Central sleep apnea and arterial compression of the medulla.

We report a 5-year-old with central sleep apnea associated with compression of the medulla oblongata by abnormal looping of the left vertebral artery. The magnetic resonance imaging findings raise the possibility that compression of the respiratory center by an aberrant vertebral artery might cause central sleep apnea.     

Sleep-Related Breathing Disorders: When CPAP Is Not Enough

Three decades ago, continuous positive airway pressure (CPAP) was introduced to treat obstructive sleep apnea (OSA). Shortly after, bilevel positive airway pressure devices (BPAP) that independently adjusted inspiratory and expiratory positive airway pressure were developed to treat complex sleep-related breathing disorders unresponsive to CPAP. Based on the bilevel positive airway pressure platform (hardware) governed by propriety algorithms (software), advanced modes of noninvasive ventilation (NIV) were developed to address complex cardiorespiratory pathophysiology beyond OSA. This review summarizes key aspects of different bilevel PAP therapies (BPAP with/without backup rate, adaptive servoventilation, and volume-assured pressure support) to treat common sleep-related hypoventilation disorders, treatment-emergent central sleep apnea, and central sleep apnea syndromes.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13311-020-00955-x.Key Words: Bilevel positive airway pressure (BPAP), Adaptive servoventilation (ASV), Volume-assured pressure support (VAPS), Sleep-related hypoventilation, Treatment-emergent central apnea, Central sleep apnea     

Is obstructive sleep apnea a problem in Parkinson’s disease?

BackgroundParkinson’s disease (PD) is associated with sleep disorders and daytime sleepiness. Upper airway dysfunction in PD may promote obstructive sleep apnea. However, the frequency and clinical relevance of sleep-disordered breathing in PD remains unclear.MethodsSleep apnea symptoms, cardiovascular events and treatment were collected in 100 patients with PD (50 unselected, consecutive patients matched for age, sex and body mass index with 50 patients referred for sleepiness) and 50 in-hospital controls. The motor and cognitive status was evaluated in patients with PD. The 150 subjects underwent a video-polysomnography.ResultsSleep apnea (defined as an apnea–hypopnea index greater than 5) was less frequent in the PD group (27% patients, including 6% with mild, 11% with moderate and 10% with severe sleep apnea) than in the control group (40% in-hospital controls, p < 0.002). Sleep apnea was not associated with increased sleepiness, nocturia, depression, cognitive impairment and cardiovascular events in patients with PD. Sleep apnea was more frequent and severe in the most disabled patients. Patients with PD did not display sleep hypoventilation, stridor and abnormal central sleep apnea. In patients with REM sleep behavior disorders, snoring and obstructive sleep apnea occurred during REM sleep, although the chin muscle tone was maintained.ConclusionObstructive sleep apnea does not seem to be a clinically relevant issue in PD. Daytime sleepiness, nocturia and cognitive impairment are mostly caused by other, non-apneic mechanisms. The maintenance of chin muscle tone during REM sleep behavior disorder has no influence on the frequency of apneic events.     

Breathing control in neurological diseases

Control of ventilation depends on a brainstem neuronal network that controls activity of the motor neurons innervating the respiratory muscles. This network includes the pontine respiratory group and the dorsal and ventral respiratory groups in the medulla, which contain neurons that fire primarily during inspiration, post-inspiration, or expiration. The ventral respiratory group includes the pre-B?tzinger complex, which contains neurokinin-1 receptor immunoreactive neurons critical for respiratory rhythmogenesis. Structural and degenerative disorders affecting this network produce abnormalities of respiration, including sleep apnea and various patterns of dysrhythmic breathing, not infrequently associated with disturbances of cardiovagal and sympathetic vasomotor control. This emphasizes the important interactions between the respiratory and cardiovascular control networks in the medulla. Common disorders associated with impaired cardiorespiratory control include brainstem stroke or compression, syringobulbia, Chiari malformation, high cervical spinal cord injuries, and multiple system atrophy. This review focuses on the functional organization of the respiratory control network and common causes of impaired control of respiration. Received: 23 April 2002, Accepted: 5 September 2002 Correspondence to Dr. Martín A. Nogués     

Brain-stem compression in vertebrobasilar dolichoectasia. A multimodal electrophysiological study.

