GPSI in Cardiology Dr Matthew Molloy considers this rarely seen presentation
What is it?
Endocarditis is a condition where the inner lining of the heart (the endocardium) becomes infected. It is rare but can be fatal. Bacteria or fungi in the bloodstream can attach to areas of the endocardium (usually already damaged area) causing the infection. This can develop into vegetations which can embolise. There are several cardiac and non-cardiac risk factors for developing endocarditis. Patients can develop endocarditis with no cardiac or non-cardiac risk factors but these risks make it much more likely.
Cardiac risk factors
- Congenital heart disease
- Valvular heart disease
- Prosthetic heart valve
- Previous infective endocarditis
- Internal cardiac devices
Non-cardiac risk factors
- IV drug use
- Recent dental / surgical procedures
- Central arterial / venous catheterisation
- Haemodialysis
How rare is it?
Endocarditis affects around 1 in 30,000 people in the UK each year, which equates to 2,000 diagnoses each year.
May be confused with…
The presentation of infective endocarditis can be variable and non-specific with patients complaining of systemic symptoms such as fever, night sweats, appetite and weight loss, breathlessness and fatigue. Differential diagnoses can include Lyme disease, meningitis, tuberculosis, atrial myxoma, lymphoma, SLE, polymyalgia rheumatics and pulmonary embolism.
Red flags
Key diagnostic factors on history and examination include the presence of risk factors, fever, a new or changing cardiac murmur, night sweats, malaise, weight loss, anorexia, myalgia, fatigue, weakness, arthralgia, headaches and breathlessness. Less commonly patients may present with meningeal signs, Janeway lesions, Osler’s nodes, Roths spots and splinter haemorrhages.
Clues for early detection
The symptoms of infective endocarditis can develop quickly in some patients but in others may take weeks or even months to develop. It is vitally important when infective endocarditis is suspected that the patient is admitted urgently as early diagnosis and treatment can prevent permanent endocardial / valve damage or death.
Investigations in primary care which may point to the diagnosis of infective endocarditis include a raised WCC or raised inflammatory markers (CRP/ESR) and urine dipstick may reveal microscopic haematuria. Infective endocarditis is worth considering as a diagnosis in cases of unexplained malaise or fever with a high CRP, especially if the patient has one or more risk factors.
At hospital key investigations include
- Blood cultures
- Transthoracic echocardiogram (TTE) is the first line imaging investigation.
- Transoesophageal echocardiogram can provide more information than TTE but is more invasive.
Diagnosis of endocarditis is based on the Duke Criteria which ranks major and minor factors.
Major Duke criteria
Positive blood cultures, which have to meet number of complex criteria. Evidence on echocardiogram of:
- Intra-cardiac vegetation (oscillating intracardiac mass)
- Abscess
- New valvular regurgitation (change in pre-existing murmurs is not included)
- New partial dehiscence of prosthetic valve
Minor Duke criteria
- Risk factors for infective endocarditis
- Fever > 38oC
- Vascular phenomena: septic emboli, Janeway lesions, conjunctival haemorrhage, intracranial haemorrhage
- Immunological phenomena: glomerulonephritis, Osler’s nodes, Roth spots, positive rheumatoid factor
- Microbiological evidence: positive blood cultures which do not meet the major criteria
Suspected cases of endocarditis are classified into definite, possible or rejected endocarditis based on these criteria.
Treatment
Management of infective endocarditis includes prolonged courses of antibiotics (or antifungals if the infection is of fungal aetiology). Antibiotics are initially given IV for at least two weeks before switching to the oral route.
European Society of Cardiology (ESC) guidance advises that treatment should last for at least six weeks in patients with prosthetic valves and two to six weeks for native valve endocarditis.
The ESC emphasises the high importance of having an established endocarditis team at each heart centre to specifically manage endocarditis.
Surgery to repair or replace the valve is sometimes required in addition to antibiotics.
Every patient with prosthetic valve endocarditis should have an urgent surgical review.
Prophylaxis
Clinicians should provide patients at risk of endocarditis with clear and consistent information about prevention, including:
- the benefits and risks of antibiotic prophylaxis and an explanation of why antibiotic prophylaxis is no longer routinely recommended
- the importance of maintaining good oral health
- Symptoms that may indicate infective endocarditis and when to seek expert advice
- The risks of undergoing invasive procedures including non-medical procedures such as body piercing or tattooing
Complications
Infective endocarditis can cause cardiac and systemic complications.
Cardiac complications
- Valve destruction and heart failure
- Arrhythmias
- Myocardial infarction
- Pericarditis
- Aortic root abscess
Systemic complications
- Emboli (e.g. stroke, splenic infarction)
- Septicaemia
- Death
Prognosis
Annual mortality for infective endocarditis remains high at up to 40% with recurrence seen in between 2% and 6% of survivors.
Patients who are elderly, who have multiple comorbidities and those who have prosthetic valves generally have worse outcomes, as do those with severe complications from endocarditis such as heart failure or stroke.
Echocardiograms may demonstrate pathology associated with a poor prognosis, such as large vegetations, severe left-sided valve regurgitation and low left ventricular ejection fraction.
Resources
European Society of Cardiology (ESC). 2023 ESC Guidelines for the management of endocarditis. November 2023
NICE. Prophylaxis against infective endocarditis: antimicrobial prophylaxis against infective endocarditis in adults and children undergoing interventional procedures. [CG64] Last updated 2016
British Heart Foundation. Endocarditis – causes, symptoms and treatments.
