What is Neurological Sequelae of Endocarditis?
Endocarditis refers to an inflammation or infection of the endocardium, the inner lining of the heart’s valves and muscles. This usually happens due to a bacterial infection, in which case it’s referred to as infective endocarditis (IE).
There’s also a condition known as non-infective endocarditis, or nonbacterial thrombotic endocarditis (NBTE). This occurs when clumps of matter that don’t contain bacteria form on the heart’s valves.
The symptoms of IE and NBTE can vary because they affect the heart differently. This depends on various factors like the type of heart valve (i.e., artificial valves, those affected by rheumatic heart disease), the structure of the heart, and the patient’s immune status (i.e., Libman-Sachs endocarditis in people with lupus).
Endocarditis can lead to a wide range of complications including issues with the heart, infections throughout the body, neurological, lung, and kidney problems. Heart failure is the most common cause of death in people with infective endocarditis.
After heart-related issues, neurological problems are the second most common complications of infective endocarditis. In the case of NBTE, the most common symptom is embolism, a blockage in one of the blood vessels, rather than heart complications.
What Causes Neurological Sequelae of Endocarditis?
Endocarditis is a condition that causes inflammation or infection of the heart valves or the endocardium, which is the inner lining of the heart chambers.
Certain heart conditions, such as rheumatic heart disease and birth defects like a bicuspid aortic valve (when the aorta has two leaflets instead of three), a ventricular septal defect (a hole in the wall separating the heart’s lower chambers), or coarctation of the aorta (a narrowing of the aorta), can make someone more likely to get infectious endocarditis.
The organisms that cause infectious endocarditis can vary and are often related to specific risk factors. These include using intravenous drugs, having a pre-existing heart valve problem, having poor dental hygiene or a recent dental procedure, having a compromised immune system, having a heart implant device, or having a history of endocarditis. In endocarditis, the risk of complications affecting the brain depends on the size of the heart valve deposits and the amount of bacteria present.
The most common germ causing infective endocarditis in the US and other developed countries is Staphylococcus aureus. This kind of infection is more likely to cause blockages in the body’s circulation than infections from other germs. Possible brain-related complications from endocarditis include:
1. Embolic stroke: This happens when bits of the heart valve deposits get stuck in the blood vessels of the brain and cause a stroke.
2. Transient ischemic attack (TIA): This is a temporary disruption of blood flow to the brain, similar to a stroke but it leaves no long-term damage.
3. Brain bleeding
4. Meningitis: Infection in the layers surrounding the brain and spinal cord.
5. Brain abscess: A collection of pus in the brain due to an infection.
6. Toxic encephalopathy: Brain dysfunction due to the effects of harmful substances.
7. Seizure
Nonbacterial thrombotic endocarditis is found in patients with connective tissue disorders, autoimmune diseases, cancer, and other conditions that make the blood more likely to clot. These deposits in the heart are usually smaller and more likely to break loose than in infectious endocarditis. Therefore, this condition puts patients at a higher risk of having small blockages in the brain’s blood supply and developing lesions in the brain.
Risk Factors and Frequency for Neurological Sequelae of Endocarditis
Infectious endocarditis often results in neurological issues which are the most typical complications besides heart-related ones. This has been consistent for the past 20 years. Such neurological problems occur in about 25% to 40% of patients with infectious endocarditis. In one study, roughly half of the patients showed these neurological symptoms first. Major brain clots (49%) are the most common of these complications, followed by brief periods where the brain doesn’t receive enough blood (18%). Patients who have seed-like growths on their heart valves that are 10mm or larger are more likely to develop blood clots. Neurological problems occur frequently in patients with endocarditis and contribute to the high rates of severe disease and death.
- Nearly 80% of NBTE (nonbacterial thrombotic endocarditis, a condition in which clots form on heart valves) is attributed to advanced cancer.
- Systemic lupus erythematosus, an autoimmune disease, is the second most common cause of NBTE.
- Interestingly, up to half of the patients with NBTE develop systemic emboli (clots that have traveled from other parts of the body), which is a much more common symptom than heart-related complications.
Signs and Symptoms of Neurological Sequelae of Endocarditis
Embolism, which is a sudden blockage of a blood vessel, is the most common brain-related complication in both Infective Endocarditis (IE) and Non-bacterial Thrombotic Endocarditis (NBTE). However, these conditions can manifest in many different ways.
