How do I present systemic sclerosis in PACES?

Lead with the spot diagnosis and the discriminating signs, then subtype and flag organ threat. For example: 'This patient has systemic sclerosis, indicated by microstomia and perioral furrowing, facial telangiectasiae, and sclerodactyly with digital pulp atrophy and pitting scars. The distribution is limited/diffuse, suggesting anti-centromere/anti-Scl-70 antibodies. I would actively screen for the leading complications — pulmonary hypertension and interstitial lung disease — and, critically, monitor blood pressure and renal function for scleroderma renal crisis.'

Why must you never stop the ACE inhibitor in scleroderma renal crisis?

The ACE inhibitor (classically captopril) is the treatment for scleroderma renal crisis, not the cause of the rising creatinine. Renal crisis is driven by intense renin-angiotensin activation, so ACE inhibition is started early and continued even as the creatinine rises. Withdrawing it — mistaking the crisis for ACE-induced injury — is a recognised fatal error and a favourite examiner trap.

How do I tell SSc-related lung fibrosis from bronchiectasis at the bedside?

SSc interstitial lung disease produces fine, end-inspiratory 'velcro' basal crepitations that do not clear with coughing, with reduced expansion and no sputum. Bronchiectasis gives coarse crepitations that change with coughing, plus sputum and finger clubbing. The face and hand signs of scleroderma then confirm which fibrosis you are dealing with.

What is the leading cause of death in systemic sclerosis?

Pulmonary hypertension is the leading cause of death, especially in limited cutaneous disease, closely followed by progressive interstitial lung disease. This is why you screen proactively with echocardiography, PFTs including DLCO and HRCT, rather than waiting to be prompted.

PACES Buddy

Systemic Sclerosis (Scleroderma) in MRCP PACES

Systemic sclerosis is one of the great spot diagnoses of PACES — the diagnosis is usually made the moment the patient walks in. It surfaces most often as an interstitial lung disease case at the respiratory station or as a hands-and-face case in a consultation station, and rewards candidates who recognise the pattern instantly and then talk fluently about organ threat.

How it presents in PACES

This is a condition you should name before you have finished shaking the patient's hand. Two archetypes recur. In the respiratory station you meet a patient with bibasal interstitial lung disease whose face and hands then give the game away — the fibrosis is the SSc, not idiopathic pulmonary fibrosis. In a consultation station you meet the classic hands-and-face vignette: tight shiny skin, a pinched beaked face and abnormal fingers, often introduced through a complaint of cold, colour-changing digits or difficulty swallowing.

The examiner is testing whether you can convert an obvious visual gestalt into a structured, safe answer: recognise it, subtype it (limited versus diffuse), name the antibody, and — most importantly — identify the organ that is going to kill the patient. Candidates who merely say 'scleroderma' and stop will pass low; those who move straight to pulmonary hypertension and renal crisis surveillance separate themselves.

Signs to look for

Inspect the face and hands together, then screen the chest and heart for organ involvement. This is the high-yield checklist:

Face: tight, shiny, waxy skin; a pinched, beaked nose; microstomia with radial furrowing around a small mouth; telangiectasiae on the cheeks and lips; salt-and-pepper dyspigmentation.
Hands: sclerodactyly — tight, tethered, tapering digital skin with early flexion contractures and a pseudo-clubbing appearance; digital pulp atrophy with pitting scars; non-healing fingertip ulcers or digital infarcts.
Subcutaneous calcinosis — firm nodules that may discharge chalky material; ragged cuticles; dilated or drop-out nailfold capillaries (offer to perform capillaroscopy).
Raynaud's phenomenon: episodic, painful, reversible digital ischaemia going white (ischaemia), then blue/dusky (stasis), then red (reactive hyperaemia).
Chest: bilateral fine end-inspiratory 'velcro' basal crepitations that do not clear with coughing, with symmetrically reduced expansion — this is ILD, not the coarse, cough-changing, sputum-and-clubbing picture of bronchiectasis.
Cardiovascular screen for the killer: a loud P2, a left parasternal heave or a raised JVP suggest pulmonary hypertension.
Useful negatives to exclude mimics: no Gottron's papules or heliotrope rash (not dermatomyositis), no malar/photosensitive rash (not lupus), no erosive small-joint synovitis or ulnar deviation (not rheumatoid arthritis).

Confirming the diagnosis & differential

Once you have named it, subtype it by skin distribution, because distribution predicts antibody and antibody predicts organ threat. Limited cutaneous SSc (the old CREST — Calcinosis, Raynaud's, oEsophageal dysmotility, Sclerodactyly, Telangiectasia) confines skin change to distal to the elbows and knees plus the face, follows years of preceding Raynaud's, carries anti-centromere antibody, and threatens pulmonary arterial hypertension late. Diffuse cutaneous SSc involves skin proximal to the elbows and the trunk, comes on rapidly, carries anti-Scl-70 (anti-topoisomerase) with a risk of ILD, or anti-RNA polymerase III with a risk of scleroderma renal crisis.

The key differential move is to prove the Raynaud's is secondary rather than primary. Secondary Raynaud's points to disease: older onset, asymmetry, digital tissue loss and pits, abnormal nailfolds and positive serology. Primary Raynaud's is a young woman with symmetrical episodes, no tissue loss, normal nailfolds and a negative ANA. Also confirm the digital ischaemia is not simply beta-blocker-induced before you attribute it to a connective tissue disease.

