Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pulmonary hypertension without any cardiovascular malformation was diagnosed by heart catheterization in a 4 year old girl with trisomy 21. A suspected obstructive sleep apnea syndrome was confirmed by polysomnography which revealed numerous obstructive apneas and hypopneas (apnea-index 23/h) with marked oxygen desaturation and a disturbed sleep pattern. Three months after adenotonsillectomy the mother reported her daughter having a quiet sleep without snoring. Polysomnography did not show any apnea nor any oxygen desaturation below 90%. A decrease of the pulmonary artery pressure was documented. Facial dysmorphias and muscle hypotonia predispose patients with trisomy 21 to obstructive sleep apnea, especially if hypertrophy of tonsills and adenoids coexist. Frequent arousals and hypoxia during sleep can result in failure to thrive and pulmonary hypertension. These consequences can be prevented by early diagnosis and treatment.
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PMID:[Obstructive sleep apnea syndrome in a child with trisomy 21]. 215 Aug 74

Obstructive sleep apnea is the underlying cause of a variety of pediatric maladies, including pulmonary hypertension and failure to thrive. In children, unlike adults, obstruction secondary to lymphoid hyperplasia is often encountered; adenotonsillectomy restores airway patency. Patients who fail this procedure, such as children with cerebral palsy and associated muscular hypotonia, may face tracheotomies. We report on 10 pediatric patients with severe mental insufficiency and obstructive sleep apnea in whom palatal hypotonicity and lack of adenotonsillar hypertrophy was identified. Uvulopalatopharyngoplasty was performed in conjunction with adenotonsillectomy to enlarge the diameter of the nasopharyngeal inlet with successful resolution of the obstructive symptoms in eight patients. The remaining two children required more surgery. This procedure is presented as a possible alternative to tracheotomy in selected patients.
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PMID:Surgical therapy of obstructive sleep apnea in children with severe mental insufficiency. 232 9

Snoring (inspiratory noise related to narrowing of the upper airways) and obstructive sleep apnea (OSA) are two aspects of the same basic disorder: sleep-related narrowing of the upper airways. Patients with OSA have been heavy snorers for years and even decades. Lying supine induces snoring and mild OSA in heavy snorers due to hypotonia of pharyngeal dilator muscles, decreasing waking neural drive and recumbent position, which contribute to functional narrowing of the upper airways. Functional factors in obstruction during sleep include (a) respiratory instability prevalent in the male sex, (b) increased extensibility of the lax tissues surrounding the oro-pharynx and (c) deficient contraction of the pharyngeal dilator muscles during inspiration. These effects are worsened by sleep deprivation and fragmentation, alcohol intake and sedatives. Anatomical factors favoring narrowing of the upper airways in snorers and OSA patients are (a) abnormally narrow airways as well as (b) increased thickness and length of the velum palatinum in snorers and OSA patients, (c) tonsillar and adenoid hypertrophy, micro- and retrognathia, and nasal insufficiency, (d) obesity with fat infiltration of the soft tissues and in particular of the oropharynx, (e) relatively open mandibular angle, hypertrophy and thickness of the tongue, and lowered hyoid bone (as shown by MRI imaging). It is possible that many anatomical abnormalities may be the consequence of snoring and obstructive apnea. During NREM sleep the ineffective inspiratory efforts progressively increase with worsening hypoxia and hypercapnia. The upper airways become patent again when arousal induces phasic activation of the dilator pharyngeal muscles.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pathogenic aspects of snoring and obstructive apnea syndrome. 318 70

Snoring usually is trivial and unimportant, but it can turn into a social or medical problem. Obesity, hypertension and heart disease are more frequent among snorers than among nonsnorers, and especially snorers with hypersomnia during the day are at risk. Hypersomnia in association with snoring usually signifies obstructive sleep apnea. Increased resistance in the upper airways, together with negative inspiratory pharyngeal pressure and muscular hypotonia during deep non-REM and REM sleep, lead to collapse of the pharynx, hypoxia and hypercapnia. Only after arousal from sleep does muscle tone return, pharyngeal obstruction reopen and airflow resume. Since this process can occur 300 or 400 times a night, repetitive alveolar hypoventilation leads to pulmonary-arterial hypertension and cor pulmonale, and the repetitive sympathetic activations can cause systemic hypertension or serious cardiac arrhythmias. The countless arousals deprive the sufferer of deep non-REM and REM sleep and their consequence is sleep fragmentation. The symptoms are excessive daytime sleepiness, intellectual deterioration and personality and behavioral changes. Oronasomaxillofacial, endocrine and neuromuscular anomalies and diseases predispose to sleep apnea, and alcohol or CNS-depressant drugs can favour its occurrence. Diagnosis is made by nighttime oxymetry, and if this is abnormal, by polysomnography. After polysomnography it is possible to distinguish between obstructive and nonobstructive sleep apnea, and the decisions for an adequate treatment can be made.
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PMID:[Dangerous snoring. Sleep-apnea syndrome]. 331 92

