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Endocarditis (Inflammation of the Inner Lining of the Heart) in Dogs

Occurrence: common
Location of illness: Chest

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

EndocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment., also known as inflammation of the inner lining of the heart, is an inflammatory condition of the inner lining of the heart (endocardium) in dogs, often caused by a bacterial infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..

The most important facts at a glance

Endocarditis in dogs is an inflammatory condition of the inner lining of the heart, often caused by bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease.. These bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. can enter the bloodstream through infections such as dental disease or skin infections and attach to the heart valves, affecting heart function. Symptoms include reduced exercise tolerance, heart murmurs, lethargy, fever, pale mucous membranes, loss of appetite, and weight loss. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. requires a thorough examination by a veterinarian, including blood tests and ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. examinations of the heart. Treatment usually includes antibiotics and may also include medications to support heart function. In severe cases, surgery may be necessary, although this is rare. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. varies depending on the severity of the disease and response to treatment. PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. includes good dental care and early treatment of infections. Research focuses on better diagnostic methods and treatment options to improve the quality of life and survival chances of affected dogs.

Causes

A dog’s heart consists of various parts, including the endocardium (inner lining of the heart), the myocardiumThe myocardium is the heart muscle itself, responsible for the heart's contraction, which enables blood circulation in the body. Diseases of the myocardium can impair the heart's pumping function. (heart muscle wall), and the pericardiumThe pericardium is the sac around the heart, a double-walled membrane that surrounds the heart, protecting it from infection and facilitating its movement within the thorax / chest. Inflammatory conditions of the pericardium can lead to diseases such as pericarditis. (outer layer of the heart). The endocardium forms the inner lining of the heart chambers and covers the heart valves. This structure is crucial for smooth blood flow and the function of the heart valves.

EndocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. usually occurs when bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. or other microorganisms enter the bloodstream and attach to the heart valves or other endocardial areas. This can lead to inflammatory conditions and damage to the heart valves, which can significantly impair heart function.

The most common causes of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs include bacterial infections. BacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. can enter the bloodstream through dental disease, skin infections, urinary tract infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., or other sources of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. A weakened immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. or the presence of valvular heart disease can further increase the risk of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment..

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

The symptoms of endocarditisEndocarditis is an inflammation of the heart’s inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs can vary and are often non-specific, which can make diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. difficult. The most common signs include fever, loss of appetite, weight loss, and lethargy. Many of these symptoms are general in nature and can also occur with other diseases.

Other symptoms may include heart murmurs caused by damage to the heart valves. These noises can be detected with a stethoscopeA stethoscope is a medical instrument used for auscultation, or listening to body sounds, such as heartbeats and lung sounds. It is a fundamental tool in medical diagnostics. during a veterinary examination. In advanced cases, heart failure may occur, which can manifest as cough, shortness of breath, and swollen limbs.

Another possible symptom is sudden lameness caused by emboli, in which small blood clots block blood vessels. These emboli can enter the bloodstream through the inflamed heart valves and cause problems elsewhere in the body.

Diagnosis

Diagnosing endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs requires a thorough clinical examination by a veterinarian. The first steps include listening to the heart to check for abnormal heart murmurs that could indicate damage to the heart valves.

Blood tests are also important to detect infections. A complete blood count may show elevated white blood cells, indicating an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. Blood cultures can help identify the specific bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. causing the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..

UltrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. examinations of the heart (echocardiographyEchocardiography is an ultrasound examination of the heart that assesses the structure and function of the heart valves and chambers. It can provide information about heart size, pumping function, and the presence of heart disease.) are crucial to detect structural changes in the heart valves and assess the extent of the damage. These imaging procedures are particularly helpful in confirming the presence of vegetations on the valves, which are typical of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment..

Therapy

The treatment of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs is often complex and requires a combination of drug therapy and supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. care. Antibiotics are the mainstay of treatment and are administered over a long period of time to combat bacterial infections. The choice of antibiotics depends on the results of blood cultures to ensure that the correct treatment is used against the identified bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease..

In addition to antibiotic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions., it may be necessary to administer medications to support heart function, especially if the endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. leads to heart failure. DiureticsDiuretics are medications that increase urine production in the kidneys to rid the body of excess salt and water. They are often used to treat high blood pressure, heart failure, and certain types of edema. may be prescribed to reduce fluid accumulation and relieve the symptoms of heart failure.

In some cases, surgical intervention may be necessary, especially if the heart valves are severely damaged. However, such procedures are rare and pose a significant risk, especially in older dogs or those with accompanying health problems.

Prognosis and follow-up care

The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. for dogs with endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. varies greatly and depends on several factors, including the type of pathogenA pathogen is a microorganism or virus that can cause disease in its host. Pathogens include bacteria, viruses, fungi, and parasites., the severity of the disease, and the response to treatment. In general, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is better with early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and appropriate treatment.

Dogs that respond well to antibiotic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. and have not suffered severe heart damage may recover completely. However, even with successful treatment, there is a risk of relapse or long-term heart damage that may require continuous medical care.

In dogs that do not respond well to treatment or in which the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made too late, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. may be worse. In such cases, the disease may progress despite treatment and ultimately lead to death.

