Introduction

• Rare.
• Cause: bacterial infection of the valves of the heart, usually mitral or aortic.
• Results in valvular incompetence with vegetations or more rarely stenosis.
• Signs: septicemia, infective thromboembolism or acute heart failure.
• Diagnosis: blood culture (not always positive), ultrasonography and clinical signs.
• Treatment: combinations of bacteriocidal antibiotics for a prolonged period.
• Prognosis: generally poor.

Pathogenesis

Etiology

• Possible relationship to congenital disease Congenital heart disease: overview such as subaortic stenosis Heart: aortic stenosis.
• Such diseases increase risk of trauma to the valves and hence allow adhesion of bacteria.
• However, in most cases the valves are normal.
• There is no relationship to mitral valve endocardiosis.

Predisposing factors

General

• Immunocompromized cats or those with congenital defects are likely to be at increased risk.

Pathophysiology

• Bacteremia is very common following surgery or any procedure involving trauma to mucosal surfaces, but usually involves different bacteria to those involved in endocarditis.
• Bacteria involved in endocarditis must also adhere to the valves possibly at a site of pre-existing damage such as a platelet thrombus to cause the disease.

• Bacteremia is common but endocarditis is rare.
• Under unknown circumstances, bacteria adhere to endocardial surfaces of the mitral or aortic valves.
• Streptococci  Streptococcus spp, Staphylococci  Staphylococcus spp, Pseudomonas spp   Pseudomonas spp, E. coli  Escherichia coli  and E. rhusiopathiae are the bacteria most frequently involved.
• Serum bacteriocidal activity is also important as resistant isolates have been shown to cause endocarditis.
• Antibodies seem to be protective as they either stop adhesion or clear the bacteremia.
• The aortic valve is most commonly affected, followed by the mitral valve.
• The tricuspid valve is rarely involved and the pulmonic valve almost never.
• The infection may cause valvular incompetence either by destroying the valve or by the production of vegetations on the valve.
• Rarely valvular stenosis is produced.
• Pieces of the vegetations may break off and embolize causing signs attributable to infarction or infection.
• Signs vary depending on the area affected.
• As a result of the chronic infection, immune-complex disease may be seen.
• Severe aortic regurgitation is poorly tolerated and may cause acute left heart failure and death within a short time.
• Endocarditis is reported as a differential diagnosis of an audible diastolic murmur.
• In addition, it should be considered if there is pulmonary edema and minimal signs of heart enlargement.
• Rarely the infection may involve the myocardium with vegetations on the mural endocardium.

Timecourse

• Usually presented within 7 days.
• If untreated rapidly progresses.

Diagnosis

Treatment

Prevention

Outcomes