Septic Emboli

What is Septic Emboli?

Septic embolism is a condition where an infected blood clot blocks a blood vessel. This infected clot travels from a different part of the body through the bloodstream and interferes with the blood flow. This leads to two main problems. One is the early disruption, also known as ischemic insult, due to the blocked blood vessel, which might cause tissue damage due to inadequate blood supply. The second is an infection that leads to swelling and possible development of an abscess, which is a collection of pus in your body caused by an infection.

Septic embolism is often a result of a condition called infective endocarditis, an infection in the inner lining of the heart’s chambers or valves. Osler nodes, which are tender purple spots or bumps, are telltale signs of infective endocarditis. They actually indicate an embolism has occurred, and taking a small tissue sample of these spots to study under a microscope can help identify the specific microorganisms causing the infection.

What Causes Septic Emboli?

Infective endocarditis, an infection of the heart’s inner lining, is often associated with septic emboli. This term refers to the condition when parts of the infected heart valve break away and travel through the bloodstream, potentially blocking blood vessels. This condition has been known since the late 19th century.

In the past, septic embolism was mainly linked to complications from septic pelvic thrombophlebitis, a condition involving inflammation and blood clots in veins, due to infections following childbirth or an abortion. Nowadays, the risk factors for septic emboli have extended to things like intravenous drug use, the presence of long-term vascular catheters (tubes inserted into a vein to deliver medicine), and those with artificial heart devices.

Healthcare providers need to be alert for possible endovascular infection and septic embolism in patients with vascular devices who report recurring or persistent bacteremia, a condition where bacteria can be found in the blood.

It’s worth noting that the location in the body where a septic emboli forms relies on the site of the infection and the structure of the blood vessels surrounding that area. For instance, an eye infection with a certain type of bacteria can lead to blood clots in the sinus and lungs.

Septic emboli can surprisingly travel to the brain due to infections related to a pacemaker, a small device placed in the chest to control irregular heart rhythms. The septic emboli can move through an opening between the heart’s upper two chambers, creating a path from the right side to the left side of the heart.

There have also been cases of septic emboli in the lungs caused by blood clots in the heart’s right atrium related to a special catheter used for kidney dialysis. Similarly, blood clots in a large vein carrying deoxygenated blood into the heart have been observed due to infections where a catheter was inserted in severely ill patients with a specific type of bacterial infection in their blood.

Infections related to heart devices are rare, but when they do occur, they can lead to loosened bits that can be detected by an ultrasound of the heart and potentially cause septic embolism. One study described inflammation and blood clots in a neck vein due to a bacterial infection following the placement of an implantable heart device.

The microbes typically associated with septic emboli include various types of bacterial species, including Staphylococcus aureus and Streptococcus. Sometimes, multiple species or even fungi such as Candida and Aspergillus may be responsible.

A recent global study on infective endocarditis suggested that most patients had an identifiable pathogen. Leading pathogens included Staphylococcus aureus and Streptococcus viridans, which often showed resistance to treatment. A significant number of patients experienced major clots in their blood vessels, most frequently travelling to their brain.

Risk Factors and Frequency for Septic Emboli

Infective endocarditis, an infection of the heart valves, can often lead to a condition called septic emboli where clots carrying bacteria spread throughout the body. Various studies reveal this to happen in different rates among patients.

In a study of 437 patients with surgical endocarditis, 10.52% had septic emboli.
Systemic embolization, a similar condition, occurs in 20% to 50% of left-sided heart valve cases.
Another study with 493 patients found septic embolism in 57% of those studied.
A large combined study found out that septic embolism is seen in 25% of patients with infective endocarditis.
At least 30% of infective endocarditis patients requiring heart valve replacement experience septic embolization.

In a 25-year study, it was noticed that the cases of infective endocarditis have changed. Instances of infective endocarditis linked to internal heart devices were more common in the last decade. Pacemaker related cases increased from 5.4% to 23%, and prosthetic valve cases saw an increase from 8.5% to 19.2% to 47.5%.

In a recent study, 44.4% of infective endocarditis patients experienced major embolic events, which are serious blockages caused by clots. The areas where these embolisms were found include: the brain (26.3%), spleen (6.8%), lungs (6.1%), kidneys (2.9%), and peripheral blood vessels (2.2%). In addition, they occurred in the coronary and mesenteric arteries, though these were less common.

