Obstructive Sleep-Disordered Breathing Is More Common than Central in Mild Familial Dysautonomia

Sleep apnoea in the elderly: a great challenge for the future

Due in part to overall improvements in health, the population of elderly individuals is increasing rapidly. Similarly, obstructive sleep apnoea (OSA) is both gaining increased recognition and also increasing due to the worldwide obesity epidemic. The overlap of OSA and aging is large, but there is strong plausibility for causation in both directions: OSA is associated with pathological processes that may accelerate aging and aging related processes; aging may cause physical and neurological changes that predispose to obstructive (and central) apnoea. In addition, the common symptoms (e.g. excessive daytime somnolence, defects in memory and cognition), possible physiological consequences of OSA (e.g. accelerated cardiovascular and cerebrovascular atherosclerosis), and changes in metabolic and inflammatory markers overlap with the symptoms and associated conditions seen in aging. There is also the possibility of synergy in the effects of these symptoms and conditions on quality of life, as well as a need to separate treatable consequences of OSA from age-related complaints. Taken together, the above make it essential to review the interaction of OSA and aging, both proven and suspected. The present review examines some aspects of what is known and points to the need for further investigation of the relationships, given the large number of potentially affected subjects.

A contemporary review of obstructive sleep apnea

PURPOSE OF REVIEW

This review provides a contemporary review of sleep apnea with emphasis on definitions, epidemiology, and consequences.

RECENT FINDINGS

Amyloid β-42 is one of the main peptides forming amyloid plaques in the brains of Alzheimer patients. Poorer sleep quality and shorter sleep duration have been associated with a higher amyloid burden. Decreased sleep time in the elderly is a precipitating factor in amyloid retention. Studies have shown that the dysregulation of the homeostatic balance of the major inhibitory and excitatory amino acid neurotransmitter systems of gamma-aminobutyric acid (GABA) and glutamate play a role in sleep disordered breathing (SDB).

SUMMARY

Untreated sleep disordered breathing (obstructive sleep apnea and/or central sleep apnea) are an important cause of medical mortality and morbidity. OSA is characterized by recurrent episodes of partial or complete collapse of the upper airway during sleep followed by hypoxia and sympathetic activation. Apneic events are terminated by arousal, followed by increases in pulse and blood pressure, and re-oxygenation and the release of inflammatory factors. Individuals with OSA have an increased risk of developing atrial fibrillation. Hypoxemia and poor sleep quality because of OSA increase the risk of cognitive decline in the elderly.

The Longest Obstructive Apnea You Have Ever Seen: A Patient With New-Onset Autonomic Dysfunction

ABSTRACT

Autonomic dysfunction (AD) has been associated with both obstructive and central sleep apneas. Several mechanisms have been proposed for the emergence of sleep apnea in AD, which include impaired sensory input, compromised local reflexes, and altered central processing. We present a case of a 70-year-old woman who had experienced cardiac arrest four times related to hypoxic events due to the apparent sudden onset of obstructive sleep apnea (OSA) in the setting of AD. The episodes of OSA were profoundly prolonged and a tracheostomy was ultimately needed due to the inability of positive airway pressure therapy with supplemental oxygen to control events. We think that this case is unique because of the extreme duration of the obstructive apneas (up to 233.8 seconds), which almost certainly reflects lack of protective autonomic control in terminating these events.

Prevalence and characteristics of sleep-disordered breathing in familial dysautonomia

OBJECTIVE

Familial dysautonomia (FD) is an autosomal recessive disorder characterized by impaired development of sensory and afferent autonomic nerves. Untreated sleep-disordered breathing (SDB) has been reported to increase the risk of sudden unexpected death in FD. We aimed to describe the prevalence and characteristics of SDB in FD.

PATIENTS/METHODS

Seventy-five patients with FD (20 adults and 55 children) underwent in-lab polysomnography, including peripheral capillary oxygen saturation (SpO2) and end-tidal capnography (EtCO2) measurements. A t-test and Spearman's correlation analysis were performed to evaluate the impact of age on sleep, occurrence of apneas, SpO2 and EtCO2 levels; and to determine the relationship between apneas and SpO2/EtCO2 measurements during different sleep stages.

RESULTS

Overall, 85% of adults and 91% of pediatric patients had some degree of SDB. Obstructive sleep apneas were more severe in adults (8.5 events/h in adults vs. 3.5 events/h in children, p = 0.04), whereas central apneas were more severe (10.8 vs. 2.8 events/h, p = 0.04) and frequent (61.8% vs. 45%, p = 0.017) in children. Overall, a higher apnea-hypopnea index was associated with increased severity of hypoxia and hypoventilation, although in a significant fraction of patients (67% and 46%), hypoxemia and hypoventilation occurred independent of apneas.

CONCLUSION

Most adult and pediatric patients with FD suffer from some degree of SDB. There was a differential effect of age in the pattern of SDB observed. In some FD patients, hypoventilation and hypoxia occurred independently of apneas. Therefore, we recommend including EtCO2 monitoring during polysomnography in all patients with FD to detect SDB.