Between 20% and 40% of patients with Infectious Endocarditis may have symptoms related to the brain, such as stroke, transient ischemic attack (TIA), meningitis, or brain abscess. Sometimes, these brain related complications could occur before the diagnosis of Infectious Endocarditis. Hence, when patients show up with a fever and neurological signs, doctors must consider the possibility of infective endocarditis. Diagnosing infectious endocarditis depends on seeing symptoms, blood cultures, and heart ultrasound studies. But sometimes, blood cultures may not show the infection; this is referred to as culture-negative endocarditis, typically seen in patients who have previously used antibiotics or live in developing countries.
On the other hand, patients with NBTE often do not have symptoms. An autopsy study in cancer patients reported that about a tenth of the patients showed clinical symptoms like stroke, delirium, or mental status changes while fifteen percent had brain vascular diseases. Fever is uncommon in NBTE patients. However, most patients with NBTE have an advanced cancer or autoimmune diseases like Systemic Lupus Erythematosus (SLE), which could present with fever.
Testing for Neurological Sequelae of Endocarditis
Diagnosing infectious endocarditis, an infection of the heart’s inner lining, relies on several tests. One of these tests is the study of microorganisms, which involves taking samples from your body, such as blood or urine, to check for bacteria or fungi. Another important test is an echocardiography, which is a type of ultrasound test that uses sound waves to create detailed images of your heart. It helps the doctor check the heart’s structure and function. These tests help establish the definitive diagnosis for infectious endocarditis based on specific criteria, known as the Duke criteria.
The diagnosis of Nonbacterial Thrombotic Endocarditis (NBTE), a condition where tiny blood clots form in the vessels around the heart, often requires a different approach. It’s generally diagnosed through pathological tests, which involve the examination of tissue samples under a microscope. However, seeing growths or vegetations on heart valves during an echocardiography, without any signs of systemic infection, acts as strong evidence for NBTE.
Interestingly, many people with endocarditis also tend to develop a silent cerebral embolism, which is a brain condition caused due to a blockage in the brain’s blood supply. While the symptoms might not be obvious, the consequences can worsen the patient’s condition. Therefore, doctors are advised to quickly carry out basic neurological checks in such cases. These quick checks usually include assessing mental alertness, the functioning of the nerves in the head (cranial nerves), the motor system, and sensation.
In patients who are unstable, a CT scan without contrast is recommended. This scan uses X-ray technology to create detailed images of the body and can help identify any problems in the brain. For an even clearer picture, Diffusion-weighted MRI (DWI) may be preferable over conventional MRI. This type of imaging is better at catching recent onset brain lesions or damage, smaller lesions, and can also tell the difference between new and old damage.
Furthermore, patients who come in with symptoms such as headache, neck stiffness, and fever may need additional tests. Analysis of cerebrospinal fluid (CSF), the fluid that surrounds the brain and spinal cord, is important to check for infections like meningitis or a brain abscess. These conditions are infections in the brain or the lining of the brain and can rapidly worsen if not managed promptly.
Treatment Options for Neurological Sequelae of Endocarditis
Treating patients based on their specific symptoms and diagnoses is crucial. When it comes to infectious endocarditis, which is an infection of the inner lining of the heart, the correct use of antibiotics is key to reducing the risk of death and serious health complications. The approach to managing neurological problems – problems related to the brain and nerves – resulting from endocarditis can vary. Let’s discuss the approach to treatment for a few specific cases:
Ischemic stroke:
Ischemic stroke occurs when the supply of blood to the brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients. Currently, we don’t have big scientific trials for managing ischemic stroke in patients with endocarditis. Starting antibiotics early not only controls the infection but also lowers the risk of developing blood clots and death. On the other hand, the use of blood thinning medications (like anticoagulants and antiplatelet drugs) or clot-dissolving therapies after a clot-induced blockage are not well researched. High blood pressure can be dangerous in acute ischemic stroke in endocarditis patients, except in cases of hypertensive crisis or emergency, or other specific conditions. For patients with Non-bacterial Thrombotic Endocarditis (NBTE), a condition where small, fragile clots form on the heart valves, anticoagulation is recommended. In these patients, addressing the underlying cancer or related autoimmune conditions is key to preventing blood clot formation.
Intracranial hemorrhage:
Intracranial hemorrhage refers to any bleeding that occurs inside the skull. There can be different causes for this in endocarditis patients – it might happen after an ischemic stroke, because of a ruptured aneurysm (a bulge in a blood vessel caused by infection), or for reasons we can’t determine. If a patient experiences an intracranial hemorrhage, all blood thinning treatments should be stopped for at least two weeks. Standard treatments for this condition might include controlling blood pressure, managing intracranial pressure, reversing the effects of blood thinners, and managing seizures. Whether surgery is needed will depend on the location of the bleeding and how the patient’s condition progresses.
