ReviewCurrent concepts in the etiology, diagnosis and treatment of narcolepsy
Section snippets
Clinical description and symptoms
Narcolepsy is the most common neurologic cause of excessive daytime sleepiness (EDS). In addition to EDS and cataplexy, the two most significant symptoms of narcolepsy, other rapid eye movement (REM) sleep phenomena such as sleep paralysis and hypnagogic hallucinations can also occur [1].
The sleepiness associated with narcolepsy often becomes irresistible, and leads to repeated daily episodes of involuntary ‘naps’ or ‘sleep attacks’ that can occur at inappropriate and unpredictable times, such
Genetics
A family history is important in the evaluation of the patient with EDS, and may include genetic testing. The diagnostic value of genetic testing however, is probably overestimated [3]. More than 99% of individuals with either the HLA DQB1*0602 and DQA1*0102 haplotypes do not have narcolepsy, and 1–5% of patients with classic narcolepsy do not have either of these haplotypes. Therefore, the absence of the pre-disposing genetic markers does not exclude the diagnosis of narcolepsy, while their
Diagnostic criteria
Diagnostic criteria for narcolepsy are summarized in Table 1 [8]. Excessive sleepiness (daytime sleepiness and frequent naps) is usually the presenting complaint in patients with narcolepsy. However, it is recognized that there is considerable overlap among the clinical features of narcolepsy and other sleep disorders. For instance, sleep attacks may occur in patients with chronic severe sleepiness as well as in patients with narcolepsy. Additionally, the classic symptoms of narcolepsy-EDS,
Therapeutic options
Although there is no cure for narcolepsy, a number of treatment options are available. Treatment should be individualized based on the severity of symptoms and it might take weeks or months before an optimal regimen is achieved. Even so, complete control of EDS and cataplexy is rarely possible.
Conclusions
Narcolepsy is a chronic neurologic disorder characterized by EDS, cataplexy, hypnagogic hallucinations, and sleep paralysis. Although patients report EDS and cataplexy as the most frequent symptoms of this condition, EDS is generally considered to be the most debilitating. The socioeconomic impact of narcolepsy may be as high as that of epilepsy. However, knowledge about narcolepsy often remains limited even among neurologists, and the disorder is frequently undiagnosed or misdiagnosed for a
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