Multiple sclerosis is the most common autoimmune inflammatory demyelinating disease of the central nervous system, and its etiology is believed to have both genetic and environmental components. Several viruses have already been implicated as triggers and there are several studies that implicate members of the Herpesviridae family in the pathogenesis of MS. The most important characteristic of these viruses is that they have periods of latency and exacerbations within their biological sanctuary, the central nervous system. The Epstein-Barr, cytomegalovirus, human herpesvirus 6 and human herpesvirus 7 viruses are the members that are most studied as being possible triggers of multiple sclerosis. According to evidence in the literature, the herpesvirus family is strongly involved in the pathogenesis of this disease, but it is unlikely that they are the only component responsible for its development. There are probably multiple triggers and more studies are necessary to investigate and define these interactions.

Background: Headache is the most common neurological symptom of patients on hemodialysis treatment. However, this condition is usually treated only after the pain has already begun. Objective: Determine the efficacy and tolerability of nortriptyline as a prophylactic treatment for patients diagnosed with hemodialysis headache. Methods: This study is an open and a prospective clinical trial. Twelve patients with hemodialysis headache were studied in this trial. They were asked to take nortriptyline (25 mg per day) during three months as a prophylaxis for their headaches. Weekly interviews were made to register eventual headaches. Additionally, other clinical features were analyzed such as the intensity of pain, its location, side effects of the drug and use of abortive medications. Results: There was a significant reduction (p < 0.05) in the intensity as well as frequency of pain. The duration of the episodes also decreased. Conclusions: Our findings suggest that nortriptyline 25 mg is capable of reducing not only the frequency, but also the intensity of the pain in the hemodialysis headache. However, further studies are necessary.