CNS infection:
Central Nervous System (CNS) infections, such as meningitis (inflammation of the brain and spinal cord) and brain abscesses (pockets of pus in the brain), can occur in patients with endocarditis. Brain abscesses are most common in very sick patients. While the bacterium pneumococcus causes less than two percent of endocarditis, it is found in 70% of cases of bacterial meningitis in patients with this infection. Treating endocarditis effectively with antibiotics early on can help prevent CNS infections. Using the appropriate antibiotics, and sometimes intravenous steroids, can also help reduce the neurological complications that can result from a CNS infection.
There is ongoing debate over the role of early heart surgery to prevent blood clots. The indications for early surgical intervention to prevent blood clots differ between studies. In general, managing endocarditis patients with neurological issues requires a team of specialists, including infection disease experts, cardiologists, neurologists and cardiac surgeons. This multidisciplinary team works together to determine the best treatment plan for the patient’s condition.
What else can Neurological Sequelae of Endocarditis be?
If a person has symptoms related to the nervous system like headaches, vomiting, changes in consciousness, and so on, a thorough check-up is essential. These symptoms may also appear in cancer patients presenting with mental health symptoms. Therefore, the possibility of a blood clot in the brain should not be ruled out. Below are some conditions that doctors might consider in their diagnosis:
- Depression
- Psychiatric disorders, mental fluctuations due to other health conditions
- Inflammatory diseases like aseptic meningitis and viral encephalitis
- Conditions affecting the cavernous sinus
- Diseases affecting the blood vessels, such as dissection syndromes
- Metastatic brain disease in cancer patients
- Stroke due to a blockage in the heart (cardioembolic stroke)
- Brain aneurysms
- Bleeding in the area between the brain and the thin tissues that cover it (subarachnoid hemorrhage)
What to expect with Neurological Sequelae of Endocarditis
When patients with endocarditis have neurological complications, it often means they may not have a good outcome. Endocarditis patients who show severe brain function issues and have bleeding in the brain typically do the worst. The kind, extent, and location of brain injuries play a crucial role in the death and disease rates.
According to research by Maija H. and team, there is no significant difference in outcomes between different types of endocarditis patients. Interestingly, even though a specific bacterium called Staphylococcus aureus is more likely to cause brain embolism (a blockage in a blood vessel in the brain) compared to other bacteria, it doesn’t increase the death rate.
In another study, they found that the Glasgow Coma Scale, which is a score that helps measure brain function impairment, and any repair of the heart valve were important factors in predicting death rates. In particular, if a stroke occurred, it was a strong indicator of potential death.
Possible Complications When Diagnosed with Neurological Sequelae of Endocarditis
Neurological effects are a major concern in cases of endocarditis, as they can lead to additional health issues. For example, an ischemic embolism can block blood flow, causing lasting neurological damage and dysfunction. Additionally, if endocarditis produces a mycotic aneurysm (a weak spot in the blood vessel), it can contribute to a brain hemorrhage if there isn’t proper infection control. Seizures can also occur due to a brain abscess, embolic infarction, or intracranial hemorrhage.
Venous thromboembolism (VTE), a condition where blood clots form in the veins, can also occur due to lack of movement after a stroke. Other possible signs of neurological damage include speech problems (aphasia), difficulty swallowing (dysphagia), urinary tract infections, bladder control issues, and sexual dysfunction.
Possible Complications:
- Lasting neurological damage and dysfunction from ischemic embolism
- Brain hemorrhage from mycotic aneurysms
- Seizures from brain abscess, embolic infarction, or internal bleeding in the brain
- Venous thromboembolism (VTE) due to lack of movement after a stroke
- Speech problems (aphasia)
- Difficulty swallowing (dysphagia)
- Urinary tract infections
- Bladder control issues
- Sexual dysfunction
Preventing Neurological Sequelae of Endocarditis
Endocarditis refers to the inflammation or infection of the heart’s lining or its valves. People with certain conditions are at a higher risk of developing endocarditis. These conditions include having a damaged heart valve, ongoing infections, artificial heart valves, advanced cancer, or a condition called systemic lupus erythematosus.
The signs and symptoms of endocarditis can vary greatly between individuals. One of its most common neurological complications, or problems affecting the nervous system, is a stroke. Thus, people with the risk factors mentioned above should be vigilant. If they begin to experience symptoms such as difficulty speaking, muscle weakness, or a headache, it may be an indication of a stroke or other neurological complications. As such, they should seek medical attention for further investigation.
