Systemic Sclerosis / Scleroderma (SSc)

Last Updated on October 2, 2022

Introduction

• A multi-system disease
• Female to male ratio 3:1
• Peak incidence: 30 – 50 years old

• 2 types: (i) limited cutaneous systemic sclerosis, (ii) diffuse cutaneous systemic sclerosis

Pathogenesis

• Widespread vascular damage involving small arteries, arterioles, and capillaries, leading to arterial lesions & chronic ischaemia
• Vasoconstriction / vasospasm occurs

• Fibroblasts stimulated to cause fibrosis: Increased quantities of collagen, fibronectin and glycosaminoglycans → fibrosis in lower dermis of the skin & internal organs

1980 ACR Scleroderma Classification Criteria

• 1 major criterion OR ≥2 minor criteria

Major criterion

• Proximal cutaneous sclerosis / non-pitting skin thickening

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Notes:
– Usually the sclerosis / skin thickening is bilateral, symmetrical and almost always including sclerodactyly

Minor criteria

• Sclerodactyly
• Pitting scars of fingertips OR loss of substance of distal finger pad
• Bibasal pulmonary fibrosis

Modified Rodnan skin score (mRSS)

Components

• Face
• Anterior chest
• Abdomen

• Fingers (left & right)
• Hands (left & right)
• Forearms (left & right)
• Upper arms (left & right)

• Feet (left & right)
• Legs (left & right)
• Thighs (left & right)

Scores

mRSS =0 — “normal skin” where the examiner appreciates fine wrinkles but no skin thickness is present.
mRSS =1 — definite but “mild” skin thickness where the examiner can easily make skin folds between 2 fingers; fine wrinkles are acceptable.
mRSS =2 — “moderate” skin thickness with difficulty in making skin folds and no wrinkles.
mRSS =3 — “severe” skin thickness with inability to make skin folds between 2 examining fingers.

Significance

Worsening mRSS is associated with higher mortality, and both negative renal and cardiac outcomes

Reference

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5431585/

Clinical Manifestation

1. Skin & face

• Tight & thickened skin over face, hands, feet
• Telangiectasia
• Perioral furrowing; microstomia
• Beaky nose
• Raynaud’s phenomenon
• Sclerodactyly
• Finger pulp atrophy
• Digital pitting scar
• Digital ulcer

2. Lungs

• Pulmonary fibrosis / interstitial lung disease
• Pulmonary hypertension

3. Heart

• Myocardial fibrosis

4. Gastrointestinal system

• Oesophagus: dysmotility / stricture / GERD
• Intestine: malabsorption, hypomotility, incontinence, pseudo-obstruction

5. Renal system

• Scleroderma renal crisis — severe HTN and worsening renal function

Clinical Features

Investigations

Bedside

• ECG

Blood investigations

• FBC
• Renal profile

• Rheumatoid factor
• Antinuclear antibody (ANA) screening

Other lab investigations

• Urine FEME

Imaging

• Chest X-ray
• Echocardiogram
• HRCT thorax

Other investigations

• OGDS
• Spirometry

Management

References

1. https://www.rheumatology.org/Portals/0/Files/SSc%20Class%20Criteria%20slides.pdf