A Case of Acute Vestibular Neuritis with Periodic Alternating Nystagmus
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Case Report Korean J Otorhinolaryngol-Head Neck Surg 2018;61(3):151-5 / pISSN 2092-5859 / eISSN 2092-6529 https://doi.org/10.3342/kjorl-hns.2016.17013 A Case of Acute Vestibular Neuritis with Periodic Alternating Nystagmus Se Won Jeong1, Jeon Mi Lee2, Sung Huhn Kim2, and Jung Hyun Chang1 1Department of Otorhinolaryngology-Head and Neck Surgery, National Health Insurance Service Ilsan Hospital, Goyang; and 2Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea 주기성 교대 안진을 동반한 전정 신경염 1예 정세원1 ·이전미2 ·김성헌2 ·장정현1 국민건강보험 일산병원 이비인후과,1 연세대학교 의과대학 이비인후과학교실2 Detection of nystagmus is an important diagnostic clue in patients with acute vertigo. Patients Received August 13, 2016 with peripheral disorders exhibit nystagmus with a constant direction whereas those with cen- Revised October 13, 2016 tral disorders exhibit nystagmus with changes in direction with or without gaze fixation. Peri- Accepted November 3, 2016 odic alternating nystagmus (PAN) is a horizontal or horizontal-rotary jerk-type nystagmus that Address for correspondence reverses its direction with time. PAN is typically observed in patients with central disorders, Jung Hyun Chang, MD, PhD such as cerebellar or pontomedullary lesions, but it is also observed in patients with peripheral Department of Otorhinolaryngology- disorders, albeit rarely. Here we report a rare case of a 58-year-old patient with vertigo with Head and Neck Surgery, PAN, which was initially suspected as a central disorder, but eventually diagnosed as a periph- National Health Insurance eral vestibular disorder. We investigated the characteristics and mechanisms of peripheral PAN Service Ilsan Hospital, in this case. The absence of central disorder symptoms, visual suppression of PAN, normal oc- 100 Ilsan-ro, Ilsandong-gu, ulomotor findings, and transient persistence are important diagnostic clues for differentiating Goyang 10444, Korea Korean J Otorhinolaryngol-Head Neck Surg 2018;61(3):151-5 Tel +82-31-900-0972 peripheral from central PAN. Fax +82-31-900-0972 Key WordsZZPeriodic alternating nystagmus ㆍVestibular neuritis ㆍVestibule of the ear. E-mail [email protected] Introduction disease presenting PAN have been also reported.4) Here we report an uncommon case of a patient with acute Periodic alternating nystagmus (PAN) is a persistent hori- vertigo presenting with PAN, which was eventually diagnosed zontal or horizontal-rotary jerk-type nystagmus that reverses as a peripheral vestibular disorder-vestibular neuritis-with- its direction in intervals of 1-6 minutes. It is known to have out other central disorders. We investigated the characteristics resting periods of 4-20 seconds between switches,1) although and mechanisms of peripheral PAN with a review of literature. the periodicity and quiescence are not regular in all cases. This condition is typically observed either in patients with a Case complaint of acute vertigo in central nervous system disor- ders, especially those of the pontomedullary area, or in patients A 58-year-old woman visited our clinic with aggravated with the congenital form of PAN.2,3) However, very rarely, pe- vertigo with an onset duration of 2 months. A review of her ripheral vestibular disorders such as labyrinthitis or Meniere’s medical history revealed mastoidectomy because of chronic This is an Open Access article distributed under the terms of the Creative Commons otitis media in the right ear 30 years ago and no other medical Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) conditions. The patient suffered a spinning type of vertigo which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. lasting 2-3 minutes, with no other otological symptoms such Copyright © 2018 Korean Society of Otorhinolaryngology-Head and Neck Surgery 151 Korean J Otorhinolaryngol-Head Neck Surg █ 2018;61(3):151-5 as hearing loss or fullness of the ear. Vertigo was relieved with lasted 15-20 seconds, and the mean maximal slow phase ve- rest, but it soon aggravated whenever the patient changed po- locity was 4-12º/second. This periodicity was repeated, sition. The ear drum was normal, with no signs of infection. which suggested that either direction of nystagmus could be Spontaneous or gaze-evoked nystagmus was not detected, started first. The pattern of the nystagmus did not change but when the head rolling test was administered, geotropic during the Dix-Hallpike or head rolling tests, indicating its nystagmus stronger in the right-sided position was observed. independence from change in position. The patient was tentatively diagnosed with benign paroxys- Neurological examination, including cerebellar function mal positional vertigo of right-sided lateral semicircular test and brain magnetic resonance imaging, was performed canalolithiasis, which was treated with the Barbecue maneu- to evaluate the possibility of central origin of nystagmus; how- ver. However, when the symptoms did not improve signifi- ever, the