Downbeat Nystagmus
Contributor: Kristina Damisch, M2
Resident Sponsor: Lorraine Provencher, MD
April 19, 2017
Additional Notes: Length 00:37
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Downbeat nystagmus (DBN) is characterized by a pathologic upward drift of gaze followed by a corrective downward saccade. DBN is most apparent when the patient is instructed to look down or to either side. It is typically accompanied by oscillopsia, which may be severe. DBN is usually due to structural pathology at the cervicomedullary junction (most commonly Arnold-Chiari malformation) or spinocerebellar degeneration (e.g. ataxia telangiectasia), which may be accompanied by a positive family history. The differential diagnosis for DBN should also include neoplasia of the cervicomedullary junction or cerebellum, stroke, trauma, paraneoplastic symdromes, drug effects (anti-epileptics, alcohol, lithium), demyelination, nutritional deficiencies (magnesium, B-12), and brainstem encephalitis. Work-up for these entities should be guided by a thorough history. Treatments such as clonazepam, baclofen, gabapentin, and 3,4-diaminopyridine may be only partially effective.
References
- American Academy of Ophthalmology. Basic and Clinical Science Course. Section 5: Neuro-Ophthalmology Ed 2014-2015. 234-236.
- Yee RD. Downbeat Nystagmus: Characteristics and Localization of Lesions. Transactions of the American Ophthalmological Society. 1989;87:984–1032.
Suggested Citation Format
Damisch K, Provencher L. Downbeat Nystagmus. EyeRounds.org. April 19, 2017; Available from: http://EyeRounds.org/atlas-video/downbeat-nystagmus.htm
