Infective Endocarditis

Infective endocarditis is a serious heart valve infection. It happens when bacteria or fungi get into the bloodstream. They then attach to the heart’s inner lining.

This condition can be very dangerous. It causes inflammation and damage to the heart valves and tissues around them.

Bacterial endocarditis is the most common type. It can grow quickly or slowly, depending on the bacteria and the person’s health. If not treated, it can lead to serious problems and even death.

It’s important to know the signs and symptoms of infective endocarditis. This helps doctors diagnose and treat it early. Knowing the risk factors, causes, and how to prevent it can also help keep people safe.

What is Infective Endocarditis?

Infective endocarditis is a serious condition where the heart’s inner lining, called the endocardium, gets infected. This usually happens when bacteria or fungi get into the bloodstream and stick to damaged heart areas. This leads to the growth of valvular vegetations on the heart valves or endocardium.

The most common causes of infective endocarditis include:

• Staphylococcus aureus, a type of bacteria often found on the skin
• Streptococcus species, bacteria commonly found in the mouth and throat
• Enterococcus species, bacteria that inhabit the digestive tract

Some risk factors make it more likely for someone to get infective endocarditis. For example, heart valve damage from conditions like rheumatic heart disease or congenital defects makes it easier for bacteria to attach. Intravenous drug use is also a big risk factor because it can introduce bacteria directly into the bloodstream. Medical procedures that involve foreign objects, like catheters or prosthetic heart valves, can also increase the risk of infection.

Other risk factors for infective endocarditis include:

Symptoms and Signs of Infective Endocarditis

Infective endocarditis symptoms can differ from person to person. Yet, some common signs are seen in many. It’s key to spot these signs early and get medical help fast to avoid serious issues.

Common Presentations

The most common symptoms include:

Other signs might be joint pain, muscle aches, loss of appetite, and weight loss. These symptoms can take days to weeks to show up.

Atypical Symptoms

Some people with infective endocarditis may have unusual symptoms. These can include:

• Skin lesions, such as painful red spots on the fingers or toes (Osler’s nodes)
• Tiny hemorrhages under the fingernails or on the retina (splinter hemorrhages)
• Neurological symptoms, like confusion, stroke, or seizures
• Abdominal pain, nausea, or vomiting

These unusual symptoms can make diagnosing infective endocarditis harder. It’s vital to get a detailed check-up from a healthcare provider.

Complications of Untreated Infective Endocarditis

Untreated infective endocarditis can cause severe problems. Two major issues are:

1. Septic embolism: Infection can lead to blood clots that block blood vessels and harm organs.
2. Heart failure: The infection can damage heart valves, causing dysfunction and heart failure if not treated quickly.

It’s critical to recognize the symptoms of infective endocarditis and get medical help early. This can prevent severe complications and improve outcomes.

Diagnostic Techniques for Infective Endocarditis

Diagnosing infective endocarditis involves several steps. These include clinical findings, lab tests, imaging studies, and specific criteria. Early and accurate diagnosis is key to start the right treatment and improve patient outcomes.

Physical Examination Findings

Physical exams may show signs of infective endocarditis. These include fever, heart murmurs, and small painful nodules on fingers or toes called Osler’s nodes. But, these signs are not always present or specific to this condition.

Laboratory Tests and Blood Cultures

Laboratory tests are vital in diagnosing infective endocarditis. Blood cultures are essential, with multiple sets drawn to find the causative microorganism. Other tests like complete blood count and C-reactive protein help show signs of infection and inflammation.

Echocardiography: Transthoracic and Transesophageal

Echocardiography is a key imaging tool for diagnosing infective endocarditis. Transthoracic echocardiography (TTE) is often the first step. But, transesophageal echocardiography (TEE) provides better views of heart valves, helping spot smaller vegetations or abscesses missed by TTE.

The Duke Criteria for Diagnosis

The modified Duke criteria are widely used for diagnosing infective endocarditis. These criteria combine clinical, microbiological, and echocardiographic findings. They help classify cases as definite, possible, or rejected endocarditis.

Pathophysiology of Infective Endocarditis

Infective endocarditis happens when bacteria or fungi attach to the heart’s endocardium. This usually occurs on damaged heart valves. The bacteria stick because of their surface components and the host’s proteins like fibronectin and collagen.

