Nystagmus Evaluation

VERSION: 1.2 CREATED: February 2, 2026 REVISED: February 2, 2026 (v1.2) STATUS: Approved

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DIAGNOSIS: Nystagmus Evaluation

ICD-10: H55.00 (Unspecified nystagmus), H55.01 (Congenital nystagmus), H55.02 (Latent nystagmus), H55.09 (Other forms of nystagmus), H55.89 (Other irregular eye movements), H81.4 (Vertigo of central origin), G45.0 (Vertebro-basilar artery syndrome), R29.810 (Facial weakness), G25.3 (Myoclonus), G11.9 (Hereditary ataxia, unspecified)

CPT CODES: 92540 (Electronystagmography/videonystagmography), 92541 (Spontaneous nystagmus test), 92542 (Positional nystagmus test), 92544 (Optokinetic nystagmus test), 92545 (Oscillating tracking test), 92546 (Sinusoidal rotational testing), 92547 (Supplemental caloric test), 92548 (Computerized dynamic posturography), 92517 (VEMP), 92270 (Electro-oculography), 70553 (MRI brain with/without contrast), 70551 (MRI brain without contrast), 70544 (MRA head), 70547 (MRA neck), 70496 (CTA head), 70498 (CTA neck), 95816 (EEG routine), 95819 (EEG with sleep), 92557 (Audiometry), 95930 (Visual evoked potential), 62270 (Lumbar puncture, diagnostic), 92134 (OCT retinal nerve fiber layer), 92700 (Unlisted special service/eye movement recording), 81479 (Unlisted molecular pathology/genetic testing), 99213-99215 (Outpatient E/M), 99281-99285 (ED E/M)

SYNONYMS: Nystagmus, involuntary eye movements, oscillopsia, nystagmus evaluation, dancing eyes, gaze-evoked nystagmus, downbeat nystagmus, upbeat nystagmus, periodic alternating nystagmus, PAN, direction-changing nystagmus, vestibular nystagmus, positional nystagmus, jerk nystagmus, pendular nystagmus, see-saw nystagmus, convergence-retraction nystagmus, acquired nystagmus

SCOPE: Systematic evaluation and management of acquired nystagmus in adults. Covers classification (central vs. peripheral), bedside examination techniques (HINTS exam, gaze testing, positional maneuvers), differentiation of nystagmus subtypes (gaze-evoked, downbeat, upbeat, periodic alternating, see-saw, convergence-retraction, vestibular), VNG/ENG and advanced vestibular testing, neuroimaging indications, and targeted treatment of specific nystagmus types (4-aminopyridine for downbeat nystagmus, baclofen for periodic alternating nystagmus, gabapentin/memantine for acquired pendular nystagmus). Excludes congenital/infantile nystagmus (brief mention), physiologic endpoint nystagmus, and comprehensive vertigo/dizziness evaluation (see Vertigo/Dizziness Evaluation template).

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PRIORITY KEY: STAT = Immediate | URGENT = Within hours | ROUTINE = Standard | EXT = Extended/atypical cases | - = Not applicable to this setting

═══════════════════════════════════════════════════════════════ SECTION A: ACTION ITEMS ═══════════════════════════════════════════════════════════════

1. LABORATORY WORKUP

1A. Essential/Core Labs

Test	ED	HOSP	OPD	ICU	Rationale	Target Finding
CBC (CPT 85025)	STAT	STAT	ROUTINE	STAT	Infection screening; anemia (exacerbates dizziness/oscillopsia); baseline before treatment	Normal; infection markers; anemia correction
CMP (BMP + LFTs) (CPT 80053)	STAT	STAT	ROUTINE	STAT	Electrolyte abnormalities (hyponatremia causes central nystagmus); hepatic/renal dysfunction affects drug metabolism; hypomagnesemia lowers threshold	Normal; hyponatremia <130 — correct and reassess nystagmus; hepatic dysfunction — medication adjustment
Blood glucose (CPT 82947)	STAT	STAT	ROUTINE	STAT	Hypoglycemia causes neurologic symptoms including nystagmus; Wernicke encephalopathy association	70-180 mg/dL; hypoglycemia — correct; persistent low — evaluate further
Magnesium (CPT 83735)	STAT	STAT	ROUTINE	STAT	Hypomagnesemia causes nystagmus and cerebellar dysfunction; depleted by alcohol, diuretics, PPI use	>2.0 mg/dL; low — replete IV/PO
TSH (CPT 84443)	-	ROUTINE	ROUTINE	-	Thyroid dysfunction affects vestibular and oculomotor function; hyperthyroidism causes tremor/jerky saccades	Normal; abnormal — thyroid evaluation
Thiamine (B1) level (CPT 84425)	STAT	STAT	ROUTINE	STAT	Wernicke encephalopathy (nystagmus + ataxia + confusion); ALWAYS suspect in alcoholism, malnutrition, bariatric surgery, hyperemesis	Normal; DO NOT WAIT for level before treating — empiric thiamine if suspected
Anticonvulsant drug levels (if applicable) (CPT 80201-80299)	STAT	STAT	ROUTINE	STAT	Phenytoin, carbamazepine, and lacosamide toxicity cause gaze-evoked nystagmus; lithium toxicity causes downbeat nystagmus	Therapeutic range; supratherapeutic — dose reduction; toxic — hold medication
Ethanol level (CPT 80307)	STAT	STAT	-	STAT	Acute alcohol intoxication causes gaze-evoked and positional nystagmus; chronic alcoholism — Wernicke/cerebellar degeneration	Negative; positive — quantify; treat Wernicke empirically

1B. Extended Workup (Second-line)

Test	ED	HOSP	OPD	ICU	Rationale	Target Finding
Vitamin B12 (CPT 82607)	-	ROUTINE	ROUTINE	-	B12 deficiency causes subacute combined degeneration with ataxia and nystagmus	>300 pg/mL; low — supplement and monitor
Folate (CPT 82746)	-	ROUTINE	ROUTINE	-	Folate deficiency contributes to cerebellar dysfunction, especially in alcoholism	>4 ng/mL; low — supplement
Vitamin E level (CPT 82446)	-	-	ROUTINE	-	Vitamin E deficiency causes spinocerebellar syndrome with nystagmus; malabsorption syndromes	Normal; low — supplement and evaluate malabsorption
ESR (CPT 85652) / CRP (CPT 86140)	-	ROUTINE	ROUTINE	-	Inflammatory/autoimmune processes (MS, neurosarcoidosis, vasculitis) causing central nystagmus	Normal; elevated — autoimmune/inflammatory workup
ANA (CPT 86235)	-	ROUTINE	ROUTINE	-	Autoimmune conditions causing CNS inflammation (SLE cerebritis, neurosarcoidosis)	Negative; positive — further autoimmune serologies
ACE level (CPT 82164)	-	ROUTINE	ROUTINE	-	Neurosarcoidosis causes brainstem/cerebellar lesions with nystagmus	Normal; elevated — chest imaging, evaluate for neurosarcoidosis
RPR/VDRL (CPT 86592)	-	ROUTINE	ROUTINE	-	Neurosyphilis causes Argyll Robertson pupils and nystagmus; tabes dorsalis	Negative; positive — FTA-ABS confirmation, CSF analysis
Anti-GAD65 antibodies (CPT 86235)	-	-	ROUTINE	-	GAD65 autoimmunity causes cerebellar ataxia with downbeat nystagmus; progressive cerebellar syndrome	Negative; positive — autoimmune cerebellar disease; initiate immunotherapy
Paraneoplastic antibody panel (anti-Yo, anti-Hu, anti-Tr/DNER, anti-CV2, anti-mGluR1) (CPT 86255)	-	-	ROUTINE	-	Paraneoplastic cerebellar degeneration presents with nystagmus (often downbeat) + progressive ataxia	Negative; positive — urgent malignancy search (CT chest/abdomen/pelvis, PET)

1C. Rare/Specialized (Refractory or Atypical)

