Obstructive sleep apnea

The high prevalence of obstructive sleep apnea (OSA) has only recently been appreciated, in part because the symptoms and signs of chronic sleep disruption are often overlooked in spite of their debilitating consequences. They typically develop insidiously during a period of years. We now know that the lives of millions of people each year are significantly impaired by the sequelae of OSA. Many of these patients go unrecognized, with tremendous medical and economic consequences for individual patients and for society. Evidence indicates that chronic, heavy snoring may be associated with increased long-term cardiovascular and neurophysiologic morbidity. Therefore considerable interest lies in the study of the epidemiology and the natural history of these related disorders. The fundamental problem in OSA is the periodic collapse of the pharyngeal airway during sleep. The pathophysiology of this phenomenon is reviewed in some detail. During apneas caused by obstruction, airflow is impeded by the collapsed pharynx in spite of continued effort to breathe. This causes progressive asphyxia, which increasingly stimulates breathing efforts against the collapsed airway, typically until the person is awakened. Hypopneas predominate in some patients and are caused by partial pharyngeal collapse. The clinical sequelae of OSA relate to the cumulative effects of exposure to periodic asphyxia and to sleep fragmentation caused by apneas and hypopneas. Some patients with frequent, brief apneas and hypopneas and normal underlying cardiopulmonary function may have considerable sleep disruption without much exposure to nocturnal hypoxia. Patients with sleep apnea often have excessive daytime sleepiness. As the disorder progresses, sleepiness becomes increasingly irresistible and dangerous, and patients develop cognitive dysfunction, inability to concentrate, memory and judgment impairment, irritability, and depression. These problems may lead to family and social problems and job loss. Cardiac and vascular morbidity in OSA may include systemic hypertension, cardiac arrhythmias, pulmonary hypertension, cor pulmonale, left ventricular dysfunction, stroke, and sudden death. The challenge for the clinician is to routinely consider the diagnosis and to incorporate several basic questions in the historical review of systems regarding daytime or inappropriate sleepiness. The diagnosis of OSA is made with polysomnography, and the decision to treat is based on an overall assessment of the severity of sleep-disordered breathing, sleep fragmentation, and associated clinical sequelae. The therapeutic options for the management of OSA are reviewed. Recognition and appropriate treatment of OSA and related disorders will often significantly enhance the patient's quality of life, overall health, productivity, and safety on the highways.     

Obstructive sleep apnea in Schwartz-Jampel syndrome

Schwartz-Jampel syndrome (SJS) is a rare entity characterized by myotonia and skeletal abnormalities. Death and respiratory distress have previously been reported in newborns and young children with SJS. We describe a patient with SJS and snoring in whom polysomnography demonstrated obstructive sleep apnea and hypoxia. Although tonsillectomy with laser palatoplasty significantly widened the oropharyngeal introitus, obstructive sleep apnea persisted. Ultimate improvement occurred only after the institution of home therapy with bi-level positive airway pressure during the night. We also discuss the specific structural and neuromuscular features of SJS that may be responsible for upper airway obstruction.     

Obstructive sleep apnea and hypertension. Diagnostic procedure--exclusion of risk factors--nCPAP treatment

Obstructive sleep apnea is a common illness with an estimated prevalence of 3% in the adult population. At least 50% of patients with obstructive sleep apnea also have hypertension, while approximately 30% of hypertensives also suffer from obstructive sleep apnea. This high level of coincidence together with the results of recent epidemiological studies and the frequent observation that hypertension may reverse under effective treatment for obstructive sleep apnea strongly suggest that this sleep disorder is an independent causal factor in the development of hypertension. The present paper considers the association of sleep apnea and hypertension and the resulting diagnostic and therapeutic consequences.     

Nocturnal pulmonary hypertension in an elderly patient with sleep apnea syndrome

We report a case of sleep apnea syndrome (SAS) with nocturnal pulmonary hypertension (NPH) in a 71-year-old man suffering from dyspnea during sleep. Severe snoring at night and daytime sleepiness were noticed before admission by his wife. Nocturnal oxygen desaturation (NOD) was documented with a pulse oximeter and severe sleep apnea syndrome was diagnosed on the basis of results of respiratory inductive plethysmography, an apnea index (AI) > 20, minimum SpO2 56%. NPH was diagnosed by Swan-Ganz catheter. The levels of NPH were severe. Elevation of systolic pulmonary arterial pressure (PAP) above 40 mmHg was observed 137 episodes at night. Both NPH and NOD were improved by 1 L/min of nasal oxygen therapy. A number of episodes of systolic PAP above 40 mmHg with oxygen therapy was 55 episodes. Peak mean PAP was 36 mmHg in room air vs 33 mmHg in oxygen therapy. Minimum SpO2 with oxygen therapy was improved to 69%. Total time of SpO2 < 90% at night was 153 minutes in room air vs 37 minutes in oxygen therapy. In this case, NPH and NOD due to severe SAS were remarkably improved by oxygen therapy.     

