[Multiple sclerosis and fatigue]

Fatigue is a frequent symptom in multiple sclerosis, known since the first descriptions of the disease, and it has been the object of special interest in recent years due to the great influence it has on the quality of life of those suffering from the disease. The fatigue of multiple sclerosis has clinical characteristics that differentiate it from the fatigue of other systemic diseases. At the same time, it is highly variable between patients and a clear distinction can be made between three types: astenia, fatigability and the worsening of symptoms with exercise. The physiopathological bases are not fully established, but there is data indicating that astenia is related to immunoactivation and evidence of the relation of fatigability to alterations of the pyramidal tract. Another point of interest in the study of fatigue is how to objectivise and quantify it, as well as the neurophysiological techniques for its evaluation and the measurement scales most frequently employed. The paper also sets out the principal therapeutic tests and considers the relative efficacy of aminopyridine and amantadine in alleviating it.