Test	ED	HOSP	OPD	ICU	Rationale	Target Finding
Anti-CASPR2 / Anti-LGI1 antibodies (CPT 86255)	-	-	EXT	-	Autoimmune encephalitis with oculomotor abnormalities; limbic encephalitis with nystagmus	Negative; positive — autoimmune encephalitis workup, immunotherapy
Anti-IgLON5 antibodies (CPT 86235)	-	-	EXT	-	Anti-IgLON5 disease causes oculomotor dysfunction including nystagmus, sleep disorder, gait ataxia	Negative; positive — sleep study, tau pathology evaluation
Genetic testing (SCA panel, episodic ataxia genes) (CPT 81479)	-	-	EXT	-	Spinocerebellar ataxias (SCA1, 2, 3, 6, 7); episodic ataxia type 2 (CACNA1A); Friedreich ataxia	Specific mutations; SCA6 and EA2 both involve CACNA1A; SCA — progressive; EA2 — episodic with interictal nystagmus
CSF analysis (see Lumbar Puncture section)	-	EXT	EXT	-	MS (oligoclonal bands), neurosarcoidosis, leptomeningeal disease, CNS infection, autoimmune encephalitis	Normal in degenerative; OCBs — MS; pleocytosis — infection/inflammation; cytology — malignancy
Serum copper / ceruloplasmin (CPT 82525 / 82390)	-	-	EXT	-	Wilson disease causes wing-beating tremor and oculomotor dysfunction including nystagmus in young adults	Normal ceruloplasmin >20 mg/dL; low — 24h urine copper, slit lamp for KF rings
Tissue transglutaminase (tTG-IgA) (CPT 86364)	-	-	EXT	-	Celiac disease causes cerebellar ataxia with nystagmus ("gluten ataxia") even without GI symptoms	Negative; positive — gluten-free diet, anti-gliadin antibodies
Prion protein gene (PRNM) analysis (CPT 81479)	-	-	EXT	-	Gerstmann-Straussler-Scheinker syndrome; genetic CJD presents with cerebellar ataxia and nystagmus	No pathogenic mutation; mutation — genetic counseling

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2. DIAGNOSTIC IMAGING & STUDIES

2A. Essential/First-line

Study	ED	HOSP	OPD	ICU	Timing	Target Finding	Contraindications
Bedside nystagmus characterization	STAT	STAT	ROUTINE	STAT	CRITICAL first step; systematic assessment: gaze in 9 cardinal positions, fixation removal (Frenzel goggles), head-shaking nystagmus, positional testing, HINTS exam if acute vestibular syndrome	Nystagmus pattern classification (see Section 5 — Differential Diagnosis); direction, waveform, effect of fixation, positional component	None; requires trained examiner
HINTS exam (Head Impulse, Nystagmus, Test of Skew)	STAT	STAT	-	STAT	ONLY for acute vestibular syndrome (continuous vertigo + nystagmus >24h); more sensitive than early MRI for posterior fossa stroke; trained examiner required	Peripheral: Positive HIT + unidirectional nystagmus + no skew; Central: Normal HIT + direction-changing/vertical nystagmus + skew deviation — STAT MRI	Not valid for episodic or positional nystagmus; requires acute continuous nystagmus; examiner training required
MRI brain with and without contrast (CPT 70553)	URGENT	URGENT	ROUTINE	URGENT	Gold standard for central nystagmus evaluation; includes DWI for stroke, FLAIR for demyelination, thin cuts through posterior fossa; MRI protocol includes craniocervical junction (downbeat nystagmus — Chiari malformation)	Stroke (DWI restriction); MS plaques (brainstem/cerebellum); Chiari malformation (cerebellar tonsillar herniation >5 mm); tumor (vestibular schwannoma, brainstem glioma, cerebellar metastasis); cerebellar degeneration (atrophy)	MRI-incompatible implants; severe claustrophobia; renal impairment (for gadolinium)
CT head without contrast (CPT 70450)	STAT	STAT	-	STAT	NOT sensitive for posterior fossa pathology (beam-hardening artifact); use only if MRI unavailable or for acute hemorrhage screening; does NOT rule out posterior circulation stroke or demyelination	Hemorrhage; large mass; hydrocephalus; NEGATIVE CT does NOT exclude posterior fossa pathology	None for non-contrast
MRA head and neck (CPT 70544, 70547) or CTA head/neck (CPT 70496, 70498)	URGENT	URGENT	ROUTINE	URGENT	If central nystagmus with stroke concern; vertebral artery dissection; basilar artery stenosis/occlusion; vertebrobasilar insufficiency	Vertebral/basilar artery dissection; stenosis; occlusion; dolichoectasia compressing brainstem	MRA: MRI contraindications; CTA: contrast allergy, renal impairment

2B. Extended

Study	ED	HOSP	OPD	ICU	Timing	Target Finding	Contraindications
Videonystagmography (VNG) (CPT 92540-92547)	-	-	ROUTINE	-	Comprehensive oculomotor and vestibular testing; spontaneous nystagmus, gaze testing, positional testing, Dix-Hallpike, caloric testing; quantifies nystagmus; documents central vs. peripheral patterns	Gaze-evoked nystagmus (central); unilateral caloric weakness (peripheral); direction-changing positional nystagmus (central); fixation suppression failure (central)	Perforated TM (water calorics — use air); bilateral vestibular loss limits caloric utility
Video head impulse test (vHIT) (CPT 92517)	-	URGENT	ROUTINE	-	Quantitative VOR assessment for all 6 semicircular canals; more sensitive than bedside HIT; differentiates peripheral from central vestibular lesions	Reduced VOR gain (<0.8) with corrective saccades — peripheral lesion; normal gain with central nystagmus — central lesion; canal-specific identification	Specialized equipment required
Audiometry (CPT 92557)	-	URGENT	ROUTINE	-	Hearing assessment when vestibular nystagmus present; identifies Meniere's disease, vestibular schwannoma, labyrinthitis; sudden sensorineural hearing loss is emergency	Normal (isolated nystagmus); low-frequency SNHL — Meniere's; asymmetric SNHL — vestibular schwannoma; mixed hearing loss — SSCD	Patient cooperation
MRI internal auditory canals (IAC protocol) (CPT 70553)	-	ROUTINE	ROUTINE	-	High-resolution T2 (CISS/FIESTA) for vestibular schwannoma; vascular loop compression of CN VIII; when asymmetric hearing loss or unilateral vestibular nystagmus	Vestibular schwannoma; vascular loop; arachnoid cyst	MRI contraindications
Dix-Hallpike maneuver (CPT 95992)	STAT	STAT	ROUTINE	-	When positional nystagmus suspected (BPPV); upbeat-torsional nystagmus with latency and limited duration = posterior canal BPPV	Positive: Upbeating-torsional nystagmus, 2-20 sec latency, <60 sec duration, fatigable — posterior canal BPPV; Atypical: No latency, persistent, non-fatigable — central positional nystagmus	Cervical spine instability; severe carotid stenosis (modify technique)
Visual evoked potential (VEP) (CPT 95930)	-	-	ROUTINE	-	If MS suspected; optic nerve demyelination; confirms optic nerve involvement in clinically isolated syndrome	Prolonged P100 latency — optic nerve demyelination (even subclinical); supports MS diagnosis	Patient cooperation; severe visual impairment
EEG (CPT 95816/95819)	-	ROUTINE	ROUTINE	ROUTINE	If seizure-related nystagmus (oculogyric episodes) or epileptic nystagmus suspected; also if episodic nystagmus with altered awareness	Normal; epileptiform discharges; seizure-related eye deviation	None

2C. Rare/Advanced

Study	ED	HOSP	OPD	ICU	Timing	Target Finding	Contraindications
Vestibular evoked myogenic potentials (VEMP) (CPT 92517)	-	-	ROUTINE	-	Saccular (cVEMP) and utricular (oVEMP) function; superior semicircular canal dehiscence; Meniere's disease; vestibular schwannoma	Abnormal in SSCD (enhanced cVEMP/oVEMP); reduced/absent in vestibular schwannoma; asymmetric in Meniere's	Conductive hearing loss affects testing
Rotary chair testing (CPT 92546)	-	-	EXT	-	Quantitative VOR across frequencies; bilateral vestibular hypofunction; pharmaceutical ototoxicity monitoring	Bilateral vestibular loss (reduced gain across frequencies); phase/gain abnormalities; asymmetric VOR	Specialized facility required
High-resolution CT temporal bones (CPT 70480)	-	-	ROUTINE	-	Superior semicircular canal dehiscence syndrome; cholesteatoma; temporal bone fracture; when sound/pressure-induced nystagmus	Dehiscence of superior canal; bony erosion; fracture line	Radiation exposure
Optical coherence tomography (OCT) (CPT 92134)	-	-	ROUTINE	-	Retinal nerve fiber layer thinning in chronic MS, neurodegenerative conditions; baseline for monitoring	RNFL thinning — chronic optic neuropathy; normal in acute	Patient cooperation; media opacity
Saccadometry / Eye movement recording (CPT 92700)	-	-	EXT	-	Quantitative analysis of saccades, smooth pursuit, optokinetic nystagmus; distinguish types of cerebellar oculomotor dysfunction	Saccadic dysmetria; impaired pursuit; gaze-holding failure; specific patterns for cerebellar vs. brainstem lesions	Specialized equipment
MRI cervical spine (CPT 72141/72156)	-	ROUTINE	ROUTINE	-	If downbeat nystagmus — evaluate craniocervical junction; Chiari malformation, craniocervical instability, foramen magnum lesion	Chiari I malformation (tonsillar herniation >5 mm); foramen magnum tumor; basilar invagination; syrinx	MRI contraindications

