American Board of Internal Medicine (ABIM) Certification Practice Exam

Mixed Connective Tissue Disease (MCTD) is characterized by the presence of features from several autoimmune conditions, which include scleroderma, polymyositis, and systemic lupus erythematosus (SLE). These three conditions are integral to the understanding of MCTD, as it presents a combination of symptoms and clinical signs that can overlap with these diseases.

Scleroderma, for instance, is associated with skin thickening and vasculopathy, while polymyositis involves muscle weakness and inflammation. Systemic lupus erythematosus is known for its diverse manifestations, including joint pain, skin rashes, and renal involvement. In MCTD, patients may exhibit features from all these disorders such as Raynaud's phenomenon, arthritis, myositis, and skin changes, leading to the classification as a distinct syndrome.

The other options do not provide an accurate combination of autoimmune diseases associated with MCTD. Arthritis, diabetes, and hypertension do not encompass the overlapping autoimmune features characteristic of MCTD, while rheumatoid arthritis, psoriasis, and scleroderma also miss the defining aspects related to polymyositis. Systemic lupus erythematosus, Sjögren's syndrome, and fibromyalgia also fail to