Objective: We present a case of Lance Adams syndrome (LAS) with see-saw nystagmus (SSN). LAS is a rare entity and first reported by Lance and Adams in 1963. SSN is also a rare ocular presentation and was first reported in 1913 by Maddox.

Background: LAS or chronic posthypoxic myoclonus (PHM) is defined as generalized action myoclonus appearing within a few days-weeks after cardiac arrest, mostly (but not exclusively) of hypoxic origin¹.  LAS is commonly cortical in origin, and manifests as multifocal myoclonus. It typically improves with time and is only rarely associated with persistent neurologic deficits². Medications for treatment include valproic acid, levetiracetam, and zonisamide, with bilateral GPi-DBS being a viable therapeutic option in refractory cases³. SSN is characterized by the cyclic movement of the eyes with a conjugate torsional component and a disjunctive vertical component.

Method: A 29yo F with history of alcohol withdrawal seizure and anoxic brain injury (ABI) presented to clinic for evaluation of dystonia. At the age of 23, upon abruptly stopping alcohol use, she had a grand mal seizure that was complicated by cardiac arrest with prolonged resuscitation efforts eventually requiring ECMO. Head imaging demonstrated ABI and repeat MRI a year later showed volume loss in occipital lobes and perirolandic regions bilaterally. At the time of discharge, she had ataxia with jerking movements of extremities, dysarthria, and vision loss secondary to cortical blindness. She developed head bobbing two years later. Upon presentation to movement disorder clinic, her primary complaint was gait imbalance.

Results: On examination she had multifocal myoclonus at rest, posture, and action that involved all extremities in addition to the neck and trunk. She also had hyperkinetic dystonia of hands and feet that worsened with action, and mirror dystonia in the right hand when writing with the left. She was also noted to have cerebellar dysarthria and SSN in primary gaze. She was diagnosed with LAS and started on valproic acid.

Conclusion: Our patient with LAS and associated SSN expands the spectrum of etiology of SSN and to our knowledge this is the first PHM case with combination of SSN. There are many etiologies of SSN, but the proposed mechanism in our case is inactivation of the torsional eye-velocity integrator, the interstitial nucleus of Cajal, with sparing of the torsional fast-phase generator, the rostral interstitial nucleus of MLF.

References: 1. Lance JW, Adams RD. The syndrome of intention or action myoclonus as a sequel to hypoxic encephalopathy. Brain 1963; 86: 111-136. 2. Werhahn KJ, Brown P, Thompson PD, Marsden CD. The clinical features and prognosis of chronic posthypoxic myoclonus. Mov Disord 1997; 12: 216-220. 3. Ramdhani R, Frucht S, Koppel B. Improvement of Post-hypoxic Myoclonus with Bilateral Pallidal Deep Brain Stimulation: A Case Report and Review of the Literature. Tremor and other hyperkinetic movements; 2017:7,461.

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