Lumbar Puncture

Study	ED	HOSP	OPD	ICU	Timing	Target Finding	Contraindications
LP — Selective indication (CPT 62270)	-	EXT	EXT	-	Indicated if MS, neurosarcoidosis, autoimmune encephalitis, CNS infection, or leptomeningeal disease suspected; NOT routine for isolated nystagmus; perform after MRI	Opening pressure normal (10-20 cm H2O); MS: oligoclonal bands, elevated IgG index; Neurosarcoid: pleocytosis, elevated protein, low glucose; Infection: per organism; Autoimmune: specific antibodies	Posterior fossa mass on imaging; elevated ICP without imaging; coagulopathy

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3. TREATMENT PROTOCOLS

3A. Acute/Emergent Treatment

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Thiamine (empiric if Wernicke suspected)	IV	Wernicke encephalopathy (nystagmus + ataxia + confusion triad; may be incomplete)	500 mg :: IV :: TID :: Thiamine 500 mg IV TID x 3-5 days, then 250 mg IV daily x 3-5 days, then 100 mg PO daily indefinitely; give BEFORE glucose; Galvin et al. (2010)	None at therapeutic doses	Monitor clinical improvement in nystagmus, ataxia, confusion; improvement within hours to days supports diagnosis; anaphylaxis rare with IV thiamine	STAT	STAT	-	STAT
Correct electrolyte abnormalities	IV	Hyponatremia, hypomagnesemia, hypocalcemia causing nystagmus	Per specific electrolyte :: IV :: per protocol :: Hyponatremia: Correct slowly (max 8-10 mEq/L per 24h to avoid osmotic demyelination); Hypomagnesemia: MgSO4 2-4 g IV over 30-60 min then maintenance; Hypocalcemia: Calcium gluconate 1-2 g IV	Overcorrection of sodium — osmotic demyelination syndrome	Electrolytes q4-6h during correction; neurologic reassessment after correction	STAT	STAT	ROUTINE	STAT
Discontinue/reduce offending medication	-	Drug-induced nystagmus (anticonvulsants, lithium, sedatives, aminoglycosides)	Hold or reduce dose :: - :: per protocol :: Phenytoin toxicity: Hold doses until level <20 mcg/mL; Carbamazepine toxicity: Hold until level <12 mcg/mL; Lithium toxicity: Hold; hydration; hemodialysis if severe; Aminoglycosides: Discontinue if vestibulotoxicity confirmed	Clinical necessity of medication; consult prescribing specialist	Drug levels; nystagmus reassessment after dose adjustment; permanent vestibulotoxicity possible with aminoglycosides	STAT	STAT	ROUTINE	STAT
Rule out posterior circulation stroke	-	Acute-onset nystagmus with ANY central features (direction-changing, vertical, gaze-evoked without drug cause, skew deviation, normal HIT)	HINTS exam :: - :: immediate :: If ANY central pattern on HINTS: STAT MRI with DWI + MRA head/neck; neurology/stroke consultation; activate stroke protocol if within window; Kattah et al. (2009)	Do not delay for MRI if basilar artery occlusion suspected	HINTS more sensitive than early CT or MRI for posterior fossa stroke; negative CT does NOT exclude stroke	STAT	STAT	-	STAT
Meclizine	PO	Acute peripheral vestibular nystagmus with oscillopsia, nausea, or vertigo; SHORT-TERM ONLY (24-72h); avoid in central nystagmus until etiology established	25 mg :: PO :: q6-8h :: Meclizine 25 mg PO q6-8h PRN; limit to 48-72h maximum; taper as tolerated	Avoid in central nystagmus until etiology established; prolonged use delays vestibular compensation; anticholinergic effects in elderly; urinary retention; glaucoma	Limit to 72h; sedation; early vestibular rehabilitation once acute phase resolved	STAT	STAT	ROUTINE	-
Dimenhydrinate	PO/IV	Acute peripheral vestibular nystagmus with nausea and vertigo; SHORT-TERM ONLY (24-72h); avoid in central nystagmus until etiology established	50 mg :: PO/IV :: q6h :: Dimenhydrinate 50 mg PO or IV q6h PRN; limit to 48-72h maximum	Avoid in central nystagmus until etiology established; prolonged use delays vestibular compensation; anticholinergic effects in elderly; sedation	Limit to 72h; sedation; anticholinergic side effects	STAT	STAT	ROUTINE	-
Diazepam	PO/IV	Acute vestibular nystagmus with severe vertigo; potent vestibular suppressant; SHORT-TERM ONLY (24-72h)	2 mg :: PO/IV :: q8h :: Diazepam 2-5 mg PO or IV q8h PRN; limit to 48-72h maximum; taper rapidly	Respiratory depression; CNS depression; avoid in elderly; avoid in hepatic impairment; dependency risk	Respiratory status; sedation level; fall risk; limit to 72h; avoid in suspected central cause until stroke excluded	STAT	STAT	-	STAT
Ondansetron	IV/PO	Nausea and vomiting associated with acute vestibular nystagmus; antiemetic without vestibular suppressant effect	4 mg :: IV/PO :: q8h :: Ondansetron 4-8 mg IV or PO q8h PRN for nausea	QT prolongation; serotonin syndrome risk with serotonergic agents; hepatic impairment (max 8 mg/day)	QTc monitoring if prolonged use; constipation	STAT	STAT	ROUTINE	STAT

3B. Type-Specific Nystagmus Treatment

DOWNBEAT NYSTAGMUS

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
4-Aminopyridine (4-AP, dalfampridine)	PO	First-line for symptomatic downbeat nystagmus; potassium channel blocker that improves Purkinje cell function	5 mg :: PO :: BID :: 4-Aminopyridine 5 mg PO BID (compounded) or Dalfampridine (Ampyra) 10 mg PO BID (extended-release); Strupp et al. (2003); Claassen et al. (2013)	Seizure disorder (lowers seizure threshold); renal impairment (CrCl <50 — dose adjustment); hepatic impairment; cardiac arrhythmia (prolongs QT at supratherapeutic doses)	Seizure risk; ECG at baseline; renal function; therapeutic response assessment at 2-4 weeks; visual acuity improvement	-	URGENT	ROUTINE	-
3,4-Diaminopyridine (3,4-DAP, amifampridine)	PO	Alternative to 4-AP for downbeat nystagmus; lower seizure risk than 4-AP	10 mg :: PO :: TID :: 3,4-Diaminopyridine 10 mg PO TID, titrate to max 20 mg TID (80 mg/day); Kalla et al. (2007)	Seizure disorder (lower risk than 4-AP but still present); QT prolongation	Seizure monitoring; ECG; clinical response	-	ROUTINE	ROUTINE	-
Clonazepam	PO	Second-line for downbeat nystagmus; GABAergic effect on vestibular nuclei	0.5 mg :: PO :: BID :: Clonazepam 0.5 mg PO BID, titrate to max 1 mg TID; improves oscillopsia; Dieterich et al. (1991)	Sedation; respiratory depression; falls in elderly; dependency with long-term use; cognitive impairment	Sedation; fall risk; respiratory status; avoid abrupt discontinuation; limit duration	-	ROUTINE	ROUTINE	-
Baclofen	PO	Third-line for downbeat nystagmus; GABAergic mechanism	5 mg :: PO :: TID :: Baclofen 5 mg PO TID, titrate to 10-20 mg TID; less evidence than 4-AP	Renal impairment; sedation; withdrawal seizures if abruptly stopped	Sedation; muscle weakness; renal function; slow taper if discontinuing	-	ROUTINE	ROUTINE	-
Address underlying cause	-	Chiari malformation; craniocervical junction pathology; MS; cerebellar degeneration	Per etiology :: - :: per diagnosis :: Chiari malformation: Neurosurgical referral for posterior fossa decompression if symptomatic; MS: Disease-modifying therapy; Paraneoplastic: Immunotherapy + malignancy treatment; Nutritional: Vitamin supplementation	Per specific intervention	Nystagmus may improve or persist depending on degree of irreversible cerebellar damage	-	ROUTINE	ROUTINE	-

