosed?

Healthcare providers can diagnose endocarditis based on symptoms, medical history, and physical exam to listen for a new or changed heart murmur. They may order tests, including:

• Blood tests such as complete blood count, ESR (erythrocyte sedimentation rate), and CRP (C-reactive protein)

• Blood cultures

• Chest X-ray

• Electrocardiogram (ECG or EKG)

• Echocardiogram (a standard transthoracic echocardiogram or a transesophageal echocardiogram or TEE)

• CT (computed tomography) scan or MRI (magnetic resonance imaging) of the chest, brain, or other parts of the body to identify the spread of the infection

• Positron emission tomography (PET) scan or nuclear medicine scan to find the location of infection in the body

How is Endocarditis Treated? 

Antimicrobial Therapy

The mainstay of treatment for bacterial endocarditis is high-dose antibiotics for 2 to 8 weeks. The type of antibiotic depends on the specific bacterium causing the endocarditis. Your doctor may start with broad-spectrum antibiotics that are effective against a wide range of bacteria and adjust the treatment with a specific antibiotic that targets the causative organism as soon as it is identified.

Most people with endocarditis require a hospital stay for a week or more so that the healthcare team can monitor if the treatment is effective. Once the severe symptoms of endocarditis subside, antibiotic therapy can be continued with visits to the doctor’s office or home care. 

Note: Antibiotics are effective for a bacterial infection only. People with fungal endocarditis are treated with antifungal medications and may need to take these drugs lifelong to prevent the fungal infection from coming back.

Surgical Procedures

If endocarditis damages a native valve, you may need heart valve surgery to replace a damaged valve. Heart valve replacement can be done using a mechanical valve or a biological tissue valve. Surgery may also be necessary to treat damage caused by fungal endocarditis or to restore heart function. Approximately 50% of people with endocarditis require some kind of surgical procedure.

How Curable is Endocarditis?

Endocarditis is curable with early diagnosis and aggressive treatment. Without treatment, it can be fatal. The prognosis (outlook) depends on the severity of the infection, underlying health status and medical history, complications, and whether it is a native valve endocarditis or prosthetic valve endocarditis. 

The average in-hospital mortality rate in people with endocarditis is around 18%. The one-year mortality rate is about 40%. Prosthetic valve endocarditis within the first 60 days of valve replacement surgery has the highest mortality rate. 

Preventive Measures and Lifestyle Adjustments

The American Heart Association has issued guidelines for antibiotic prophylaxis (preventive antibiotics) before certain dental procedures to lower the risk of bacterial endocarditis in people at high risk, such as those with a prosthetic (artificial) heart valve, congenital heart disease, previous episode of bacterial endocarditis, and heart valve disease after heart transplantation.

After heart valve replacement surgery, your healthcare provider may prescribe anticoagulants (blood thinners) to prevent blood clots from forming on the valve. Examples of blood thinners include warfarin (Coumadin), apixaban (Eliquis), dabigatran (Xarelto), ticagrelor (Brilinta), prasugrel (Effient), rivaroxaban (Pradaxa), and edoxaban (Savaysa). 

To lower your risk of infectious diseases like bacterial endocarditis:

• Practice good oral hygiene and take care of your teeth and gums by brushing twice a day and flossing daily.

• Get regular dental checks every 6 months.

• Tell all your health care providers and dentist you have heart disease (damaged heart valves or artificial heart valves) and are at an increased risk of developing endocarditis.

• Take antibiotic prophylaxis (preventive antibiotics) before dental procedures.

• Carry an American Heart Association identification card with guidelines for antibiotic therapy in your wallet.