Sleep-related laryngeal obstruction presenting as snoring or sleep apnea

Sleep Dysfunction in Movement Disorders: a Window to the Disease Biology

PURPOSE OF REVIEW

To comprehensively summarize the sleep pathologies associated with movement disorders, focusing on neurodegenerative diseases.

RECENT FINDINGS

Mounting evidence has further implicated both sleep and circadian disruption in the pathophysiology of many movement disorders. In particular, recent data illuminate the mechanisms by which poor sleep quality and circadian dysfunction can exacerbate neurodegeneration. In addition, anti-IgLON5 disease is a recently described autoimmune disease with various symptoms that can feature prominent sleep disruption and parasomnia. Many movement disorders are associated with sleep and circadian rhythm disruption. Motor symptoms can cause sleep fragmentation, resulting in insomnia and excessive daytime sleepiness. Many neurodegenerative movement disorders involve brainstem pathology in regions close to or affecting nuclei that regulate sleep and wake. Further, commonly used movement medications may exacerbate sleep concerns. Providers should screen for and address these sleep symptoms to improve function and quality of life for patients and caregivers.

Polysomnography: assessment of decannulation readiness in chronic upper airway obstruction

OBJECTIVES/HYPOTHESIS

To evaluate the clinical value of polysomnography in patients with a tracheotomy due to chronic upper airway obstruction prior to attempting decannulation.

STUDY DESIGN

Retrospective chart review.

METHODS

Subjects with chronic upper airway obstruction were identified using a clinical database between 2000 and 2014. All subjects had a tracheotomy, were assessed by the senior author in a tertiary care academic center, and underwent polysomnography prior to attempting decannulation. Patients were excluded if they did not undergo polysomnography or had severe obstructive sleep apnea as the primary indication for tracheotomy.

RESULTS

Fifteen patients were identified. The majority (87.5%) of patients were successfully decannulated after their first polysomnography showed acceptable results when carried out with the tracheotomy occluded. Obstructive sleep apnea was identified in four of the nine patients who tolerated overnight tracheotomy occlusion, and continuous positive airway pressure (CPAP) was initiated. An additional four of the remaining six patients were decannulated after subsequent polysomnography demonstrated improvement with CPAP, and two required an additional airway procedure.

CONCLUSIONS

Chronic upper airway obstruction requiring tracheotomy can be challenging to treat and successfully decannulate. Indirect laryngoscopy is essential to evaluate the anatomy of the larynx; however, it cannot assess potential increased obstruction during sleep. The study indicates that polysomnography can assist with the evaluation of decannulation readiness in patients with chronic upper airway obstruction as an adjunct measure in addition to imaging and laryngoscopy.

LEVEL OF EVIDENCE

4.

Sleep Disorders in Atypical Parkinsonism

Sleep disorders are commonly seen in atypical parkinsonism, with particular disorders occurring more frequently in specific parkinsonian disorders. Multiple systems atrophy (MSA) is a synucleinopathy often associated with nocturnal stridor which is a serious, but treatable condition highly specific to MSA. In addition, this disorder is strongly associated with rapid eye movement (REM) sleep behavior disorder (RBD), which is also seen in dementia with Lewy bodies (DLB). RBD is far less prevalent in progressive supranuclear palsy (PSP), which is a tauopathy. Insomnia and impaired sleep architecture are the most common sleep abnormalities seen in PSP. Corticobasilar degeneration (CBD) is also a tauopathy, but has far fewer sleep complaints associated with it than PSP. In this manuscript we review the spectrum of sleep dysfunction across the atypical parkinsonian disorders, emphasize the importance of evaluating for sleep disorders in patients with parkinsonian symptoms, and point to sleep characteristics that can provide diagnostic clues to the underlying parkinsonian disorder.

