What is Endocarditis?
Infective endocarditis, an infection that affects the heart’s inner lining, is a major cause of illness and death in children and teenagers, even though there have been advancements in its treatment and prevention. This infection can be caused by different types of bacteria, leading to either acute or subacute bacterial endocarditis. There are also types caused by viruses, fungi, and other microscopic organisms. Over time, the type of organism causing the infection has changed, which can make it challenging to diagnose in the early stages. Often, by the time it’s identified, a serious infection is already present.
With the development of techniques in cardiology and radiology, an infection by Staphylococcus aureus, a type of bacteria, is becoming increasingly significant in cases of infective endocarditis. It’s alarming to note that nearly 30% of patients with this condition die within a year. Apart from damaging the heart valves, there’s also a risk of blockages moving through the body (embolization) and causing a stroke. Diagnosing and managing infective endocarditis can be quite challenging.
What Causes Endocarditis?
The main cause of endocarditis, an infection of the heart’s inner lining, in kids is a type of bacteria called Staphylococcus aureus. It’s closely followed by another type of bacteria known as Viridans-type streptococci, also known as alpha-hemolytic streptococci. There are other organisms that can cause endocarditis but they are less common. Normally, staphylococcal endocarditis is often seen in patients with no prior heart disease. If a dental procedure was recently done, this can raise suspicions that the viridans group streptococcal infection is involved.
Pseudomonas aeruginosa or Serratia marcescens are usually found in intravenous drug users. Fungal organisms can also cause problems during open-heart surgery. If a central venous catheter, a tube placed into a patient’s large vein is inserted, a non-disease causing staphylococcus bacteria is often detected as the cause.
Endocarditis can affect the natural valves in the heart:
* It often involves the mitral valve, followed by the aortic valve
* It occurs more in people with a birth defect of the heart or any defect that causes high blood flow tension
* Around 20% of cases involve a condition called mitral valve prolapse
* It can also occur due to degenerative heart disease like the bicuspid aortic valve disease, Marfan syndrome, or syphilis.
In the case of prosthetic valve endocarditis (PVE), which affects artificial heart valves:
* Early PVE is caused by S aureus and S epidermidis bacteria, including a drug-resistant form known as MRSA
* Streptococci bacteria usually cause late PVE
Endocarditis is also observed in people who use intravenous drugs:
* Symptoms might include a new heart murmur (an abnormal heart sound) and/or chest pain
* S. aureus is the most common cause, but rates of MRSA, a drug-resistant bacteria, are increasing
* Gram-negative organisms, a category of bacteria, are rarely involved
The risk factors for endocarditis include:
* Previous damage to a heart valve
* Having diabetes
* Use of steroids
* Being older
* Having a pacemaker, a device to regulate heartbeat.
Risk Factors and Frequency for Endocarditis
Infective endocarditis, a heart complication, can often occur in people with congenital heart diseases or rheumatic heart diseases. But, it’s worth noting that this condition can also affect children who don’t have any heart abnormalities.
- In developed countries, the key factor that makes a person more likely to get infective endocarditis is having a congenital heart disease.
- For about 30% of people with this condition, a predisposing factor can be identified.
- If a person has had a dental procedure, symptoms of infective endocarditis may appear anywhere from 1 to 6 months later.
- While it’s rare to get this condition just from a routine heart surgery, the use of artificial materials in the heart can increase the risk.
Signs and Symptoms of Endocarditis
The symptoms of this disease can vary — they could start off mild and show up over several months, or they could be severe and come on quickly. For some people, the first sign might be a lasting fever without any other symptoms. Others might experience a high fever that comes and goes. Additional symptoms, which can be vague, might include tiredness, muscle pain, joint pain, headaches, chills, nausea, and vomiting.
Changes in heart sounds or new heart murmurs could indicate heart failure. People with this disease might also have an enlarged spleen, or develop several types of skin and eye manifestations — Roth spots, Janeway lesions, splinter hemorrhages, Osler nodes, and petechiae are common. There can also be neurological signs that the disease is associated with a staph infection. These include symptoms of meningitis, increased pressure inside the skull, changes in consciousness, symptoms that suggest brain involvement, strokes caused by clots, brain abscesses, swollen blood vessels that can bleed, and bleeding.
