What is the approach to evaluating and managing a patient with nystagmus?

Approach to Nystagmus

Begin by determining whether the nystagmus is infantile (onset in first 6 months) or acquired (later onset), as this fundamentally dictates your diagnostic pathway—infantile nystagmus requires ophthalmological examination and genetic workup rather than neuroimaging, while acquired nystagmus mandates MRI brain to exclude structural lesions, particularly when accompanied by decreased visual acuity, asymmetric presentation, progressive course, or concurrent neurological symptoms. 1

Initial Clinical Characterization

History Elements to Establish

• Age of onset is the single most critical piece of information—onset in first 6 months suggests infantile nystagmus (typically retinal disease, albinism, low vision, or fusion maldevelopment syndrome), while later onset indicates acquired nystagmus requiring structural evaluation 1, 2
• Acute versus chronic onset—acute or newly symptomatic nystagmus warrants evaluation for cranial nerve palsy, thyroid eye disease, myasthenia gravis, or central nervous system pathology 1
• Associated symptoms: oscillopsia (subjective sensation of visual world movement indicates acquired nystagmus), decreased visual acuity, vertigo, diplopia, or other neurological symptoms 3, 4
• Medication history—antiepileptics and chronic alcohol abuse commonly cause gaze-evoked nystagmus 5

Physical Examination Components

• Eye position assessment and testing for gaze-evoked nystagmus in all directions of gaze 6
• Versions and ductions testing to evaluate range of eye movements 6
• Dix-Hallpike maneuver for posterior semicircular canal BPPV—look for 5-20 second latency, crescendo-decrescendo pattern, and resolution within 60 seconds 6, 7
• Supine head roll test for lateral canal assessment—rotate head 90° to one side while observing for horizontal nystagmus 6
• Complete motility examination including cover-uncover and alternate-cover testing 1
• Assessment for compensatory head position, which may indicate a null zone where nystagmus is minimized 1, 2

Critical Red Flags Requiring Urgent MRI

Order MRI brain immediately if any of the following are present:

• Downbeat nystagmus without torsional component—strongly suggests bilateral floccular lesion or cervicomedullary junction pathology 7
• Direction-changing nystagmus that does not follow typical BPPV patterns—indicates central pathology 7
• Baseline nystagmus present in primary position—suggests CNS involvement 7
• Associated cerebellar signs (ataxia, dysmetria, dysdiadochokinesia)—indicate central lesions 7
• Bruns nystagmus (gaze-dependent bidirectional pattern)—indicates significant mass effect and brainstem distortion requiring immediate intervention 7
• Convergence-retraction nystagmus—obtain MRI brain 6
• Additional cranial neuropathies or neurologic signs accompanying nystagmus 6
• Asymmetric/unilateral nystagmus—neurological disease should be suspected 1, 2

Imaging Algorithm

For Children with Isolated Nystagmus

• MRI head without and with IV contrast is the appropriate initial imaging modality—15.5% of children with isolated nystagmus have abnormal intracranial findings including white matter signal abnormalities (4%), Chiari 1 malformation (3.4%), and optic pathway glioma (2%) 1
• IV contrast is not required in all cases and can be reserved for children with suspicious lesions on initial MRI 1
• Dedicated orbital sequences benefit only 2% of patients and should be added only if initial brain MRI is suspicious for orbital abnormalities 1
• CT imaging has no role in nystagmus evaluation as it inadequately visualizes posterior fossa structures and brainstem 7

Special Considerations

• Spasmus nutans (triad of nystagmus, head bobbing, and torticollis appearing at 1-3 years) requires thorough neuro-ophthalmological and neuroradiological workup with MRI, as it cannot be easily differentiated from nystagmus associated with anterior visual pathway tumors 1
• Vestibular nystagmus requires imaging primarily to exclude VIII cranial nerve or brainstem lesions 1

Management Approach by Nystagmus Type

BPPV-Related Nystagmus

• Do not order routine neuroimaging or vestibular testing in patients meeting diagnostic criteria for BPPV (positive Dix-Hallpike with appropriate latency and duration) without additional vestibular signs or symptoms inconsistent with BPPV 7

Downbeat Nystagmus

• First-line treatment: 4-aminopyridine or 3,4-diaminopyridine 3, 5
• Alternative options: clonazepam or gabapentin 3, 4

Upbeat Nystagmus

• Treatment options: memantine, 4-aminopyridine, or baclofen 3
• Aminopyridines are effective treatment options 5

Acquired Periodic Alternating Nystagmus

• Baclofen is the therapy of choice and often completely suppresses this type 3, 4, 8
• Memantine can be effective in refractory cases 3

Acquired Pendular Nystagmus

• In multiple sclerosis patients: gabapentin or memantine 3, 4, 8
• In oculopalatal tremor: gabapentin, memantine, or trihexyphenidyl 3, 8

Infantile Nystagmus Syndrome

• Pharmacological options: gabapentin, memantine, acetazolamide, or topical brinzolamide 3, 8, 2
• Optical interventions: contact lenses or base-out prisms to induce convergence 3, 8
• Surgical therapy may be considered in symptomatic patients, but requires preoperative evaluation of visual acuity and nystagmus intensity in different gaze positions 3, 8
• In cases with obvious head posture, eye muscle surgery can shift the null zone into primary position and alleviate neck problems 2

Common Pitfalls to Avoid

• Do not misdiagnose downbeat nystagmus as BPPV—the absence of torsional component distinguishes central from peripheral causes 7
• Avoid or modify positional testing in patients with cervical stenosis, severe kyphoscoliosis, limited cervical range of motion, Down syndrome, severe rheumatoid arthritis, cervical radiculopathies, Paget's disease, ankylosing spondylitis, low back dysfunction, spinal cord injuries, and morbid obesity 6, 7
• Do not rely on prism testing alone in adult strabismus with childhood-onset nystagmus—response to prism can be misleading due to anomalous retinal correspondence, which often changes postoperatively 1
• Video-assisted examination should be used when nystagmus findings are equivocal or unclear 6

Follow-Up Protocol

• Reassess patients within 1 month after initial treatment to document resolution or persistence 7
• Evaluate persistent symptoms for unresolved pathology or alternative diagnoses 7
• Monitor/observe if symptoms are mild, occasional, and well tolerated, or if the patient is opposed to treatment 1