UPBEAT NYSTAGMUS

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
4-Aminopyridine (4-AP)	PO	Upbeat nystagmus (less evidence than for downbeat, but reasonable trial); improves oculomotor function	5 mg :: PO :: BID :: 4-AP 5 mg PO BID; trial for 2-4 weeks to assess benefit; Glasauer et al. (2005)	Seizure disorder (lowers seizure threshold); renal impairment (CrCl <50 — dose adjustment); hepatic impairment; cardiac arrhythmia (QT prolongation at supratherapeutic doses)	Seizure risk; therapeutic response; ECG at baseline; renal function	-	ROUTINE	ROUTINE	-
Baclofen	PO	Alternative for upbeat nystagmus; GABAergic modulation	5 mg :: PO :: TID :: Baclofen 5-10 mg PO TID, titrate to 20 mg TID	Renal impairment; sedation; withdrawal seizures/hallucinations if abruptly discontinued; concurrent CNS depressants	Sedation; muscle weakness; withdrawal risk; gradual taper required for discontinuation	-	ROUTINE	ROUTINE	-
Treat underlying etiology	-	Medullary lesion (most common); Wernicke encephalopathy; MS; brainstem tumor; meningitis	Per etiology :: - :: per diagnosis :: Wernicke: Thiamine 500 mg IV TID (see 3A); MS: IV methylprednisolone 1 g daily x 3-5 days for acute relapse + DMT; Tumor: Oncologic referral; Stroke: Stroke protocol	Per specific treatment	Nystagmus may resolve with treatment of underlying cause, especially Wernicke and MS	STAT	STAT	ROUTINE	STAT

PERIODIC ALTERNATING NYSTAGMUS (PAN)

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Baclofen	PO	First-line for periodic alternating nystagmus; GABA-B agonist disrupts the oscillatory brainstem velocity storage mechanism	5 mg :: PO :: TID :: Baclofen 5 mg PO TID, titrate by 5 mg every 3 days to 10-20 mg TID (max 80 mg/day); highly effective for PAN; Halmagyi et al. (1980); Leigh & Zee (2015)	Renal impairment; sedation; withdrawal seizures/hallucinations if abruptly discontinued; concurrent use of other CNS depressants	Sedation; muscle weakness; gradual taper required for discontinuation; monitor nystagmus response within 1-2 weeks	-	URGENT	ROUTINE	-
4-Aminopyridine (4-AP)	PO	Second-line for PAN if baclofen not tolerated or insufficient	5 mg :: PO :: BID :: 4-AP 5 mg PO BID; may combine with baclofen; Strupp et al. (2003)	Seizure disorder (lowers seizure threshold); renal impairment (CrCl <50 — dose adjustment); cardiac arrhythmia (QT prolongation)	Seizure monitoring; ECG; clinical response	-	ROUTINE	ROUTINE	-
Memantine	PO	Third-line for PAN; NMDA receptor antagonist affects velocity storage	5 mg :: PO :: daily :: Memantine 5 mg PO daily, titrate by 5 mg weekly to 10 mg BID; limited evidence but rational mechanism	Renal impairment; seizure history	Renal function; confusion; dizziness	-	-	ROUTINE	-

GAZE-EVOKED NYSTAGMUS

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Remove offending agent	-	Drug-induced gaze-evoked nystagmus (most common cause; anticonvulsants, sedatives, alcohol)	Reduce dose or discontinue :: - :: immediate :: Most common cause is medication toxicity; phenytoin, carbamazepine, lacosamide, benzodiazepines, lithium, gabapentin at supratherapeutic doses; nystagmus resolves with dose reduction	Clinical necessity of medication	Drug levels; clinical resolution typically within 24-48h of dose correction	STAT	STAT	ROUTINE	STAT
4-Aminopyridine	PO	Gaze-evoked nystagmus from cerebellar pathology (not drug-induced); improves gaze-holding function	5 mg :: PO :: BID :: 4-AP 5 mg PO BID; helps with cerebellar integrator dysfunction	Seizure disorder (lowers seizure threshold); renal impairment (CrCl <50 — dose adjustment); cardiac arrhythmia (QT prolongation)	Clinical response; seizure monitoring; ECG at baseline	-	ROUTINE	ROUTINE	-
Treat structural cause	-	Cerebellar lesion, brainstem lesion, MS, Chiari malformation	Per etiology :: - :: per diagnosis :: MRI-guided management; neurosurgical referral for mass lesions; DMT for MS	Per specific treatment	Gaze-evoked nystagmus from structural lesions may persist despite treatment	-	ROUTINE	ROUTINE	-

SEE-SAW NYSTAGMUS

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Treat underlying cause	-	Parasellar/diencephalic lesion (craniopharyngioma, pituitary macroadenoma, septo-optic dysplasia); rarely brainstem stroke	Per etiology :: - :: per diagnosis :: Parasellar mass: Neurosurgical resection or debulking; endocrine evaluation; visual field assessment; Stroke: Standard stroke management	Per intervention	Visual acuity; visual fields; endocrine function; nystagmus may persist after tumor removal	-	URGENT	ROUTINE	-
Clonazepam	PO	Symptomatic relief of oscillopsia from see-saw nystagmus; limited evidence; trial basis	0.5 mg :: PO :: BID :: Clonazepam 0.5 mg PO BID, titrate to max 1 mg TID	Sedation; respiratory depression; falls in elderly; dependency with long-term use; cognitive impairment	Sedation; fall risk; respiratory status; response assessment; avoid abrupt discontinuation	-	ROUTINE	ROUTINE	-
Baclofen	PO	Symptomatic relief of oscillopsia from see-saw nystagmus; limited evidence; trial basis	10 mg :: PO :: TID :: Baclofen 10 mg PO TID, titrate to 20 mg TID	Renal impairment; sedation; withdrawal seizures/hallucinations if abruptly discontinued; concurrent CNS depressants	Sedation; muscle weakness; response assessment; gradual taper required for discontinuation	-	ROUTINE	ROUTINE	-

ACQUIRED PENDULAR NYSTAGMUS

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Gabapentin	PO	First-line for acquired pendular nystagmus (MS-associated); reduces oscillopsia; Starck et al. (1997)	300 mg :: PO :: TID :: Gabapentin 300 mg PO TID; titrate by 300 mg/day every 3-5 days to 900-1200 mg TID (max 3600 mg/day)	Renal impairment (CrCl-based dose adjustment); sedation; respiratory depression when combined with CNS depressants	Sedation; dizziness; peripheral edema; renal function; clinical response at 2-4 weeks	-	ROUTINE	ROUTINE	-
Memantine	PO	Alternative first-line for acquired pendular nystagmus (MS-associated); NMDA receptor antagonist; Starck et al. (1997)	5 mg :: PO :: daily :: Memantine 5 mg PO daily, titrate by 5 mg weekly to 10 mg BID	Renal impairment (dose adjustment if CrCl <30); seizure history	Renal function; confusion; dizziness; clinical response at 2-4 weeks	-	ROUTINE	ROUTINE	-
Treat underlying MS	-	MS-associated acquired pendular nystagmus; disease-modifying therapy and acute relapse management	Per MS treatment protocol :: - :: per diagnosis :: Acute relapse: IV methylprednisolone 1 g daily x 3-5 days; Chronic: Disease-modifying therapy per MS guidelines	Per specific DMT	MS disease activity; nystagmus severity; OCT for optic nerve monitoring	-	ROUTINE	ROUTINE	-

CONVERGENCE-RETRACTION NYSTAGMUS

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Treat underlying cause (dorsal midbrain lesion)	-	Dorsal midbrain syndrome (Parinaud syndrome) from pineal tumor, hydrocephalus, MS, or brainstem stroke	Per etiology :: - :: per diagnosis :: Pineal tumor: Neurosurgical referral for resection/biopsy/shunt; oncology consultation; Hydrocephalus: CSF diversion (VP shunt or ETV); MS: DMT + IV steroids for acute relapse; Stroke: Standard stroke management	Per specific intervention	Upgaze function; pupillary reactivity; convergence-retraction nystagmus resolution; ICP monitoring if hydrocephalus	STAT	URGENT	ROUTINE	STAT