Staph infections can also cause complications such as inflammation and abscesses in the heart muscle, which can damage the system that controls the heart’s rhythm and cause heart block. If an abscess breaks open into the lining around the heart, it can cause an infection there.
Cell skin changes like Osler nodes, Janeway lesions, and splinter hemorrhages usually occur at later stages of the disease. These lesions indicate inflammation of the blood vessels due to circulating immune complexes.
Early detection of this disease largely depends on the high suspicion of infection in a child who has underlying health conditions that put them at risk.
Testing for Endocarditis
If your child is sick, even with just a mild illness, it’s important to take a blood sample as quickly as possible. To get the most accurate result, doctors usually ask for about 3 to 5 separate blood samples. The skin at the collection site needs to be thoroughly cleaned before the sample is taken to avoid any bacteria on the skin contaminating the sample. The time at which the samples are taken doesn’t matter because the bacteria causing the illness are always present in the blood. In about 90% of endocarditis cases, doctors can identify the bacteria causing the illness from the first 2 blood samples.
If your child was treated with antibiotics before the blood samples were taken, this can reduce the chance of identifying the bacteria by half. In such cases, the lab staff need to be informed so they can use other methods to identify the bacteria.
If your child has certain risk factors for endocarditis, doctors might use an echocardiogram to help diagnose the illness. An echocardiogram is a type of ultrasound that looks at the heart and can provide helpful information, such as whether your child has large growths called “vegetations” on their heart, which can be a sign of endocarditis and can also cause other complications. However, even if the echocardiogram doesn’t show any vegetations, this doesn’t mean your child doesn’t have endocarditis. Certain features of vegetations, like being larger than 1 cm or easily moveable, can possibly indicate a higher risk of complications.
Doctors use the Duke criteria to diagnose endocarditis. According to these criteria, a diagnosis is highly likely if your child has positive blood cultures and evidence of endocarditis on an echocardiogram. Other factors that can help diagnose endocarditis include having certain risk factors, fever, vascular signs, complex immune reactions, a single positive blood culture, or echocardiographic signs not meeting the major criteria. To confirm a diagnosis of infective endocarditis, at least 1 major and 3 minor, or 5 minor criteria need to be met.
There are certain cases – about 5 -12% – where doctors can’t isolate the bacteria from the blood samples. This usually happens either because the bacteria are hard to culture in the lab or because your child received antibiotic therapy beforehand.
An ECG, or electrocardiogram, which measures the electrical activity in the heart, might show a delayed signal or a condition known as heart block. These could indicate a complication of endocarditis where the root of the aorta, the main blood vessel leaving the heart, is affected.
Treatment Options for Endocarditis
If a firm diagnosis is confirmed, antibiotic treatment should be started as soon as possible. The type of antibiotics used, how they are given, and the duration of the treatment should be carefully coordinated with specialists knowledgeable in pediatric (child) infections and heart conditions.
Initial or “empirical” treatment usually starts with the antibiotics vancomycin and gentamycin. These are chosen because they’re effective against the most common bacteria seen in these infections, which include strains such as Staphylococcus aureus, Enterococcus, and Vviridans streptococci. Treatment typically lasts around four to six weeks to allow for the clearance of bacterial clusters, known as vegetations, which can take several weeks to form. The type and schedule of antibiotics might be adjusted based on how the patient is doing and the results from the lab testing of their blood. The antibiotics should be given directly into the patient’s vein to ensure consistent and reliable levels of the medicine in the body.
If complications like heart failure—when the heart can’t pump enough blood to meet the body’s needs—thus arise, further treatments could include diuretics and reducing agents. These help to drive off excess fluids and reduce heart workload, respectively. For serious infections impacting parts of the heart such as the aortic valve, mitral valve, or prosthetic valve, surgical intervention may be recommended, particularly if heart failure becomes severe and unmanageable.
Fungal endocarditis, or heart infection caused by fungi, is difficult to manage and is generally only seen in patients with deeply compromised immune systems who have previously undergone heart surgery. In these cases, treatment with antifungal medications such as amphotericin B and 5-fluorocytosine is recommended. Surgery to remove the fungal vegetations may also be an option in some cases.
The use of anticoagulants (drugs that decrease the clotting ability of your blood) is somewhat of a controversial topic, since studies have noted that patients on these treatments tend to have worse outcomes.