Circadian rhythms and cardiovascular health

The functional organization of the cardiovascular system shows clear circadian rhythmicity. These and other circadian rhythms at all levels of organization are orchestrated by a central biological clock, the suprachiasmatic nuclei of the hypothalamus. Preservation of the normal circadian time structure from the level of the cardiomyocyte to the organ system appears to be essential for cardiovascular health and cardiovascular disease prevention. Myocardial ischemia, acute myocardial infarct, and sudden cardiac death are much greater in incidence than expected in the morning. Moreover, supraventricular and ventricular cardiac arrhythmias of various types show specific day-night patterns, with atrial arrhythmias--premature beats, tachycardias, atrial fibrillation, and flutter - generally being of higher frequency during the day than night--and ventricular fibrillation and ventricular premature beats more common, respectively, in the morning and during the daytime activity than sleep span. Furthermore, different circadian patterns of blood pressure are found in arterial hypertension, in relation to different cardiovascular morbidity and mortality risk. Such temporal patterns result from circadian periodicity in pathophysiological mechanisms that give rise to predictable-in-time differences in susceptibility-resistance to cyclic environmental stressors that trigger these clinical events. Circadian rhythms also may affect the pharmacokinetics and pharmacodynamics of cardiovascular and other medications. Knowledge of 24-h patterns in the risk of cardiac arrhythmias and cardiovascular disease morbidity and mortality plus circadian rhythm-dependencies of underlying pathophysiologic mechanisms suggests the requirement for preventive and therapeutic interventions is not the same throughout the day and night, and should be tailored accordingly to improve outcomes.

[Guideline: Treatment of obstructive sleep apnea in adults]

The current guideline discusses conservative and surgical therapy of obstructive sleep apnea (OSA) in adults from the perspective of the ear, nose and throat specialist. The revised guideline was commissioned by the German Society of Ear-Nose-Throat, Head-Neck Surgery (DG HNO KHC) and compiled by the DG HNO KHC's Working Group on Sleep Medicine. The guideline was based on a formal consensus procedure according to the guidelines set out by the German Association of Scientific Medical Societies (AWMF) in the form of a"S2e guideline". Research of the literature available on the subject up to and including December 2008 forms the basis for the recommendations. Evaluation of the publications found was made according to the recommendations of the Oxford Centre for Evidence-Based Medicine (OCEBM). This yielded a recommendation grade, whereby grade A represents highly evidence-based studies and grade D those with a low evidence base.

Idiopathic laryngeal spasm: management and long-term outcome

Idiopathic laryngeal spasm (ILS) is an uncommon disorder characterised by brief episodes of stridor, occurring at any time. Subsequent outpatient ENT examination is normal. These episodes cause considerable anxiety for both patient and physician. Little is known about the initiating event(s) in this condition or the long-term outcome. Using a combination of telephone and postal questionnaires with case note review, we have reviewed a cohort of 21 patients with this diagnosis managed by the senior author over the last 15 years. None of the 19 patients who responded were worse; 13 (68%) described improvement or complete resolution of symptoms. ILS is difficult to classify in the spectrum of vocal cord disorders, but appears distinct to those previously described. The condition responds well to a conservative management approach of reassurance and counselling.

Different mechanism of vocal cord paralysis between spinocerebellar ataxia (SCA 1 and SCA 3) and multiple system atrophy

While multiple system atrophy (MSA) is frequently associated with vocal cord paralysis (VCP) causing severe respiratory failure, it is still unknown whether hereditary types of spinocerebellar degeneration develop similar laryngeal paralysis. We analyzed the laryngeal function from the viewpoints of fiberoptic laryngoscopy and laryngeal myopathology and then attempted to clarify the difference of the mechanism of VCP among the patients with spinocerebellar ataxia type 1 (SCA 1), type 3 (SCA 3), and MSA. Seven patients with SCA 1, nineteen with SCA 3, and eleven with MSA were studied. Vocal cord movement was analyzed by fiberoptic laryngoscopy during wakefulness and diazepam-induced sleep (sleep load test). Paraffin-embedded sections or cryosections of the intrinsic laryngeal muscles from five autopsied cases (one with SCA 1 and four with SCA 3) were histologically examined. VCP was found in two of the seven SCA 1 patients (29%), three of the nineteen SCA 3 patients (16%), and in nine of the eleven MSA patients (82%). VCP observed in SCA 1 and SCA 3 was various in the severity and showed no exacerbation on sleep load test in all of the eight patients but one SCA 3 patient. In this patient, the findings of fiberoptic laryngoscopy were quite similar to those found in MSA. All the intrinsic laryngeal muscles including cricothyroid (CT), interarytenoid (IA), and posterior cricoarytenoid (PCA) muscles showed neurogenic atrophy in one autopsied SCA 1 and four SCA 3 patients. Our conclusion is that VCP in SCA 1 and SCA 3 contrasts with that in MSA in its occurrence, response to the sleep load test, and the distribution of the neurogenic abnormalities among the intrinsic laryngeal muscles.