Prevention

The preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs focuses on minimizing the risks of bacterial infections and promoting good general health. Regular dental care is crucial, as dental disease is a common source of bacterial infections that can lead to endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment.. Regular dental cleanings by the veterinarian and good oralOral means "through the mouth" and refers to the intake of food, medication, or other substances through the mouth. In veterinary medicine, many treatments are administered orally. hygiene at home can help reduce the risk.

In addition, any infections, such as skin infections or urinary tract infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., should be treated early to prevent bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. from entering the bloodstream. A healthy immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. is also important to ward off infections, so a balanced diet and regular health care should be ensured.

In dogs with pre-existing valvular heart disease or other risk factors, the veterinarian may consider prophylactic antibiotics, especially before procedures that could increase the risk of bacteremia. However, such measures should be carefully considered and tailored to the individual.

Outlook on current research

Research into endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs is a dynamic field that is constantly evolving. Scientists are working to better understand the causes, diagnostics, and treatment options for this heart disease. One of the main causes of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs is bacterial infections that spread to the inner lining of the heart. Current studies are investigating which types of bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. are most commonly involved and how they enter the bloodstream. Common entry points are gingivitis or skin lesions, which can lead to bacteremia. Researchers are also looking at whether certain breeds or age groups are more susceptible to this infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..

Another important area of research is the development of improved diagnostic methods. Currently, the diagnosis of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs is often challenging because the symptoms can be non-specific and other heart diseases show similar signs. Modern imaging techniques such as echocardiographyEchocardiography is an ultrasound examination of the heart that assesses the structure and function of the heart valves and chambers. It can provide information about heart size, pumping function, and the presence of heart disease. and advanced blood tests are being investigated to improve the accuracy and speed of diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients.. There are also efforts to identify biomarkers that can be detected in the blood of dogs with endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. and could enable early detection.

The treatment of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. currently focuses primarily on the administration of antibiotics to combat the underlying bacterial infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. However, there is increasing research examining alternative and complementary therapies, including the role of antioxidants and anti-inflammatory drugsAnti-inflammatory drugs are medications that reduce inflammation. They can be divided into nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids and are used in dogs and cats to reduce Inflammatory conditions and Pain. in supporting heart health. It is also being investigated how surgical intervention, such as the removal of infected tissue sections, can support severe cases of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment.. Genetic research could also play a role in the future by helping to understand which dogs may have a higher genetic risk of developing this disease.

Overall, current research aims to improve the quality of life and survival chances of dogs with endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment.. By better understanding the pathophysiologyPathophysiology deals with the changes in physiological processes caused by diseases or injuries. It examines how these changes lead to the symptoms and signs of a disease., risk factors, and optimal treatment strategies, veterinary medicine hopes to develop preventive measures and improve the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. for affected dogs.

Frequently asked questions (FAQs)

What is endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs? EndocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. is an inflammatory condition of the inner layer of the heart, usually caused by a bacterial infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. This inflammatory condition can affect the heart valves and heart function.
What symptoms does a dog with endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. show? Symptoms can include fever, lethargy, loss of appetite, respiratory distress, cough, and weight loss. In severe cases, heart murmurs and signs of heart failure may also occur.
How is endocarditis diagnosed in dogs? The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through a combination of clinical examination, blood tests, urinalysis, and imaging techniques such as X-rays and echocardiographyEchocardiography is an ultrasound examination of the heart that assesses the structure and function of the heart valves and chambers. It can provide information about heart size, pumping function, and the presence of heart disease.. Blood cultures are important to identify the specific bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease..
Which dogs are most at risk of developing endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment.? Dogs with pre-existing heart disease, older dogs, and those with a tendency to gingivitis or skin infections are particularly at risk. Certain breeds may also be more susceptible, but further research is needed.
How is endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. treated in dogs? Treatment usually involves administering antibiotics over a long period of time. Depending on the severity, heart medications or anti-inflammatory agents may also be necessary. In some cases, surgical intervention may be necessary.
How long does endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. treatment take? Treatment can take several weeks to months, depending on the severity of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. and the response to therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions.. Early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment significantly improves the outlook.
Can endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. be cured in dogs? In some cases, the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. can be successfully treated, but the damage to the heart valves may be permanent. Long-term medical care and regular check-ups are often necessary to monitor the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the disease.
How can you reduce the risk of endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment. in dogs? Good dental hygiene, regular veterinary examinations, and treatment of skin infections can help reduce the risk. Vaccinations and avoiding situations that can lead to injuries are also important.
Are certain seasons more risky for endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment.? There are no specific seasons that are associated with an increased risk. However, environmental factors such as humidity or temperature can indirectly affect the risk of infections that can lead to endocarditisEndocarditis is an inflammation of the heart's inner lining, the endocardium, often caused by a bacterial infection. It can damage heart valves and is a serious condition requiring immediate medical treatment..
Are there new research or treatments on the horizon? Yes, research is constantly evolving. Scientists are investigating new diagnostic methods, alternative treatments, and genetic factors that could lead to a better understanding and management of the disease. Antioxidants and new medications are also in testing.