Surgery may be required in certain cases, such as:
- For most fungal endocarditis diagnoses, other than H capsulatum
- For ongoing heart failure that isn’t responding to medical treatment
- For persistent sepsis, which is a serious infection that’s not improving with antibiotic treatment
- For conduction disturbances, when the infection has impacted the part of the heart responsible for transmitting electrical signals (the aortic root)
- For recurrent septic emboli, which are clots caused by infection traveling through the bloodstream
- For “kissing infection”, when both the aortic and mitral valves of the heart are infected
What else can Endocarditis be?
There are several medical conditions that may cause similar symptoms, and physicians need to consider these when making a diagnosis:
- Atrial Myxoma (a type of heart tumor)
- Antiphospholipid Syndrome (an autoimmune disorder that causes blood clots)
- Connective Tissue Disease (conditions that affect the tissues connecting the body’s structures)
- Fever of Unknown Origin (a long-term fever with no clear cause)
- Infective Endocarditis (an infection of the inner lining of the heart)
- Intra-Abdominal Infections (infections inside the abdomen)
- Lyme Disease (an infectious disease caused by ticks)
- Primary Cardiac Neoplasms (tumors in the heart)
- Polymyalgia Rheumatica (an inflammatory disorder that causes muscle pain and stiffness)
- Reactive Arthritis (joint pain and swelling triggered by an infection)
Physicians will consider these and conduct tests to accurately determine the patient’s condition.
What to expect with Endocarditis
Infective endocarditis, an infection of the inner lining of the heart chambers and valves, remains quite severe with more than half of the kids diagnosed with it suffering health issues. Common issues include heart failure, which often occurs due to blockages on the heart valves, heart muscle abscesses (pus-filled area in heart muscle), toxic inflammation of the heart muscle, and dangerous irregular heartbeat patterns.
Some of the serious complications are systemic emboli, which are blood clots that move through the bloodstream and can affect the brain and other parts of the body. Other complications include a mycotic aneurysm, which is a bulging and weakened area in the wall of an artery filled with infection; an acquired ventricular septal defect (a hole in the wall separating the lower chambers of the heart); and heart block, a condition where the heart’s electrical signals are disrupted.
The death rate for people with infective endocarditis varies between 7-15%.
Possible Complications When Diagnosed with Endocarditis
- Pericarditis – Inflammation of the tissue surrounding the heart
- MI – Heart attack
- Valvular insufficiency – A condition where one of the heart valves doesn’t function properly
- CHF – Congestive heart failure
- Myocardial abscess, conduction block – An abscess in the heart muscle, affecting its electrical system
- Sinus of Valsalva aneurysm – A bulge in one of the heart’s main arteries
- Arthritis – Inflammation of the joints
- Stroke – A blockage or rupture of a blood vessel in the brain
- Glomerulonephritis – A type of kidney disease
- Arterial emboli – Blockage of an artery
Preventing Endocarditis
There has been a big decrease in cases of infective endocarditis, a type of heart infection, in patients who’ve had a procedure done. This change is largely due to the use of preventive treatment. However, keep in mind that not every procedure requires this preventive treatment.
In 2007, the American Heart Association (AHA) updated their guidelines on preventing infective endocarditis. Since then, fewer people needed preventive treatment for dental, genitourinary (relating to the urinary and reproductive systems), and gastrointestinal (relating to the stomach and intestines) procedures.
According to the updated 2007 AHA guidelines, you might need preventive treatment if you have:
- A prosthetic (artificial) heart valve or material used for heart valve repair
- A previous case of infective endocarditis
- Specific types of Congenital Heart Disease (CHD), including:
- Unrepaired cyanotic CHD (a type of heart defect causing low oxygen levels, including artificial tubes or connections called shunts and conduits)
- CHD that’s been completely fixed with artificial material or a device, but only within the first 6 months after the procedure
- Repaired CHD with remaining issues near the site of an artificial patch or device
- If you have had a heart transplant and developed issues with your heart valves (cardiac valvulopathy)
These recommendations depend on the person’s individual condition. So it’s a good idea to consult with a pediatric cardiologist (a heart doctor for children) to figure out if you still need the preventive treatment.