Isokinetic Muscle Strength, Torque, Ultrasonographic Muscle Thickness in Fibromyalgia Syndrome: A Case-Control Study

Fibromyalgia syndrome (FMS) is a chronic disease characterized by widespread body pain and tenderness in specific points, which may be accompanied by sleep disturbances, depression, fatigue, cognitive symptoms such as memory problems and attention deficit, and somatic symptoms such as irritable bowel syndrome and constipation. The prevalence of FMS has been found to be approximately 2%. It is more frequently diagnosed in women between the ages of thirty and fifty . It is more common in individuals with low socioeconomic status and education level. Its etiology is not fully known. Genetic and some environmental factors are thought to be influential. Central sensitization, autonomic nervous system dysfunction, immune system dysregulation, intestinal microbiota changes, hypothalamic-pituitary-adrenal (HPA) axis and endocrine system disorders are implicated in the pathogenesis (5; 6; 7; 8). FMS diagnostic criteria were first established in 1990 by the American College of Rheumatology (ACR). According to these criteria, FMS is diagnosed based on the presence of widespread pain and tender points in the body. In 2010, the ACR updated the diagnostic criteria by adding the Widespread Pain Index and Symptom Severity Scale. Currently, the 2016 ACR classification criteria are used in the diagnosis of FMS. These criteria consider the presence of pain for at least 3 months, the widespread pain index which assesses the presence of pain in 5 different areas of the body, and the symptom severity scale which assesses fatigue, waking up without rest, and cognitive symptoms. In these criteria, a diagnosis of fibromyalgia can be made independently of other diagnoses; the presence of fibromyalgia does not rule out the presence of other diseases. The treatment approach for FMS is multidisciplinary. It is considered both non-pharmacological and pharmacological. Non-pharmacological treatment consists of patient education, lifestyle modification, cognitive behavioral therapy, and exercise. Pharmacological treatment includes tricyclic antidepressants, selective serotonin reuptake inhibitors, serotonin norepinephrine reuptake inhibitors, and pregabalin. The aim of the study is to evaluate muscle strength, muscle power, muscle thickness, vitamin D levels, and sleep quality in individuals with and without fibromyalgia syndrome, and to identify possible risk factors.

Inclusion Criteria: Patient group: * female gender * 18-55 years old * Clinical diagnosis of Fibromyaljia syndrome Control group: * female gender * 18-55 years old * absence of fibromyalgia syndrome diagnosis Exclusion Criteria: * Rheumatological disease, crystal arthropathy, septic arthritis * Advanced osteoarthritis * History of major orthopedic surgery (total knee and hip replacement, etc.) * Neurological disease (Parkinson's disease, multiple sclerosis, cerebrovascular event, etc.) * Neuromuscular disease (Polyneuropathies, myasthenia gravis) * Active malignancy * Advanced organ failure/transplantation