Infective Endocarditis

1 · Think of it

The presentation is usually fever plus something:

• Fever with a new or changed murmur
• Fever with no obvious source in someone with a prosthetic valve, pacemaker or ICD, congenital heart disease, or previous endocarditis
• Fever in a person who injects drugs — think right-sided, tricuspid, with septic pulmonary emboli
• Fever with an indwelling vascular line
• Weeks of malaise, weight loss, night sweats and anaemia — the indolent streptococcal picture
• Embolic stroke or a new focal deficit with fever

Peripheral stigmata (splinters, Osler's nodes, Janeway lesions, Roth spots) support the diagnosis but are frequently absent — their absence proves nothing.

2 · Blood cultures — before antibiotics

Three sets of blood cultures, 10ml per bottle, from separate sites.

This is the step that is most often got wrong and the hardest to undo: once antibiotics are running, cultures can stay negative for days, and culture-negative endocarditis is far harder to treat correctly.

• The 2023 Duke-ISCVID criteria removed the strict requirement for spaced timing and separate venepunctures, but taking them properly remains best practice
• The exception: if the patient is septic or haemodynamically unstable, take what you can and give antibiotics — do not delay treatment in sepsis
• Tell microbiology you suspect endocarditis so bottles are held longer for fastidious organisms

3 · Other bedside work

• ECG — a new conduction delay or lengthening PR interval suggests an aortic root abscess and is an alarming sign
• Urinalysis — haematuria is common (emboli, glomerulonephritis)
• Bloods: FBC, U&E, LFT, CRP, clotting, group & save
• CXR — septic pulmonary emboli in right-sided disease, pulmonary oedema in valve failure
• Examine for embolic phenomena, splenomegaly and new neurology

4 · Echo

• Transthoracic echo (TTE) first, urgently
• A normal TTE does not exclude endocarditis. If suspicion remains, or there is a prosthetic valve or intracardiac device, transoesophageal echo (TOE) is needed
• Looking for: vegetation, abscess, new valvular regurgitation, new dehiscence of a prosthetic valve
• Repeat imaging if the clinical picture changes

5 · Antibiotics and the Endocarditis Team

• Discuss every suspected case with microbiology / infectious diseases — empirical choice depends on native versus prosthetic valve, suspected organism, and local resistance
• Local antimicrobial policy overrides any national default. This app does not give you a regimen to use unreviewed
• Treatment is prolonged IV therapy, typically 4–6 weeks, guided by the organism
• ESC recommends management by a multidisciplinary Endocarditis Team including cardiology, cardiac surgery and ID
• Consider OPAT for the completion phase once stable and discussed

6 · Know the surgical triggers

Surgery is considered — often urgently — for:

• Heart failure from acute valvular regurgitation (the commonest indication)
• Uncontrolled infection: abscess, fistula, enlarging vegetation, persistent fever and positive cultures despite appropriate antibiotics
• Prevention of embolism: large vegetations, particularly >10mm with an embolic event already, and especially on the mitral valve
• Prosthetic valve endocarditis and device-related infection

Recognising these and escalating is the F1's job; deciding is the team's.