OBJECTIVE: To evaluate the effects of mechanical compression of the brain-stem in patients with vertebrobasilar dolichoectasia (VBD). METHODS: In the framework of a prospective, observational study that collected clinical and laboratory data in patients with VBD, we studied 20 patients with compression of the brain-stem due to ectatic, tortuous basilar or vertebral arteries. Patients with cerebral lesions other than small lacunae in the white matter of the cerebral hemispheres were excluded from the study. Patients underwent vestibular and auditory function testing, including brain-stem auditory evoked potentials (BAEPs), blink reflex (BR), somatosensory evoked potentials (SEPs), and motor evoked potentials (MEPs). RESULTS: Almost all of the patients complained of auditory or vestibular symptoms and none had symptoms or signs of impairment of long tracts or the facial and trigeminal nerves. The most consistent findings were BR abnormalities with prolongation of ipsilateral R1 latency in cases of compression of the pons (10/16) and prolongation of the R2 and R2c latencies with compression of the medulla oblongata (5/15). Subclinical impairment of corticospinal pathways was found in 13 out of 25 instances of compression, and this was more frequent with compression of the pons. Abnormal BAEPs or SEPs were less frequently encountered, and only in cases with compression of the pons. CONCLUSIONS: Neurovascular compression of the brain-stem, even with severe distortion, is seldom associated with overt clinical signs, whereas subclinical dysfunctions are relatively frequent. The central pathways of the BR and the corticospinal pathways are more susceptible to compression than acoustic and sensory pathways. BR, MEP and BAEP data provide a functional evaluation of the brain-stem and some cranial nerves, which is lacking in imaging studies. Functional investigations may be useful in the long-term management of these patients, since VBD may be progressive and surgical correction may be required at some stage.     

Stridor combined with other sleep breathing disorders in multiple system atrophy: a tailored treatment?

ObjectivesTo determine the frequency of sleep breathing disorders in multiple systemic atrophy (MSA, combining Parkinsonism, cerebellar syndrome, and dysautonomia) and evaluate the benefit/tolerance of various modes of ventilation.MethodsWe retrospectively analyzed 45 patients with MSA having undergone a videopolysomnography. Their sleep characteristics were compared to those of 45 patients with Parkinson's disease and 45 healthy controls, matched for age and sex. Patients with MSA received fixed continuous positive airway pressure (CPAP) when stridor was isolated, auto-adjusting CPAP when it was combined with obstructive sleep apnea, and adaptive servo-ventilation (ASV) when combined with central sleep apnea.ResultsHigher periodic leg movements index and more frequent REM sleep behavior disorder were observed in MSA patients, compared to patients with Parkinson's disease and healthy controls. In MSA, 28/45 (62.2%) patients had sleep breathing disorders, including (overlapping samples) stridor (n = 17, 38%), obstructive sleep apnea (n = 14, 31%), central sleep apnea (n = 4, 9%), and ataxic breathing (n = 1). Except for three initial refusals and two yet untreated patients, fixed CPAP (n = 9), auto-adjusting CPAP (n = 8) and ASV (n = 2) were well-tolerated (limited leaks and good compliance) and successfully controlled stridor plus sleep apnea. Treated patients had survival times similar to those of patients without any sleep breathing disorder.ConclusionIn this small group, tailored management of stridor in MSA as an independent issue or combined with obstructive and central sleep apnea, yields a survival similar to survival in patients without sleep breathing disorders.     

Auditory brainstem response (ABR) in congenital central alveolar hypoventilation

Auditory brainstem responses (ABRs) were studied in a child with congenital central alveolar hypoventilation showing marked depression of respiratory drive during sleep. During wakefulness and normoventilation no ABR abnormalities were found, either at the age of 14 months or five years. ABR recordings during sleep at 14 months of age showed marked wave V latency and wave I to wave V interpeak latency prolongation of about 0.4 ms both for periods of hypoventilation and normoxic hypercapnia. ABR findings of this and other studies carried out in sleep apneas are discussed with respect to brainstem dysfunction associated with varied sleep apnea syndromes.     