Obstructive sleep apnea and related disorders

OSAS, a common cause of disrupted sleep and EDS, result from repetitive closure of the upper airway during sleep. It probably represents the most severe syndrome related to obstruction of the upper airway; less severe forms include UARS, a syndrome characterized by the need for increased effort to breath but no prominent apneas or hypopneas, and primary snoring. Initial clues to the presence of OSAS and related disorders are derived from the history and include loud snoring, EDS or insomnia, and witnessed apneas. Some patients, especially women, may complain mostly of tiredness or fatigue, and children may present with behavioral abnormalities. Obesity, a large neck circumference, and a crowded oropharynx are common on physical examination. Nonobese patients, in particular, often have retrognathia, a high-arched narrow palate, macroglossia, enlarged tonsils, temporomandibular joint abnormalities, or chronic nasal obstruction. The clinical suspicion of obstructed nocturnal breathing is confirmed by overnight polysomnography, and an MSLT may be used to assess sleepiness. Esophageal manometry during polysomnography facilitates diagnosis of UARS. Treatment most commonly consists of nasal CPAP or BPAP, although problems with compliance make surgical treatment preferable in some cases. Although UPPP eliminates sleep apnea only in a minority of patients, combining UPPP with maxillofacial procedures appears to improve outcomes. Other treatments such as the use of dental appliances or medications, weight loss, and positional therapy may be useful as adjunctive therapy for moderate to severe OSAS or as primary treatments for UARS or mild OSAS.     

Obstructive sleep apnea syndrome and bronchial hyperreactivity

Cyclosporin A (CsA) inhibits the development of mature thymocytes from their CD4+ CD8+ precursors, but may allow autoreactive cells to mature. Using 3-color flow cytometry, we have followed the progressive development of thymocytes, including potentially autoreactive cells, during CsA treatment. Numbers of CD4+ CD8+ CD3high thymocytes dropped immediately, suggesting that the generation of these mature thymocyte precursors, normally dependent upon positive selection, was inhibited by CsA. Numbers of CD4+ CD8- thymocytes also declined rapidly, but CD4 - CD8+ thymocytes were unaffected for 2 days, suggesting that the mature single-positive subsets are not symmetrically derived from a common GsA-sensitive precursor. An exceptional subset of CD8 SP thymocytes, expressing CD45RA, did not respond to CsA for about 10 days, indicating that they are distantly derived from a CsA-sensitive precursor. Apoptosis of TCR-V beta 3 + thymocytes caused by Mtv-6, quantified according to the down-regulation of CD4 and CD8 on immature thymocytes, was partially inhibited by CsA, to maximal effect within 24 hours. This did not, however, facilitate their development into mature thymocytes.     

Obstructive sleep apnea treatment with dental appliance

The case of a 40-year-old male patient with obstructive sleep apnea syndrome (OSAS) is reported, with emphasis on treatment with a dental appliance. This therapeutic approach, which has been focused on recent research, has as its objective, the posturing of the mandibule and, consequently, the tongue more anteriorly, thus in turn leading to an increase in the posterior oropharyngeal airway space (PAS). Cephalometry contributed determining in this case whereby enlargement limits were observed in the PAS with mandibular displacement. Clinical and polysomnographic controls showed subjective reduction of the excessive daytime sleepiness and objective decrease in apneas intensity to normal limits. Eight months follow-up evidenced the steady improvement.     

Obstructive sleep apnea in patients with coronary heart disease

Patients with obstructive sleep apnea have an increased cardiovascular morbidity and mortality, those with co-existent coronary artery disease being particularly at risk. The object of our study was to evaluate the prevalence of obstructive sleep apnea in patients with coronary artery disease. 153 patients (117 men, 36 women) with verified coronary artery disease were given a highly sensitive standardized questionnaire. The 59 patients with pathological results were then checked with a 6-channel non-laboratory monitoring system. 22.2% of all patients had a respiratory disturbance index (RDI) above 5/h. and 14.4% above 10/h. 13.3% had a pathological RDI and additionally suffered from excessive daytime sleepiness. Patients with coronary artery disease have a high prevalence of obstructive sleep apnea and should consequently be screened for this sleep-related breathing disorder.     