Signs and Symptoms of Septic Emboli

Septic emboli are fragments of a blood clot that are infected with bacteria. These pieces can travel in the bloodstream and lodge in different parts of the body. In some cases, septic emboli may cause no symptoms, while in severe cases they can lead to complications that are life-threatening. The symptoms that do appear depend on where in the body the emboli get lodged.

For example, if the emboli are found in the lungs (caused by right-sided heart infection), symptoms may include fever, shortness of breath, chest pain, a cough, and sometimes coughing up blood. If they travel to different organs (due to left-sided heart infection), symptoms will vary:

Cerebral emboli: Symptoms associated with a stroke, such as weakness, numbness, or difficulty speaking. In some cases, a person with an infection of the heart’s lining may have an embolism to the brain that does not show any symptoms. This was found in a study where 80% of the patients with left-sided heart infection had a brain embolism detected on MRI, and almost half of them had no symptoms.
Splenic emboli: These often lead to bleeding or abscesses in the spleen.
Coronary artery emboli: These have been documented in some people with infection of the aortic valve.
Mesenteric emboli: These cases can lead to blockage of the arteries that supply the intestines, resulting in infection of one of the heart’s valves.

Other possible complications include:

Vein thrombosis originating from an abdominal infection, causing fever and abdominal pain.
Pyogenic liver abscesses that could spread the infection to other parts of the body.
Embolism in limbs: This leads to different levels of limb ischemia, ranging from temporary ischemia to severe ischemia needing amputation.
Embolism in skin: One such case has been reported in a patient with bacterial heart infection.
Lemierre syndrome: This originates from a throat infection and progresses to infections of veins and surrounding tissues, leading to septic emboli in various parts of the body.

In less common instances, septic emboli have been reported due to infected radial artery catheters and following dental surgery. Moreover, if significant kidney tissue is affected, this can lead to kidney failure.

Testing for Septic Emboli

If your doctor suspects that you’re experiencing septic emboli, which are clots containing infectious material, they are likely to conduct several tests. One of these is a blood test. In cases of septic emboli, the infection usually shows up in at least three separate blood cultures.

Imaging studies, which produce pictures of the inside of your body, are also helpful. Arterial and venous duplex studies can help your doctor identify clots in your arteries or veins.

Another test is echocardiography, a type of ultrasound test that uses sound waves to produce images of your heart. Specifically, a type of echocardiography called transesophageal echocardiography is often used because it provides a more detailed picture of any vegetations, or clumps of bacteria, on your heart valves.

A chest X-ray might not provide definitive evidence of septic pulmonary emboli, or clots in your lungs. If your doctor suspects you have these, you may require a chest CT scan. This special type of X-ray can provide more detailed images of your lungs. This scan typically uses an injectable dye, or contrast, to highlight your blood vessels and tissues.

Additionally, a type of test called an ultrasound may show unusual areas in your spleen or kidneys. These could suggest septic emboli in these organs.

If your doctor suspects that the septic emboli have affected your spleen, they may order an abdominal computed tomography (CT) scan. CT scans use a combination of X-rays and computer technology to provide images of your belly area.

In some cases, if a contrast dye can’t be used for a chest CT scan, a ventilation/perfusion scan of the lung might be done. This scan uses a small amount of radioactive material to examine airflow and blood flow in your lungs.

If your doctor thinks the septic emboli may have spread to your brain, they may order a brain MRI. For this scan, you will be given a contrast agent, which helps to highlight certain areas of your brain. In some cases, both with and without contrast scanning may be needed.

Another type of scan, called F-FDG-PET/CT, has shown to be valuable in detecting septic emboli. While this type of scan is limited in its ability to detect brain involvement, it can play an important role in overall patient care and treatment planning. Remember, SPECT/CT and [18F] FDG PET/CT are types of imaging scans that may help find septic emboli at an early stage.

Treatment Options for Septic Emboli

Management of septic emboli, or infectious blood clots, mainly involves the use of long-term antibiotic therapy and source control, which is the treatment to eliminate the source of the infection.

The choice of antibiotics depends on the specific bacteria causing the infection, the organ affected by the emboli, and the way the available drugs work in the body. Also, the treatment plan can change depending on where the septic blood clot has lodged and how big the resultant inflamed area or tissue death (infarct) is.