A giant fusiform basilar aneurysm treated by bilateral vertebral artery occlusion.

OBJECTIVE AND IMPORTANCE: Fusiform aneurysms of the vertebrobasilar arteries that progressively enlarge causing symptomatic brainstem compression are dangerous and their treatment is difficult. A patient with such an aneurysm treated successfully with staged, microsurgical occlusions of the proximal vertebral arteries is described, and the literature pertaining to this rare condition is briefly reviewed. CLINICAL PRESENTATION: A 48-year-old man with a fusiform basilar trunk aneurysm of uncertain etiology presented initially with transient ischemic attacks (TIAs) of the posterior circulation that ceased with anticoagulation. Four years later he presented again with progressive ataxia, dysphagia and dysphonia due to considerable enlargement of the aneurysm causing brainstem compression. INTERVENTION: Staged microsurgical vertebral artery occlusions proximal to the aneurysm were performed. The second (left) vertebral artery was clipped only after the patient passed its temporary occlusion with an endovascular test balloon. The aneurysm subsequently thrombosed, the distal basilar artery kept patent by a single (left) posterior communicating artery. The patient's clinical condition improved markedly over a number of months as the aneurysm mass atrophied. CONCLUSION: Giant vertebrobasilar aneurysms are rare but treacherous lesions, sometimes justifying aggressive management. Carefully selected patients with progressive and severe symptoms due to brainstem compression may tolerate proximal vertebral artery occlusions, provided there is adequate collateral flow to the basilar termination and all of its perforating branches.     

Vertebrobasilar artery territory infarction as an initial manifestation of systemic lupus erythematosus.

Cerebral infarction is a well-documented complication of systemic lupus erythematosus (SLE), that usually occurs several years after the diagnosis of SLE. To our knowledge, however, strokes associated with vertebrobasilar artery involvement were not reported to present as an initial manifestation of SLE. We report two patients, who presented with vertebrobasilar territory infarction as an initial manifestation of SLE. Patient 1 was a 16-year-old girl, who developed dysarthria and ataxia. MRI showed multiple infarcts in the pons, cerebellum and thalamus. Four-vessel cerebral angiography showed multifocal stenoses in the vertebral and basilar arteries with beaded appearance. Patient 2 was a 26-year-old woman, who developed headache associated with dysarthria, dizziness and ataxia. MRI showed multiple infarcts in the cerebellum, medulla, pons, midbrain and thalamus. Cerebral angiography revealed occlusion of both vertebral arteries at the first cervical vertebral level with non-visualization of the basilar artery. Both patients were diagnosed as having SLE supported by laboratory results. Although rare, posterior circulation stroke can present as an initial manifestation of SLE, which may be attributed to vasculitis or dissection in the vertebral/basilar artery.     

An easy adjustable method of ectatic vertebrobasilar artery transposition for microvascular decompression

Background

Microvascular decompression (MVD) of trigeminal neuralgia (TN) or hemifacial spasm (HFS) caused by an elongated, tortuous or enlarged vertebral or basilar artery has a higher rate of incomplete cure.

Objective

We used an easily applied and adjustable method of vertebrobasilar artery transposition and fixation to improve the immediate surgical outcome of MVD of TN or HFS due to compression by an ectatic vertebrobasilar artery system.

Methods

Vertebral or basilar artery transposition was performed using the vascular sling with a strip of unabsorbable dural tape. The vertebrobasilar artery-sling complex was then fixed to the dura over the petrous bone by aneurysm clip through the dural bridge. The direction and angle of traction on the vertebrobasilar artery was adjustable using different lengths of clip or the horizontal level of the dural bridge.

Results

The sling and clip fixation method has been applied in 7 cases of MVD associated with vertebral or basilar artery compression. All 3 patients with TN and one with HFS had total remission of symptoms right after the procedure; one patient was completely free of spasm within 1 week after MVD and one had achieved 80% improvement of spasm in his last clinical visit 3 months after MVD. There was no major surgical complication in these 7 patients. Surprisingly, refractory hypertension was unexpectedly cured in one patient with TN following the procedure.

