This article describes three cases of undiagnosed hypothyroidism in a developed stage which manifest themselves with myopathic syndrome (myalgia, muscular fatigue, and higher serum levels of creatine kinase, aminotranferases, and lactate dehydrogenase) without the „classic“ symptoms of hypothyroidism. In addition, two of the three patients were receiving hypolipidemic drugs for secondary hyperlipoproteinemia, which could have affected the development of the myopathy. Emphasis is placed on the description of atypical symptoms of hypothyroidism and the necessity of endocrinological examination in each case of myopathy with indefinite etiology.

        Key words: Hyperlipoproteinemia - Hypothyroidism - Creatine kinase - Myopathy - Thyroid autoantibodies - Thyroid-stimulating hormone