Persistence of Apnea in Wakefulness in a Patient with Postradiation Pharyngitis

We report on a patient with the onset of recurrent nocturnal awakenings associated with postawakening stridor with onset a few weeks after receiving radiation therapy to the neck. The onset of nocturnal stridor was also accompanied by complaints of snoring and excessive daytime sleepiness. Stridor did not occur during daytime wakefulness. Nocturnal polysomnography (NPSG) recorded with a calibrated pneumotachometer demonstrated snoring and severe obstructive sleep apnea (OSA) with a apnea/hypopnea index of 51 events/hr. One apneic episode persisted for 17 sec after the onset of wakefulness as evidenced by standard NPSG scoring criteria for arousals. With this event, video monitoring revealed the patient abruptly sitting upright and clutching his throat and auditory recording demonstrated stridorous sounds. During wakefulness endoscopy revealed moderate edema and erythema of the supraglottic region, epiglottis, palatine tonsils, and false and true vocal cords. Vocal cord function appeared normal. This case report represents the observation of two rare findings in a single patient, persistence of apnea in wakefulness, and OSA onset following neck irradiation. We review the literature on the persistence of apnea in wakefulness and discuss possible mechanisms for its occurrence in this patient.

Pathogenesis of laryngeal narrowing in patients with multiple system atrophy

1. We do not fully understand the pathogenesis of nocturnal laryngeal stridor in patients with multiple system atrophy (MSA). Recent studies suggest that inspiratory thyroarytenoid (TA) muscle activation has a role in the development of the stridor. 2. The breathing pattern and firing timing of TA muscle activation were determined in ten MSA patients, anaesthetized with propofol and breathing through the laryngeal mask airway, while the behaviour of the laryngeal aperture was being observed endoscopically. 3. Two distinct breathing patterns, i.e. no inspiratory flow limitation (no-IFL) and IFL, were identified during the measurements. During IFL, significant laryngeal narrowing was observed leading to an increase in laryngeal resistance and end-tidal carbon dioxide concentration. Development of IFL was significantly associated with the presence of phasic inspiratory activation of TA muscle. Application of continuous positive airway pressure suppressed the TA muscle activation. 4. The results indicate that contraction of laryngeal adductors during inspiration narrows the larynx leading to development of inspiratory flow limitation accompanied by stridor in patients with MSA under general anaesthesia.

Stridor and death in multiple system atrophy

Patients with multiple system atrophy (MSA) have a mean survival of 8 to 10 years. Nocturnal stridor has been considered a poor prognostic feature. We analyzed demographic, clinical, and polysomnographic data and obtained follow-up information from 42 patients with MSA (30 with follow-up data) seen in a Sleep Disorders Center. Group I consisted of 17 patients with nocturnal stridor, including seven with daytime stridor. Group II consisted of 25 patients without stridor. Analysis of survival curves of 30 patients with follow-up information showed a significantly shorter survival from the sleep evaluation, but not from disease onset, for patients with stridor compared with those without. Nine of 11 patients with stridor died a median of 2 years from presentation and the only two survivors had undergone tracheostomy. Patients with daytime stridor and immobile vocal cords had especially poor prognoses. However, two of four patients with tracheostomies also died, as did six of 19 without stridor. We postulate that central hypoventilation and its complications may have been responsible for many of these other deaths. We conclude that stridor does carry a poor prognosis in patients with MSA but that there are also other causes of death. We recommend consideration of tracheostomy for patients with MSA who have stridor, but also assessment for central hypoventilation and appropriate management if it is present.

Evaluation and management of bilateral vocal cord immobility

Bilateral vocal cord immobility can be life threatening for some patients. Others, who have an open glottic chink, may have a breathy dysphonia, intermittent dyspnea, and stridor. These signs and symptoms may also be found in a number of other conditions that cause weakness or paradoxical motion of the vocal cords that mimics paralysis. These other conditions include central nervous system diseases, neuromuscular disorders, laryngospasm, and psychogenic disorders. In addition, patients with cricoarytenoid joint immobility or interarytenoid scar can also have similar symptoms at presentation. It is critical to consider the differential diagnosis of an assumed bilateral vocal cord paralysis and understand the management of paradoxical movement, weakness, joint fixation, interarytenoid scar, laryngospasm, and psychogenic disorders. The treatment for bilateral immobility should proceed only after a thorough evaluation, which might include electromyography and/or examination during general anesthesia under dense anesthetic paralysis. Reconstructive procedures are the treatments of choice, and destructive procedures should be chosen only as a last resort.

