Written by Carol Smith, PA-C, sleep medicine physician assistant at Iowa Sleep
The CDC ( Centers for Disease Control and Prevention ) estimates that 80 % of patients with Multiple Sclerosis (MS) have pathological fatigue that does not improve with bed rest and may worsen with physical or mental activity. Studies have shown sleep disorders are a common comorbidity with MS including narcolepsy, insomnia and rapid eye movement (REM) sleep behavior disorder. In patients with significant fatigue as a complaint sleep apnea and narcolepsy are often overlooked. This is a surprising finding as MS is listed as fourth most frequent cause of narcolepsy .
Two common theories on the cause of MS and narcolepsy are genetic links and hypothalamic damage or lesions. Patients with MS who have narcolepsy commonly have lesions in the hypothalamus. This area of the brain is damaged in narcolepsy we believe by an autoimmune reaction. This occurs when a person's autoimmune system recognizes a part of the body as foreign and tries to destroy it . Inflammation and infection have been theorized as a trigger of autoimmune disease. Damage to the hypothalamus results in a decrease in hypocretin a neuropeptide that is responsible for promoting wakefulness. Hypocretin levels can be checked in the spinal cord fluid that can be obtained by a spinal tap. There have been reported cases of MS patients with narcolepsy who had resolution of their narcolepsy when treated with corticosteroids.
The take away here is that cases of fatigue, daytime sleepiness should trigger further questioning about sleep disorders by the clinician and the patient with referral to a sleep specialist so that appropriate testing can be determined .
This information was cited from a magazine article in "Sleep Review" January 2017 pg. 28 by Yoona Ha. References in the article are attributed to a book by Robert S. Rosenberg, DO, FCCP who is a board certified sleep specialist The Doctor's Guide to Sleep Solutions for Stress & Anxiety .
If you have questions, we encourage you to reach out to a doctor at Iowa Sleep by sending us a question. We can help you identify the reasons you may not be sleeping well and get you on the path to sleeping better to take on another day. You can also call (800) 226-6084 to schedule an consult with one of our board certified sleep physicians.