After attaching, the bacteria grow and form vegetations. These are clusters of bacteria, fibrin, platelets, and immune cells. As the infection grows, these vegetations can damage the valves, causing serious problems.

The body’s immune response is key in infective endocarditis. It releases substances like cytokines that damage tissues and help form vegetations. Conditions like rheumatic heart disease or congenital heart defects also raise the risk by providing a good spot for bacteria to attach.

Knowing how infective endocarditis works is vital for finding better treatments. Early treatment with antibiotics is essential to stop the disease from getting worse. This can greatly improve a patient’s chances of recovery.

Microbiology of Infective Endocarditis

Infective endocarditis can be caused by many microorganisms, mostly bacteria. Knowing the microbiology is key for correct diagnosis and treatment. The type of pathogen affects the disease’s symptoms, progression, and treatment options.

Common Bacterial Pathogens

Staphylococcus aureus and Streptococcus species are the top causes of infective endocarditis. Staphylococcus aureus, including MRSA, is a major cause of both community and hospital-acquired cases. Viridans group streptococci, like Streptococcus mitis and Streptococcus sanguinis, are also common, often in those with heart valve problems.

Other bacteria that can cause infective endocarditis include:

Fungal Endocarditis

Fungal endocarditis is less common but more challenging to diagnose and treat. Candida species, mainly Candida albicans, are the main culprits. Risk factors include weakened immune systems, intravenous drug use, and prosthetic valves. Treatment often requires long-term antifungal therapy and surgery.

Culture-Negative Endocarditis

In some cases, blood cultures can’t find the pathogen, leading to culture-negative endocarditis. This might be due to antibiotics, slow-growing bacteria, or non-bacterial causes like fungi. New diagnostic tools like PCR and 16S rRNA sequencing help find the cause in these cases.

Treatment Strategies for Infective Endocarditis

Infective endocarditis is a serious condition that needs quick and focused treatment. The main treatment is antibiotic therapy given through an IV for weeks. Sometimes, oral antibiotics are used to finish the treatment.

The choice of antibiotics depends on the infection cause, found through blood cultures and tests. Common antibiotics for infective endocarditis include:

Surgical Interventions

For some, antibiotics alone may not be enough. Surgery, like valve repair or replacement, might be needed. This is for those with severe damage, large vegetations, or not responding to antibiotics. Surgery is usually done within the first week to prevent more problems.

Monitoring Treatment Response

It’s important to watch how the patient is doing during treatment. Regular check-ups, blood tests, and echocardiograms help see if the treatment is working. Patients need to be closely watched for the whole treatment time and a few months after to make sure they fully recover.

Complications of Infective Endocarditis

Infective endocarditis can cause severe problems if not treated early. It’s important to catch it quickly and treat it right. This helps avoid serious issues and improves the patient’s chances of getting better.

Valvular Destruction and Heart Failure

One major problem is damage to the heart valves. The infection can harm or destroy them. This leads to the heart working too hard, causing heart failure.

Symptoms of heart failure include:

Septic Embolism and Stroke

Septic embolism is another serious issue. Pieces of infected tissue can break off and travel in the blood. They can get stuck in organs, causing damage.

When these pieces reach the brain, they can cause a stroke. This can lead to problems like:

• Weakness or numbness on one side of the body
• Difficulty speaking or understanding speech
• Vision problems
• Severe headache
• Confusion or altered mental state

Septic emboli can also harm other organs, like the lungs, spleen, or kidneys. This can cause specific symptoms and problems. It’s key to find these issues early and use strong antibiotics to stop them from getting worse.

Prevention of Infective Endocarditis

Preventing infective endocarditis is very important for those at high risk. Keeping your teeth clean is a big part of this. Brushing, flossing, and regular dental visits can help stop bacteria from getting into your heart.

Some people might need antibiotics before dental work or surgery. This is to prevent bacteria from entering the bloodstream. Always talk to your doctor or dentist about this.

Staying away from intravenous drugs is also key. It helps avoid bacteria getting into your blood. If you have heart problems or artificial valves, be extra careful. Working closely with your healthcare team is essential to lower your risk of infective endocarditis.