Diagnostic and Treatment Approach for Nystagmus in a 6-Year-Old Child
MRI of the brain without and with IV contrast is the recommended initial imaging study for a 6-year-old child with nystagmus, particularly when the nystagmus is acquired (onset after 6 months of age), asymmetric, progressive, or accompanied by neurological symptoms. 1
Classification and Etiology
Pediatric nystagmus can be classified into two main categories:
Infantile Nystagmus (onset in first 6 months of life)
- Common causes:
- Albinism
- Retinal diseases
- Low vision or vision deprivation (e.g., congenital cataracts)
- Fusion maldevelopment syndrome
- Idiopathic infantile nystagmus (can be caused by FRMD7 gene mutations) 2
- Common causes:
Acquired Nystagmus (onset after 6 months of life)
Diagnostic Approach
Step 1: Detailed Ophthalmological Examination
- Assess visual acuity
- Evaluate for ocular albinism
- Check for retinal diseases
- Look for congenital cataracts
- Document any anomalous head posture
- Determine if nystagmus is:
- Unilateral or bilateral
- Symmetric or asymmetric
- Horizontal, vertical, or torsional
- Associated with head bobbing or torticollis (spasmus nutans) 1
Step 2: Sensory Testing
- Perform Worth 4-Dot Testing and stereoacuity tests when feasible
- Assess for fusion and binocular vision 1
Step 3: Cycloplegic Refraction
- Essential for accurate assessment of refractive errors
- Important for diagnosing and treating amblyopia 1
Step 4: Neuroimaging
- MRI of the brain without and with IV contrast is the recommended initial imaging study 1
- Indications for urgent neuroimaging:
Step 5: Additional Testing (as indicated)
- Genetic testing (especially for FRMD7 gene in suspected hereditary X-linked nystagmus) 2, 3
- Electrophysiology tests
- Laboratory tests for metabolic disorders 3
Treatment Approach
1. Correction of Underlying Cause (if identified)
- Treatment of identified structural lesions
- Management of metabolic disorders
2. Optical Correction
- Correct even minor refractive errors
- Consider contact lenses (may offer advantages over glasses) 2
3. Pharmacological Treatment
- Gabapentin has shown efficacy for infantile nystagmus, nystagmus in albinism, and sensory nystagmus 2, 3, 4
- Memantine is another effective option 2, 3
- Carbonic anhydrase inhibitors may be considered 2
- Baclofen is effective for periodic alternating nystagmus 5, 4
Note: Pharmacological treatment is rarely used in children due to limited effects on vision, need for lifelong therapy, and potential side effects. Common adverse reactions with gabapentin include somnolence (21%), dizziness (28%), and ataxia (3%) 6, 2
4. Surgical Interventions
- Anderson or Kestenbaum procedure to correct nystagmus-related anomalous head posture
- Artificial divergence (Cüppers concept) may help decrease nystagmus intensity in patients whose nystagmus dampens with convergence
- Four-muscle-tenotomy (disinsertion and reinsertion of horizontal muscles) has limited positive effect on visual acuity 2, 7
Important Considerations
Neurological evaluation is essential for children with:
- New onset nystagmus
- Spasmus nutans
- Vertical or unilateral nystagmus
- Seesaw nystagmus 2
In a study of 148 children with isolated nystagmus who underwent MRI, 15.5% had abnormal intracranial findings, including:
- Abnormal T2 hyperintense signal in white matter (4%)
- Chiari 1 malformation (3.4%)
- Optic pathway glioma (2%) 1
IV contrast is not required in all cases with isolated nystagmus but should be considered when there is a suspicious lesion on initial MRI 1