Anticoagulants, which are blood thinners, have been a subject of debate when it comes to treating infective endocarditis and septic emboli. But, in some cases of left-sided infective endocarditis, if there are no other reasons to avoid it, patients who were already on blood thinners might need to continue taking them.

People suffering from endocarditis, an infection of the heart valves or inner lining, with a sudden onset of symptoms are at higher risk of severe in-hospital complications and even death. Therefore, early surgery within two days of diagnosis can be crucial in managing these patients.

Certain situations, like an acute ischemic stroke resulting from septic emboli due to bacterial endocarditis, require a case-specific approach that falls outside common treatment guidelines. Endovascular treatment, which involves conducting surgery through the blood vessels, can be effective in treating acute septic emboli and mycotic aneurysms, which are bulging, weakened areas of an artery wall caused by infection, though more evidence is needed.

Treating a splenic abscess, an infection in the spleen, caused by an embolic event generally involves removal of the spleen or drainage of the infection under imaging guidance. However, a case has been reported where a large complex splenic abscess was successfully treated with antibiotics alone, specifically in a patient with aortic valve infective endocarditis.

For patients with infected cardiac implantable electronic devices, treatment usually involves removing the infected device wires through a vein. However, this procedure carries a small risk of stroke.

Mycotic aneurysm of the superior mesenteric artery, which is responsible for supplying blood to the intestines, is typically treated by surgery. This involves removing the infected bulge in the artery, the infected clots, and the replaced infected valve.

As per guidelines, the treatment of infective endocarditis and related septic emboli usually involves 4-6 weeks of intravenous antibiotic therapy. Selection of the appropriate antibiotic therapy should be guided by trusted sources like the American Heart Association’s scientific statement on infective endocarditis in adults. Other helpful references could be the JCS 2017 Guidelines on Prevention and Treatment of Infective Endocarditis.

When diagnosing certain heart and blood conditions, doctors often consider various conditions that may present similar symptoms but have different causes. They include:

Marantic endocarditis and Libman-Sacks endocarditis – these are non-infectious and typically linked with cancers and collagen vascular diseases. They should be taken into account, especially in patients who show signs of endocarditis in their blood cultures but no conceptive organisms, and those who present high inflammation markers.
Metastatic disease and tumor embolism – these require a high degree of suspicion and knowledge of a history of underlying cancer.
Disseminated fungal or mycobacterial infections – these could lead to multi-organ manifestations, such as widespread histoplasmosis and blastomycosis. These are usually dependent on geographic location and common in specific areas. Determining these requires microbiological diagnostic methods like tissue biopsies, cultures, antigen detection, and PCR testing. These infections like nontuberculous mycobacteria and miliary tuberculosis should be considered in patients with weakened immune system such as those with HIV infections or those on immune suppressing or modulating therapy.

Additionally, non-infective blood clots in patients with conditions like atrial fibrillation (a type of irregular heart rhythm) who aren’t using blood thinners or other types of heart arrhythmias also need considering. Doctors also consider the possibility of fat embolisms after surgical procedures.

What to expect with Septic Emboli

The outcome of certain medical conditions can differ greatly. It can be as benign as having no symptoms, or as severe as resulting in a high risk of death. This can depend on what organs are affected and the combined impact of a lack of blood supply (ischemia) and infection.

Let’s look into a disease called Infective endocarditis, for example. This is a condition where the inner lining of your heart gets infected. According to a study done by Habib et al., 17.1% of patients (532 people) died in the hospital. This was more frequent in patients having an infection in their artificial heart valve.

The independent predictors of death included a high Charlson comorbidity index (a method to predict the risk of death from comorbid diseases), creatinine level of greater than 2 mg/dl (a sign of kidney problems), congestive heart failure, vegetation length over 10 mm (basically, the size of the infected mass in the heart), brain complications, abscess (a pocket of pus), and not undergoing surgery when it’s needed.

Possible Complications When Diagnosed with Septic Emboli

Septic emboli, or blood clots infected with bacteria, can affect different organs in the body, leading to various complications. The problems that arise depend on which organ is impacted and the size of the embolus or clot.

A septic cerebral emboli, that is, when the blood clot moves to the brain, can potentially cause a stroke due to blockage in the brain’s blood flow. In some cases, the clot might lead to a brain abscess, with symptoms varying based on the location and extent of the damage. Septic cerebral emboli can also increase the risk of developing a brain bleed after clot-busting treatments.

