Infective endocarditis (brief) Flashcards
What causes it?
Tends to runs an insidious course, and is known as subacute (bacterial) endocarditis (SBE). Infections occur in the following:
- On valves, which have a congenital or acquired defect (usually on the left side of the heart). Right sided is more common in IVDUs.
- On normal valves with virulent organisms such as Streptococcus pneumoniae or Staphylococcus aureus.
- On prosthetic valves, when infection may be early (<60 days) or late
- In association with VSD or persistent ductus arteriosus
Strep viridans, enterococci are also common causes
How does it present?
Systemic features of infection, such as malaise, fever, night sweats, weight loss and anaemia. Slight splenomegaly is common. Clubbing is rare and occurs late
Valve destruction: Leading to heart failure and new or changing heart murmurs (in 90%)
Vascular phenomena due to embolization of vegetation’s and metastatic abscess formation in the brain, spleen and kidney. Embolization from right side causes pulmonary infarction and pneumonia
Immune complex deposition in blood vessels producing a vasculitis and petechial haemorrhages in the skin, under the nails and in the retinae (Roth’s spots). Osler’s nodes (tender subcutaneous nodules in the fingers) and Janeway lesions (painless erythematous macules on the palms) are uncommon. Immune complex deposition in the joints causes arthralgia and, in the kidney, acute glomerulonephritis. Microscopic haematuria occurs in 70% of cases but AKI is uncommon
Investigations
Blood cultures.
ECHO.
Serology.
CXR may show heart failure of evidence of septic emboli.
ECG may show MI.
Blood count shows a normochromic, normocytic anaemia with a raised ESR and often a leucocytosis.
Diagnosis relies on minor and major signs from duke’s criteria (2 major, or 1 major and 3 minor)
Treatment
Empirical ABX until sensitivity performed. Surgery to replace valves if there is severe heart failure, extensive damage, or it’s just getting worse.