Conclusion

The vertebrobasilar artery transposition and fixation method used in the present study provided surgeons an easy and adjustable way to perform MVD safely and effectively.     

Sudden bilateral hearing loss with vertigo due to vertebral artery occlusion]

We report a case of sudden bilateral hearing loss associated with an occlusion of the right vertebral artery. A 66-year-old man was admitted to hospital suffering from sudden onset vertigo, deafness, and vomiting. He could not walk due to truncal ataxia. There was positional nystagmus to the right; spontaneous and gaze-evoked nystagmus were absent. He had no facial nerve palsy, dysarthria, pyramidal tract signs, limb ataxia, and sensory impairment. Pure tone audiometry demonstrated a profound sensorineural deafness of both ears. A tentative diagnosis of sudden deafness was made. He was treated with intravenous infusion of corticosteroid; hearing loss of the left ear slightly improved. Cranial MR imaging demonstrated fresh small infarcts in the right cerebellar tonsil, the left cerebellar medulla, and the left middle cerebellar peduncle. MR angiography demonstrated an occlusion of the right vertebral artery. It is possible that reduced perfusion of the anterior inferior cerebellar arteries and internal auditory arteries on both sides resulted in multiple "border zone" infarcts and damage to the inner ear. Clinicians should be aware of the possibility of vertebrobasilar occlusive disease in case of sudden bilateral hearing impairment, even when brainstem or cerebellar signs are absent.     

Sleep apnea and hypoventilation syndrome associated with acquired nonprogressive dysautonomia: Clinical and pathological studies in a child

A 6-year-old girl had subacute onset of hypoventilation and apnea during sleep. Diffuse dysautonomic changes were identified, including dilated, nonreactive pupils, decreased tearing and sweating, and abnormal temperature and cardiovascular control. All-night polysomnographic studies revealed frequent obstructive and central sleep apnea episodes. Her serum contained cytotoxic antineuroblastoma immunoglobulins. She died two years later during sleep. The general pathological examination revealed a ganglioneuroma originating in the sympathetic ganglia. Abnormalities in the brain were confined to the brainstem and consisted of complete loss of neurons with severe fibrillary gliosis in the region of the Edinger-Westphal nuclei as well as loss of neurons with gliosis in the locus ceruleus and in the reticular formation bilaterally.     

Establishing a Role for Polysomnography in Hospitalized Children

BackgroundChildren with medical complexity have a high prevalence of sleep disorders. However, outpatient polysomnography to evaluate for these conditions may be difficult to perform because of lack of skilled nursing care. The aim of this study was to explore polysomnography indications in hospitalized children and assess its impact on patient care.MethodsData from 85 inpatient polysomnographies of 70 children hospitalized between March and December 2014 were retrospectively collected.ResultsSixty percent of patients were boys with ages 6.5 ± 6 years. Chronic respiratory failure was present in 33.8%, airway obstruction due to defects of the tracheobronchial tree or craniofacial abnormalities in 54.3%, neurological complications of the perinatal period in 22.9%, genetic syndromes and neurodegenerative disorders in 31.4%, congenital myopathies in 5.7%, metabolic diseases in 4.3% and congenital cyanotic heart defects in 4.3%. Indications for polysomnography included assessment of chronic pulmonary disease (60%), ventilator requirements (41.2%), apnea/desaturation (23.5%), and acute life-threatening events (1.2%). Abnormal results were found in 89.4%. The observed diagnosis was obstructive sleep apnea in 64.7%, signs of chronic lung disease in 34.1%, hypoventilation in 9.4%, periodic breathing in 3.5%, and periodic limb movement of sleep in 4.7%. The following interventions were performed: adjustment of ventilator parameters (45.8%), positive airway pressure initiation (24.7%), otorhinolaryngology referral (30.6%), supraglottoplasty (2.4%), tracheostomy decannulation (2.4%), and tracheostomy placement (3.5%). Nine patients had available follow-up polysomnograms, all showing improvement in sleep variables after adherence to recommended interventions.ConclusionsIn individuals with complex medical disorders, inpatient polysomnographies give invaluable information to guide immediate medical decision making and should be strongly considered if resources allow this.     

