Corinna Lechner

Not so benign positional vertigo: paroxysmal downbeat nystagmus from a superior cerebellar peduncle neoplasm.

A 65-year-old man gave a 3-year history of brief spells of spinning vertigo brought on by rolling over in bed or bending down. Dix-Hallpike testing with either ear down provoked almost immediate paroxysms of downbeat-nystagmus and vertigo lasting between 5 and 10 seconds (See Supplemental DigitalContentVideosAandB,http://links.lww.com/MAO/A190, http://links.lww.com/MAO/A191, which demonstrate downbeat nystamgus with no latency in the right and left DixHallpike positions, respectively; Fig. 1C). His examination was otherwise normal, with no spontaneous or gaze-evoked nystagmus, normal saccadic and pursuit eye movements, FIG. 1. Brain MRI with contrast (A and B) and video nystagmography. A, Coronal T1-weighted imaging illustrating the left cerebellarhemangioblastoma (arrow). B, Edema within the cerebellum and brainstem on axial T2-image (arrow).C, Videonystagmography, illustrating paroxysmal downbeat nystagmus lasting 5 to 10 seconds on Dix-Hallpike testing.

Bedside Assessment of Acute Dizziness and Vertigo

Dizziness is a common symptom in emergency departments, general practice, and outpatient clinics. Faced with an acutely dizzy patient, the frontline physician must determine whether or not the symptoms are vestibular in origin and, if they are, which vestibular disorder they best fit. A focused history provides useful clues to the likely cause of dizziness, yet it is the clinical examination that yields the final answer. This article summarizes history and examination techniques that are useful in the assessment of acutely dizzy patients and discusses oculomotor signs that accompany common vestibular disorders.

Vestibular schwannoma mimicking horizontal cupulolithiasis

Positional vertigo and nystagmus can be due to canalithiasis, cupulolithiasis and less commonly, an underlying peripheral or central vestibular disorder. We present a patient with vestibular schwannoma who initially sought treatment for positioning vertigo. Video-oculography on the roll-test revealed direction-changing horizontal apogeotropic nystagmus, consistent with horizontal cupulolithiasis. However, further audio-vestibular investigations and imaging confirmed a right vestibulopathy attributable to a schwannoma of the right vestibular nerve. This case report suggests that vestibular schwannoma should be considered as another potential mimicker of horizontal cupulolithiasis.

Lhermitte–Duclos disease presenting with atypical positional nystagmus

We describe a patient with dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease) who presented with an acute onset of positional disequilibrium. Video-oculography in the right Hallpike position revealed rightward torsional down-beat nystagmus, initially thought to be right anterior canal benign positional vertigo. However, the presence of spontaneous nystagmus, the persistent character of the positional nystagmus and the absence of fatigability indicated central positional nystagmus, attributable to his right-sided Lhermitte-Duclos disease. These findings emphasise the need for clinicians to reconsider a central cause before diagnosing the rare anterior canal benign positioning vertigo variant.