Narcolepsy: Clinical features, co-morbidities & treatment

Narcolepsy is a neurologic illness that typically begins in the second and third decades of life. It is chronic in nature and negatively impacts the quality of life of affected patients. The classic presentation is a tetrad of excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations. The exact cause remains unknown, but there is significant evidence that hypocretin deficiency plays an integral role. Some primary conditions that result in secondary narcolepsy include traumatic brain injury, congenital disorders, tumours, and strokes. Some medical and psychiatric disorders share characteristics of narcolepsy, at times leading to diagnostic inaccuracy. Other sleep disorders are commonly co-morbid. Diagnosis relies on patient history and objective data gathered from polysomnography and multiple sleep latency testing. Treatment focuses on symptom relief through medication, education, and behavioural modification. Both classic pharmacological treatments as well as newer options have significant problems, especially because of side effects and abuse potential. Novel modalities are being examined to expand options for treatment.