Citation: Economou, N.-T.; Cholidou, K.; Kallianos, A.; Weiss, K.; Knechtle, B.; Nikolaidis, P.T.; Trakada, G. “Peculiar” Snoring in a 40-Year-Old Patient: A Case Report and Review of Literature. Healthcare 2022, 10, 1051. https://doi.org/10.3390/ healthcare10061051 Academic Editors: Axel Steiger and Maria Basta Received: 27 March 2022 Accepted: 26 May 2022 Published: 6 June 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). healthcare Case Report “Peculiar” Snoring in a 40-Year-Old Patient: A Case Report and Review of Literature Nicholas-Tiberio Economou 1 , Kyriaki Cholidou 1 , Anastasios Kallianos 1 , Katja Weiss 2 , Beat Knechtle 2, * , Pantelis T. Nikolaidis 3 and Georgia Trakada 1 1 Department of Clinical Therapeutics, Division of Pulmonology, National and Kapodistrian University of Athens School of Medicine, Alexandra Hospital, 11528 Athens, Greece; nt_economou@yahoo.it (N.-T.E.); kg.cholidou@yahoo.gr (K.C.); kallianos.pulm@gmail.com (A.K.); gtrakada@hotmail.com (G.T.) 2 Institute of Primary Care, University of Zurich, 8000 Zurich, Switzerland; katja@weiss.co.com 3 School of Health and Caring Sciences, University of West Attica, 12243 Athens, Greece; pademil@hotmail.com * Correspondence: beat.knechtle@hispeed.ch Abstract: This is a case description of a patient with previously diagnosed rapid eye movement sleep behavior disorder (RBD) and nocturnal enuresis, who complained about a “peculiar sound” while sleeping and, occasionally, while awake during intensive exercise, for the last three months. A home audio recording, which his wife obtained while he was sleeping, showed a high-pitched sound identified as stridor. Full video polysomnography revealed no apneas or hypopneas. The flow-volume loop yielded an inspiratory plateau, indicating variable extrathoracic obstruction. The upper and lower respiratory system computed tomography did not show any anomalies or mechanical lesions (e.g., masses and scars). Fiberoptic laryngoscopy revealed an abnormal activity of the vocal cord abductor during quiet breathing and inspiration in a supine position, leading to partial obstruction. A positive dopamine transporter scan and the coexistence of stridor, RBD, and nocturnal enuresis were diagnostic for multiple system atrophy. The patient was treated with continuous positive airway pressure as a symptomatic therapy for stridor and levodopa. Keywords: stridor; rapid eye movement sleep behavior disorder; nocturnal enuresis; sleep; dopamine transporter scan 1. Introduction Stridor is defined as a strained, high-pitched, harsh respiratory sound, mainly inspi- ratory, occurring only during sleep or during both sleep and wakefulness, and caused by laryngeal dysfunction, leading to narrowing of the rima glottidis (ICD 10 code R06.1). Stridor is a high-pitched inspiratory sound that indicates a dynamic or stable narrowing of airway diameter and is a common symptom encountered by pulmonary physicians, especially when accompanied by dyspnea [1]. When it is recognized, pulmonary function testing (PFTs) and other interventional procedures, such as bronchoscopy, should be per- formed. The clinical diagnosis of stridor is challenging because patients, family members, or caregivers may be unaware of its presence, especially when it occurs at night. Nocturnal stridor can be the initial manifestation of multiple system atrophy (MSA) in 4–5.2% of patients [2,3]. MSA is a progressive, fatal neurodegenerative disorder character- ized by a variable combination of autonomic failure, cerebellar ataxia, and parkinsonian feature, with two phenotypes—parkinsonian (MSA-P) and cerebellar (MSA-C) (ICD 10 code G90.3) [4]. MSA is characterized by gross abnormalities of the striatonigral and/or olivopontocerebellar systems, which upon microscopic examination are associated with severe neuronal loss, gliosis, myelin pallor, and axonal degeneration. The term “peculiar snoring” was first introduced by Kakitsuba et al. [5] to describe nocturnal stridor in MSA due to the vibration of the vocal folds in inspiration, with a fundamental acoustic frequency Healthcare 2022, 10, 1051. https://doi.org/10.3390/healthcare10061051 https://www.mdpi.com/journal/healthcare