findings revealed no definite abnormalities. Evalu- cantly, the patient was hospitalized for conservative treatment. ation for tumor biomarkers or neuromyelitis optica antibodies After 2 days of hospitalization, the pattern of nystagmus was to rule out paraneoplastic syndrome, revealed negative find- observed to have changed. The patient exhibited spontaneous ings. Vestibular function tests were then performed. Smooth nystagmus beating to one side, followed by a change in direc- pursuit and saccadic eye movement exam revealed normal tion to the opposite side, with a quiescence period of 4-6 sec- vestibule-ocular reflex, with minor variations due to sponta- onds between reversals (Fig. 1). Each unidirectional cycle neous nystagmus. Bithermal caloric test was performed to in- 30 20 Fig. 1. A 30-second trace of sponta- 10 neous nystagmus in the dark. Right 0 horizontal beating nystagmus (Rt) transformed to left horizontal beat- -10 Rt Q Lt ing nystagmus (Lt) after 12 seconds -20 of quiescence (Q). The trace repre- sents horizontal eye movement (de- Time (sec) gree). Lateral impulse test: 2014-03-27 10:31 Left mean: 0.82, σ: 0.24 Test operator: IMPULSE ICS Right mean: 0.48, σ: 0.15 Left Left mean 300 300 Right Right mean 1.2 200 200 1.0 0.8 100 100 0.6 Gain 0 0 0.4 Head & eye velocity Head & eye velocity 0.2 -100 -100 0.0 -140 0 560 -140 0 560 40 60 80 100 120 140 160 180 200 220 240 260 280 300 Peak velocity (deg/sec) Left lateral ms Right lateral ms LARP impulse test: 2014-03-27 10:34 LA mean: 0.86, σ: 0.10 Test operator: IMPULSE ICS RP mean: 0.64, σ: 0.08 LA LA mean 300 300 RP RP mean 1.2 200 200 1.0 0.8 100 100 0.6 Gain 0.4 0 0 Head & eye velocity Head & eye velocity 0.2 -100 -100 0.0 -140 0 560 -140 0 560 40 60 80 100 120 140 160 180 200 220 240 260 280 300 Peak velocity (deg/sec) Left amerior ms Right posterior ms RALP impulse test: 2014-03-27 10:33 LP mean: 0.95, σ: 0.06 Test operator: IMPULSE ICS RA mean: 0.48, σ: 0.07 LP LP mean 300 300 RA RA mean Fig. 2. Video head impulse test was 1.2 200 200 performed during the hospital stay. 1.0 Right sided canals showed decreased 0.8 100 100 gain and following catch-up saccade 0.6 Gain during the test, suggesting peripher- 0.4 0 0 0.2 Head & eye velocity Head & eye velocity al vestibulopathy in right side. LARP: -100 -100 left anterior right posterior, LA: left 0.0 -140 0 560 -140 0 560 40 60 80 100 120 140 160 180 200 220 240 260 280 300 Peak velocity (deg/sec) Left posterior ms Right anterior ms anterior, RP: right posterior, RALP: right anterior left posterior. 152 Peripheral Vertigo Case with PAN █ Jeong SW, et al. vestigate the canal function. It was impossible to calculate thrust position, which supported our diagnosis of vestibular the canal paresis and the directional paresis value because di- neuritis. After 2 weeks of vestibular rehabilitation therapy, rection-changing nystagmus remained still during the test. the patient exhibited improvement in her symptoms and has However, nystagmus was well suppressed during the caloric not complained of relapse in follow-up evaluations till date. test with visual fixation. Video head impulse test was per- Follow-up serial posturographic findings revealed improve- formed to evaluate the function of each canal. Right sided ment as well (Fig. 3). canals showed decreased gain with following catch-up sac- cades, suggesting peripheral vestibulopathy (Fig. 2). Cervical Discussion vestibular evoked myogenic potential test revealed no re- sponse in the right ear and a threshold of 85 dB in the left ear. PAN is differentiated as either an acquired condition or a Upon posturography, the patient constantly fell in conditions type of congenital nystagmus. Congenital PAN often presents 4, 5, and 6 (Fig. 3A), and decreased vestibular function in during the first 6 months after birth and has been reported to sensory analysis (Fig. 3B). Consequently, the patient was di- be associated with sensory defects such as albinism.5) Acquired agnosed with acute vestibular neuritis affecting the right side, PAN, although less common, is equally important to identify rather than a central disorder. The patient continued to receive because of its association with central nervous system disor- conservative care with vestibular rehabilitation therapy. ders involving the pontomedullary area, caudal brainstem, After 6 days from its first observation, PAN had resolved or vestibulocerebellum.1) Anticonvulsant medications, hepat- completely, while spontaneous nystagmus beating to left side, ic encephalopathy, and trauma and the consequent vision loss which was constant while changing position, persisted. Head are also known to cause PAN.5) thrust test revealed corrective saccade movement in the right However, PAN has also been observed in patients with pe- Equilibrium score Equilibrium score 100 100 75 75 50 50 25 25 Fall Fall 1 2 3 4 5 6 Composite 1 2 3 4 5 6 Composite 33 59 A Conditions B Conditions Sensory analysis Sensory analysis 100 100 75 75 50 50 25 25 0 0 C SOM VIS VEST PREF D SOM VIS VEST PREF Fig.