What is the evaluation and treatment approach for nystagmus in a child?

Evaluation and Treatment of Nystagmus in Children

Initial Clinical Assessment

All children with nystagmus require thorough neuro-ophthalmological evaluation to distinguish between infantile (onset in first 6 months) and acquired forms, as this distinction fundamentally determines the diagnostic workup and urgency of intervention. 1, 2

Key Clinical Features to Identify

• Age of onset: Infantile nystagmus typically appears in the first 3-6 months of life, while acquired forms appear later 3, 4
• Waveform characteristics: Pendular versus jerk nystagmus patterns help differentiate etiologies 3, 4
• Symmetry: Asymmetric, unilateral, or progressive nystagmus strongly suggests neurological disease requiring immediate imaging 2, 3
• Associated symptoms: Oscillopsia, head bobbing, torticollis, or concurrent neurological symptoms mandate urgent evaluation 1, 2
• Visual acuity: Decreased vision may indicate underlying retinal or optic nerve pathology 2, 3

Ophthalmological Examination

• Complete eye examination including fundoscopy to identify albinism, retinal dystrophies, optic nerve hypoplasia, or macular abnormalities 3, 5
• Assessment for refractive errors (even minor errors should be corrected) 5
• Evaluation of head posture and null zone position 3, 5
• Testing for latent nystagmus by covering each eye (beats toward the fixing eye in infantile esotropia syndrome) 4

Neuroimaging Indications

MRI of the brain without and with IV contrast is the imaging modality of choice when neuroimaging is indicated. 1

Absolute Indications for MRI

• Acquired or late-onset nystagmus (after 4 months of age) 2, 4
• Asymmetric, unilateral, or progressive nystagmus 2, 4
• Concurrent neurological symptoms (vertigo, nausea, ataxia) 4
• Spasmus nutans (triad of nystagmus, head bobbing, torticollis at 1-3 years) - cannot be reliably differentiated from anterior visual pathway tumors 1
• Convergence retraction nystagmus (suggests dorsal midbrain syndrome) 6
• Downbeat nystagmus (suggests cerebellar or cervicomedullary junction pathology) 2
• Vestibular nystagmus (to exclude VIII cranial nerve or brainstem lesions) 1
• Seesaw nystagmus (may indicate suprasellar or mesodiencephalic lesions) 5

Expected MRI Findings

In children with isolated nystagmus who undergo MRI, 15.5% have abnormal intracranial findings 1:

• Abnormal T2 hyperintense signal in white matter (4%) 1, 2
• Chiari 1 malformation (3.4%) 1, 2
• Optic pathway glioma (2%) 1, 2

Imaging Protocols

• MRI head and orbits may be obtained concurrently for comprehensive evaluation 1
• IV contrast is not required in all cases but should be considered if a suspicious lesion is identified 1, 6
• CT imaging has no role in the initial evaluation of isolated nystagmus 1
• Dedicated orbital sequences are rarely beneficial (only 2% show intraorbital abnormalities) 1

Treatment Approach

Optical Correction

• Correct all refractive errors, even minor ones - this is the foundation of management 5
• Contact lenses offer advantages over glasses for visual rehabilitation 5
• Magnifying visual aids may be beneficial for patients with reduced visual acuity 4

Pharmacological Treatment

Pharmacological therapy is effective for specific nystagmus types but is rarely used in children due to limited visual improvement, need for lifelong therapy, and potential side effects. 5

Infantile Nystagmus Syndrome (IIN)

• Gabapentin and memantine are effective options 5, 7
• Carbonic anhydrase inhibitors may also be beneficial 5

Acquired Forms

• Downbeat nystagmus: 3,4-diaminopyridine, 4-aminopyridine, gabapentin, baclofen, or clonazepam 8
• Periodic alternating nystagmus: Baclofen is the therapy of choice 8, 7
• Acquired pendular nystagmus: Gabapentin is often effective; memantine, clonazepam, or valproate are alternatives 8, 7

Surgical Treatment

Eye muscle surgery is indicated for patients with significant head posture (abnormal head turn) to shift the null zone into primary position. 3, 5

• Anderson or Kestenbaum procedure: Corrects nystagmus-related anomalous head posture 5
• Artificial divergence (Cüppers concept): May decrease nystagmus intensity in patients whose nystagmus dampens with convergence 5
• Four-muscle tenotomy: Disinsertion and reinsertion of horizontal muscles at original insertion; has proven but limited positive effect on visual acuity 5
• Optimal timing: Age 6-8 years for patients with head turn 4

Common Pitfalls to Avoid

• Do not dismiss "mild" nystagmus without evaluation - 15.5% have significant intracranial pathology 2
• Do not confuse spasmus nutans with benign infantile nystagmus - it requires MRI to exclude anterior visual pathway tumors 1
• Do not use CT imaging - it has no role in nystagmus evaluation and provides inferior soft tissue detail 1
• Do not assume infantile nystagmus is benign without ophthalmological examination - underlying retinal disease, albinism, or optic nerve hypoplasia must be excluded 3, 4
• Do not overlook convergence retraction nystagmus - it mandates brain MRI to evaluate for dorsal midbrain pathology or multiple sclerosis 6