远外侧入路手术中椎动脉颅内段的显微解剖应用研究

目的 对椎动脉颅内段进行观察和测量,探讨远外侧人路手术中如何保护椎动脉颅内段和小脑后下动脉. 方法 手术显微镜下对20例带颈成人头颅标本模拟远外侧人路开颅,到达颈静脉孔区,显露椎动脉颅内段及其主要分支,观察其走形特点和形态,并测量相关数据. 结果椎动脉颅内段穿寰枕筋膜后在基底动脉沟与对侧椎动脉合成基底动脉.椎动脉与舌下神经关系密切,本组30侧椎动脉穿经舌下神经根的腹侧达桥脑延髓沟,8侧椎动脉穿舌下神经根丝之间,2侧椎动脉经舌下神经根丝的背侧.70%的椎动脉与舌下神经有接触,其中30%的椎动脉对舌下神经造成压迫.椎动脉颅内段主要分支有小脑后下动脉、脊髓前动脉、脑膜后动脉和一些穿动脉.小脑后下动脉是椎动脉最大的分支,本组全部发自椎动脉颅内段,行程多为袢状并同后组颅神经关系密切.小脑后下动脉的起始点因人而异,同一标本左右也不一致,大多起自椎动脉颅内段的中上1/3.本组未见小脑前下动脉起源于椎动脉.脊髓前动脉均起于双侧椎动脉的末段,在中线吻合成一单干,沿脊髓前正中裂迂曲下降供应脊髓. 结论 熟悉椎动脉颅内段及其分支的走形特点和解剖变异有助于远外侧入路到颈静脉孔区手术中识别和保护椎动脉颅内段的主要分支.     

Neurological basis of respiratory complications in achondroplasia

Evaluation of 32 individuals with achondroplasia revealed that 28% had a history of apnea and 22% had respiratory abnormalities on polysomnography. In those patients requiring posterior fossa decompressive surgery, improvement was noted in follow-up polysomnograms. Multimodality studies suggested that brainstem compression was common in achondroplasia and could account in part for the abnormal respiratory function in this disorder, including obstructive apnea, central apnea, and hypoxemia.     

Vertebral artery compression of the medulla

BACKGROUND: Intracranial arteries in the subarachnoid space may compress the brain parenchyma and cranial nerves. Most arterial compressive lesions have been attributed to dolichoectasia in the vertebral-basilar system, and prior reports have concentrated on the pressure effects of basilar artery ectasia. Much less is known about vertebral artery compression of the medulla. OBJECTIVE: To describe a series of patients with vertebral arteries compressing the medulla oblongata. DESIGN: Prospective case studies. SETTING: Tertiary care center. PATIENTS: Nine symptomatic patients, 4 men and 5 women, between the ages of 32 and 79 years. MAIN OUTCOME MEASURES: Clinical phenomena, radiographic findings, treatment, and outcomes. RESULTS: We found that compression most commonly occurs at the ventrolateral surface. The clinical features can be transient or permanent and are predominantly motor and cerebellar or vestibular, but a poor correlation exists between the clinical findings and the severity or extent of impingement. The vertebral arteries were angulated, tortuous, or dilated but not necessarily dolichoectatic to cause obvious indentation. Seven patients were treated with antiplatelets and anticoagulants or analgesics, whereas 2 underwent microvascular decompression, resulting in temporary or no relief. One surgical patient developed cranial nerve complications. Among the medically treated patients, none had progression of deficits, and those with single episodes had no recurrence of symptoms. CONCLUSION: This study is the largest collection, to our knowledge, of patients with medullary vascular compression. Further studies are needed to estimate its frequency, natural course, and preferred management.     

