Autonomic Dysfunction in Childhood Hypersomnia Disorders

USA: One-third of children having primary hypersomnia had symptoms of orthostatic intolerance (OI) at initial presentation of the sleep diagnosis, according to a recent study in the journal Sleep Medicine.

Orthostatic intolerance is a common sign of autonomic dysfunction which is characterized by palpitations and light-headedness in the upright position with relief when reclining. It can affect quality of life. Spoorthi Jagadish, Department of Neurology, Mayo Clinic, Rochester, MN, USA, and colleagues aimed to examine the prevalence and characteristics of autonomic symptoms in children and adolescents with hypersomnia disorders.

For the purpose, the researchers reviewed medical records of children and adolescents with hypersomnia disorders. It included patients diagnosed with narcolepsy types 1 or 2 (NT1 or NT2), idiopathic hypersomnia (IH) or the KLS, or hypersomnia related to medical conditions and who were under 18 years of age at sleep diagnosis. Those with major depression and obstructive sleep apnea were excluded.

The medical records were reviewed for symptoms at initial presentation suggestive of autonomic dysfunction, such as orthostatic intolerance, headache, fatigue, nausea, palpitations and abdominal pain. In case, these symptoms were recorded, the chart was examined further to determine if an autonomic reflex screen (ARS) battery had been conducted. The ARS battery examines both sympathetic and parasympathetic function.

ARS battery consists of a tilt table test, heart rate and blood pressure responses to the Valsalva maneuver and deep breathing, a quantitative sudomotor axon reflex test and beat-to-beat blood pressure measurements during the Valsalva maneuver. An autonomic neurology specialist (WS) interpreted the results of the ARS battery who otherwise was not involved in the care of the patients. Medications taken at the time of autonomic testing were recorded.

Key Findings of the Study

• There were 89 patients with hypersomnia disorders. Forty-six patients had NT1, 17 had NT2, 18 had IH, 1 with KLS, and 7 had hypersomnia associated with medical disorders.
• Thirty-three of 89 subjects (37%) had the symptom of OI at initial presentation, hence had undergone autonomic reflex screen testing.
• In the group with OI, 25/33 had not received medications for treating hypersomnia at the time of autonomic testing. OI was not related to the degree of sleepiness - the mean sleep latency in the subjects with OI was 5.3 ± 2.9 min while in those without OI it was 4.5 ± 3.8 min.
• The symptom of OI was not more likely to occur in any specific type of hypersomnia. OI however tended to occur predominantly in females - the female: male ratio in the OI subgroup was 2:1 (n = 33) while in the subgroup without OI, it was 1:2.1 (n = 56; p = 0.0015).
• Additional symptoms recorded in the OI subgroup included lightheadedness in 25/33, palpitations in 6/33, nausea and vomiting in 4/33, fatigue in 25/33, headache in 15/33 and constipation in 3/33.
• The symptoms of OI were reproduced during the tilt table test in 17/33 subjects; 5 of these patients had a rise in heart rate consistent with postural orthostatic tachycardia syndrome (POTS).

"Our findings showed that one third of children with hypersomnia disorders exhibited the symptom of OI at initial presentation, with female predominance," wrote the authors. "A smaller subgroup met criteria for POTS. Screening for autonomic symptoms in children with hypersomnia is important because the former seems to be a treatable co-morbidity that impacts the sense of well-being."

The study titled, "Autonomic dysfunction in childhood hypersomnia disorders," is published in the journal Sleep Medicine.

DOI: https://www.sciencedirect.com/science/article/abs/pii/S1389945720305402