Hypoxic response of hypoglossal motoneurones in the in vivo cat

1. In current and voltage clamp, the effects of hypoxia were studied on resting and synaptic properties of hypoglossal motoneurones in barbiturate-anaesthetized adult cats. 2. Twenty-nine hypoglossal motoneurones with a mean membrane potential of -55 mV responded rapidly to acute hypoxia with a persistent membrane depolarization of about +17 mV. This depolarization correlated with the development of a persistent inward current of 0.3 nA at holding potentials close to resting membrane potential. 3. Superior laryngeal nerve (SLN) stimulation-evoked EPSPs were reduced in amplitude by, on average, 46% while IPSP amplitude was reduced by 31% SLN stimulation-evoked EPSCs were reduced by 50-70%. 4. Extracellular application of adenosine (10 mM) hyperpolarized hypoglossal motoneurones by, on average, 5.6 mV, from a control value of -62 mV. SLN stimulation-evoked EPSPs decreased by 18% and IPSPs decreased by 46% during adenosine application. 5. Extracellular application of the KATP channel blocker glibenclamide led to a blockade of a persistent outward current and a significant increase of SLN stimulation-evoked EPSCs. 6. We conclude that hypoglossal motoneurones have a very low tolerance to hypoxia. They appear to be under metabolic stress even in normoxia and their capacity to activate protective potassium currents is limited when compared with other brainstem neurones. This may help to explain the rapid disturbance of hypoglossal function during energy depletion.

Early diagnosis and stage classification of vocal cord abductor paralysis in patients with multiple system atrophy

OBJECTIVES

Vocal cord abductor paralysis (VCAP) is a life threatening complication which may cause nocturnal sudden death in patients with multiple system atrophy. However, the early diagnosis of VCAP is often difficult to make on routine laryngoscopy performed during wakefulness, as stridor, which is the sole symptom of VCAP in the early stage, develops only during sleep. The aim was to investigate laryngeal dysfunction in patients with multiple system atrophy while awake and asleep.

METHODS

Seven patients with multiple system atrophy with nocturnal stridor and five control patients were studied. Vocal cord movement was analysed by laryngoscopy while the patients were awake and also during sleep induced by intravenous diazepam.

RESULTS

When awake, for the seven patients with multiple system atrophy normal movement of the vocal cords occurred in three, mild abduction restriction in three, and paradoxical movement in one. When asleep, however, all showed obvious paradoxical movement with high pitched inspiratory stridor. In controls, there were no differences in the vocal cord movement between wakefulness and sleep. From these findings, VCAP could be divided into four stages: stage 0 (normal) with normal vocal cord movement during both wakefulness and sleep, stage 1 (mild VCAP) with normal movement during wakefulness and paradoxical movement during sleep, stage 2 (moderately severe VCAP) with abduction restriction during wakefulness and paradoxical movement during sleep, and stage 3 (severe VCAP) with an almost midline position for the vocal cords during both wakefulness and sleep.

CONCLUSIONS

Laryngoscopy during sleep can disclose subclinical VCAP, making an early diagnosis of VCAP in patients with multiple system atrophy. Stage 2 of VCAP seems to be a suitable stage for tracheostomy in patients with multiple system atrophy.

Vocal cord abductor paralysis (VCAP) in Parkinson's disease: difference from VCAP in multiple system atrophy

Vocal cord abductor paralysis (VCAP) is rare in Parkinson's disease (PD), while it is frequent in multiple system atrophy (MSA). Although VCAP is a life-threatening complication it has not yet been clarified whether there is any difference in the mechanism of VCAP between PD and MSA. Examining 3 autopsy-proven PD patients who developed severe VCAP requiring tracheostomy, we found the following differences in the mechanism of VCAP between MSA and PD: (1) clinical and laryngofiberscopic examination showed that VCAP in PD was not exacerbated during sleep, unlike in MSA; (2) On histological examination of the intrinsic laryngeal muscles, the posterior cricoarytenoid muscle demonstrated no abnormalities in PD, while the muscle showed characteristic neurogenic atrophy in MSA. There seemed to be two types of VCAP, namely the nonparalytic type observed in PD, and the paralytic type observed in MSA. Severe dysphagia requiring tube-feeding was common among PD patients who presented with VCAP. Although the relationship between VCAP and dysphagia is unknown, one should be aware of the possibility of fatal VCAP in PD patients with severe dysphagia.