A rare neurological complication of infective endocarditis, or heart valve infection, is intracranial mycotic aneurysms which represent less than 10% of such issues. Netlike structures of small blood vessels, or vasa vasorum, in the arteries can be invaded by septic emboli, causing a focal dilation, or mycotic aneurysm, of an infected arterial wall. Despite the name, most mycotic aneurysms are bacterial and rarely fungus-based.

Mycotic aneurysms can cause a variety of issues. They might undergo spontaneous clotting, reduction in size, quick enlargement, or rupture. They are particularly common in patients with heart valve problems or those abusing intravenous drugs. Infected or septic emboli can be filtered out by the tiny blood vessels in major organs such as the lungs, liver, and spleen.

A septic emboli can also affect the spleen. Complications can include a splenic abscess or splenic infarction, causing intense abdominal pain or severe bleeding requiring urgent surgery.

In the case of the kidneys, septic emboli can result in renal infarction. For the lungs, the impact of septic emboli can range widely, depending on how severe the damage is and the extent of lung tissue affected. The issues can range from symptom-free nodules seen in lung scans to severe shortness of breath and hypoxemic respiratory failure, where not enough oxygen is in the blood. Septic emboli can also potentially lead to long-term cavities or holes in the lungs. In rare cases, it can lead to pneumothorax, a condition where the lung collapses due to air leaking into the chest, such as in severe Staphylococcus aureus bloodstream infections.

Septic cerebral emboli: stroke, brain abscess, increased risk of brain bleed post clot-busting treatments
Intracranial mycotic aneurysms: rare complication of infective endocarditis
Mycotic aneurysms: clotting, reduction in size, quick enlargement, or rupture
Septic splenic emboli: splenic abscess or splenic infarction leading to severe abdominal pain or severe bleeding
Septic renal emboli: renal infarction or damage to kidney tissue
Septic pulmonary emboli: nodules in lung scans, severe shortness of breath, hypoxemic respiratory failure, long-term lung cavities, pneumothorax

Recovery from Septic Emboli

Septic emboli, or infections that travel through your blood, can cause significant damage depending on where they end up in your body and how much harm they do. For example, if they reach your brain, this often leads to stroke-like symptoms, which would need immediate rehabilitation.

Likewise, when these infection particles settle in your lungs, it can lead to a severe breathing problem known as acute hypoxemic respiratory failure. This condition often needs treatment with mechanical breathing assistance, a long stay in the ICU, and a course of pulmonary rehabilitation to help restore normal breathing.

Similarly, if septic emboli travel to your limbs, they could potentially block the blood flow, causing acute limb ischemia. In severe cases, this might result in having to amputate the affected limb. Afterward, you would need physical rehabilitation to cope with this change.

The care required after having heart valve surgery, in cases where septic emboli have traveled to the brain, can be complex. This is due to the risk of a hemorrhagic transformation, which is bleeding occurring when using blood-thinning medicines during the surgery.

Preventing Septic Emboli

Septic emboli are essentially infected blood clots. They start at a site of infection and then travel through your bloodstream to another area in your body. Once there, they can block the blood supply to that area and cause inflammation because the infection spreads to this new area. This puts an extra strain on the tissues of the affected area, as they deal with both a lack of blood supply and the infection itself.

These infected blood clots often result from a serious heart infection called infective endocarditis. This is an infection of the heart’s inner lining and its valves. However, septic emboli can also be caused by intravenous drug abuse or medical procedures that involve inserting central lines into large veins. The symptoms and effects of septic emboli can vary greatly and depend on where in the body they end up, the size of the clot, and how severe the original infection was.

To diagnose septic emboli, doctors typically obtain images of various parts of your body. They identify the bacteria or other microorganisms causing the infection by testing samples of your blood or other tissues.

The main goal in treating septic emboli is to control and eliminate the original infection that caused the clots. This typically involves a long course of antibiotic therapy.

Frequently asked questions

The prognosis for Septic Emboli can vary depending on the specific circumstances and individual factors. It can range from having no symptoms to a high risk of death. The outcome can depend on which organs are affected, the extent of the lack of blood supply (ischemia), and the presence of infection.

