Autonomic dysfunction in multiple sclerosis is better detected by heart rate variability and is not correlated with central autonomic network damage.

BACKGROUND: MS-associated autonomic dysfunction (AD) in multiple sclerosis (MS) is poorly understood and the best method for its detection unestablished. We compared classical Ewing battery and newer methods as heart rate variability (HRV) and spontaneous baroreflex sensibility (BRS) to detect AD in MS and related them to central autonomic network (CAN) lesions. METHODS: We enrolled 20 relapsing-remitting MS patients, median age of 36 (interquartile range 32-46) years, disease duration of 5.5 (2.2-6.8) years, Expanded Disability Status Scale (EDSS) score of 1.0 (1.0-1.5) and 20 age- and gender-matched healthy controls. We assessed Ewing battery and spontaneous HRV and BRS. CAN involvement was evaluated by magnetic resonance imaging. RESULTS: HRV showed both parasympathetic and sympathetic significant impairment in MS (p<0.05). From Ewing battery only isometric test was significantly decreased in MS (p=0.006). Disease duration and severity, lesion burden and CAN involvement were not correlated with laboratorial parameters. CONCLUSIONS: Our MS cohort had both sympathetic and parasympathetic dysfunction independently from disease duration, neurological deficits and lesion burden or CAN involvement. HRV analysis maybe more useful than classical Ewing battery to screen AD.

Prevalence of autonomic dysfunction in patients with multiple sclerosis.

BACKGROUND: Autonomic nervous system dysfunction is commonly seen in multiple sclerosis patients and should be explored in the routine evaluation. Composite Autonomic Symptom Score questionnaire was validated as a self-assessment instrument of autonomic symptoms. OBJECTIVES: Determine the frequency of autonomic symptoms in multiple sclerosis patients through a Portuguese version of Composite Autonomic Symptom Score; compare questionnaire results between patients and a control group; assess the feasibility of this questionnaire application in multiple sclerosis Portuguese patients. MATERIAL AND METHODS: This case-control study used a Portuguese translated version of Composite Autonomic Symptom Score to determine the frequency of autonomic symptoms in multiple sclerosis patients. RESULTS: One-hundred and three relapsing-remitting multiple sclerosis patients - median age 41 years, median disease duration 6 years, median EDSS score 1 - and 80 healthy subjects were included. Alterations in autonomic function were reported in 97.1% of the cases, with statistical significance in orthostatic intolerance and gastrointestinal domain scores. Nevertheless, the difference between multiple sclerosis patients (41.7%) without confounding factors that could interfere with autonomic dysfunction (i.e. comorbidities or medications) and controls showed no statistical significance. DISCUSSION: Our results may be related to the short disease duration, young age and lowdisability status of our patients unaffected by confounding factors. The questionnaire was not designed specifically for multiple sclerosis and it may not be as sensible to early autonomic symptoms as to more severe manifestations. CONCLUSIONS: Further studies are needed to achieve more robust results, validate this questionnaire and assess its application in multiple sclerosis patients in Portugal.

Introdução: A disfunção do sistema nervoso autónomo é comum na esclerose múltipla e deveria ser explorada na avaliação de rotina. O questionário Composite Autonomic Symptom Score foi validado como instrumento de auto-avaliação de sintomas autonómicos. Objetivos: Determinar a frequência de sintomas autonómicos em doentes com esclerose múltipla através de uma versão portuguesa do Composite Autonomic Symptom Score; comparar os resultados do questionário entre um grupo de doentes e um grupo controlo; avaliar a viabilidade da aplicação deste questionário em doentes portugueses. Material e Métodos: Neste estudo caso-controlo utilizou-se uma tradução portuguesa do questionário para determinar a frequência de sintomas autonómicos em doentes com esclerose múltipla. Resultados: Incluíram-se 103 doentes com esclerose múltipla surto-remissão ­ idade média 41 anos, mediana de duração da doença 6 anos, EDSS médio 1 - e 80 indivíduos saudáveis. Dos doentes, 97,1% tinham alterações da função autonómica, com significado estatístico nos domínios intolerância ortostática e gastrointestinal. Não encontramos diferenças estatísticas entre doentes (41,7%) sem fatores de confundimento que podiam interferir com a função autonómica (i.e. comorbilidades ou medicações) e o grupo controlo. Discussão: Os resultados obtidos podem estar relacionados com a curta duração de doença, idade jovem e baixo grau de incapacidade dos doentes sem fatores de confundimento. O questionário utilizado não foi desenhado especificamente para a esclerose múltipla e pode não ser tão sensível para sintomas autonómicos mais precoces como para manifestações mais graves da doença. Conclusões: Outros estudos serão necessários para obter resultados mais robustos, validar este questionário e avaliar a sua aplicação nos doentes portugueses.