Endocarditis: bacterial
Introduction
- Rare.
- Valvular (usually mitral and aortic valves). Less commonly mural.
- Cause: usually history of previous septic focus or febrile illness (but not always).
- Signs: episodic illness with pyrexia, multi-system involvement, and variable heart murmurs.
- Diagnosis: history, signs, ultrasonography.
- Treatment: antibiotic.
- Prognosis: guarded.
Presenting signs
- Malaise, inappetence.
- Lameness, joint swelling or pain.
- History or signs of original injury/infection.
- Signs of heart failure (left sided).
Acute presentation
- Sudden death.
Breed/Species predisposition
- Breeds predisposed to congenital subaortic stenosis Heart: aortic stenosis. Endocarditis can affect aortic valves.
Large breeds
- German Shepherd Dog German Shepherd Dog.
- Great Dane Great Dane.
- Boxer Boxer.
Cost considerations
- Depends on investigations and treatment - may be expensive for many owners.
Special risks
- Same as congestive cardiac failure Heart: congestive heart failure.
Pathogenesis
Etiology
- Bacteremia (Streptococcusspp Streptococcus spp ,E. coli Escherichia coli ,Staphylococcusspp Staphylococcus spp ), and sequestration as colony on valve leaflet, with platelet and fibrin deposition and accumulation over time.
Predisposing factors
General- Previous infection/wound inappropriately treated.
- Non-aseptic surgical procedure.
- Immunosuppressive therapy (glucocorticoids).
- Long-term indwelling venous cannula.
- Aortic stenosis Heart: aortic stenosis (congenital).
Pathophysiology
- Bacterial infection → bacteremia → adherence to normal or abnormal valve and fibrin deposition over time → develops into a vegetation → bacteria can seed off intermittently → episodic pyrexia and variable clinical signs depending on terminus of septic embolism → destruction of valve → insufficiency or stenosis.
- Septic embolization usually causes signs other than cardiac dysfunction, eg septic arthritis Arthritis: septic , septic emboli in kidneys Kidney: thromboembolism.
- Septic embolization → valve vegetation → altered hemodynamics of the specific valve → valvular insufficiency → valvular stenosis → heart failure.
- Also, valvular vegetation → seed septic emboli to other organs → variable manifestations.
Timecourse
- Variable, eg 6-12 weeks after non-specific pyrexic illness.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Peddle G & Sleeper M M (2007) Canine bacterial endocarditis: a review. JAAHA 43 (5), 258-263 PubMed.
- Sykes J E, Kittleson M D, Pesavento P A, Bryne B A, MacDonald K A & Chomel B B (2006) Evaluation of the relationship between causative organisms and clinical characteristics of infective endocarditis in dogs: 71 cases (1992-2005). JAVMA 228 (11), 1723-1734 PubMed.
- Boswood A (1996) Resolution of dysrhythmias and conduction abnormalities following treatment for bacterial endocarditis in a dog. JSAP 37 (7), 327-332 PubMed.
- Bennett D, Taylor D J (1988) Bacterial infective arthritis in the dog. JSAP 29 (4), 207-230 VetMedResource.
- Ellison G W, King R R, Calderwood-Mays M (1988) Medical and surgical management of multiple organ infarts, secondary to bacterial endocarditis in a dog. JAVMA 193 (10), 1289-1291 PubMed.