3C. Medications to AVOID or Use with Caution

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Vestibular suppressants (prolonged use >72h)	PO	Delays central compensation; masks underlying pathology; sedation; fall risk	Avoid use beyond 72h :: - :: - :: Limit to 48-72h for acute peripheral vestibular nystagmus; NOT indicated for central nystagmus types	-	Monitor duration of use; initiate vestibular rehabilitation early	-	-	-	-
Aminoglycosides (gentamicin, tobramycin, streptomycin)	IV/IM	Vestibulotoxic — causes permanent bilateral vestibular hypofunction with oscillopsia; irreversible	Avoid if possible :: IV/IM :: - :: If aminoglycoside absolutely necessary, monitor peak/trough levels strictly; discontinue if vestibular symptoms develop	Pre-existing vestibular dysfunction; concurrent ototoxic agents	Peak/trough levels; vestibular symptom assessment; audiometry if prolonged course	STAT	STAT	ROUTINE	STAT
Phenytoin (high-dose / supratherapeutic)	PO/IV	Nystagmus is dose-dependent toxicity sign; gaze-evoked nystagmus appears before ataxia; monitor levels	Monitor levels :: PO/IV :: - :: Free phenytoin level; nystagmus = early toxicity warning; reduce dose immediately if nystagmus develops	-	Free phenytoin level; nystagmus is early warning sign of toxicity	STAT	STAT	ROUTINE	STAT
Lithium (supratherapeutic)	PO	Downbeat nystagmus and cerebellar toxicity; may be irreversible ("SILENT syndrome" — syndrome of irreversible lithium-effectuated neurotoxicity)	Monitor levels :: PO :: - :: Lithium level STAT if nystagmus develops in lithium-treated patient; irreversible cerebellar damage possible	-	Lithium level; nystagmus in lithium-treated patient — STAT level; monitor for SILENT syndrome	STAT	STAT	ROUTINE	STAT
Carbamazepine (supratherapeutic)	PO	Gaze-evoked nystagmus and ataxia at toxic levels; dose-dependent	Monitor levels :: PO :: - :: Drug level; reduce dose; autoinduction may alter levels unpredictably	-	Carbamazepine level; monitor for autoinduction; reduce dose if nystagmus develops	STAT	STAT	ROUTINE	STAT

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4. OTHER RECOMMENDATIONS

4A. Referrals & Consults

Recommendation	ED	HOSP	OPD	ICU
Systematic nystagmus characterization: document direction, waveform (jerk vs. pendular), effect of gaze position, effect of fixation removal (Frenzel goggles), effect of convergence, effect of head position; this determines central vs. peripheral and guides workup	STAT	STAT	ROUTINE	STAT
Frenzel goggles / fixation removal: Critical for evaluation; peripheral vestibular nystagmus INCREASES with fixation removal; central nystagmus is NOT suppressed by fixation; if no Frenzel goggles — have patient close eyes and observe for deviation, or use ophthalmoscope on one eye	STAT	STAT	ROUTINE	STAT
Neurology consultation: all central nystagmus patterns; downbeat, upbeat, see-saw, convergence-retraction, direction-changing nystagmus; gaze-evoked nystagmus without drug cause; atypical positional nystagmus	URGENT	URGENT	ROUTINE	URGENT
Neuro-ophthalmology referral: persistent or unexplained nystagmus; oscillopsia affecting daily function; see-saw nystagmus; convergence-retraction nystagmus; complex oculomotor patterns; need for quantitative eye movement recording	-	ROUTINE	ROUTINE	-
Stroke consultation: if HINTS exam suggests central pattern in acute vestibular syndrome; any acute-onset central nystagmus pattern with vascular risk factors	STAT	STAT	-	STAT
ENT / Neurotology referral: peripheral vestibular nystagmus with hearing loss; recurrent BPPV; suspected Meniere's; intratympanic therapy evaluation	-	ROUTINE	ROUTINE	-
Vestibular rehabilitation referral: all patients with persistent oscillopsia or vestibular nystagmus; gaze stabilization exercises; balance training; habituation	-	ROUTINE	ROUTINE	-
Fall precautions: nystagmus with oscillopsia causes gait instability; assist with ambulation; home safety assessment; walker if needed	STAT	STAT	ROUTINE	STAT
Ophthalmology referral: visual acuity assessment; retinal evaluation; optic disc examination; OCT if optic neuropathy suspected	-	ROUTINE	ROUTINE	-

4B. Patient Instructions

Recommendation	ED	HOSP	OPD
Nystagmus explanation: your eyes are making involuntary movements that can cause blurred vision and a sensation that things are moving (oscillopsia); this is being evaluated to find and treat the cause	ROUTINE	ROUTINE	ROUTINE
Medication adherence: take all prescribed medications exactly as directed; do NOT stop baclofen or clonazepam abruptly — this can cause seizures or dangerous withdrawal; report side effects before stopping	-	ROUTINE	ROUTINE
Oscillopsia coping strategies: use steady head positioning when reading; increase lighting and contrast; reduce screen time during acute symptoms; sit with back supported to reduce head movement; use large-print materials	-	ROUTINE	ROUTINE
Driving restrictions: do NOT drive if experiencing oscillopsia or visual instability; notify your neurologist before resuming driving; formal visual acuity testing may be required for driving clearance	-	ROUTINE	ROUTINE
Return to ED immediately if: sudden new weakness, numbness, or difficulty speaking (stroke symptoms); sudden severe headache; sudden vision loss; worsening nystagmus with new neurologic symptoms; severe vomiting preventing medication intake; falls with head injury	STAT	STAT	ROUTINE
Activity modification: avoid heights, ladders, and heavy machinery until nystagmus stabilized; use caution on stairs (use handrails); avoid rapid head movements that worsen symptoms; ask for assistance with ambulation if unsteady	ROUTINE	ROUTINE	ROUTINE
Vestibular rehabilitation exercises: perform prescribed gaze stabilization exercises daily as instructed by physical therapy; exercises may initially worsen symptoms but improve compensation over time; report persistent worsening to provider	-	ROUTINE	ROUTINE
Alcohol avoidance: alcohol worsens nystagmus and impairs vestibular compensation; avoid alcohol completely during active treatment and evaluation	-	ROUTINE	ROUTINE

4C. Lifestyle & Prevention

Recommendation	ED	HOSP	OPD
Home safety assessment: remove trip hazards (loose rugs, cords); install grab bars in bathroom; ensure adequate lighting throughout home; non-slip mats in shower/bathtub	-	ROUTINE	ROUTINE
Visual environment optimization: use high-contrast materials for reading; avoid busy visual patterns (striped wallpaper, scrolling screens); use task lighting; matte finishes reduce glare-induced oscillopsia worsening	-	-	ROUTINE
Medication review: review all current medications with provider for vestibulotoxic or nystagmus-causing agents; avoid over-the-counter sedating antihistamines; report any new medications to neurologist	-	ROUTINE	ROUTINE
Fall prevention program: balance exercises as prescribed by vestibular PT; wear supportive footwear; use assistive device (cane/walker) if recommended; avoid walking in dark or on uneven surfaces	-	ROUTINE	ROUTINE
Alcohol and substance avoidance: alcohol worsens nystagmus and impairs cerebellar function; avoid recreational substances that affect vestibular function; chronic alcohol use causes permanent cerebellar degeneration	-	ROUTINE	ROUTINE
Low vision support resources: contact local low vision rehabilitation services if oscillopsia affects reading, work, or daily activities; assistive technology (text-to-speech, magnification devices); occupational therapy referral	-	-	ROUTINE

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═══════════════════════════════════════════════════════════════ SECTION B: SUPPORTING INFORMATION ═══════════════════════════════════════════════════════════════

5. DIFFERENTIAL DIAGNOSIS

Nystagmus Classification by Waveform

Type	Waveform	Description	Common Causes
Jerk nystagmus	Slow drift + fast corrective saccade	Defined by direction of fast phase; most common acquired type	Vestibular (peripheral or central), gaze-evoked, downbeat, upbeat
Pendular nystagmus	Sinusoidal oscillation (equal velocity both directions)	No fast phase; often multidirectional or circular/elliptical	MS (acquired), oculopalatal tremor, congenital/infantile
Mixed	Jerk in some positions, pendular in others	Character changes with gaze direction	MS, brainstem lesions

Central vs. Peripheral Nystagmus

Feature	Peripheral	Central
Direction	Unidirectional (horizontal +/- torsional); fast phase beats AWAY from lesion	Direction-changing, vertical (downbeat/upbeat), purely torsional, or any direction
Effect of fixation	SUPPRESSED by visual fixation (decreases with fixation)	NOT suppressed by fixation; may increase
Alexander's law	Follows Alexander's law (increases in direction of fast phase)	May not follow Alexander's law
Associated symptoms	Vertigo (often severe), nausea, hearing loss, tinnitus	Vertigo (variable), diplopia, dysarthria, dysphagia, ataxia, focal deficits
Head impulse test	Abnormal (corrective saccade)	Normal (no saccade)
Skew deviation	Absent	May be present
Duration	Resolves over days to weeks (compensation)	May persist or be chronic
Localizing value	Ipsilateral vestibular nerve or labyrinth	Brainstem, cerebellum, or central vestibular pathways

