Systemic Sclerosis and Sclerodermoid Disorders

Published on 05/03/2015 by admin

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Systemic Sclerosis and Sclerodermoid Disorders

Systemic Sclerosis (SSc)

An uncommon autoimmune connective tissue disease (AI-CTD) that affects the skin, blood vessels, and several other organs (e.g. kidney, lung).

Etiology unknown but pathogenesis involves vasculopathy, endothelial dysfunction, tissue fibrosis, and immune system activation.

Seen more frequently in women; onset typically in the 3rd to 4th decades of life; diffuse cutaneous SSc more frequently seen in African-Americans.

There are three major clinical subtypes of SSc, based on the amount of skin sclerosis (Fig. 35.2):

Limited cutaneous SSc (lcSSc).

Diffuse cutaneous SSc (dcSSc).

SSc sine scleroderma (ssSSc).

LcSSc and dcSSc can also occur in conjunction with other AI-CTD (called ‘overlap syndrome’), most notably polymyositis and SLE; another minor form is pre-SSc, in which the full extent of the patient’s cutaneous sclerosis has not been reached.

Raynaud’s phenomenon (RP) is present in almost all SSc patients and is often the earliest presenting feature (Table 35.1; Figs. 35.335.5).

Mat telangiectasias (Fig. 35.6) and proximal nailfold abnormalities (dilated capillary loops) are present in both lcSSc and dcSSc subtypes and are important clues to the Dx; additional common cutaneous findings are outlined in Table 35.1.

Patients often have a characteristic facies with microstomia, retraction of the lips, perioral furrows, and a beaked nose; three types of dyspigmentation can also be seen, including diffuse hyperpigmentation and leukoderma of SSc (Fig. 35.7).

In all three subtypes there can be internal organ involvement (Table 35.2), but patients with dcSSc are at increased risk for more clinically severe extracutaneous disease and overall worse outcomes.

Most patients (~98%) with SSc are ANA (+), usually in a speckled or nucleolar pattern; the presence of certain nucleolar antibodies is associated with characteristic clinical presentations (Table 35.3).

There are three phases of cutaneous disease:

(1) Early edematous phase, featuring puffy hands and pitting edema of the digits (see Fig. 35.5A).

(2) Indurated phase, characterized by hardening of the skin with taut and shiny appearance (see Fig. 35.5B).

(3) Atrophic phase, with potential/gradual softening of the skin.

The degree of skin sclerosis does not predict the degree of internal organ involvement, and survival is dependent on the type and degree of internal organ involvement.

Pulmonary disease (interstitial lung disease (ILD) > pulmonary arterial hypertension (PAH)) is the most common cause of mortality.

All SSc patients should be screened and periodically monitored for internal organ involvement, especially lung and renal disease (Table 35.2).

DDx includes other sclerodermoid conditions (Table 35.4) and other AI-CTD (e.g. mixed connective tissue disease; see Chapter 37).

Table 35.4

Differential diagnosis of sclerodermoid conditions.

image

** Primary cutaneous amyloidosis can also occur in patients with systemic sclerosis and generalized morphea.

 May also be observed in patients with congenital erythropoietic porphyria and hepatoerythropoietic porphyria.

GVHD, graft-versus-host disease; POEMS, polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes.

Recommendations for the initial evaluation of all patients with suspected SSc are presented in Table 35.2.

Rx options for various cutaneous and extracutaneous features of SSc are outlined in Tables 35.1 and 35.2.

Raynaud’s Phenomenon

Characterized by episodic vasospasm of the digital arteries, resulting in white, blue, and red discoloration of the fingers and toes secondary to cold stimuli.

Occurs in two settings: primary Raynaud’s phenomenon (Raynaud’s disease) and secondary Raynaud’s phenomenon (Table 35.5).

Primary Raynaud’s phenomenon is common, affecting 3–5% of the population and typically develops in adolescent girls and young women (median age at onset, ~14 years) and is not associated with any underlying medical issues.

Secondary Raynaud’s phenomenon is uncommon and is associated with an underlying medical problem (Table 35.6).

SSc is one of the leading causes of secondary Raynaud’s phenomenon.

An approach to differentiating primary from secondary Raynaud’s phenomenon is presented in Fig. 35.8.

Rx: Table 35.1.

Sclerodermoid Disorders