Resumen:
Background: Meniere's disease is often characterized by a changing horizontal nystagmus during the crisis; however, vertical nystagmus is not often detected. The horizontal nystagmus is frequently studied in the irritative or destructive phases of the disease. Clinical findings: We report the case of a 70 years-old man suffering for 3 years of Meniere's disease in his right ear. During an attack we found an infrequent nystagmus that was a downbeat nystagmus in primary position. He was then closely followed in the ward during 5 days and daily tests were performed. We first ruled out a central cause and were able to explain that as due to a peripheral deficit in the right posterior semicircular canal. Other features of the vertigo attacks in patients with MD were recorded. We studied a patient presenting a vertigo attack with a downbeat nystagmus. Our findings show that this nystagmus was caused by his own Meniere's disease, specifically by a posterior canal hypofunction, and not by a central disorder. There is no evidence about this kind of nystagmus in Meniere disease and, to the best to our knowledge, this is one of the first reports its evaluation using the test nowadays available. Conclusion: In this case, our result demonstrate that the downbeat nystagmus was caused by a hypofunction of the posterior semicircular canal.
