Disclosures: Emily Ryan-Michailidis, DO: No financial relationships or conflicts of interest

Case Description: A 68-year-old male presented with recent organizing pneumonia resulting in hypoxic arrest and tracheostomy dependence with subsequent severe post-hypoxic myoclonus. After optimization of his multiple medical issues, including tracheostomy decannulation, the patient remained with fluctuations in cognition and arousal. Additionally, myoclonus severely limited functional abilities. He was trialed on multiple antiepileptics for myoclonus. All medications resulted in modest alleviation of his symptoms, but increased sedation and worsened activity tolerance.

Setting: Inpatient rehabilitation.

Patient: 68-year-old male with post-hypoxic myoclonus. Assessment/

Results: After admission for treatment of his functional deficits, the patient initially required moderate-to-maximum assistance for mobility due to myoclonic activity in all limbs. With intensive therapies, he progressed to minimum-to-moderate assistance level. Balance, endurance, and fine motor movements remained limited by diffuse myoclonic activity. Treatment with sodium oxybate was then initiated at 0.75g daily. He demonstrated global reduction in myoclonus for several hours after administration with improved arousal and verbal output; ambulation progressed to contact guard level. Improved motor control led to independent feeding and writing tasks, which was never achieved prior. The trial was terminated after four doses as the patient was consistently noted to have confusion, irritability, emesis, and somnolence several hours after administration. Downtitration to 0.5g did not alleviate side effects.

Discussion: Sodium oxybate is a salt of gamma-hydroxybutyrate (GHB). It has been previously reported to improve refractory myoclonus, although side effects of the medication are rarely reported. Here we present a case of poor patient tolerance to sodium oxybate despite modest treatment dose. Other authors have described dosage up to 9g per day without increased somnolence. Side effects of the medication were likely amplified by patient’s underlying impaired arousal from anoxic encephalopathy and history of upper airway obstruction.

Conclusion: This case highlights that although sodium oxybate can reduce myoclonus, its use should be considered cautiously in patients with baseline impairments in arousal.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/effectiveness-and-complications-of-sodium-oxybate-administration-for-treatment-of-post-hypoxic-myoclonus-a-case-report/