Square-Wave Ocular Oscillation and Ataxia in an Anti-GAD-Positive Individual With Hypothyroidism.

Abstract

Cerebellar ataxia is an uncommon manifestation of hypothyroidism with unknown pathomechanism. The few descriptions of the clinical phenotype range from limb, gait, and trunk ataxia to various ocular motor abnormalities. We evaluated a 62-year-old woman with previously undetected severe hypothyroidism who presented with prominent saccadic intrusions and gait ataxia. She had high titers of antithyroid autoantibodies and anti-glutamic acid decarboxylase (anti-GAD) antibodies. Horizontal eye movement recordings revealed a series of nearly continuous pseudoharmonic square wave jerks (SWJs) constituting a square wave oscillation. Amplitudes reached maximum values of about 4, and wave frequency approached 100 cycles per minute. Thyroxine substitution and corticosteroid administration had little effect on SWJ parameters. The square wave oscillation nearly completely resolved after a single treatment session with intravenous immunoglobulin suggesting a causal link between an autoimmune process and the cerebellar dysfunction. Current concepts of the genesis of saccadic intrusions favor a role for anti-GAD antibodies in the etiology of SWJs.

• Authors: Chrysoula Brokalaki, Evangelia Kararizou, Antonis Dimitrakopoulos, Ioannis Evdokimidis, Evangelos Anagnostou
• Journal: Journal of neuro-ophthalmology : the official journal of the North American Neuro-Ophthalmology Society (J Neuroophthalmol) Vol. 35 Issue 4 Pg. 390-5 (Dec 2015) ISSN: 1536-5166 [Electronic] United States
• PMID: 26035807 (Publication Type: Case Reports, Journal Article)

Chemical References

• Autoantibodies
• Glutamate Decarboxylase

Topics

• Autoantibodies (blood)
• Biological Clocks (physiology)
• Cerebellar Ataxia (etiology)
• Female
• Glutamate Decarboxylase (immunology)
• Humans
• Hypothyroidism (complications)
• Middle Aged
• Ocular Motility Disorders (etiology)