Clinical observation of a patient with mixed connective tissue disease in an outpatient practice

   Systemic connective tissue diseases are a heterogeneous group of diseases with unclear etiology, the pathogenesis of which is represented by an autoimmune process, a heterogeneous clinical picture and a variable course. Classical variants of the disease that do not cause difficulties in their verification are most common in clinical practice. But some patients have signs characteristic of various connective tissue diseases. This combination of symptoms is called mixed connective tissue disease or “cross syndrome” (Overlap-syndrome). The multi-organ nature of the clinical picture of the disease presents a diagnostic difficulty for the clinician and leads to late diagnosis, ineffective therapy, and disability of the patient. The article presents a clinical case of mixed connective tissue disease in a middle-aged patient. An analysis of literary sources, clinical data, and laboratory results was carried out.