A 70-year-old lady presents to her GP with recurrent fevers, fatigue, confusion and shortness of breath on exertion, which started a few weeks earlier. On examination she is febrile with a temperature of 38.4°C. The GP notes that she has a newly discovered early diastolic heart murmur. Chest examination is normal and there is mild, bilateral ankle oedema. Her past medical history includes type 2 diabetes and hypertension.
The GP suspects endocarditis and urgently refers her to A&E.
Endocarditis is defined as an infection that affects the inner lining of the heart (the endocardium), including the heart valves. It’s a rare condition but it carries a risk of mortality and can cause significant cardiac damage. It requires early diagnosis and treatment.
Risk factors for developing endocarditis include:
- Foreign materials such as prosthetic heart valves, pacemaker leads and in-dwelling lines.
- Bicuspid aortic valve.
- Hypertrophic cardiomyopathy.
- Intravenous drug use.
- Poor dental hygiene.
Endocarditis can have a non-specific and insidious onset. Symptoms can develop acutely or slowly over weeks or sometimes months.
The most common features are non-specific flu-like symptoms including fever, myalgia, fatigue, rigors, headache, cough and a sore throat. Unexplained weight loss might be noted, along with the presence of a new heart murmur.
Endocarditis is caused by infective organisms, such as bacteria and fungi, which colonise the endothelial surface of the heart. It has a predilection for the heart valve leaflets (native or prosthetic), where vegetations (an accumulation of platelets in which microorganisms and inflammatory cells embed) form. This may be visible on echocardiography and may embolise, leading to strokes and peripheral or pulmonary emboli, or systemic dispersion of infection.
Other features can include:
- Splinter haemorrhages resulting from vasculitis and microembolisation, seen as vertical lines under the fingernails.
- Janeway lesions – painless red or purple flat spots seen on the palms or soles.
- Osler’s nodes – painful, red, raised spots on the hands and feet caused by immune complex deposition.
Other signs include:
- Roth’s spots – red spots with pale centres, seen on the retina.
- Finger clubbing.
These stigmata are less frequent in earlier presentations of the disease.
Red flags to suggest possible endocarditis
Consider the diagnosis in patients with:
- Known underlying structural heart condition
- Previous cardiac surgery or cardiac intervention
- Intravenous drug use
- In-dwelling venous or other systemic catheters
And in patients with the following symptoms:
- Fever, defined as temperature >38°C for several days without obvious cause
- Unexplained night sweats
- New-onset general lethargy (flu-like symptoms)
- New heart murmur
- Vascular phenomena such as major arterial emboli, septic pulmonary infarcts, infectious (mycotic) aneurysm, intracranial haemorrhage, conjunctival haemorrhages, or Janeway lesions
- Immunological phenomena such as glomerulonephritis, Osler’s nodes or Roth’s spots
Consider especially if there is:
- Prolonged unexplained fever
- High level of inflammatory markers (high CRP, ESR or white cell count)
The spectrum of clinical presentation is wide and can depend on what the causative organism is, where the infection occurs, the presence of underlying heart disease and whether the patient is immunocompromised. The greatest risk is in patients who have had heart surgery or have used drugs intravenously.
As a result, endocarditis can present acutely with sepsis, heart failure and evidence of systemic embolisation, or more insidiously with persistent fever and fatigue.
Acute endocarditis is usually caused by Staphylococcus aureus, but if the presentation is subacute, commonly implicated organisms include viridans streptococci, enterococci, coagulase-negative staphylococcus or gram-negative coccobacilli.1
Early-stage infection can masquerade as other illnesses, making it hard to seal a diagnosis. Some of the red flags that might point you towards the diagnosis are highlighted below. The Duke criteria are commonly used in clinical practice, to accompany clinical judgment.2
Investigations that may be helpful include:
- Blood tests – may show anaemia of chronic disease, raised white cell count, renal failure and elevated inflammatory markers.
- Echocardiogram in the local hospital – may reveal vegetations, regurgitant heart valves or valve destruction.
- ECG – to show new arrhythmia such as atrial fibrillation.
- Chest X-ray.
- Cardiac MRI/CT scan to show mycotic aneurysms.
The most important management aspect if a GP suspects endocarditis is to avoid giving antibiotics. It is important that blood cultures are taken first so proper treatment can be given, using antibiotics to which the organism is sensitive.
Therefore, if endocarditis is suspected, the GP should:
- Do a full and careful examination to document temperature, heart murmurs and evidence of peripheral emboli or immune complexes.
- Arrange blood tests (FBC, renal function, CRP/ESR).
- Admit urgently for full investigations and treatment if the patient is unwell, there is strong suspicion, or if the investigation or blood tests increase suspicion.
Prolonged courses of IV antibiotics are often required and liaison with the hospital is important. Further investigations might be needed, or even heart surgery.
Early characterisation of the implicated organism and sensitivities allows tailoring of therapy, particularly as resistance is becoming an increasing issue.3 Regimens are recommended by the European Society of Cardiology.4 Most regimens include a penicillin for four to six weeks, combined with gentamicin for up to two weeks.
The European Society of Cardiology supports the use of prophylactic antibiotics in high-risk patients undergoing dental surgery, as decided by the specialist.4
Dr Louise Tulloh is a GP at Mendip Vale Medical Group, north Somerset. Professor Robert Tulloh is a consultant congenital cardiologist at Bristol Heart Institute.
- Damlin A, Westling K, Maret E et al. Associations between echocardiographic manifestations and bacterial species in patients with infective endocarditis: a cohort study. BMC Infect Dis 2019;19:1052
- Habib G, Lancellotti P et al. ESC Guidelines for the management of infective endocarditis. Eur Heart J 2015;36:3075-128
- Habib G, Hoen B, Tornos P et al. Guidelines on the prevention, diagnosis and treatment of infective endocarditis (new version 2009): the Task Force on the Prevention, Diagnosis and Treatment of Infective Endocarditis of the European Society of Cardiology (ESC). Eur Heart J 2009;30:2369-413
- Davierwala P, Marin-Cuartas M, Misfeld M et al. The value of an ‘Endocarditis Team’. Ann Cardiothorac Surg 2019;8:621-629