Endocarditis Flashcards
What may cause acute infective endocarditis?
Rapidly progressive infection – tends to occur on normal valves and may present with acute heart failure + emboli
Risk factors: Skin breaches e.g. dermatitis, IV lines, wounds, dental surgery Renal failure Immunosuppression Diabetes mellitus
What may cause subacute/chronic disease endocarditis?
Low-grade fever and non-specific symptoms – tends to occur on abnormal valves
Risk factors: Aortic or mitral valve disease Tricuspid valves in IV drug users Coarctation of the aorta Patent ductus arteriosus Ventricular septal defects Prosthetic valves (Staph. epidermidis)
What signs of endocarditis may be seen on examination?
- Petechiae - Common but nonspecific finding (remember to look at the mucosa)
- Subungual (splinter) haemorrhages - Dark red linear lesions in the nail beds
- Osler nodes - Tender subcutaneous nodules usually found on the distal pads of the digits
- Janeway lesions – Non-tender maculae on the palms and soles
- Roth spots - Retinal haemorrhages with small, clear centres; rare and observed in only 5% of patients.
Signs and symptoms of infective endocarditis?
Septic signs: Fevers, rigors, night sweats, malaise, weight loss, anaemia, splenomegaly, clubbing
Cardiac lesions: New murmur, or changes in pre-existing murmurs
Immune complex deposition: Vasculitis, microscopic haematuria, glomerulonephritis, acute kidney injury
- Splinter haemorrhages under nails, Roth spots (boat-shaped retinal haemorrhages with pale centres), Osler nodes (tender, pulpy infarcts in fingers and toes), mucosal petechiae
Embolic phenomena: Emboli may cause abscesses in relevant organs e.g. brain, heart, kidney, spleen, gut, lung
- If in skin, termed Janeway lesions: non-tender, erythematous, haemorrhagic/pustular spots on the palms or soles. Pathognomonic with Osler nodes
What tests and investigations can be done for infective endocarditis?
- Blood cultures: Do three sets, at different times, from different sites, at the peak of fever
- Blood tests: Normocytic, normochromic anaemia, neutrophilia, ↑ESR/CRP. Rheumatoid factor positive
- U&Es, Mg, LFTs
- Urinalysis: For microscopic haematuria
- ECG: Look for signs of heart block. Aortic root abscess causes lengthening of the PR interval, and may lead to complete AV block. LVF can cause death
- CXR: Cardiomegaly, pulmonary oedema
- Echocardiogram: Trans-thoracic may show vegetations, but trans-oesophageal is more sensitive and better for visualising mitral lesions and aortic root abscesses
- CT: Look for emboli in organs e.g. spleen, brain
What is needed for the Duke Criteria for diagnosis of endocarditis?
Requires either 2 Major, 1 Major + 3 minor, or 5 minor
What are the majors in the Duke criteria for endocarditis?
Positive blood culture – typical organism in two separate cultures OR persistently positive cultures >12h apart OR single positive culture for C. burnetii
Evidence of endocardial involvement:
- Positive echocardiogram (vegetation, abscess, pseudoaneurysm, dehiscence of prosthetic valve)
- Abnormal activity around prosthetic valve on PET/CT or SPECT/CT
- Paravalvular lesions on cardiac CT
- New valvular regurgitation
What are the minors in the Duke criteria for endocarditis?
- Predisposition e.g. pre-existing heart condition, IV drug use, immunosuppression
- Fever > 38.C
- Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial haemorrhage, conjunctival haemorrhages and Janeway’s lesions
- Immunological phenomena: glomerulonephritis, Osler’s nodes, Roth’s spots and rheumatoid factor
- Microbiological phenomena: positive blood culture but does not meet a major criterion as noted above or serological evidence of active infection with organism consistent with IE
- Echocardiographic findings consistent with IE but do not meet a major criterion as noted above
- PCR: broad-range PCR of 16S (polymerase chain reaction using broad-range primers targeting the bacterial DNA that codes for the 16S ribosomal subunit)
Management of endocarditis?
- Antibiotic therapy in accordance with Trust Policy; liaise early with microbiologists and cardiologists
- Therapy for prosthetic valve IE should be longer (>6wks) than in native valve IE (2-6wks)
- Surgery: In HF, valvular obstruction, repeated emboli, fungal IE, persistent bacteraemia, myocardial abscess, unstable infected prosthetic valve
What prevention can be done for infective endocarditis?
AB prophylaxis is no longer recommended for those at risk of IE undergoing invasive procedures, but if they receive AB for other reasons, common organisms should be covered
Give clear information about:
- Importance of maintaining good oral health
- Symptoms indicating IE and when to seek advice
- Risks of invasive procedures, including non-medical procedures e.g. body piercing, tattooing
