Bacterial endocarditis

Introduction

  • Infection on heart valves which have a poor blood supply and so often cannot get rid of infection
  • Depending on bacteria causing infection may present as a severe acute illness (e.g. staphylococcus aureus) or more chronic illness developing over weeks or even months (e.g. streptococcus milleri)
  • Infected vegetations on the heart valves can embolise to the brain or other organs (see illustration below)
  • Emboli may block blood vessels causing ischaemic stroke or cause the blood vessels to become aneurysmal and to rupture causing a haemorrhagic stroke
  • Most commonly affects the mitral and aortic valves. If affects tricuspid or pulmonary valves unlikely to cause strokes
  • May be detected on transthoracic echocardiogram but transoesophageal echocardiography more likely to show vegetations
  • Positive blood cultures after stroke may indicate the presence of endocarditis

Heart showing close up section of aortic valve with bacterial endocarditis

Image label:

Aortic valve with bacterial endocarditis