CREST

CREST
Name	CREST syndrome
Synonyms	Limited cutaneous systemic sclerosis
Field	Rheumatology, Immunology
Symptoms	Calcinosis, Raynaud's phenomenon, Esophageal dysmotility, Sclerodactyly, Telangiectasias
Complications	Pulmonary arterial hypertension, Gastroesophageal reflux disease, Digital ulcer
Diagnosis	Based on clinical criteria, Antinuclear antibody testing, Nailfold capillaroscopy
Treatment	Calcium channel blocker, Proton-pump inhibitor, Endothelin receptor antagonist, Immunosuppressive drug
Prognosis	Variable; better than diffuse systemic sclerosis but risk from specific organ involvement

CREST. CREST syndrome is a clinical subset of systemic sclerosis, a chronic autoimmune connective tissue disease, characterized by a more limited form of skin involvement. It is an acronym representing five primary features: Calcinosis, Raynaud's phenomenon, Esophageal dysmotility, Sclerodactyly, and Telangiectasias. The condition is often associated with specific autoantibodies, particularly anti-centromere antibodies, and generally follows a more indolent course compared to the diffuse form of the disease, though serious complications like pulmonary arterial hypertension can develop.

Overview

CREST syndrome is classified within the spectrum of systemic sclerosis, a disorder involving excessive collagen deposition and vascular pathology. It was first described as a distinct clinical entity by researchers including Richard M. Winterbauer in the 1960s. The syndrome is more prevalent in women and typically has a later onset than diffuse systemic sclerosis. Its recognition is crucial for prognosis and management, as it is associated with a different pattern of internal organ involvement and a generally better long-term survival rate, though significant morbidity can occur from its specific features and potential progression to complications such as pulmonary fibrosis and biliary cirrhosis.

Clinical Features

The hallmark features encapsulated in the CREST acronym manifest variably among patients. Calcinosis involves the deposition of calcium crystals in the skin and subcutaneous tissues, often over bony prominences like the fingers. Raynaud's phenomenon, an exaggerated vascular response to cold or stress, is frequently the initial symptom and can lead to digital ulcers and gangrene. Esophageal dysmotility results from smooth muscle atrophy and fibrosis, leading to symptoms of dysphagia and severe gastroesophageal reflux disease. Sclerodactyly refers to thickened, tight skin confined to the fingers, while telangiectasias are dilated blood vessels visible on the skin, particularly on the face, hands, and mucous membranes.

Diagnosis

Diagnosis is primarily clinical, based on the presence of the characteristic features. Serological testing is highly supportive, with a high prevalence of anti-centromere antibodies, detectable via indirect immunofluorescence on HEp-2 cells. Other relevant autoantibodies include anti-Scl-70, which is more associated with diffuse disease and pulmonary fibrosis. Nailfold capillaroscopy is a valuable non-invasive tool that reveals characteristic microvascular changes like dilated capillaries and avascular areas. Further evaluation often involves esophageal manometry, high-resolution computed tomography of the chest to assess for interstitial lung disease, and echocardiography to screen for pulmonary arterial hypertension.

Pathophysiology

The pathophysiology involves a complex interplay of vascular injury, immune activation, and fibrosis. An initial endothelial cell injury triggers vasoconstriction and structural changes in small blood vessels, exemplified by Raynaud's phenomenon. This is followed by a perivascular inflammatory infiltrate involving T cells, B cells, and mast cells. Fibroblasts are activated by cytokines such as transforming growth factor beta, leading to the excessive production of extracellular matrix components like collagen and fibronectin. The specific targeting of the centromere by the immune system, producing anti-centromere antibodies, remains a distinctive but not fully understood aspect of the limited disease phenotype.

Management

Management is symptomatic and organ-specific, as no therapy universally halts disease progression. For Raynaud's phenomenon and digital ulcers, calcium channel blockers like nifedipine, phosphodiesterase inhibitors such as sildenafil, or endothelin receptor antagonists like bosentan are used. Esophageal involvement is managed with proton-pump inhibitors like omeprazole and prokinetic agents. Calcinosis can be challenging; treatments include colchicine, bisphosphonates, or surgical excision. For developing pulmonary arterial hypertension, targeted therapies include endothelin receptor antagonists, phosphodiesterase inhibitors, and prostacyclin analogues. Immunosuppressants like methotrexate or mycophenolate mofetil may be considered for overlapping features like arthritis or skin tightening.

Prognosis

The prognosis of CREST syndrome is generally more favorable than that of diffuse cutaneous systemic sclerosis, with a slower progression and less frequent severe internal organ involvement. Life expectancy is often near normal, but significant morbidity is common due to chronic symptoms. The major cause of mortality is the development of pulmonary arterial hypertension or, less commonly, interstitial lung disease. Other serious complications include malnutrition from severe esophageal dysmotility, digital gangrene requiring amputation, and an increased risk of cancer, particularly lung cancer and hepatocellular carcinoma. Regular monitoring by specialists in rheumatology and pulmonology is essential for early detection and management of these complications.

Category:Autoimmune diseases Category:Rheumatology Category:Connective tissue diseases