Canis ISSN: 2398-2942

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.

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

• 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

Treatment

Outcomes