Respiratory manifestations of systemic disease — structured oral (viva)

Branch 1 — The concern and first thought

Examiner: "What concerns you most about this girl, and what is your leading diagnosis?" Candidate: What concerns me most is progressive exertional breathlessness with a dry cough, fine bibasal crackles, and early clubbing in a child with juvenile dermatomyositis, because that combination points to interstitial lung disease rather than deconditioning. In juvenile dermatomyositis the lung can be affected out of proportion to the skin and muscle, so her currently mild rash and weakness do not reassure me. My leading diagnosis is connective tissue disease-associated interstitial lung disease, and I would treat this as a lung complication of her systemic disease. [1]

Branch 2 — Why the antibody matters

Examiner: "Which feature of her disease would most change how urgently you act?" Candidate: The most important factor is her myositis antibody status, particularly whether she is anti-MDA5 positive, because anti-MDA5 juvenile dermatomyositis is associated with rapidly progressive interstitial lung disease that can be fatal even when the skin and muscle signs are subtle. If she carries that antibody I would escalate the urgency of imaging, lung function, and treatment considerably, and I would not be reassured by her mild myositis. [1]

Branch 3 — Investigation

Examiner: "How will you investigate her?" Candidate: I would confirm and characterise the lung disease with a high-resolution CT to define the interstitial pattern and its extent, and with pulmonary function tests looking for a restrictive defect with reduced diffusing capacity that I can track over time. I would add echocardiography to screen for pulmonary hypertension, review her myositis-specific antibodies, and consider bronchoscopy if infection needs to be excluded, since she is immunosuppressed and infection can mimic disease activity. Serial lung function is what tells me whether treatment is working before fibrosis fixes. [2] [1]

Branch 4 — Management and the general reflex

Examiner: "Assume HRCT confirms interstitial lung disease and she is anti-MDA5 positive. How do you manage her, and how does this generalise?" Candidate: I would treat aggressively and early because this subtype can progress to fatal respiratory failure, using corticosteroids with combination immunosuppression chosen with the rheumatology team, and I would monitor the response with serial lung function and imaging. More generally, this illustrates the reflex I apply to any child with a systemic disease and new respiratory signs: treat the chest problem as a complication of that disease, sort the child into the haematological, connective tissue, immunodeficiency, or malignancy group, and act before the complication becomes irreversible — just as I would treat a sickle child with fever and chest signs presumptively for acute chest syndrome. [1] [3]