Spectrum of polysomnographic abnormalities in children with epilepsy

This study sought to evaluate polysomnographic abnormalities in a cohort of 40 children with epilepsy who underwent a sleep study because of various sleep complaints. Retrospective analyses included polysomnographic variables, antiepileptic drugs, type of epilepsy, and seizure control. The subgroup with epilepsy and obstructive sleep apnea syndrome was compared with 11 children who manifested uncomplicated obstructive sleep apnea syndrome. Thirty-three patients (83%) exhibited snoring (42.5%), sleep-disordered breathing (obstructive hypoventilation, 12.5%; obstructive sleep apnea, 20%; and upper-airway resistance syndrome, 7.5%), or periodic limb movements of sleep (10%). Children with poor seizure control demonstrated significantly lower sleep efficiency, a higher arousal index, and a higher percentage of rapid-eye-movement sleep compared with children who were seizure-free or exhibited good seizure control. Patients with epilepsy and obstructive sleep apnea had significantly a higher body mass index, longer sleep latency, a higher arousal index, and a lower apnea-hypopnea index, but significantly more severe desaturation compared with patients with uncomplicated obstructive sleep apnea. A significant proportion of children with epilepsy referred for polysomnography with diverse sleep problems manifest sleep-disordered breathing, including obstructive sleep apnea syndrome.     

Canadian Association of Neuroscience Review: Respiratory control and behavior in humans: lessons from imaging and experiments of nature

The purpose of this review is to demonstrate that respiration is a complex behavior comprising both brainstem autonomic control and supramedullary influences, including volition. Whereas some fundamental mechanisms had to be established using animal models, this review focuses on clinical cases and physiological studies in humans to illustrate normal and abnormal respiratory behavior. To summarize, central respiratory drive is generated in the rostroventrolateral medulla, and transmitted to both the upper airway and to the main and accessory respiratory muscles. Afferent feedback is provided from lung and muscle mechnoreceptors, peripheral carotid and aortic chemoreceptors, and multiple central chemoreceptors. Supramedullary regions, including cortex and subcortex, modulate or initiate breathing with volition, emotion and at the onset of exercise. Autonomic breathing control can be perturbed by brainstem pathology including space occupying lesions, compression, congenital central hypoventilation syndrome and sudden infant death syndrome. Sleep-wake states are important in regulating breathing. Thus, respiratory control abnormalities are most often evident during sleep, or during transition from sleep to wakefulness. Previously undiagnosed structural brainstem pathology may be revealed by abnormal breathing during sleep. Ondine's curse and 'the locked-in syndrome' serve to distinguish brainstem from supramedullary regulatory mechanisms in humans: The former comprises loss of autonomic respiratory control and requires volitional breathing for survival, and the latter entails loss of corticospinal or corticobulbar tracts required for volitional breathing, but preserves autonomic respiratory control.     

Cardiovascular and respiratory consequences of bilateral involvement of the medullary intermediate reticular formation in syringobulbia

We studied five patients with clinical and radiological evidence of syringobulbia (SB) to determine whether the distribution of lesions in relationship to the cardiorespiratory control networks in the medullary intermediate reticular zone (IRt) correlates with the presence of abnormalities in autonomic cardiovascular and respiratory control in these patients. All patients underwent high resolution MRI to characterize the size, volume and distribution of the SB lesions, cardiovascular autonomic function testing and polysomnography. One patient with bilateral IRt involvement at both the rostral and caudal medulla had orthostatic hypotension (OH), absent HR_DB, abnormal Valsalva ratio, exaggerated fall of BP during phase II and absent phase IV during VM, and a dramatic fall of BP during head up tilt; this patient also had severe obstructive sleep apnea (OSA) and exhibited BP drops during each respiratory effort. A second patient, with bilateral IRt involvement restricted to the caudal medulla, had less severe cardiovascular autonomic dysfunction but also exhibited severe OSA. The other three patients had small SB cavities sparing the IRt and had sleep apnea but no autonomic dysfunction. Autonomic dysfunction could not be related to the size of the syrinx or the degree of atrophy in the cervical spinal cord in any of the five patients. Bilateral involvement of the IRt by SB produces cardiovascular autonomic failure and sleep apnea. In patients with more restricted lesions, autonomic and respiratory dysfunction may be dissociated. Clinico-radiological correlations using high resolution MRI assessment of medullary lesions can provide insight into the central organization of cardiovascular and respiratory control in humans. Received: 6 August 2002, Accepted: 26 September 2002 Correspondence to Dr. Martín Nogués