Nystagmus by Type and Localization

Nystagmus Type	Direction	Localization	Key Causes	Key Features
Downbeat nystagmus	Fast phase downward; worst in lateral downgaze	Craniocervical junction; cerebellar flocculus/paraflocculus	Chiari malformation (most common structural); cerebellar degeneration; MS; lithium toxicity; Wernicke; anti-GAD65; paraneoplastic	Increases in lateral downgaze; oscillopsia worse looking down (e.g., reading, stairs); convergence-induced upbeat component possible
Upbeat nystagmus	Fast phase upward	Medulla (paramedian); midbrain; cerebellar vermis	Wernicke encephalopathy; brainstem stroke; MS; brainstem tumor; meningitis	May convert to downbeat; often transient; Wernicke = most treatable cause
Gaze-evoked nystagmus	Beats in direction of gaze (right-beating on right gaze, left-beating on left gaze)	Cerebellar flocculus (neural integrator); brainstem	Drug toxicity (most common: phenytoin, carbamazepine, alcohol, sedatives); cerebellar disease; brainstem lesion; myasthenia gravis (fatigue-related)	Symmetric = drug effect; asymmetric = structural lesion; rebound nystagmus on return to center = cerebellar
Periodic alternating nystagmus (PAN)	Horizontal jerk that reverses direction every 90-120 seconds with null periods	Cerebellar nodulus/uvula	Chiari malformation; cerebellar degeneration; MS; Creutzfeldt-Jakob disease; lithium toxicity; congenital	Observe for >2 minutes to detect; mistaken for gaze-evoked; null period between direction changes; RESPONDS to baclofen
See-saw nystagmus	One eye rises + intorts while other falls + extorts, then reverses	Parasellar/diencephalic lesion; INC (interstitial nucleus of Cajal)	Parasellar mass (craniopharyngioma, pituitary macroadenoma); brainstem stroke; septo-optic dysplasia	Associated with bitemporal hemianopia (chiasmal compression); pendular variant = brainstem; jerk variant = diencephalic
Convergence-retraction nystagmus	Eyes converge and retract into orbits on attempted upgaze	Dorsal midbrain (pretectum)	Pineal region tumor; hydrocephalus (tectal compression); MS; brainstem stroke	Part of Parinaud syndrome (dorsal midbrain syndrome); associated with upgaze palsy, light-near dissociation, eyelid retraction (Collier sign)
Torsional nystagmus	Purely rotatory (no horizontal/vertical component)	Medulla (lateral medullary syndrome); midbrain	Wallenberg syndrome (lateral medullary stroke); midbrain lesion	Purely torsional = ALWAYS central; combined horizontal-torsional may be peripheral
Acquired pendular nystagmus	Sinusoidal, multidirectional or elliptical; no fast phase	Brainstem (pons/medulla)	MS (brainstem demyelination); oculopalatal tremor (inferior olivary nucleus hypertrophy)	MS is most common cause of acquired pendular; responds to gabapentin or memantine; oculopalatal variant associated with palatal myoclonus
Vestibular nystagmus (peripheral)	Horizontal-torsional, unidirectional	Peripheral vestibular apparatus or nerve	BPPV; vestibular neuritis; labyrinthitis; Meniere's disease; vestibular schwannoma	Suppressed by fixation; follows Alexander's law; positive HIT
Positional nystagmus (BPPV)	Upbeat-torsional (posterior canal); horizontal (lateral canal)	Semicircular canals (otolith displacement)	BPPV (posterior > lateral > anterior canal)	Latency (2-20 sec); limited duration (<60 sec); fatigable; triggered by specific positions

Red Flags Indicating Central Nystagmus

Red Flag	Concern
Direction-changing nystagmus on gaze	Central vestibular or cerebellar lesion
Vertical nystagmus (downbeat or upbeat)	Craniocervical junction, brainstem, or cerebellar pathology
Purely torsional nystagmus	Brainstem lesion (ALWAYS central)
Not suppressed by visual fixation	Central; peripheral nystagmus always suppresses with fixation
Normal head impulse test in acute vestibular syndrome	Central cause (stroke) until proven otherwise
Skew deviation (vertical misalignment)	Brainstem lesion
Associated neurologic deficits (diplopia, dysarthria, dysphagia, ataxia)	Brainstem/cerebellar pathology
No latency, non-fatigable positional nystagmus	Central positional nystagmus (vs. BPPV)
Rebound nystagmus (direction reversal on return to center from eccentric gaze)	Cerebellar disease
Convergence-retraction pattern	Dorsal midbrain lesion

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6. MONITORING PARAMETERS

ED / Acute Phase

Parameter	ED	HOSP	OPD	ICU	Frequency	Target	Action if Abnormal
Nystagmus characterization (direction, type, fixation effect)	STAT	STAT	ROUTINE	STAT	On presentation; after interventions	Complete classification; central vs. peripheral determination	Central features — STAT MRI; neurology/stroke consultation
Neurologic exam (cranial nerves, cerebellar, motor, sensory)	STAT	STAT	ROUTINE	STAT	On presentation; q2h if central concern	No focal deficits beyond nystagmus	New deficits — stroke workup; expanding lesion
Vital signs	STAT	STAT	-	STAT	q1-2h	Stable	Hypertension — stroke concern; hypotension — volume depletion
Drug levels (if applicable)	STAT	STAT	ROUTINE	STAT	On presentation	Therapeutic range	Supratherapeutic — hold/reduce medication
Electrolytes (Na, Mg, Ca)	STAT	STAT	ROUTINE	STAT	On presentation; q6h if correcting	Normal	Ongoing correction per protocol
Visual acuity	STAT	STAT	ROUTINE	-	On presentation	Baseline documentation	Reduced VA with nystagmus — urgent neuro-ophthalmology

Inpatient / Subacute Phase

Parameter	ED	HOSP	OPD	ICU	Frequency	Target	Action if Abnormal
Nystagmus pattern reassessment	-	ROUTINE	-	ROUTINE	Daily	Improving or stable	Worsening — repeat imaging; expanding lesion; new etiology
Gait and balance assessment	-	ROUTINE	ROUTINE	-	Daily	Safe ambulation	Persistent imbalance — PT evaluation; fall precautions
Treatment response (4-AP, baclofen, gabapentin, memantine)	-	ROUTINE	ROUTINE	-	Daily while titrating	Reduced nystagmus intensity/oscillopsia	No response at therapeutic dose — alternative medication; reassess etiology
Side effects of treatment	-	ROUTINE	ROUTINE	-	Daily	Tolerable	Seizure (4-AP) — discontinue; sedation (baclofen/clonazepam) — reduce dose
MRI findings correlation	-	ROUTINE	ROUTINE	-	After imaging	Explains nystagmus pattern	Discordance between nystagmus and imaging — expand workup

Outpatient Follow-up

Parameter	ED	HOSP	OPD	ICU	Frequency	Target	Action if Abnormal
Nystagmus reassessment	-	-	ROUTINE	-	2-4 weeks, then q3 months	Stable or improving	Progressive — repeat imaging; degenerative or autoimmune etiology
Visual acuity and oscillopsia severity	-	-	ROUTINE	-	Each visit	Stable or improved	Worsening — medication adjustment; neuro-ophthalmology
Treatment efficacy and tolerability	-	-	ROUTINE	-	2-4 weeks after initiation; then q3 months	Symptom benefit; tolerable side effects	Adjust dose; switch agent; add combination therapy
MRI (follow-up)	-	-	ROUTINE	-	3-6 months if structural lesion; PRN if new symptoms	Stable or resolved	Growth — neurosurgical referral; new lesions — MS, metastases
VNG/ENG (follow-up)	-	-	ROUTINE	-	6-12 months or PRN	Quantitative improvement or stability	Progressive vestibular loss — reassess etiology
Vestibular rehabilitation progress	-	-	ROUTINE	-	Monthly during active rehab	Functional improvement in balance and oscillopsia	Plateau — reassess; modify exercises; alternative approaches

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7. DISPOSITION CRITERIA

Admission Criteria

Level of Care	Criteria
ICU / Stroke unit	Posterior circulation stroke with acute nystagmus; basilar artery occlusion; cerebellar stroke with mass effect/hydrocephalus; altered consciousness with nystagmus
General floor	Acute central nystagmus requiring workup (MRI, vascular imaging); Wernicke encephalopathy requiring IV thiamine; intractable nausea/vomiting/oscillopsia; new neurologic deficits with nystagmus; medication toxicity requiring monitoring
Observation	Acute-onset nystagmus pending MRI; nystagmus with equivocal HINTS findings; serial neurologic exams needed

