Infective endocarditis — structured clinical encounter

Task 1 — Diagnosis (5 minutes)

Establish the diagnosis by applying the Modified Duke criteria. State that the two major criteria (a typical organism in two separate blood cultures, and an echocardiographic vegetation) are both met, making this definite endocarditis. Confirm that the cultures were drawn before any antibiotic, and explain why that discipline protects the diagnosis. [4]

Task 2 — Management (5 minutes)

Outline the targeted antibiotic therapy: penicillin or ceftriaxone for the penicillin-susceptible viridans streptococci, with or without a short course of gentamicin for synergy, for four to six weeks intravenously. State that the duration is non-negotiable because the biofilm within the vegetation shields the organism from a short course. [1]

Task 3 — Complications and the surgical threshold (5 minutes)

Describe the two findings that would prompt urgent surgical referral: heart failure from acute aortic regurgitation (the commonest surgical indication), and a new atrioventricular block signalling an aortic-root abscess. Explain that an abscess is a mechanical problem that no antibiotic regimen can rescue. [1]

Task 4 — Prophylaxis and discharge counselling (5 minutes)

Counsel the family on the cardiac conditions that still require prophylaxis before dental procedures that manipulate the gingiva, including her repaired congenital heart disease. Explain that amoxicillin is given thirty minutes before the procedure, and emphasise the importance of dental health as the orodental source of viridans streptococci. [3]