PassFinals
Cardiovascular

Infective Endocarditis

Infective endocarditis is infection of the endocardium, usually a valve or intracardiac device; obtain adequate blood cultures, image early and involve the endocarditis team urgently.

In a nutshell

Suspect infective endocarditis with fever plus a murmur, bacteraemia, embolic features, new regurgitation or conduction disease. Take adequate blood cultures before antibiotics when safe, obtain early echocardiography, involve the endocarditis team and escalate rapidly for heart failure, uncontrolled infection, abscess, prosthetic/device infection or embolic complications.

Classic presentation

Subacute fever, fatigue, weight loss and a new murmur, or acute sepsis/heart failure with persistent bacteraemia; peripheral stigmata may be absent.

Key points

  • IE can be acute or subacute and may lack a murmur or peripheral signs.
  • Take three blood-culture sets as separate draws before antibiotics when the patient is stable; in shock, do not delay life-saving treatment after immediate cultures.
  • TTE is first-line; TOE is needed when TTE is negative/inadequate but suspicion persists, for prosthetic valves/devices or to define complications.
  • Use an endocarditis team involving infection/microbiology, cardiology, echocardiography and cardiac surgery; ensure rapid heart-centre access.
  • Do not copy a fixed antibiotic regimen: empirical and directed therapy depend on valve type, acquisition, cultures, susceptibility, allergy, renal function and local guidance (see BNF/local antimicrobial protocol).
  • Urgent surgery discussions are triggered by heart failure from valve dysfunction, uncontrolled infection/peri-valvular extension, device/prosthetic infection or major embolic risk.
  • NICE routine antibiotic prophylaxis is not recommended for most dental, gastrointestinal, genitourinary or respiratory procedures; oral health and prompt infection treatment matter.

First-line investigation

Three blood-culture sets before antibiotics when safe, plus prompt TTE and baseline organ-function tests.

Management

Recognise sepsis and cardiac complications

  • Shock, pulmonary oedema, new AV block, prosthetic/device infection or major embolic events need urgent senior care and heart-centre discussion.3,1

Obtain cultures and image early

  • Take three blood-culture sets before antibiotics when safe, then perform TTE and escalate to TOE when indicated.4,1,3

Start specialist antimicrobial care

  • Use local/BSAC/BNF guidance for empirical therapy, then narrow promptly to organism and susceptibility results (see BNF/local antimicrobial protocol).2,5

Refer for surgery or device source control

  • Discuss HF from valve dysfunction, uncontrolled infection, abscess/new block, prosthetic/device infection, fungal disease or major embolic risk urgently with the IE team.3

Manage embolic and treatment complications

  • Look actively for neurological, renal, splenic, pulmonary and spinal complications; coordinate anticoagulation and procedures through the MDT.3,1

Prevent recurrence

  • Provide oral-health, infection and recurrence advice; routine antibiotic prophylaxis is not recommended for most listed procedures under NICE CG64.6

Exam traps

  • A single positive blood culture may be contamination; interpret with organism, number of positive sets and clinical context.
  • A negative TTE does not exclude IE when suspicion remains; escalate to TOE and repeat imaging.
  • Do not delay cultures unnecessarily, but do not delay antibiotics in septic shock or severe instability.
  • IE with a mechanical valve is not an automatic indication to continue anticoagulation unchanged; neurological and surgical risks require MDT review.
  • NICE prophylaxis guidance concerns prevention in at-risk people, not treatment of suspected IE.

Illustrations

Vegetation formation on damaged endotheliumDiagram showing platelet-fibrin deposition on injured endothelium followed by bacterial seeding to form a vegetation.PassFinals · original
Cutaneous stigmata of infective endocarditis on the hand (Osler's nodes / Janeway lesions)Composite clinical image of splinter haemorrhages, Janeway lesions, Osler's nodes and Roth spots produced by septic emboli and immune-complex deposition.Roberto J. Galindo, Wikimedia Commons · CC-BY-SA-4.0
Echocardiogram showing a valve vegetationEchocardiographic still demonstrating a vegetation attached to a heart valve leaflet with associated regurgitation.Daisuke Koya, Kazuyuki Shibuya, Ryuichi Kikkawa and Masakazu Haneda, Wikimedia Commons · CC-BY-2.0

Key sources

  1. NICE CKS: Infective endocarditis (UK diagnostic and management topic)
  2. BSAC: Guidelines for diagnosis and antibiotic treatment of endocarditis in adults (UK antimicrobial treatment guidance and organism-directed therapy principles)Published 1 May 2012
  3. Joint British Societies: Expert consensus recommendations for infective endocarditis services (IE teams, referral, heart-centre access, diagnosis and care pathways)Published 11 Aug 2023
  4. UKHSA: UK SMI S12 — Sepsis and systemic or disseminated infections (Blood-culture collection and microbiological investigation standards)Published 27 Feb 2023 | Updated 28 Dec 2023
  5. NHS Scotland Medicines: Cardiovascular infective endocarditis (UK antimicrobial pathway example for cultures, empirical therapy and monitoring)Updated 1 Feb 2024
  6. NICE CG64: Prophylaxis against infective endocarditis (Risk groups, oral health, infection treatment and antibiotic-prophylaxis recommendations)Published 17 Mar 2008 | Updated 8 Jul 2016

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.