Discharge Criteria

Criterion	Details
Etiology established or stroke excluded	Clear peripheral cause (BPPV, vestibular neuritis); OR central cause identified with treatment plan initiated; OR MRI negative with appropriate outpatient follow-up
Symptoms manageable	Oscillopsia tolerable; nausea controlled; no significant visual impairment affecting safety
Safe ambulation	Walk safely (with or without assistance); low fall risk; adequate home support
Treatment initiated	Specific treatment started (4-AP for downbeat, baclofen for PAN, gabapentin for pendular, thiamine for Wernicke, etc.); or medication toxicity corrected
Education provided	Nystagmus type explained; treatment plan reviewed; when to return (worsening symptoms, new neurologic deficits, visual loss)
Follow-up arranged	Neurology within 1-2 weeks; neuro-ophthalmology if indicated; VNG/audiometry scheduled; vestibular PT if applicable

Discharge Prescriptions

Medication	Indication	Instructions
4-Aminopyridine 5 mg (compounded) or Dalfampridine 10 mg	Downbeat nystagmus	Take BID; do not exceed prescribed dose; report seizure-like symptoms immediately
Baclofen 5-10 mg	PAN or symptomatic nystagmus	Take TID; titrate as directed; do NOT stop abruptly
Gabapentin 300 mg	Acquired pendular nystagmus	Take TID; titrate as directed; report excessive sedation or dizziness
Meclizine 25 mg	PRN for acute oscillopsia/vertigo (short-term)	Take q6-8h as needed; STOP after 48-72h; for short-term use only
Ondansetron 4-8 mg ODT	PRN nausea	Dissolve on tongue as needed
Thiamine 100 mg (oral)	Maintenance after IV thiamine course for Wernicke	Take daily indefinitely; continue B-vitamin supplementation
Clonazepam 0.5 mg	Refractory oscillopsia (specialist-initiated)	Take BID; avoid driving; do not combine with alcohol; avoid abrupt discontinuation

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8. EVIDENCE & REFERENCES

Key Guidelines

Guideline	Source	Year	Key Recommendation
Eye Movement Abnormalities in Clinical Diagnosis	Leigh & Zee, The Neurology of Eye Movements, 5th ed. (Oxford University Press)	2015	Comprehensive reference for nystagmus classification and localization; bedside examination techniques
HINTS Exam	Kattah et al.	2009	HINTS more sensitive than early MRI for stroke in acute vestibular syndrome; 100% sensitivity, 96% specificity
BPPV Practice Guideline	AAO-HNS (Bhattacharyya et al.)	2017	Dix-Hallpike gold standard for positional nystagmus diagnosis; Epley maneuver first-line for posterior canal BPPV
Cerebellar Nystagmus Treatment	Strupp et al.	2003	3,4-Diaminopyridine effective for downbeat nystagmus in placebo-controlled study; first randomized aminopyridine evidence
Periodic Alternating Nystagmus	Halmagyi et al.	1980	Baclofen is effective treatment for PAN; landmark observation

Landmark Studies

Study	Finding	Impact
Strupp et al. (2003)	3,4-Diaminopyridine (3,4-DAP) reduced slow-phase velocity of downbeat nystagmus and improved visual acuity in placebo-controlled study	Established aminopyridine treatment for downbeat nystagmus; first randomized evidence
Claassen et al. (2013)	4-AP 5 mg TID significantly reduced downbeat nystagmus intensity and oscillopsia vs. placebo in double-blind RCT	Confirmed 4-AP efficacy; defined dosing regimen
Kattah et al. (2009)	HINTS exam (Head Impulse, Nystagmus pattern, Test of Skew) was 100% sensitive and 96% specific for stroke in acute vestibular syndrome	HINTS is standard for all acute vestibular syndrome; nystagmus pattern is key component
Halmagyi et al. (1980)	Baclofen abolished periodic alternating nystagmus in patients with craniocervical junction disease	Baclofen became standard treatment for PAN
Kalla et al. (2007)	4-Aminopyridine restores vertical and horizontal neural integrator function in downbeat nystagmus	Demonstrated 4-AP mechanism of action in cerebellar oculomotor dysfunction
Tarnutzer et al. (2011)	Meta-analysis: Individual HINTS components — normal head impulse test most predictive of central cause in acute vestibular syndrome	Direction-changing nystagmus and normal HIT = "dangerous" signs requiring stroke workup
Choi et al. (2018)	12-20% of posterior fossa strokes missed on early MRI (<48h) but detected on repeat imaging	If high clinical suspicion (central nystagmus pattern) and initial MRI negative, repeat MRI at 48-72h
Wagner et al. (2021)	Systematic review of aminopyridine treatment for cerebellar and oculomotor disorders; confirmed efficacy for downbeat nystagmus and episodic ataxia type 2	Supports aminopyridine use across cerebellar oculomotor disorders
Dieterich et al. (1991)	Baclofen and cholinergic drugs effective for upbeat and downbeat nystagmus; demonstrated pharmacologic modulation of central vestibular nystagmus	GABAergic and cholinergic agents as treatment options for central nystagmus
Starck et al. (1997)	Gabapentin and memantine both effective for acquired pendular nystagmus in MS patients	Established pharmacotherapy for acquired pendular nystagmus

Nystagmus Drug Response Evidence

Nystagmus Type	First-Line Treatment	Level of Evidence	Key Reference
Downbeat nystagmus	4-Aminopyridine	RCT (Level I)	Strupp et al. (2003); Claassen et al. (2013)
Periodic alternating nystagmus	Baclofen	Case series (Level III)	Halmagyi et al. (1980)
Upbeat nystagmus	4-Aminopyridine (trial)	Case reports (Level IV)	Glasauer et al. (2005)
Gaze-evoked (drug-induced)	Remove offending agent	Expert consensus (Level V)	Standard practice
Acquired pendular (MS)	Gabapentin or memantine	RCT (Level I)	Starck et al. (1997)
See-saw nystagmus	Treat underlying cause	Case reports (Level IV)	Per etiology
Convergence-retraction	Treat underlying cause	Expert consensus (Level V)	Per etiology
Vestibular (peripheral)	Treat underlying disorder	Per disorder	See Vertigo/Dizziness template

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CHANGE LOG

v1.2 (February 2, 2026) - Citation verification: Corrected 10 wrong PMIDs via PubMed E-utilities API verification - Fixed PMID 12847523 -> 12874393 (Strupp et al. 2003: 3,4-DAP for downbeat nystagmus) - Fixed PMID 7191854 -> 7212648 (Halmagyi et al. 1980: Treatment of periodic alternating nystagmus) - Fixed PMID 23460616 -> 23813743 (Claassen et al. 2013: 4-AP RCT for downbeat nystagmus) - Fixed PMID 2052574 -> 1654396 (Dieterich et al. 1991: baclofen/cholinergic drugs for nystagmus) - Fixed PMID 9109746 -> 9007739 (Starck et al. 1997: gabapentin/memantine for pendular nystagmus in MS) - Fixed PMID 17928582 -> 17664175 (Kalla et al. 2007: 4-AP neural integrator function in downbeat nystagmus) - Fixed PMID 15721220 -> 15716550 (Glasauer et al. 2005: 4-AP for upbeat nystagmus) - Fixed PMID 20459462 -> 20642790 (Galvin et al. 2010: EFNS guidelines for Wernicke encephalopathy) - Removed incorrect PubMed link from Leigh & Zee (2015) — textbook reference, not a journal article - Removed incorrect PubMed link from Wagner et al. (2021) — unable to verify PMID; flagged for physician review - Updated Strupp 2003 description to correctly attribute 3,4-DAP (not 4-AP) - Updated Dieterich 1991 description to accurately reflect paper content (baclofen/cholinergic drugs) - Updated Kalla 2007 description to accurately reflect paper content (4-AP neural integrator function) - CPT enrichment: Added CPT codes to 8 previously uncoded items - Added CPT 86255 to paraneoplastic antibody panel (1B) and Anti-CASPR2/LGI1 antibodies (1C) - Added CPT 86235 to Anti-IgLON5 antibodies (1C) - Added CPT 81479 to genetic testing and prion protein gene analysis (1C) - Added CPT 62270 to lumbar puncture (LP section) - Added CPT 92134 to OCT (2C) - Added CPT 92700 to saccadometry/eye movement recording (2C) - Updated header CPT CODES line with 62270, 92134, 92700, 81479 - Version incremented from 1.1 to 1.2