Septic emboli can occur when infected blood clots break away from the heart valve and travel through the bloodstream, potentially blocking blood vessels in different parts of the body. They can be caused by various factors such as infections related to heart devices, intravenous drug use, the presence of long-term vascular catheters, and certain types of bacterial infections.

The signs and symptoms of septic emboli depend on where in the body the emboli get lodged. Here are some examples: - If the emboli are found in the lungs (caused by right-sided heart infection), symptoms may include fever, shortness of breath, chest pain, a cough, and sometimes coughing up blood. - Cerebral emboli can cause symptoms associated with a stroke, such as weakness, numbness, or difficulty speaking. However, it's important to note that some people with an infection of the heart's lining may have a brain embolism that does not show any symptoms. - Splenic emboli often lead to bleeding or abscesses in the spleen. - Coronary artery emboli have been documented in some people with infection of the aortic valve. - Mesenteric emboli can lead to blockage of the arteries that supply the intestines, resulting in infection of one of the heart's valves. - Other possible complications include vein thrombosis originating from an abdominal infection, pyogenic liver abscesses, embolism in limbs leading to different levels of limb ischemia, embolism in the skin, and Lemierre syndrome originating from a throat infection and progressing to infections of veins and surrounding tissues, leading to septic emboli in various parts of the body. - In less common instances, septic emboli have been reported due to infected radial artery catheters and following dental surgery. Additionally, if significant kidney tissue is affected, this can lead to kidney failure.

The types of tests that a doctor may order to properly diagnose septic emboli include: - Blood tests, such as blood cultures, to detect the infection - Imaging studies, such as arterial and venous duplex studies, echocardiography (specifically transesophageal echocardiography), chest CT scan, ultrasound, abdominal CT scan, ventilation/perfusion scan of the lung, brain MRI, and F-FDG-PET/CT scan - These tests can help identify clots, vegetations on heart valves, clots in the lungs, unusual areas in the spleen or kidneys, and brain involvement - The choice of tests may vary depending on the specific situation and the suspected location of the septic emboli.

Marantic endocarditis and Libman-Sacks endocarditis, Metastatic disease and tumor embolism, Disseminated fungal or mycobacterial infections, non-infective blood clots in patients with conditions like atrial fibrillation, fat embolisms after surgical procedures.

When treating septic emboli, there can be various side effects depending on the organ affected and the extent of the damage. Some of the potential side effects include: - Septic cerebral emboli: stroke, brain abscess, increased risk of brain bleed post clot-busting treatments. - Intracranial mycotic aneurysms: rare complication of infective endocarditis. - Mycotic aneurysms: clotting, reduction in size, quick enlargement, or rupture. - Septic splenic emboli: splenic abscess or splenic infarction leading to severe abdominal pain or severe bleeding. - Septic renal emboli: renal infarction or damage to kidney tissue. - Septic pulmonary emboli: nodules in lung scans, severe shortness of breath, hypoxemic respiratory failure, long-term lung cavities, pneumothorax.

You should see an infectious disease specialist or a cardiologist for septic emboli.

Septic emboli is seen in 25% of patients with infective endocarditis.

Septic emboli are typically treated with long-term antibiotic therapy and source control. The choice of antibiotics depends on the specific bacteria causing the infection and the affected organ. The treatment plan may also vary depending on the location and size of the septic blood clot. In some cases, anticoagulants may be used, particularly for left-sided infective endocarditis. Early surgery within two days of diagnosis can be crucial for managing patients with endocarditis. Certain situations, such as acute ischemic stroke resulting from septic emboli, may require a case-specific approach. Treatment for splenic abscesses may involve removal of the spleen or drainage under imaging guidance. Infected cardiac implantable electronic devices are usually treated by removing the infected device wires, although this carries a small risk of stroke. Mycotic aneurysms are typically treated with surgery. The recommended treatment duration for infective endocarditis and related septic emboli is 4-6 weeks of intravenous antibiotic therapy. Trusted sources like the American Heart Association's scientific statement on infective endocarditis and the JCS 2017 Guidelines on Prevention and Treatment of Infective Endocarditis can guide the selection of appropriate antibiotic therapy.

Septic emboli is a condition where an infected blood clot blocks a blood vessel, leading to disrupted blood flow and potential tissue damage. It can be caused by infective endocarditis and is characterized by tender purple spots or bumps called Osler nodes.

Arterial or Venous Occlusion Embolism Health Infections Septic Emboli