Blackwell Science, LtdOxford, UK SBRSleep and Biological Rhythms1446-92352003 Japanese Society of Sleep Research 12June 2003 18 Sleep apnea and vocal cord paralysis A Ikematsu et al. 10.1046/j.1446-9235.2003.00018.x Short Communication123124BEES SGML

Sleep and Biological Rhythms 2003; 1: 123–124

SHORT PAPER

Sleep apnea syndrome complicated with idiopathic vocal cord paralysis Akiko IKEMATSU,1 Masayuki MIYAMOTO,2 Tomoyuki MIYAMOTO,2 Keiichiro KUMAHARA,3 Hiroko SATO3 and Koichi HIRATA2 1

Ikematsu Takenosuke Snoring Research Center, Chiba, 2Department of Neurology Dokkyo University School of Medicine, Tochigi and 3Ikematsu Takenosuke Memorial Clinic, Chiba, Japan

Abstract A 38-year-old-man with sleep apnea syndrome (SAS) was presented. A laryngoscopic examination performed because of the patient’s inspiratory stridor revealed vocal cord paralysis during sleep. At the time of this examination, he showed no neurological abnormalities, suggesting multiple system atrophy. We diagnosed him as having Gerhardt syndrome. With the application of nasal continuous positive airway pressure, indices reflecting sleep apnea were improved, but he continued to exhibit inspiratory stridor. We herein report this rare case of SAS complicated with vocal cord paralysis during sleep, and stress the importance of an acoustic analysis of snoring and laryngoscopic examinations when patients with SAS show inspiratory stridor.

Key words: acoustic analysis of snoring, Gerhardt syndrome, laryngoscopic examinations, sleep apnea syndrome, vocal cord paralysis.

INTRODUCTION

CASE REPORT

We herein report a rare patient with sleep apnea syndrome (SAS) who also has vocal cord paralysis during sleep (Gerhardt syndrome1). Gerhardt syndrome may be a complication in cases with SAS. Although polysomnography is still considered to be the gold standard for diagnosing sleep apnea syndrome, the standard polysomnography setup fails to provide information on the vocal cords. The diagnosis in the present case was obtained based on an acoustic analysis of snoring and laryngoscopic examinations, which were performed because of the patient’s inspiratory stridor during sleep. In the light of the present case, we would like to stress the importance of an acoustic analysis of snoring and laryngoscopic examinations in patients with SAS showing inspiratory stridor.

A 38-years-old man presented with complaints of snoring and daytime sleepiness. His medical history was unremarkable. In 1998, he rapidly gained 15 kg in weight, his snoring intensified, and he began noticing occasional sleep apnea. At the starting of spring in 2000, his family informed him of his high-pitched snoring, and he presented for consultation in November of that year. At that time, he had a cold and had become aware of throat hoarseness and pain, which continues to the present. At an initial examination, his blood pressure was 128/70 mmHg, pulse rate 57/min, body mass index 31.1 kg/m2, and the Epworth Sleepiness Scale (ESS) score was 13 points. Otorhinolaryngological findings were left nasal septum curvature, with no craniofacial morphological abnormalities. Laryngoscopy, when he was awake, revealed no vocal cord dilator impairment at inspiration. During sleep, however, the glottis closed at inspiration, and was only slightly patent on the left side at expiration. There were no abnormal neurological findings such as autonomic disorder, parkinsonism, or

Correspondence: Dr A Ikematsu, Ikematsu Takenosuke Snoring Research Center, 226 Nakanodai Noda, Chiba 278-0035, Japan. Email: [email protected] Accepted for publication 10 January 2003.

© 2003 Japanese Society of Sleep Research

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A Ikematsu et al.

Figure 1 Summary of an all-night polysomnogram during nasal autocontinuous positive airway pressure (auto-CPAP) therapy. There were improvements in sleep apnea, oxygen desaturation, and sleep structure with auto-CPAP (pressure ranged from 5 to 14 mmH2O), but inspiratory stridor remained. BPM, beats per minute; LEG, leg movement; Su, supine position.

Hours

cerebellar ataxia. A blood examination, urinalysis, electrocardiogram, standing test, plain chest X-ray, head and chest CT scans, and brain MRI were not remarkable. Overnight polysomnography (PSG) revealed an apnea– hypopnea index (AHI) of 92.4/h, with a mean SpO2 of 92% during non-REM sleep and 89% during REM sleep, and an arousal index of 68.7/h. An evaluation of his sleep parameters revealed a total sleep time (TST) of 456 min, 62.8% of which was sleep stage 1 (S1), 32.6% sleep stage 2 (S2), 0.1% sleep stages 3 and 4 (S3 + 4), and 5.3% sleep stage REM (SREM). High-pitched, intense snoring occurred 23 times/min at inspiration, and tachypnea was observed. The maximum acoustic pressure was 72 db, and snoring occurred during all stages of sleep. From the PSG findings, severe SAS was diagnosed, and treatment with nasal auto-continuous positive airway pressure (auto-CPAP; Virtuoso LX; Smartcard System, Respironics, Murrysville, PA, USA) was started. The pressure variation ranged from 5 to 14 cmH2O. His condition improved to an AHI of 3.2/h, mean SpO2 of 96%, and arousal index of 8.1/h. There were also improvements in his sleep structure. The TST was 502 min, 15.0% of which was S1, 44.2% S2, 16.4% S3 + 4, and 24.1% SREM. His ESS score was seven. Even with CPAP at 14 cmH2O, snoring with a basic frequency of 210–300 Hz remained, similar to that observed with vocal cord paralysis (Fig. 1).

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DISCUSSION We encountered a patient with SAS complicated by idiopathic impairment of vocal cord movement during sleep (Gerhardt syndrome1). He had no neurological diseases such as multiple system atrophy. The glottis is rarely the site of the obstruction in cases of SAS. A search of the literature revealed no definite information on the morbidity of vocal paralysis in SAS. We found only one case report by Higami et al., who reported a similar patient with SAS caused by glottis dilator impairment.2 In cases when the SAS disappears with CPAP treatment but inspiratory stridor remains, detailed investigations including an acoustic analysis of snoring and laryngoscopic examinations are needed for the early diagnosis of vocal cord paralysis.

REFERENCES 1 Gerhardt C. Studien und Beobachtungen über stimmbandlähmung. Arch. Pathol. Anat. Berl. 1863; 27: 68– 98. 2 Higami Y, Higami S, Takeuchi H et al. A case reportObstructive sleep apnea patients whose vocal cords fix at paramedian position only during sleeping. Otologia Fukuoka 2000; 46: 174–6.

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