Orthostatic intolerance, autonomic dysfunction in youngsters with hypersomnia

A third of 89 children and adolescents diagnosed with primary hypersomnia had symptoms of orthostatic intolerance (OI) at the time of initial sleep diagnosis, researchers found in a study published in Sleep Medicine.

OI is a common sign of autonomic dysfunction that can affect quality of life. In addition, the treatment of hypersomnia often requires the use of stimulants, which can increase dizziness and palpitations in patients with OI. The study researchers attempted to determine the prevalence and characteristics of OI in pediatric patients with hypersomniac disorder, as these characteristics were not the focus of a systematic investigation.

The study researchers identified 89 pediatric patients with hypersomnia (46 with type 1 narcolepsy, 17 with type 2 narcolepsy, 18 with idiopathic hypersomnia, 7 with hypersomnia-related medical disorders, and 1 with Klein-Levin syndrome) who were on The Center for Sleep Medicine at Mayo Clinic

They performed an autonomous reflex screen test consisting of a quantitative sudomotor axon reflex test, an orthostatic blood pressure and a heart rate response to 70 (degrees) head-up inclination, a heart rate response to deep breathing and the Valsalva maneuver, as well as a Beat-to-beat composite blood pressure responses to the Valsalva maneuver. The results were quantified with the Composite Autonomic Severity Score (CASS), in which points are given for adrenergic, sudomotor and cardiovagal impairments.

33 patients (girls, 22; boys, 11; mean age at diagnosis, 14.5 years) had a history of OI and were not more common in any hypersomnia type (P = 0.47). About 75% of patients with OI reported dizziness and fatigue at the time the sleep disorder was diagnosed, and 46% reported headaches.

About half of them became symptomatic during the tilt table test. 5 patients had heart rate changes significant enough to diagnose postural orthostatic tachycardia syndrome (POTS) and 8 had abnormal CASS values ​​(> 1), including 2 patients with moderate autonomic impairment.

25 patients either received no neurological / psychoactive medication or had stopped taking them for at least 72 hours before the test. The group with no OI symptoms had a girl to boy ratio of 1: 2.1 (P = 0.0015 by chi-square test).

The study’s researchers recommended inquiring about symptoms of orthostatic intolerance at the time of the initial diagnostic evaluation of hypersomnia before starting medication.

One of the limitations of the study was its retrospective nature, a referral bias in that patients who underwent autonomous testing were selected for the presence of orthostatic symptoms and actigraphy was not systematically obtained.

“Once treatment for hypersomnia with central nervous system stimulants, selective serotonin reuptake inhibitors, or tricyclic agents is initiated, the assessment of autonomic function can be masked.” difficult, concluded study researchers.


Jagadish S, Singer W, Kotagal S. Autonomous dysfunction in hypersomnic disorders in childhood. Sleep Med. 2021; 78: 43- 48. doi: 10.1016 / j.sleep.2020.11.040

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