To further elucidate the pathogenesis of obstructive sleep apnea (OSA), we recorded sternocleidomastoid (SCM), genioglossal (GG), and abdominal (ABD) muscle activity, using surface electromyograms (EMGs), during 45 polygraphic studies in 39 children referred for possible OSA. For each muscle, an index of electromyographic (EMG) activity was developed, allowing an interpatient regression analysis of EMG amplitude versus highest PACO2 and lowest transcutaneous O2 tension (tcPO2) during sleep. Phasic inspiratory SCM activity was present during more than 50% of sleep time in 16 of 20 patients with OSA versus only 2 of 15 patients without OSA; SCM EMG activity increased with increasing PACO2 (r = 0.45, p less than 0.02) and decreasing tcPO2 (r = 0.51, p less than 0.01). Phasic inspiratory GG activity was present during more than 50% of sleep time in 15 of 18 patients with OSA versus none of 4 without OSA; GG EMG activity increased with increasing PACO2 (r = 0.51, p less than 0.05) and with decreasing tcPO2 (r = 0.60, p less than 0.02). Phasic expiratory ABD activity was present during more than 50% of sleep time in 10 to 20 patients with OSA versus 1 of 12 patients without OSA. These findings suggest the following conclusions: (1) inspiratory (SCM), airway-maintaining (GG), and expiratory (ABD) muscles contract during sleep-related partial airway obstruction in children; (2) augmented GG activity during periods of sleep-related partial airway obstruction suggests that pediatric OSA involves pathogenic mechanisms other than GG hypotonia; (3) expiratory ABD muscle activity suggests that some children with OSA have increased expiratory, as well as inspiratory, airway resistance during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Electromyographic study of some accessory muscles of respiration in children with obstructive sleep apnea. 623 78

Six patients with obstructive sleep apnea were studied with our system of simultaneous video recording of the polysomnographic record and the endoscopic image from the pharyngeal airway. Preoperative and postoperative recordings were made during sleep in each patient. Tracheotomized patients recreated their preoperative laryngeal inlet obstruction and its immediate cessation by alternately opening and closing the tracheotomy tube. This demonstration coupled with the physical examination findings of "disproportionate anatomy," leads to the determination that the mechanism of obstructive sleep apnea is twofold: (1) an underlying CNS propensity to hypotonia of pharyngeal musculature during sleep and (2) either an isolated obstructive upper airway lesion or a combination of alterations in normal relationships within the upper airway that cause a passive narrowing of the upper airway. This combination of altered relationships is collectively referred to as "disproportionate anatomy."
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PMID:Videoendoscopic determination of the mechanism of obstruction in obstructive sleep apnea. 642 64

Both muscular hypotonia and anatomic abnormalities have been implicated in the pathogenesis of the obstructive sleep apnea syndrome (OSAS). The upper airways of 25 patients with OSAS were evaluated to determine potential sites of obstruction. Significant airway compromise was found in all patients with some patients having multiple sites of airway narrowing.
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PMID:Anatomic abnormalities in obstructive sleep apnea. 714 39

Polygraphic recordings demonstrated complex tongue movements as unusual phasic phenomena during rapid-eye-movement (REM) sleep in patients with narcolepsy, sleep apnea syndrome, or posterior fossa lesions, and in normal controls. These tongue movements may counteract posterior displacement of the tongue to prevent obstructive sleep apnea, which may otherwise occur in REM sleep because of genioglossal hypotonia. Hypotonia affected not only the genioglossus but also other muscles innervated by pontomedullary neurons during non-REM-sleep-related apnea in patients with sleep apnea syndrome.
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PMID:Phasic tongue movements in human rapid eye-movement sleep. 718 42

Based on previous studies, we hypothesized that the pharynx collapses at multiple sites in most patients with obstructive sleep apnea (OSA). The purpose of this study was to document, in a population of apneic subjects, the site(s) of narrowing and closing pressure of the hypotonic pharynx. We endoscopically examined the pharynx in 45 OSA patients during sleep while they received nasal continuous positive airway pressure (CPAP), which produces hypotonia of pharyngeal muscles. Intrapharyngeal images and pressures were obtained at the end of expiration during single-breath tests (SBT). The fractional narrowing (FN) of each pharyngeal segment (nasopharynx, oropharynx, and hypopharynx) was calculated as the relative change in area when nasal airway pressure was reduced from a pressure that held the pharynx fully distended to the pressure at which the airway closed. The frequency distribution of FN for the nasopharynx was skewed toward larger values, and the frequency was relatively evenly distributed for the oropharynx and hypopharynx. A site having FN greater than 0.75 was defined as a site of primary narrowing, and a site showing FN 0.25 to 0.75 was defined as a site of secondary narrowing. The nasopharynx was a site of primary narrowing in 80% of patients, and two or more sites of narrowing were commonly observed (82%). Four categories of combined narrowing were identified: (1) primary narrowing only at the nasopharynx (18%); (2) primary narrowing at the nasopharynx plus other sites of secondary narrowing (40%); (3) primary narrowing at the nasopharynx plus other sites of primary narrowing (22%); and (4) other patterns (20%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pharyngeal narrowing and closing pressures in patients with obstructive sleep apnea. 836 30

Obstructive sleep apnea is a common breathing problem that results in recurrent episodes of nighttime hypoxemia, hypercapnia, bradytachycardia, and hypertension, as well as sleep disturbance and daytime hypersomnolence. The obstruction is located in the oropharynx and is caused by hypotonia of the pharyngeal dilator muscles. In this paper, the various mechanisms affecting motor output to the upper airway muscles are reviewed. In particular, the respiratory function of the pharyngeal dilator muscles, the various reflex mechanisms underlying their control, and the effects of sleep on these mechanisms are discussed. The literature relevant to the central neuronal circuits and neurotransmitters that may be involved in the state-dependent activity of the pharyngeal dilator muscles is also reviewed. In addition to an examination of these basic mechanisms, consideration is given throughout this review as to how these mechanisms may relate to the normal control of pharyngeal patency awake and asleep and how they may be involved in the pathogenesis of obstructive sleep apnea.
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PMID:Motor control of the pharyngeal musculature and implications for the pathogenesis of obstructive sleep apnea. 908 93


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