Thread by @theneurolander

Nystagmus series – Part VI
(periodic alternating nystagmus, PAN)

“Nystagmus processor for EEG machines”

Italian-American neurologist Joseph Toglia (1927 – 2018)

#MedTwitter #neurotwitter #EndNeurophobia #tweetorials @TempleUniv

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Definition

“horizontal nystagmus reverses direction every 2 minutes”

During transition period
-upbeating, downbeating, square-wave jerks can occur

- acquired form is rare, but it is the best understood and the first to have effective treatment

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Pathophysiology

“lesion in cerebellum nodulus & uvula”

nodulus & uvula
- responsible for velocity-storage mechanism
- inhibitory control on vestibular rotation using GABA (baclofen-responsive)

vestibular system
- repair mechanism
- reverse direction of nystagmus

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Fixation in central vestibular nystagmus

“poorly suppressed by fixation of a visual target”

- abnormal smooth-pursuit system



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Associated symptoms

Periodic alternating head turns
- minimizing nystagmus by Alexander’s law
- head turn in the direction of the quick-phase

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Management

Acquire form
- baclofen

Congenital form
- horizontal recti resection

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Obs

a) vestibular stimuli (head rotations) can transiently change nystagmus
b) periodic alternating gaze deviation, if brainstem is affected
c) persist during sleep remaining horizontal in vertical gaze
d) see for 4 minutes every central position horizontal nystagmus

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Differ

a)acquired vs congenital: congenital has congenital features & irregular time
b)ping-pong gaze: ocular deviations reverse after seconds; bihemispheric lesion
c)alternating windmill nystagmus: horizontal&vertical planes
d)paroxysm mixed torsional-horizontal-vertical

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Acquired periodic alternating nystagmus – features

i) horizontal nystagmus reverses direction every 2 minutes

ii) transition phase ⬇️⬆️🔲

iii) no suppress by visual fixation

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Acquired periodic alternating nystagmus

i) horizontal nystagmus reverses direction every 2 minutes
ii) transition phase ⬇️⬆️🔲
iii) no suppress by visual fixation

dizziness-and-balance.com via: Timothy C. Hain

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Acquired periodic alternating nystagmus

i) horizontal nystagmus reverses direction every 2 minutes
ii) transition phase ⬇️⬆️🔲
iii) no suppress by visual fixation

via: moran CORE

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Acquired periodic alternating nystagmus

i) horizontal nystagmus reverses direction every 2 minutes
ii) transition phase ⬇️⬆️🔲
iii) no suppress by visual fixation

via: Raed Behbehani

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Acquired periodic alternating nystagmus

i) horizontal nystagmus reverses direction every 2 minutes
ii) transition phase ⬇️⬆️🔲
iii) no suppress by visual fixation

via: Raed Behbehani

13/

Acquired periodic alternating nystagmus

i) horizontal nystagmus reverses direction every 2 minutes
ii) transition phase ⬇️⬆️🔲
iii) no suppress by visual fixation

via: lmkaud

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Acquired periodic alternating nystagmus

i) horizontal nystagmus reverses direction every 2 minutes
ii) transition phase ⬇️⬆️🔲
iii) no suppress by visual fixation

via: Dr.Aishwarya Anand

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Acquired periodic alternating nystagmus

i) horizontal nystagmus reverses direction every 2 minutes
ii) transition phase ⬇️⬆️🔲
iii) no suppress by visual fixation

via: Doc Callan

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Acquired periodic alternating nystagmus

i) horizontal nystagmus reverses direction every 2 minutes
ii) transition phase ⬇️⬆️🔲
iii) no suppress by visual fixation

via: Alain Thiry

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Differ

acquired periodic alternating nystagmus vs ping-pong gaze

ping-pong gaze
- ocular deviations reverse after few seconds
- large bihemispheric lesion
- unconscious patients

via: Jama Network

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Differ

acquired periodic alternating nystagmus vs ping-pong gaze

ping-pong gaze
- ocular deviations reverse after few seconds
- large bihemispheric lesion
- unconscious patients

via: NEJM

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Differ

acquired periodic alternating nystagmus vs alternating windmill nystagmus

alternating windmill nystagmus
- horizontal & vertical planes oscillations
- blind patients (most freq)

DOI: doi.org/10.1212/WNL.00… via: Neurology

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Nystagmus general description

"Nystagmus – Moving eyes!!!"


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