Sleep-related laryngospasm

Seven patients (mean age 46.6; range 33-58; 6M,1F) presented with sleep-related choking episodes and were found to have features in common that distinguished them from other known causes of choking episodes during sleep. The characteristic features include: an awakening from sleep with an acute choking sensation, stridor, panic, tachycardia, short duration of episode (less than 60 seconds), infrequent episodes (typically less than 1 per month), and absence of any known etiology. The disorder most commonly occurs in middle-aged males who are otherwise healthy. In one patient an episode of laryngospasm was polysomnographically documented to occur during stage 3. The clinical features and the polysomnographic findings suggest spasm of the vocal cords of unknown etiology.

Laryngeal electromyography with separated surface electrodes in patients with multiple system atrophy presenting with vocal cord paralysis

When recording the activity of the posterior cricoarytenoid muscle (PCA) with surface electrodes, there is contamination from the surrounding muscles such as the cricopharyngeal muscle. We therefore devised a new oesophageal catheter electrode of the separate type, having three individual surface electrodes for the PCA, cricopharyngeal muscle and diaphragm. The records obtained with this catheter demonstrated satisfactory separation between PCA and cricopharyngeal muscle activities. We used this catheter in patients with multiple system atrophy presenting with vocal cord paralysis, who were awake or asleep. There were two interesting electromyographical findings, which were inspiratory activity of the adductor muscle (the thyroarytenoid muscle) and fade-out of the abductor muscle, that is, PCA activity during sleep. Although vocal cord paralysis is one of the most serious life-threatening complications, the precise mechanism has not been clarified. We believe that our catheter may be useful in investigating the mechanism of vocal cord paralysis which could cause sudden death in neurodegenerative disorders, including multiple system atrophy.

Bilateral vocal cord paralysis with Shy-Drager syndrome

Shy-Drager syndrome consists of progressive autonomic nervous system failure with Parkinson's disease-like symptoms and orthostatic hypotension. It can also result in airway compromise from bilateral vocal cord paralysis. Fewer than 30 cases of severe bilateral vocal cord paresis or paralysis associated with the Shy-Drager syndrome have been reported in the English literature. We present a case of a 72-year-old man who had a 2-year history of orthostatic hypotension, neurogenic bladder, impotence, anhydrosis, and extremity weakness and paresthesias. Hoarseness and dyspnea with stridor developed as a result of bilateral vocal cord paralysis in the median position and required an emergency tracheotomy. This combination of symptoms resulted in the diagnosis of Shy-Drager syndrome. We present the case along with literature review of bilateral vocal cord paralysis with the Shy-Drager syndrome.

Autonomic nervous system function in patients with primary obstructive sleep apnoea syndrome

Ten patients with obstructive sleep apnoea syndrome cured by uvulopalatopharyngoplasty were compared to nine patients considered as surgical failures, using cardiovascular reflex tests--Valsalva manoeuvre, respiratory sinus arrhythmia, isometric handgrip and head-up tilt. Two patients had signs of moderate vagal dysfunction, but no case of definite autonomic nervous dysfunction was diagnosed. The overall results indicated sympathetic overreactivity, positively correlated to oxygen desaturation indices and remaining after successful treatment. Four patients did not exhibit bradycardia during sleep apnoea. Two of them had decreased respiratory sinus arrhythmia when awake, but two had normal values. This implies a difference in vagal responsiveness between the awake and sleeping states, or that other factors besides vagus function influence the bradycardia response to apnoea. The group mean values were all within normal limits. There was no significant difference between the two groups in any test. Autonomic nervous dysfunction therefore does not seem to contribute to surgical failure, nor to occur with increased incidence among patients with primary obstructive sleep apnoea syndrome.

Vocal cord paralysis in the Shy-Drager syndrome. A cause of postoperative respiratory obstruction

A case is presented in which unexpected and persistent postoperative respiratory problems led to the finding of bilateral abductor vocal cord paralysis and confirmed the diagnosis of the Shy-Drager syndrome. Anaesthetists should be aware that vocal cord paralysis may be a feature of this uncommon condition, and should consider the possibility of glottic obstruction as a cause of ventilatory difficulties.