🧿 Nystagmus Overview
• Rhythmic, repetitive oscillations of one or both eyes
• Jerk nystagmus: slow phase + fast corrective phase
• Pendular nystagmus: equal velocity both directions
• Congenital vs acquired — key distinction
👶 Congenital Nystagmus
• Sensory nystagmus: due to visual impairment (most common)
• Idiopathic congenital nystagmus: appears first 3 months, compensatory head tilt
• Associated with albinism, achromatopsia, Leber congenital amaurosis
• Neuroimaging recommended if cause not evident
⚠️ Acquired Nystagmus = RED FLAG
• May indicate intracranial neoplasm, demyelination, infection, trauma
• Vertical nystagmus → posterior fossa lesion until proven otherwise
• Drug-induced (phenytoin, barbiturates, alcohol)
• Requires neuroimaging (MRI brain)
🩺 Spasmus Nutans
• Triad: bilateral asymmetric nystagmus + head nodding + torticollis
• Onset 4-12 months, resolves by age 3 years
• Benign but neuroimaging recommended to rule out CNS tumor (optic pathway glioma)
🌀 Other Abnormal Movements
• Ocular myoclonus: eye oscillations + soft palate/face/diaphragm movements
• Labyrinthitis: vertigo + nystagmus after viral illness/otitis media
• End-gaze nystagmus (1-2 beats) — normal variant
📌 Decision strategy: Any acquired nystagmus or nystagmus with abnormal neurologic exam → urgent MRI. Vertical nystagmus is particularly concerning for posterior fossa pathology. Spasmus nutans requires imaging to exclude tumor despite benign course.