The dilemma: scleroderma renal crisis vs lupus nephritis in a patient with mixed connective tissue disorder

Abstract

Introduction: Mixed connective tissue disorder (MCTD) is a rare connective tissue disorder characterized by features of systemic lupus erythematosus, dermatomyositis, systemic sclerosis, and rheumatoid arthritis. MCTD is associated with an elevated antibody titer to U1 small nuclear ribonucleoprotein.

Case description: A 49-year-old man presented to the emergency department for evaluation of worsening shortness of breath with associated for bilateral hand pain and swelling associated with morning stiffness which was initially thought to be related to systemic lupus erythematous (SLE). He was also found to have a positive autoantibody, and he was later diagnosed with MCTD complicated by scleroderma renal crisis.

Conclusion: MCTD is a rare connective tissue disorder with overlapping features of SLE, dermatomyositis, systemic sclerosis, and rheumatoid arthritis. The diagnosis of MCTD requires a high index of suspicion and careful workup. Immunosuppressive therapy is the mainstay of treatment that improves patient outcomes.

Keywords: Kasukawa diagnostic criteria; Systemic lupus erythematosus; dermatomyositis; mixed connective tissue disorders; systemic sclerosis.

Figure 1.

Bilateral soft tissue swelling of the hands with loss of skin crease and clubbing of the fingers

Figure 2.

Chest X-ray above shows central vascular prominence with abnormal alveolar opacities in the mid and lower lungs bilaterally in addition to small effusions

Figure 3.

High-resolution CT chest above showing diffuse ground-glass opacity in the lungs and bilateral pleural effusion

Figure 4.

Reveals an occluded arteriole