Description of Autoimmune Disorders
Sleep disorders and excessive daytime sleepiness are common in multiple sclerosis (MS), an autoimmune disorder that causes white matter plaques in affected areas of the brain. The most common sleep complaints include excessive daytime sleepiness and insomnia. Approximately 40% of patients with multiple sclerosis have insomnia. Other sleep complaints include restless legs syndrome and periodic limb movement disorder (36%) and obstructive sleep apnea and rapid eye movement sleep behavior disorder. There is increased incidence of narcolepsy as well. Depression is a common comorbid condition in multiple sclerosis and some of the symptoms of fatigue, daytime sleepiness, and insomnia may be further complicated by depression. Finally, chronic pain (present in 50%) can exacerbate insomnia and both pain and insomnia increase susceptibility to depression. Nocturia and urinary incontinence can also contribute to fragmented sleep.
The syndrome of fatigue commonly reported in multiple sclerosis may or may not be related to abnormal nocturnal sleep. The differential diagnosis is difficult and a polysomnogram may be needed.
Evaluation of Autoimmune Disorders
As in other disorders described in this site, the evaluation is the same. The neurologic disorder is treated first. A sleep evaluation is performed as in Image Standard approach to sleep disorders in neurologic patients, while maintaining a higher index of suspicion for certain disorders based on the descriptions above and location of lesions in the particular patient.
Treatment of Autoimmune Disorders
Pharmacologic treatment should be directed as described elsewhere to treat the identified sleep disorder. As fatigue is common in multiple sclerosis, addition of modafinil may be helpful. The smallest effective dose, up to 400 mg per day, is appropriate. If insomnia occurs, limiting afternoon dosing should help. Modafinil may not be helpful if symptoms of fatigue are not related to abnormal sleep. If benzodiazepines or other respiratory depressing medications are used, sleep apnea should be evaluated and treated first.
Nonpharmacologic treatment should be directed as described elsewhere to treat the identified sleep disorder.