Acute rheumatic fever and rheumatic heart disease — branching viva

Opening: recognise and score

The candidate opens by recognising that a school-aged child with a sore throat followed by migratory polyarthritis and a new apical pansystolic murmur has acute rheumatic fever until proven otherwise. The major criteria are the polyarthritis and the clinical carditis. The candidate applies the Jones criteria and identifies that the high-risk criteria apply across all of Australia and New Zealand per the 2020 guideline, so monoarthritis or polyarthralgia may substitute for polyarthritis — though here the full polyarthritis is present. [1] [3]

The candidate confirms the streptococcal link with antistreptolysin O and anti-DNase B titres, and requests echocardiography to assess the valve and look for subclinical carditis. The candidate names the five major criteria — carditis, polyarthritis, chorea, erythema marginatum, subcutaneous nodules — and the four minor criteria — fever, arthralgia, raised acute-phase reactants, prolonged PR. [1]

Branch 1: the 2015 subclinical carditis revision

The examiner probes what changed in the 2015 revision. The candidate explains that Doppler echocardiography is far more sensitive than the stethoscope for detecting valvulitis, so the 2015 revision allows subclinical carditis — pathological valve regurgitation on echo without an audible murmur — to count as a major criterion. A child presenting with polyarthritis and a normal stethoscope but a pathological echo therefore meets two major criteria and has ARF, and the child is committed to the same secondary prophylaxis as the child with an audible murmur. [1]

The candidate contrasts this with the pre-2015 era, when subclinical carditis was missed, children were under-diagnosed, and the disease progressed to RHD undetected. The revision reflects the reality that the stethoscope is not sensitive enough in this disease. [1]

Branch 2: Sydenham chorea with a normal ASO

The examiner branches to a thirteen-year-old girl with involuntary grimacing and writhing movements of the face and hands, three months after a febrile illness, with a normal antistreptolysin O titre. The candidate recognises Sydenham chorea and explains that the chorea appears weeks to months after the streptococcal infection, by which time the ASO has often normalised. The diagnosis is made clinically — the characteristic movements plus the history — without the requirement for evidence of preceding GAS. [5]

The candidate starts secondary prophylaxis immediately to protect the valve from a future recurrence, treats the chorea symptomatically with diazepam or carbamazepine, and provides a supportive, low-stimulation environment. The candidate warns against being dissuaded by the normal serology. [5] [1]

Branch 3: the secondary prophylaxis regimen and duration

The examiner asks for the prophylaxis regimen and duration. The candidate answers that intramuscular benzathine penicillin G is given every twenty-one to twenty-eight days, at four hundred and fifty milligrams (six hundred thousand units) for children under twenty kilograms and nine hundred milligrams (one point two million units) for those twenty kilograms and above. Intervals longer than twenty-eight days are the commonest reason for recurrence. [3]

The duration, per the 2020 Australian guideline, is until at least age twenty-one for those with no established RHD, and for a minimum of five years after the last episode of ARF, whichever is longer. For established mild RHD, prophylaxis continues to at least age thirty-five or ten years after the last episode. For moderate to severe disease, prophylaxis may be lifelong. The candidate emphasises that every child is entered on the regional register, because the register-based recall and reminder system is the backbone of effective prophylaxis. [3]

Branch 4: the cumulative-damage principle

The examiner probes why secondary prophylaxis is so effective. The candidate explains the cumulative-damage principle: each untreated streptococcal reinfection triggers a new autoimmune assault on the same valve, and each episode adds to the irreversible scarring. The first episode may resolve fully, but repeated episodes leave permanent damage. Preventing recurrence therefore prevents RHD, and the single most effective intervention in the entire disease pathway is the benzathine penicillin injection every three to four weeks. [5] [3]

Branch 5: the pregnant young woman with established mitral stenosis

The examiner closes with a twenty-two-year-old woman of Pacific Islander background presenting at twelve weeks of gestation with exertional dyspnoea and an opening snap with a mid-diastolic rumble. The candidate recognises established rheumatic heart disease with mitral stenosis, presenting under the haemodynamic load of pregnancy. The candidate explains that undiagnosed RHD is a leading cause of maternal mortality in endemic regions, and the fellowship lesson is that the assessment and intervention must happen before conception, not at the first antenatal visit. [8]

The candidate manages the immediate presentation with rate control of any atrial fibrillation, anticoagulation, diuretics, and a joint obstetric-cardiology approach, and considers balloon mitral valvotomy if the stenosis is severe. The candidate closes with the systems-level point that the structured transition from paediatric to adult care is designed to catch the young woman before the first pregnancy, and loss to follow-up at that transition is the failure that perpetuates the disease. [8] [3]