ABSTRACT
The symptoms of narcolepsy can occur during the course of other neurologic conditions (ie, symptomatic narcolepsy). Inherited disorders, tumors, and head trauma were the three most frequent causes for symptomatic narcolepsy. Other causes include multiple sclerosis (MS), vascular disorders, and encephalitis. Cerebrospinal fluid hypocretin-1 measures were carried out in some recent cases with symptomatic narcolepsy, and moderate decreases in hypocretin levels were seen in a large majority of these cases. Excessive daytime sleepiness (EDS) in these symptomatic cases was sometimes reversible with an improvement of the causative neurologic disorder and with an improvement of the hypocretin (orexin) status. Recently, we found that several symptomatic narcoleptic cases with MS show unique bilateral symmetric hypothalamic lesions associated with significant hypocretin ligand deficiency. In addition, these patients often share the clinical characteristics of neuromyelitis optica (NMO) and the detection of NMO-IgG (or anti-aquaporin-4 [AQP4] antibodies), suggesting a new clinical entity. Further studies of the involvement of the hypocretin system in symptomatic narcolepsy and EDS are helpful to understand the pathophysiologic mechanisms for occurrence of EDS and cataplexy.
Subject(s)
Disorders of Excessive Somnolence/physiopathology , Narcolepsy/etiology , Narcolepsy/physiopathology , Adolescent , Child , Disorders of Excessive Somnolence/pathology , Humans , Hypothalamus/metabolism , Hypothalamus/pathology , Intracellular Signaling Peptides and Proteins/metabolism , Magnetic Resonance Imaging , Male , Middle Aged , Narcolepsy/pathology , Neuromyelitis Optica/immunology , Neuromyelitis Optica/pathology , Neuromyelitis Optica/physiopathology , Neuropeptides/metabolism , OrexinsABSTRACT
The definition of insomnia is surprisingly quite difficult. It is not possible to decide whether a person has insomnia just by the length of his sleep time. This is because there is a significant difference in how much sleep each person needs. Insomnia is a state in which the patient' s physical, psychological, and social activities are interfered with by a strong feeling of sleep deficiency upon waking in the morning. Insomnia is a symptom, not a name of a disease. In treatment of insomnia, it is not enough to just make the patient sleep by use of sleeping pills. It is essential to research what lies beneath the insomnia, identify the cause, and remove it.
