Periodic alternating nystagmus of peripheral vestibular origin

Abstract

4.

A Case of Acute Vestibular Neuritis with Periodic Alternating Nystagmus

“…This condition is typically observed either in patients with a complaint of acute vertigo in central nervous system disorders, especially those of the pontomedullary area, or in patients with the congenital form of PAN. 2,3) However, very rarely, peripheral vestibular disorders such as labyrinthitis or Meniere's disease presenting PAN have been also reported. 4) Here we report an uncommon case of a patient with acute vertigo presenting with PAN, which was eventually diagnosed as a peripheral vestibular disorder-vestibular neuritis-without other central disorders.…”

“…ripheral vestibular disorders, albeit rarely. Kim, et al 2) reported 10 patients with peripheral vestibular disorder presenting PAN and defined the distinguishing characteristics of peripheral and central PAN. Central PAN can be identified by the presence of symptoms of central disorders, such as ataxia, motor weakness, dysarthria, lethargy, or abnormal cerebellar function findings.…”

“…All cases of peripheral PAN reported till date, including the present case, progressed to unidirectional spontaneous nystagmus within 48 hours. 2) Visual suppression of nystagmus and normal oculomotor findings are other clinical features of peripheral PAN. 2) In contrast, PAN associated with central disorders are generally not influenced by visual fixation.…”

“…2) Visual suppression of nystagmus and normal oculomotor findings are other clinical features of peripheral PAN. 2) In contrast, PAN associated with central disorders are generally not influenced by visual fixation. 5) Similar to the clinical features, the pathomechanisms underlying central and peripheral PAN are thought be distinct.…”

“…On the other hand, the mechanisms resulting in peripheral PAN are thought to occur during the transition period when irritative nystagmus changes to paralytic nystagmus. 2) In the irritative phase, unilateral vestibular nuclei are stimulated, and nystagmus is observed in the direction of the stimulated side. Then, as input to the vestibular nuclei decreases, the direction of nystagmus changes to the contralateral side, with paralysis of the peripheral vestibular system.…”