Periodic alternating nystagmus. A case report.

A 71-year-old man complained of 5 years of progressive postural instability, more intense when standing up from bed, especially in darkness and during the day when walking on street. It lasted a few seconds and resolved spontaneously. No reference to vegetative symptoms, hearing loss or rotatory movements. Relevant personal clinical antecedents were slowly progressive visual loss that began at age 20, followed by the diagnosis of pigmentary glaucoma at age 40, and three episodes of retinal detachment repair (twice in the right eye and once on left eye, during the last two decades), and 6 months ago he underwent a combined surgery directed to right glaucoma and cataract. Other antecedents were lymph node tuberculosis and radical prostatectomy three years ago and benign paroxysmal positional vertigo of horizontal and posterior right semicircular canals treated with repositioning maneuvers two years ago.