INTRODUCTION: Fibromyalgia can be defined as a non-inflammatory musculoskeletal pain syndrome. It is a chronic condition, commonly associated with fatigue and non-restorative sleep. However, such symptoms may result from coexisting diseases, for instance hypothyroidism. OBJECTIVE: Based on this evidence, the aim of this study was to describe the concomitance of fibromyalgia in patients with hypothyroidism, the cases of hypothyroidism in patients diagnosed with fibromyalgia and determine the symptoms associated with above clinical conditions. METHODS: One hundred and sixty-six patients with fibromyalgia and 56 patients with hypothyroidism were evaluated. Volunteer patients answered a questionnaire to detect the main signs and symptoms of these diseases and then underwent serum determination of thyroid stimulating hormone (TSH), free thyroxine (FT4) and anti-thyroperoxidase (a-TPO). RESULTS: Among 166 patients with fibromyalgia, 35 (21.1%) were diagnosed with clinical or sub-clinical hypothyroidism. Among 56 patients with hypothyroidism, 36 (64.3%) had the diagnosis of fibromyalgia confirmed, according to the American College of Rheumatology's (ACR) criteria. In patients with previously diagnosed hypothyroidism, fatigue, non-restorative sleep and chronic headache were symptoms statistically more frequent among those with the diagnosis of fibromyalgia. Morning stiffness prevailed in patients diagnosed with hypothyroidism and without fibromyalgia. CONCLUSION: We can concluded from this study that, in order to enhance the diagnostic approach and follow-up treatment, the presence of clinical or laboratorial manifestations of thyroid dysfunction in patients with fibromyalgia must be considered, as well as manifestations of fibromyalgia in patients with hypothyroidism.
fibromyalgia; hypothyroidism; chronic autoimmune thyroiditis
