Case Study: New Onset Myasthenia Gravis and Narcolepsy With Cataplexy

Case Study: New Onset Myasthenia Gravis and Narcolepsy With Cataplexy
Case Study: New Onset Myasthenia Gravis and Narcolepsy With Cataplexy

SEATTLE, WA—An 80-year-old male with new onset myasthenia gravis and narcolepsy with cataplexy had symptomatic improvement with sodium oxybate—but not with immune-modulating agents, results of a case study presented at SLEEP 2015 have shown.

A patient being treated with “prednisone 20mg/day, pyridostigmine 60mg/day, and IVIG concurrently presented with persistent excessive daytime sleepiness and prolonged periods of sleep for the previous six months,” stated D.F. Garcia-Anton, of the UHealth Sleep Medicine Program, Miller School of Medicine, University of Miami, FL, USA. “He additionally reported sleep paralysis, visual hallucinations, and daily cataplexy with anger and laughter.”

An overnight polysomnography showed severe obstructive sleep apnea (OSA), with an AHI of 33 per hour. Bi-level positive airway pressure (PAP) was found to treat his respiratory events adequately, with a residual AHI of 4.1 per hour. However, “despite optimal therapy with PAP, the patient continued endorsing hypersomnia and cataplexy,” Garcia-Anton stated.

Seven months after PAP therapy was initiated, repeat polysomnography with Multiple Sleep Latency Test (MSLT) was performed. Two MSLTs showed reduced sleep latency (mean 2.1 minutes); however, but no sleep-onset rapid eye movement periods were detected. A repeat MSLT was performed with similar results. The patient was negative for HLA DQB1*0602; cerebrospinal fluid hypocretin-1 was not assessed.

Based on his clinical symptoms, sodium oxybate 7.5mg/day and venlafaxine 75mg/day were initiated. This resulted in significant improvement in his excessive daytime sleepiness; the Epworth Sleepiness Scale score declined from 20 to 8. This treatment also resolved his sleep-wake hallucinations, sleep paralysis, and cataplexy.

“Additionally, PAP compliance was optimal, with normal residual AHI at Months 3 and 6 after initiation of narcolepsy pharmacotherapy,” Garcia-Anton concluded.

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