A restorative good night sleep makes us feel better. We feel more alert, more energetic, happier, and better able to function following a good night of sleep.
However, for patients with breathing problems during sleep, a night of sleep may not leave them feeling refreshed in the morning. Poor quality of sleep leaves patients feeling perpetually tired, ruins concentration, and a leads to the over-whelming urge to take a nap during the day.
For patients with familial dysautonomia (FD) – a rare Jewish genetic disease – sleep can be a very dangerous time. Patients with FD have long pauses in breathing at night and lack the ability to sense when they stop breathing. Therefore, rather than waking up when they stop breathing (which is the normal mechanism in people without FD), a high number of patients with FD can die unexpectedly in their sleep, and the risk of dying increases not using non-invasive ventilation at night (CPAP or BiPAP).
Abnormalities in the control of breathing at night can be studied with polysomnography (a sleep study), a non-invasive test. Patients sleep with electrode sensors over the head to track brainwaves and sensors over the chest to monitor muscle activity as you breathe. Blood oxygen levels are also measured. This is typically done in a hospital or medical center. During the study, the doctors can see if a patient stops breathing at night, how many times, for how long, how low their oxygen levels go, and the overall quality of sleep. The study can also tell whether the pauses in breathing are due to lack of stimulus from the brain (i.e., central apnea) or because obstruction in the airway caused, for instance, by enlarged tonsils (obstructive apnea).
Even known that this test can give doctors valuable information and that is completely non-invasive and painless, many patients are reluctant to have this test performed. However, the information can be key to implement treatments that can improve sleep and reduce the risk of nocturnal fatal events for patients with FD.
A publication authored by the NYU Dysautonomia Center team including information from the largest series of patients with FD undergoing polysomnography was recently published in the journal Sleep Medicine. The results are clear: 90% of patient with FD have some degree of sleep-disordered breathing. This is certainly alarming. The work also shows that the pattern of sleep disordered breathing changes as patients get older. In this regard, children with FD tend to have “central” apneas, in which the brain cannot communicate with the lungs to make them take a breath. In contrast, adults with FD tend to have more “obstructive” apneas, in which the airway becomes intermittently blocked so the airflow is cut off. Either type of apnea is potentially dangerous and the more events a patient has at night, the lower their oxygen levels fall and the higher their carbon dioxide levels rise.
Highly prevalent and potentially very dangerous
Recognizing how prevalent sleep disordered breathing is at night for patients with FD is an essential first step. However, it is important to know that, just because a patient with FD doesn’t report frequent awakenings at night, doesn’t necessarily mean that they have normal ventilatory control at night. As found in the Sleep Medicine publication, 90% of patients with FD have this problem. Being vigilant and sending patients for a sleep study – in spite of the fact that they may not like it– is the only way to diagnose this. Having a correct diagnosis is required to get patients on the right path to treatment.
It can be treated
Pauses in breathing during sleep can be treated with non-invasive ventilation (CPAP or BiPAP). It is important to know that most of these problems do not improve with oxygen through a nasal cannula alone. Moreover, oxygen alone can worsen respiratory problems at night in patients with FD.
Only sleeping with a mask or nasal prongs that supply air pressure into the airway, can prevent collapse and maintain airflow. The technology is advancing rapidly and new models of non-invasive ventilation devices are more and more comfortable and convenient. Patients who get used to sleeping with CPAP or BiPAP to treat their respiratory problems feel the difference: they wake up in the morning feeling more refreshed and better able to concentrate. For patients with FD, this may come with the added advantage of protecting them from long pauses from which they may never wake up.
The study was published in Sleep Medicine, was a collaboration of the NYU Dysautonomia Center at the NYU Division of Pediatric Pulmonology, supported by the Dysautonomia Foundation, Inc.
Singh K, Palma JA, Kaufmann H, Tkachenko N, Norcliffe-Kaufmann L, Spalink C, Kazachkov M, Kothare SV. Prevalence and characteristics of sleep-disordered breathing in familial dysautonomia. Sleep Med. 2018 May;45:33-38. doi: 10.1016/j.sleep.2017.12.013. PMID: 29680425
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