Makindo Medical Notes.com

The presence of an Endocarditis Team is crucial in IE. This multidisciplinary approach has been shown to significantly reduce the 1-year mortality in infective endocarditis. Do not start antibiotics before taking multiple blood cultures (at least 3 over a period of 12+ hrs) with excellent asepsis.

About

• Infective Endocarditis (IE) is a serious infection of the inner lining of the heart chambers and valves, typically caused by bacteria.
• It's a condition that requires prompt diagnosis and treatment to prevent complications.

Aetiology

• Infection of Heart valve (native or prosthetic), Endocardium, blood vessel, Congenital anomaly VSD, Aortic valve.
• Often pre-existing endocardial damage due to jets and turbulence from MR/VSD which is vulnerable to infection.
• Infection causes vegetations, composed of organisms, fibrin and platelets, to grow and may break away as emboli.
• Local tissue destruction. Abscesses form and valves fail to function with regurgitation.
• Immune response can lead to vasculitis and skin lesions, immune complex deposition.
• Emboli can occur to the brain and other organs.

Epidemiology

• Commoner in men
• Older patients
• IV drug abuse
• Rheumatic heart disease

Organisms

Risk Factors

• Pre-existing heart valve disease (e.g., rheumatic heart disease)
• Prosthetic heart valves
• Congenital heart defects
• Intravenous drug use
• Recent dental procedures or surgeries
• Immunocompromised state

High risk groups

• Prosthetic valve: Higher risk of IE, a higher mortality and morbidity than patients with native valves and an identical pathogen. Also applies to transcatheter-implanted prostheses and homografts.
• Previous IE: greater risk of new IE, higher mortality and higher incidence of complications than patients with a first episode of IE
• Untreated cyanotic congenital heart disease (CHD): and those with CHD who have postoperative palliative shunts, conduits or other prostheses. Recommend prophylaxis for the first 6 months after the procedure until endothelialisation of the prosthetic material has occurred.

Vegetations on Mitral valve

Clinical

• Malaise, weight loss, fever, chills
• New murmurs, AF, Dyspnoea
• New stroke or embolic episode e.g. strokes, splenic infarct, lung
• Roth spots in fundi, Clubbing
• Splinter haemorrhages under the nails
• Osler's nodes and Janeway lesions
• Pulmonary oedema, rotten teeth/gums
• Right-sided endocarditis seen IV drug users. May be TR and lung consolidation.

Roth spots

Digital infarcts

Diagnosis of IE typically involves

• Blood cultures: Multiple blood cultures are taken to identify the causative organism.
• Echocardiography: Transthoracic (TTE) or transesophageal echocardiography (TEE) to detect vegetations or abscesses.
• Duke Criteria: Used to establish the diagnosis, combining clinical, microbiological, and echocardiographic findings.

Pathological criteria

• Positive histology or microbiology of pathological material obtained at autopsy or cardiac surgery (valve tissue, vegetations, embolic fragments, or intracardiac abscess content)

Major criteria

• Two positive blood cultures showing typical organisms consistent with infective endocarditis, such as Streptococcus viridans and the HACEK group OR
• Persistent bacteraemia from two blood cultures taken > 12 hours apart or three or more positive blood cultures where the pathogen is less specific, such as Staphylococcus aureus and Staph epidermidis OR
• Positive serology for Coxiella burnetii, Bartonella species, or Chlamydia psittaci OR
• Positive molecular assays for specific gene targets
• Positive echocardiogram showing oscillating structures, abscess formation, new valvular regurgitation, or dehiscence of prosthetic valves

Minor criteria

• Predisposing heart disease
• Fever > 38°C
• Immune phenomena e.g. glomerulonephritis, Osler's nodes, Roth spots, +ve RF
• Microbiological evidence not fitting major criteria
• Elevated C reactive protein or erythrocyte sedimentation rate
• Vascular phenomena e.g. major emboli, splenomegaly, clubbing, splinter haemorrhages, petechiae, purpura

Definite infective endocarditis

• Pathological criteria positive OR
• Two major criteria OR
• One major and two minor criteria OR
• Five minor criteria

Microbiology

• Strep viridans: subacute, oral/resp
• Enterococci: subacute, Gut/Urinary
• Staph. Aureus: Severe acute infection. IV Drug users
• Staph. Epidermidis: Skin, Post cardiac op
• Gram-negative HACEK group
  • Haemophilus spp.
  • Actinobacillus
  • Cardiobacterium hominis
  • Eikenella spp.
  • Kingella kingae).
• Coxiella burnetiid (Q fever) |Brucella : from animals
• Yeasts/fungi: immunocompromised

Investigations

• Bloods: normochromic, normocytic anaemia. Raised WCC. Raised ESR and CRP: U&E: Usually normal
• Urinalysis: Microscopic haematuria
• Blood cultures: crucial. Send 3 sets 12 hours apart before starting antibiotics. Cultures guide treatment. Starting antibiotics is a senior decision.
• Echocardiography: defines valve status and detects abscess. Trans oesophageal is best.
• ECG: Sinus tachycardia, AF, AV block (aortic root abscess)
• CXR: evidence of cardiac failure
• CT/MRI head if new neurology: Embolic infarcts from endocarditis often bleed if anticoagulated. IE can present as a Haemorrhagic stroke.

Mitral valve vegetation see on TOE/TEE

Medical Management: Diagnose as above. Needs referral to Endocarditis service

• Medical: Remove infection source e.g. dental/skin abscess. Choice of antibiotic will be based on blood cultures which must be sent off early and before antibiotics started. There must be multiple from multiple sites and done with strict asepsis.
• Prosthetic Valve Endocarditis: treatment should last longer (at least 6 weeks) than that of Native valve endocarditis (NVE) (2-6 weeks)

Surgical Management

• Valve Replacement
  • Mechanical or Bioprosthetic Valve Replacement: The infected valve is removed, and a new mechanical or bioprosthetic valve is implanted. Mechanical valves are more durable, but bioprosthetic valves are often preferred in older patients or those who cannot take long-term anticoagulation.
  • Homograft: Use of a human donor valve (allograft) is sometimes considered, particularly in complex cases like aortic root abscess.
• Valve Repair : When feasible, valve repair is preferred over replacement, especially in cases involving the mitral valve. This may involve debridement of infected tissue, patching of perforations, and reconstruction of valve leaflets.
• Debridement of Infected Tissue: Removal of all infected and necrotic tissue, particularly in cases of abscesses or extensive perivalvular infection, to create a clean environment before reconstruction.
• Abscess Drainage: Surgical drainage and debridement of perivalvular abscesses are critical to prevent further destruction and spread of infection.
• Fistula Repair: Surgical correction of fistulae that may develop between cardiac chambers or between the heart and surrounding structures.
• Removal of Infected Devices: removal of any infected prosthetic material, such as pacemaker leads or defibrillators, which may act as a source of persistent infection.
• Timing of Surgery: may be urgent in cases of acute heart failure, ongoing embolization, or uncontrolled infection, surgery is often performed on an urgent basis, even during active infection.
• Elective Surgery: less acute the surgery may be delayed until after a course of antibiotics to stabilize the patient and decrease the risk of surgical complications.
• Early intervention: in appropriate cases can significantly reduce mortality and improve long-term survival and quality of life.

References

• 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC)