1327 Resolution of Central Sleep Apnea in a Patient with a Chiari 1 Malformation Following Surgical Decompression

Abstract Introduction Central respiratory events, including hypoventilation and apneas, are caused by compression of the brainstem in Type 1 Chiari malformations (CM1). Central sleep apnea (CSA) occurs in 15-34% of children with CM1, and compensated central hypoventilation is present in 15%. Other potential complications of CM1 include nystagmus, headaches, and, in rare and devastating cases, a risk of sudden unexpected nocturnal death. We describe a case of an adolescent with CSA due to CM1 that improved with surgical decompression. Report of case(s) A 17-year-old female with a history of ADHD presented to Sleep Medicine clinic with daytime fatigue and brain-fog. No significant snoring was noted, and she had an Epworth sleepiness scale (ESS) score of 16. The initial home sleep test had a central apnea-hypopnea index (AHI) of 21 and an obstructive AHI of 6.5. Subsequent polysomnography (PSG) showed predominantly central sleep apnea with a combined AHI of 42.6 (central AHI 41.6), and the patient was managed on Bilevel ST 12/6 RR 10. She had modest improvement in her daytime symptoms. As she had no history of underlying central nervous system pathology, her CSA was initially presumed to be idiopathic. However, 2 years later, she developed recurrent debilitating headaches and downbeat nystagmus, so an MRI of the head was completed. This showed CM1 with tonsils 32 mm below the foramen magnum; therefore, surgical decompression was performed via craniectomy and C1 arch removal with duraplasty. Postoperatively, the patient had reduction of headaches and nystagmus and denied daytime fatigue without the use of Bilevel PAP therapy, and ESS was reduced to 8. Subsequent PSG showed no significant sleep apnea with the combined AHI of 4 events/hr (central AHI of 3.2 events/hr) without any PAP therapy. She was able to discontinue use of Bilevel therapy and continued to feel improvement in her fatigue. Conclusion This case demonstrates that in an otherwise healthy adolescent patient with unexplained central sleep apnea, a type 1 Chiari Malformation could be a profound cause that should be considered during evaluation. Surgical decompression can improve associated symptoms and significantly improve central sleep apnea to the extent that the patient may not need continued PAP therapy. Support (if any)