Mixed Connective Tissue Disease

Snapshot

• A 31-year-old woman presents to her primary care physician’s office with general malaise, myalgias, and low-grade fever. She notices that during the winter months the tips of her fingers turn blue and then returns to her baseline color when in a warm environment. On physical exam, there is a malar rash, sclerodactyly, and joint tenderness. Laboratory testing is positive for anti-nuclear antibodies (ANA) and anti-U1 RNP antibodies.

Introduction

• Clinical definition
  • generalized connective tissue disorder with clinical features of systemic lupus erythematosus, systemic sclerodermia, and polymyositis
    • along with high levels of anti-U1-RNP antibodies
• Epidemiology
  • demographics
    • more common in women
    • 15-25 years of age but can occur at any age
• Pathogenesis
  • autoimmune process
• Prognosis
• generally a favorable outcome

Presentation

• Symptoms
  • Raynaud phenomenon
  • arthralgia
  • arthritis
  • myositis
  • sclerodactyly
• hand swelling

Imaging

• Echocardiography
  • indication
• for early diagnosis of pulmonary arterial hypertension and for the evaluation of valvular disease

Studies

• Labs
  • positive for anti-U1-RNP antibodies 
• Diagnostic criteria
• clinical diagnosis supported by anti-U1-RNP antibodies on serology

Differential

• Systemic lupus erythematosus (SLE)
• Scleroderma
• Polymyositis
• Rheumatoid arthritis
• Idiopathic pulmonary arterial hypertension

Treatment

• Management approach
  • treatment is aimed at controlling symptoms and is targeted to organ involvement
• Medical
  • prednisone
    • indications
      • responsive in patients presenting with symptoms consistent with SLE
      • in patients with fatigue, myositis, myalgias, arthralgias, pleuritis, pericarditis, autoimmune anemia, and thrombocytopenia
  • calcium channel blockers
    • indications
      • pulmonary arterial hypertension
• Raynaud phenomenon

Complications

• The major cause of death is pulmonary hypertension in MCTD