Other causes of secondary Raynaud's include mixed connective tissue disease (anti-U1-RNP), lupus, dermatomyositis, Sjögren's and rheumatoid arthritis. For the lower-zone fibrosis differential, run through Rheumatoid, Asbestosis, Scleroderma and Idiopathic (IPF, a diagnosis of exclusion) — SSc-related lung disease is usually an NSIP pattern, which carries a better prognosis than UIP.

The viva: what examiners ask

Bedside first: recheck the blood pressure yourself and start a serial chart, dipstick the urine for protein, perform nailfold capillaroscopy, check SpO2 and an ECG — this frames renal-crisis surveillance up front.
Bloods and immunology: FBC and film (schistocytes if microangiopathic haemolysis), U&E and creatinine as a renal baseline, LDH/haptoglobin, CK for a myositis overlap, ANA (positive in ~90%), then the specific antibodies — anti-centromere, anti-Scl-70 and anti-RNA polymerase III.
Organ assessment: HRCT thorax is the investigation of choice for ILD; PFTs with DLCO show a restrictive pattern with reduced transfer factor, and an isolated low DLCO hints at pulmonary hypertension; echocardiography screens for PAH, with right-heart catheterisation as the gold standard; add OGD or manometry for reflux and dysmotility.
Classification: cite the ACR/EULAR 2013 criteria.
Management is MDT and rheumatology-led. Raynaud's: keep warm, stop smoking, stop beta-blockers, start a calcium-channel blocker first-line, and escalate critical digital ischaemia to sildenafil, IV iloprost or bosentan. ILD: mycophenolate or cyclophosphamide, with nintedanib as an antifibrotic for progressive disease. Reflux: high-dose PPI. Renal crisis: an ACE inhibitor (captopril) is the treatment — start early and continue even as the creatinine rises. Avoid high-dose steroids, which precipitate renal crisis.

Common pitfalls / how to score

The can't-miss complication is scleroderma renal crisis: abrupt severe new hypertension with an acute kidney injury, sometimes with a microangiopathic haemolytic anaemia (falling haemoglobin, thrombocytopenia, schistocytes). Risk is highest in early diffuse disease, anti-RNA polymerase III positivity and recent moderate-to-high-dose steroids. The fatal traps are labelling it essential hypertension, and — the classic examiner favourite — stopping the ACE inhibitor because the creatinine is climbing. The ACE inhibitor is the treatment, not the cause. A creeping blood pressure in known SSc is the sentinel of impending crisis, so recheck it yourself.

Remember that pulmonary hypertension is the leading cause of death, particularly in limited disease, so screen for it actively rather than waiting to be asked. Distinguish the fixed velcro creps of fibrosis from cough-changing bronchiectatic creps. And earn easy marks by offering relevant negatives that exclude dermatomyositis, lupus and rheumatoid arthritis — it shows the examiner you considered the family of connective tissue disease before committing.

FAQ

How do I present systemic sclerosis in PACES?: Lead with the spot diagnosis and the discriminating signs, then subtype and flag organ threat. For example: 'This patient has systemic sclerosis, indicated by microstomia and perioral furrowing, facial telangiectasiae, and sclerodactyly with digital pulp atrophy and pitting scars. The distribution is limited/diffuse, suggesting anti-centromere/anti-Scl-70 antibodies. I would actively screen for the leading complications — pulmonary hypertension and interstitial lung disease — and, critically, monitor blood pressure and renal function for scleroderma renal crisis.'
What is the difference between limited and diffuse systemic sclerosis?: Limited cutaneous SSc (formerly CREST) confines skin change to distal to the elbows and knees plus the face, follows long-standing Raynaud's, carries anti-centromere antibody, and threatens pulmonary arterial hypertension. Diffuse cutaneous SSc involves skin proximal to the elbows and the trunk, comes on rapidly, and carries anti-Scl-70 (ILD risk) or anti-RNA polymerase III (renal-crisis risk).
Why must you never stop the ACE inhibitor in scleroderma renal crisis?: The ACE inhibitor (classically captopril) is the treatment for scleroderma renal crisis, not the cause of the rising creatinine. Renal crisis is driven by intense renin-angiotensin activation, so ACE inhibition is started early and continued even as the creatinine rises. Withdrawing it — mistaking the crisis for ACE-induced injury — is a recognised fatal error and a favourite examiner trap.
How do I tell SSc-related lung fibrosis from bronchiectasis at the bedside?: SSc interstitial lung disease produces fine, end-inspiratory 'velcro' basal crepitations that do not clear with coughing, with reduced expansion and no sputum. Bronchiectasis gives coarse crepitations that change with coughing, plus sputum and finger clubbing. The face and hand signs of scleroderma then confirm which fibrosis you are dealing with.
What is the leading cause of death in systemic sclerosis?: Pulmonary hypertension is the leading cause of death, especially in limited cutaneous disease, closely followed by progressive interstitial lung disease. This is why you screen proactively with echocardiography, PFTs including DLCO and HRCT, rather than waiting to be prompted.

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