OSCE — Calciphylaxis (calcific uraemic arteriolopathy) · MBBS OSCE

Brief (to candidate)

You will assess a patient with a presentation consistent with Calciphylaxis (calcific uraemic arteriolopathy). ^[1] You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.

Clinical context

Calciphylaxis (calcific uraemic arteriolopathy, CUA) is a rare, life-threatening vasculopathy of the small cutaneous arterioles and venules characterised by medial calcification, intimal hyperplasia, and luminal microthrombosis leading to exquisitely painful ischaemic skin necrosis. It occurs almost always in end-stage renal disease (ESRD) on dialysis but also in warfarin-associated non-uraemic, primary hyperparathyroidism, malignancy-related, and obesity-related forms. Cutaneous hallmarks: livedo racemosa, indurated violaceous plaques, and eschar-forming ulcers disproportionately tender to palpation, distributed on medial thighs, calves, abdomen, breasts, buttocks, and penile shaft. Mortali ^[1]

Candidate tasks

Clarify onset, severity, associated features, and red-flag symptoms. ^[1]
State focused examination priorities.
List first-line investigations and any named score/criteria.
Give immediate resuscitation steps.
Outline definitive management with doses/routes where standard.
Name complications and disposition (ward / HDU / theatre / discharge safety-net).
Mention one special-population modifier (pregnancy, child, elderly, CKD).

Examiner checklist

Domain	Pass behaviours
Definition	Correct working diagnosis language
Assessment	Focused, prioritised, red flags sought
Investigations	Appropriate first-line + interpretation
Emergency care	ABC / time-critical actions first
Definitive care	Specific drugs/procedures, not generic phrases
Safety	Exquisitely painful, indurated, violaceous plaque with central ulceration an
Safety	Proximal distribution (medial thighs, abdomen, buttocks, breasts) carries **
Safety	Penile shaft involvement — mortality >80%; urgent urology for partial penect
Communication	Clear plan and safety-netting

Model outline

Lead with the working diagnosis and life threats. Resuscitate before definitive tests when unstable. Use guideline-standard therapy with named agents and doses. Document escalation criteria and follow-up. A safe candidate is specific, structured, and never delays critical care for non-urgent imaging. ^[1]

References2Show

[1]Nigwekar SU, Thadhani R, Brandenburg VM Calciphylaxis N Engl J Med, 2018.PMID 29719190
[2]Nigwekar SU, Brunelli SM, Meade D, Wang W, Hymes J, Lacson E Jr Sodium thiosulfate therapy for calcific uremic arteriolopathy Clin J Am Soc Nephrol, 2013.PMID 23520041

Clinical context

Candidate tasks

Clarify onset, severity, associated features, and red-flag symptoms. ^[1]

State focused examination priorities.

List first-line investigations and any named score/criteria.

Give immediate resuscitation steps.

Outline definitive management with doses/routes where standard.

Name complications and disposition (ward / HDU / theatre / discharge safety-net).

Mention one special-population modifier (pregnancy, child, elderly, CKD).

Examiner checklist

Domain	Pass behaviours
Definition	Correct working diagnosis language
Assessment	Focused, prioritised, red flags sought
Investigations	Appropriate first-line + interpretation
Emergency care	ABC / time-critical actions first
Definitive care	Specific drugs/procedures, not generic phrases
Safety	Exquisitely painful, indurated, violaceous plaque with central ulceration an
Safety	Proximal distribution (medial thighs, abdomen, buttocks, breasts) carries **
Safety	Penile shaft involvement — mortality >80%; urgent urology for partial penect
Communication	Clear plan and safety-netting

Model outline

References2Show

[1]Nigwekar SU, Thadhani R, Brandenburg VM Calciphylaxis N Engl J Med, 2018.PMID 29719190
[2]Nigwekar SU, Brunelli SM, Meade D, Wang W, Hymes J, Lacson E Jr Sodium thiosulfate therapy for calcific uremic arteriolopathy Clin J Am Soc Nephrol, 2013.PMID 23520041