Delayed nocturnal stridor from bilateral vocal cord paralysis post thyroidectomy surgery masquerading as obstructive sleep apnea

Abstract

Obstructive sleep apnoea (OSA) is typically caused by multilevel obstruction of the upper airway. Laryngeal obstruction from bilateral vocal cord paralysis (BVCP) is a rare cause of OSA. The predominance of nocturnal symptoms is likely due to decreased tone and activity of the laryngeal muscles during sleep, therefore reducing the glottic calibre and limiting airflow through the glottis.While BVCP is a rare cause of OSA, it is a well-recognized and significant complication of thyroid surgery due to the proximity of the recurrent laryngeal nerve to the thyroid gland. However, patients classically develop acute stridor in the immediate post-operative period, rather than a delayed presentation of “snoring”.In this article, we describe a series of two rare cases of non-obese patients with BVCP, presenting with “snoring” to the ENT Sleep Clinic, some months to years after their thyroid surgery. One patient decided on expectant management, the other underwent a tracheostomy with relief of her symptoms.This case series illustrates the importance of performing a flexible nasoendoscopy to evaluate the upper airway tract, especially the vocal cords, in a patient who has a history of thyroid surgery and/or thyroid pathology who presents to the Sleep Clinic with seemingly benign “snoring”.

Keywords

• Obstructive sleep apnoea (OSA)
• Atypical and rare presentation of OSA
• Bilateral vocal cord paralysis
• Laryngeal obstruction
• Thyroid surgery