Clinical scenario where endocarditis should be considered

Fever with

• new valvular regurgitation murmur.

• Preexisting predisposing cardiac lesion and no other obvious source of infection

• Predisposition, new intervention, and bacteraemia

• congestive heart failure

• new conduction disturbance

• vascular or immunological phenomenon

• new stroke

• peripheral abscess (spleen, renal, cerebral, vertebral), of unknown cause

Blood culture

• Unexplained persistent blood culture

• CRBSI, bacteremia persisting even 72 hours after catheter removal.

Condition

• protracted history of sweats, weight loss, anorexia or malaise and an at-risk cardiac lesion

• A new embolic phenomenon

Who should be considered for ECHO?

• All patients with suspected endocarditis

• All patients with Staph aureus bacteraemia/candidaemia, ideally first week of treatment & if suspecting endocarditis, within 24 hours.

• At the end of the antibiotic therapy.

When to do trans-oesophageal ECHO (TOE)?

Transthoracic ECHO (TTE) is the investigation of choice. TOE is not indicated in patients with a good-quality negative TTE and low clinical suspicion of IE. TOE could be done in cases of

• high clinical suspicion of IE and a non-diagnostic TTE.

• Consider TOE in all adults with a positive TTE.

• Consider TOE in prosthetic valve intracardiac device.

When to repeat ECHO?

• When initially TTE/TOE is negative, if the clinical suspicion of IE remains high, repeat TTE/ TOE, 7–10 days later.

• if there is evidence of cardiac complications or suboptimal response to treatment.

• At the completion of therapy.

• Preferably take blood cultures before antibiotic

• Chronic/subacute endocarditis - 3 sets of optimally filled blood cultures, with ≥6 hours between them.

• When a patient is unwell/present with sepsis- two sets of blood cultures, separated in time, within 1 hour of presentation.

• How long to incubate - Routine incubation >7 days is not necessary.

• When to repeat blood culture - if the patient remains febrile 7 days after antibiotic treatment.

• What if suspecting endocarditis and the patient is on abx - Stop abx if safe to do so, and take blood culture, may have to wait 7-10 days.

Why 2-3 sets of blood cultures separated in time?

The bacteraemia in endocarditis is continuous in nature. So if only one blood culture becomes positive, it should be regarded with caution.

1. If culture-negative test Q fever (available in RIPL) and Bartonella (not available anymore in the UK). Q fever antiphase I IgG antibody titres and anti-Bartonella titre of >1:800 is positive.

2. If QF/Bartonella negative, test Legionella, Mycoplasma, Chlamydia.

3. If risk factors present - test Brucella

4. Candida serology should not be used.