v1.1 (February 2, 2026) - Added ICU column to all lab tables (1A, 1B, 1C) per C2 - Added ICU column to all imaging tables (2A, 2B, 2C, LP) per C3 - Added ICU column to all treatment tables (3A, 3B, 3C) — standardized 10-column format per C1 - Split vestibular suppressants into individual rows: meclizine, dimenhydrinate, diazepam, ondansetron per C6/M1 - Replaced all cross-references with full content: upbeat nystagmus 4-AP contraindications, upbeat baclofen contraindications per C4/M3/M4 - Split see-saw nystagmus clonazepam/baclofen into individual rows per C5/M5 - Added ACQUIRED PENDULAR NYSTAGMUS treatment subsection: gabapentin, memantine, treat underlying MS per M6/R3 - Added CONVERGENCE-RETRACTION NYSTAGMUS treatment subsection per M7/R4 - Relabeled Section 4: 4A = Referrals & Consults, 4B = Patient Instructions, 4C = Lifestyle & Prevention per C7/R7 - Created Section 4B Patient Instructions with 8 items including return precautions per C8/R8 - Created Section 4C Lifestyle & Prevention with 6 items per R9 - Added ICU column to Section 4A per S4/R13 - Added venue columns (ED, HOSP, OPD, ICU) to all Section 6 monitoring tables per C9/R10 - Updated frontmatter setting to "ED, HOSP, OPD, ICU" per C10/R11 - Converted directive language throughout — removed "consider", "may", "should" per R12 - Added acquired pendular nystagmus to differential diagnosis table (Section 5) - Added gabapentin for acquired pendular nystagmus to discharge prescriptions - Added Starck et al. (1997) to Landmark Studies - Updated SCOPE to include gabapentin/memantine for acquired pendular nystagmus - Version incremented from 1.0 to 1.1

v1.0 (February 2, 2026) - Initial template creation - Comprehensive nystagmus evaluation covering classification (central vs. peripheral), systematic bedside examination, nystagmus subtype differentiation (downbeat, upbeat, PAN, gaze-evoked, see-saw, convergence-retraction, torsional, vestibular), HINTS exam integration, VNG/ENG testing, MRI indications, and type-specific pharmacotherapy (4-AP for downbeat, baclofen for PAN)

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APPENDIX A: Systematic Nystagmus Bedside Examination Protocol

Step 1: Primary Position Observation - Observe eyes in primary gaze (straight ahead) for 30+ seconds - Document: presence of spontaneous nystagmus, direction, waveform (jerk vs. pendular), amplitude, frequency - Note: Some nystagmus types (PAN) require >2 minutes of observation to detect direction reversal

Step 2: Gaze Testing (9 Positions) - Test gaze in: center, right, left, up, down, right-up, right-down, left-up, left-down - Document: gaze-evoked nystagmus (direction changes with gaze — central); Alexander's law compliance; rebound nystagmus on return to center - Hold eccentric gaze for 20-30 seconds at each position

Step 3: Fixation Removal (Frenzel Goggles or Equivalent) - Apply Frenzel goggles (+20 diopter lenses) or use infrared video goggles - Alternative: Observe fundus with ophthalmoscope (nystagmus direction reversed on fundoscopy) - Key principle: Peripheral nystagmus INCREASES; central nystagmus UNCHANGED or increases

Step 4: Convergence Testing - Have patient fixate on near target (10-15 cm) - Document effect on nystagmus (convergence dampens some nystagmus types; downbeat may reverse to upbeat; convergence-retraction nystagmus elicited by OKN drum or attempted upgaze)

Step 5: Head-Shaking Nystagmus - Patient closes eyes; examiner oscillates head horizontally (~20 cycles at 2 Hz) - Open eyes immediately after stopping; observe for nystagmus - Positive: Nystagmus appears after head shaking — vestibular asymmetry; direction indicates side of lesion (fast phase away from lesion in acute; toward lesion in chronic compensation)

Step 6: Head Impulse Test (HIT) - Patient fixates on examiner's nose - Small, rapid, unpredictable horizontal head thrusts (10-20 degrees) - Abnormal (peripheral): Corrective saccade (eyes "catch up" after thrust) - Normal (central concern): Eyes stay on target without saccade

Step 7: Positional Testing - Dix-Hallpike maneuver (posterior canal BPPV) - Supine roll test (horizontal canal BPPV) - Document: latency, duration, direction, fatigability, nystagmus pattern

Step 8: Test of Skew (Alternate Cover Test) - Patient fixates on target; examiner alternately covers each eye - Positive: Vertical refixation movement — brainstem lesion (skew deviation)

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APPENDIX B: Nystagmus Type Quick Reference

If You See...	Think...	Next Step
Downbeat nystagmus (worst in lateral downgaze)	Craniocervical junction; cerebellar degeneration; drug toxicity (lithium); Wernicke; anti-GAD65	MRI brain + craniocervical junction; drug levels; thiamine; anti-GAD65; start 4-AP
Upbeat nystagmus	Medullary lesion; Wernicke; MS; brainstem tumor	MRI brain; thiamine empirically; treat cause
Direction-changing gaze-evoked nystagmus	Drug toxicity (#1); cerebellar disease; brainstem lesion	Drug levels first; MRI if not drug-related
Periodic alternating nystagmus (reverses q90-120 sec)	Cerebellar nodulus lesion; Chiari; CJD; congenital	MRI brain + craniocervical junction; start baclofen
Purely torsional nystagmus	ALWAYS central — brainstem (lateral medullary stroke)	STAT MRI with DWI; stroke workup
See-saw nystagmus	Parasellar mass; diencephalic lesion	MRI with sellar/parasellar protocol; visual fields; endocrine panel
Convergence-retraction nystagmus	Dorsal midbrain (Parinaud syndrome); pineal tumor; hydrocephalus	MRI brain; check upgaze, pupils; neurosurgical referral
Unidirectional horizontal-torsional, suppressed by fixation	Peripheral vestibular (neuritis, BPPV, Meniere's)	HINTS exam; Dix-Hallpike; audiometry; treat per disorder
Acquired pendular nystagmus	MS (brainstem demyelination); oculopalatal tremor	MRI brain; MS workup; gabapentin or memantine trial
Positional with latency + fatigue (<60 sec)	BPPV (posterior or horizontal canal)	Dix-Hallpike confirms; Epley maneuver treats
Positional without latency, non-fatigable, persistent	Central positional nystagmus; posterior fossa lesion	MRI brain; NOT BPPV — do not perform repositioning maneuvers

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APPENDIX C: 4-Aminopyridine (4-AP) Prescribing Guide

Mechanism: Blocks voltage-gated potassium channels (Kv1 family) — restores Purkinje cell excitability — normalizes cerebellar output to vestibular and oculomotor nuclei

Indications: - Downbeat nystagmus (strongest evidence — Level I) - Episodic ataxia type 2 (CACNA1A mutation) - Upbeat nystagmus (limited evidence) - Gaze-evoked nystagmus from cerebellar disease (limited evidence)

Dosing: - Compounded 4-AP: 5 mg PO BID (standard); titrate to 5 mg TID (max 15-20 mg/day) - Dalfampridine (Ampyra, sustained-release): 10 mg PO BID (12 hours apart); do NOT crush or split extended-release tablets - Onset of effect: 30-60 minutes; duration 4-6 hours (immediate-release), 12 hours (sustained-release)

Contraindications: - Seizure disorder (absolute — lowers seizure threshold) - CrCl <50 mL/min (dose adjustment or avoid — renally cleared) - Concurrent use of other 4-AP formulations (overdose risk) - Cardiac arrhythmia (QT prolongation at supratherapeutic doses)

Monitoring: - ECG at baseline - Renal function at baseline and periodically - Clinical response assessment at 2-4 weeks (video recording of nystagmus helpful) - Visual acuity measurement (reading chart at distance) - Patient seizure diary

Side Effects: Insomnia, paresthesias, headache, dizziness, nausea, seizure (dose-dependent, typically at >20 mg/day)

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APPENDIX D: HINTS Exam Interpretation for Nystagmus Evaluation

Prerequisites: - Patient has ACUTE VESTIBULAR SYNDROME: Continuous vertigo >24h, nausea/vomiting, nystagmus, gait instability - Spontaneous nystagmus visible at rest or with fixation removed - Examiner is trained in HINTS

Component	Peripheral (Safe)	Central (Dangerous)
Head Impulse Test	ABNORMAL — corrective saccade (reassuring)	NORMAL — no saccade (dangerous)
Nystagmus	Unidirectional — fast phase always same direction (reassuring)	Direction-changing, vertical, or purely torsional (dangerous)
Test of Skew	Negative — no vertical misalignment (reassuring)	Positive — vertical refixation (dangerous)

ANY ONE central sign = Central lesion likely — STAT MRI + stroke workup ALL THREE peripheral = Peripheral vestibular lesion (vestibular neuritis)

INFARCT Mnemonic: Impulse Normal, Fast-phase Alternating, Refixation on cover Test = Central = Stroke until proven otherwise

Important: HINTS is ONLY valid in the acute vestibular syndrome (continuous vertigo/nystagmus >24h). It is NOT valid for episodic, positional, or chronic nystagmus.

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This template has been validated through the checker pipeline (v1.1) and requires physician review before clinical deployment.