Avaliação de preditores de fadiga em pacientes com esclerose múltipla com baixo grau de comprometimento funcional: marcadores inflamatórios, função respiratória e incapacidade

Abstract

Introduction: Fatigue is one of the most frequent and disabling symptoms in Multiple Sclerosis (MS). It is a multifactorial and complex symptom, and its pathophysiology is not yet fully known. Central, psychological and peripheral factors can contribute to the occurrence of fatigue. Deficits in quality of life, reduction of muscle strength, depression and the inflammatory process of the disease are reported in the literature as being associated with higher levels of fatigue among MS patients. The lack of a definite concept allied to the unknown etiology and vague clinical descriptions made fatigue difficult to evaluate. Objectives: To identify the presence of fatigue and to evaluate potential determinants for its occurrence in patients with Multiple Sclerosis- Recurrent Sclerosis (RRMS) with low level of functional impairment. Materials and Methods: The case-control study consisted of a sample of 39 patients diagnosed with MS and 39 healthy subjects. The two groups were submitted to the calculation of Body Mass Index (BMI); maximal inspiratory force (MIP), maximal expiratory force (MEP) (through manovacuometry), measurement of peak expiratory flow (PEF) (peak flow) and application of following scales: Expanded Functional Disability Scale (EDSS), Guy Neurological Disability Scale (GNDS), Functional Quality of Life Rating Scale (DEFU), Modified Fatigue Impact Scale (MFIS). Results: Patients with RRMS compared to healthy controls had higher incidence of fatigue and difference in the concentration of inflammatory biomarkers (IFN, TNF, IL-10, IL-6, IL-4, IL-2). Patients with fatigue EMRR scored higher disability scores, higher frequency of use of associated medications, and lower quality of life index when compared to RRMS without fatigue. The higher the level of fatigue in the RRMS population, the higher the level of disability, depressive symptoms, associated pathologies and the use of associated medications. The higher the level of fatigue in this group, the lower the quality of life indexes and the MEP values. Conclusion: The degree of disability caused by the disease is a determinant of fatigue in MS patients. It is suggested that they are also related to the occurrence of fatigue: lower quality of life indices, higher prevalence of depressive symptoms, higher prevalence of associated pathologies and consequent use of medications. Future studies in a larger sample should provide more information about the pathophysiology of MS manifestations, helping to understand the highly disabling symptom of fatigue.