Scleroderma, mixed connective-tissue disease and overlap syndromes: Viva

This is a branching oral built to probe the reasoning that holds the localised and the systemic scleroderma and the overlap syndrome apart, and to expose the candidate who has memorised the headline without the organ-specific corners. The questions escalate from the framing to the classification, the organ screen, and the management, with the deliberate probes into the renal crisis and the pulmonary hypertension. [1]

Opening question: framing the problem

The examiner opens with the Raynaud phenomenon and the skin tightening and asks: how do you frame this problem in a single sentence, and what is your first priority? [1]

A strong answer names the juvenile systemic sclerosis as the working diagnosis, because the Raynaud phenomenon with the puffy hands and the proximal skin tightening is the classic presentation, and it distinguishes the systemic disease from the localised morphea that stays in the skin without the Raynaud. The first priority is the antibody panel, the nailfold capillaroscopy, and the baseline organ screen for the lung and the heart. [1][4]

Model answer. This child has the juvenile systemic sclerosis until proven otherwise, because the Raynaud phenomenon, the puffy hands and the proximal skin tightening together declare the multisystem disease. My first priority is the antibody panel, the nailfold capillaroscopy, and the baseline pulmonary function tests and the echocardiography to screen for the interstitial lung disease and the pulmonary hypertension. [1]

Probe one: the classification and the criteria

The examiner presses: what are the PReS and ACR provisional classification criteria, and how do you classify the cutaneous subtype? [2]

A strong answer reproduces the major criterion of the proximal skin sclerosis plus at least two minor criteria from the nine organ systems, and it classifies the cutaneous subtype into the diffuse (the proximal skin and the trunk) and the limited (the distal skin and the face) disease. The cutaneous subtype maps to the organ risk: the diffuse disease carries the early interstitial lung disease and the renal crisis, and the limited disease the later pulmonary hypertension. [2][3]

Pitfall probe. Why does the cutaneous subtype matter? Because the diffuse disease carries the early and the aggressive organ disease, and the limited disease the later and the more indolent disease, and the surveillance and the therapy are built around the subtype. [3]

Probe two: the antibody map

The examiner asks: which antibodies do you send, and how does each map to the organ risk? [1]

A strong answer names the anti-Scl-70 for the diffuse disease and the interstitial lung disease, the anti-centromere for the limited disease and the pulmonary hypertension, the anti-RNA polymerase three for the renal crisis, and the anti-U1-RNP for the mixed connective-tissue disease if the overlap features are present. In the child, the anti-Scl-70 is more common than the anti-centromere, the reverse of the adult. [1][4]

Branch one: the scleroderma renal crisis

The examiner pivots: imagine the child presents with the new hypertension and the rising creatinine in the early diffuse disease. What is the diagnosis and the immediate management? [1]

A strong answer names the scleroderma renal crisis and states that the angiotensin-converting enzyme inhibitor is begun immediately and titrated, even when the creatinine rises in the first days, because the inhibition of the renin-angiotensin axis is the one intervention that reverses the crisis. The high-dose corticosteroid above fifteen milligrams per day is avoided because it precipitates the crisis. The dialysis may be needed transiently. [1][4]

Pitfall probe. Why is the high-dose corticosteroid dangerous? Because it precipitates the renal crisis in the diffuse disease, and the fellow manages the diffuse systemic sclerosis with the steroid-sparing immunosuppression. [1]

Branch two: the evolving pulmonary hypertension

The examiner pivots again: imagine the child has the isolated fall of the diffusion capacity and the rising pro-B-type natriuretic peptide at the follow-up. What is evolving, and how do you confirm it? [5][10]

A strong answer names the evolving pulmonary arterial hypertension and states that the right heart catheterisation is the definitive test. The pulmonary arterial hypertension therapy, with the phosphodiesterase five inhibitor, the endothelin receptor antagonist and the prostacyclin, is begun early, because the pulmonary hypertension is the leading cause of the mortality in the systemic sclerosis and the mixed connective-tissue disease. [5]

Branch three: the overlap and the anti-U1-RNP

The examiner pivots once more: imagine the child also has the proximal muscle weakness and the arthritis, and the anti-U1-RNP is positive at the high titre. How does the diagnosis and the management change? [10]

A strong answer names the mixed connective-tissue disease, the high-titre anti-U1-RNP overlap of the lupus, the scleroderma and the myositis. The disease is managed by the dominant feature, the arthritis with the methotrexate and the hydroxychloroquine, the myositis with the corticosteroid and the immunosuppression, and the pulmonary hypertension screened for the life of the disease. [10][11]

Closing question: counselling the family

The examiner closes: the diagnosis of the juvenile systemic sclerosis is confirmed. How do you counsel the family? [1]

A strong answer describes the honest conversation that names the diagnosis, explains that the disease is rare in childhood and that the pulmonary disease is the leading concern, and that the management runs the multidisciplinary team of the rheumatology, the cardiology, the respiratory, the nephrology and the physiotherapy. The family is taught the surveillance, the vascular protection, and the warning signs of the renal crisis and the digital ischaemia, and the long-term plan is begun from the day of the diagnosis. [1][4]