Obstructive sleep apnea due to endogenous testosterone production in a woman

Quantitative buffy coat (QBC) analysis has been reported to have a high degree of methodical sensitivity in the detection of human filariasis. This study was conducted to evaluate its usefulness in the diagnosis of filariasis using a Dirofilaria immitis/dog model. By necropsy of 244 stray dogs, 40.6% of the animals were found to harbor 1-58 worms of D. immitis (mean 6.5 +/- 8.4 worms/infected dog). The QBC analysis and thick blood smear (TBS) method detected microfilaremia in 31.6% and 21.3% of these dogs, respectively. The results of these two methods were highly correlated with the presence of bisexual worms in the dogs. The QBC analysis was more sensitive (55% versus 39%) and efficient (79% versus 72%) than the conventional TBS method. However, accurate speciation of the microfilariae was impossible using the QBC analysis. Although this technique is more sensitive, simpler, and less time-consuming and does not require as much skill or experience in comparison with the conventional TBS method, the failure in speciation of the parasites may limit its usefulness.     

Obstructive sleep apnea. Warding off the sometimes dire consequences

Obstructive sleep apnea (occlusion of the upper airway despite continued respiratory muscle activity) is accompanied by increased morbidity and mortality from cardiovascular and cerebrovascular disease. Daytime sleepiness due to the disorder may also be a factor in a higher incidence of automobile accidents in these patients. An overnight polysomnogram is used to confirm the diagnosis and assess severity of physiologic disturbances. Initially, simple measures, such as avoidance of alcohol and sedatives before bedtime and sleeping on the side rather than the back, may be tried. Nasal continuous positive airway pressure is considered first-line therapy, and compliance can be improved by education and counseling of the patient. Uvulopalatopharyngoplasty is beneficial in only 50% of patients. Tracheostomy gives the most consistent long-term benefit but is accompanied by significant emotional morbidity.     

Pulmonary hypertension in patients with obstructive sleep apnea syndrome

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is associated with an increased cardiovascular morbidity, including pulmonary hypertension. Little is known about factors influencing the degree of pulmonary hypertension and left ventricular dysfunction in patients with OSAS, especially in the absence of concomitant lung disease. METHODS: Right heart catheterization, arterial blood gas analysis, and pulmonary function tests were performed in 92 consecutive patients (81 men and 11 women; mean +/- SD age, 53.1 +/- 11.0 years) with polysomnographically verified OSAS, in whom clinically significant lung disease was excluded. RESULTS: Eighteen patients (20%) had mild pulmonary hypertension; 8 (44%) of them also had increased pulmonary capillary wedge pressures (Ppew). Left ventricular dysfunction was associated with arterial hypertension. Only Ppcw (r = 0.51; P < .001) and the percentage of time during sleep spent with an oxygen saturation below 90% (as an indicator of the severity of OSAS) (r = 0.34; P = .003) were significantly and independently associated with pulmonary artery pressure. CONCLUSIONS: Obstructive sleep apnea syndrome can cause mild pulmonary hypertension, even in the absence of pulmonary disease. In these patients, pulmonary hypertension is of the postcapillary type, or-in patients with normal left ventricular function-strongly related to the severity of OSAS. Our findings indicate that OSAS may constitute an important, and independent, risk factor for pulmonary hypertension.     

Isoxsuprine in hypertension during pregnancy

AIM: Direct cytokine modulation may benefit patients with inflammatory bowel disease. PATIENTS: Subcutaneous interferon gamma (1.5 microgram/kg) was given three times a week in an open pilot study to four patients with active Crohn's disease unresponsive to standard immunosuppressive drug treatment. RESULTS: In one patient, the C-reactive protein and Crohn's disease activity index returned to normal and the patient became asymptomatic. The other three patients did not complete the 12-week treatment course, one because of drug failure, one because of drug side effects, and one because of incidental disease. However, the Crohn's disease activity index fell substantially and the C-reactive protein returned to normal in three out of four patients. CONCLUSIONS: Interferon gamma may have a role in the treatment of resistant patients, but only if the dose can be optimised and drug side effects overcome.     

Hemodynamics in sleep-induced apnea. Studies during wakefulness and sleep

Twelve patients with predominantly obstructive type sleep apnea underwent cardiac catheterization, hemodynamic monitoring, and arterial blood gas analysis during wakefulness and sleep. Abnormalities during wakefulness included systemic hypertension in four of 12, exercise-induced mild pulmonary hypertension in five of 12, and alveolar hypoventilation in one. During sleep nine patients had cyclic elevations of arterial pressure with each apneic episode, exceeding 200 mm Hg systolic in three of 12. Pulmonary artery pressures increased in 10 of 12, exceeding 60 mm Hg systolic in five. Marked degrees of hypoxemia (arterial P02, less than 50 mm Hg in eight of 12) and moderate hypercapnia with respiratory acidosis were associated with these hemodynamic changes. Cyclic upper airway obstruction during sleep may result in hypercapnia, acidosis, and pronounced hypoxemia, which can lead to hemodynamic abnormalities during sleep. Sustained pulmonary hypertension and possibly systemic hypertension may follow. Tracheostomy is an effective therapy and is recommended to symptomatic patients who have predominantly obstructive apnea but no relievable anatomic cause of upper airway obstruction.