Narcolepsy Quiz: Test Your Medical IQ

Narcolepsy is a sleep disorder in which the brain is unable to regulate wakefulness and sleep.

Narcolepsy is fairly rare, affecting about 1 in 2,000 people in the general population. However, the disorder is often unrecognized or misdiagnosed so the incidence may be higher.

Narcolepsy affects men and women equally, and it can affect both children and adults. Narcolepsy can occur at any age, but it is commonly diagnosed in one of two peak time periods, around 15 years of age and 36 years of age.

Narcolepsy may have several possible causes. Most people with narcolepsy along with cataplexy (sudden loss of muscle control) have very low levels of a naturally occurring chemical called hypocretin (also called orexin), that helps regulate wakefulness and sleep.

Narcolepsy is thought to result from a combination of factors including:

• Autoimmune disorders: abnormalities in the immune system may result in low levels of hypocretin
• Genetics: while most cases of narcolepsy occur sporadically (in people who have no family history), the condition can run in some families
• Brain injuries: in rare cases, narcolepsy can result from traumatic injury or tumors to parts of the brain that regulate wakefulness and REM sleep

The predominant symptom of narcolepsy is excessive daytime sleepiness (EDS), which is characterized by an irresistible urge to sleep, and patients may experience "sleep attacks" in which they fall asleep suddenly and without warning.

Other symptoms of narcolepsy include:

• Automatic behaviors, in which patients perform actions without conscious awareness
• Disrupted nighttime sleep
• Sleep paralysis
• Sleep-related hallucinations
• Cataplexy (sudden loss of muscle control)
• Eye problems due to sleepiness such as blurred vision

Narcolepsy can significantly impact a person's overall health and well-being. "Sleep attacks," in which patients with narcolepsy may fall asleep suddenly, drowsiness, and cataplexy (sudden loss of muscle control) can lead to motor vehicle accidents.

The excessive daytime sleepiness caused by narcolepsy can interfere with work, school, and relationships. The stigma attached to narcolepsy can lead to social withdrawal.

Narcolepsy also increases a person's risk of other health conditions such as obesity, high blood pressure, and psychiatric disorders including depression, anxiety, and attention-deficit/hyperactivity disorder (ADHD).

In addition to a patient history and physical examination, a diagnosis of narcolepsy is made using:

• A sleep journal noting the times of sleep and symptoms over a one- to two-week period
• Multiple sleep latency test (MSLT) which measures how quickly a person falls asleep and if they enter rapid eye movement (REM) sleep
• Polysomnogram (PSG or sleep study)
• Measuring levels of hypocretin in the cerebrospinal fluid (the fluid that surrounds the brain and spinal cord)

Symptoms of narcolepsy can be treated with medications and lifestyle changes.

Medications used to treat narcolepsy include:

• Modafinil (Provigil), a central nervous system stimulant, used to reduce daytime drowsiness and improve alertness
• Amphetamine-like stimulants to help with excessive daytime sleepiness (EDS) such as methylphenidate (Ritalin, Methylin), methamphetamine (Desoxyn), dextroamphetamine (Dexedrine Spansule, Zenzedi, ProCentra), and manzindol
• Other stimulants such as selegiline (Eldepryl, Zelapar, Emsam) and pemoline
• Antidepressants to help with cataplexy, sleep paralysis, and hallucinations
• Tricyclics, including imipramine (Tofranil), desipramine (Norpramin), clomipramine (Anafranil), and protriptyline
• Selective serotonin reuptake inhibitors (SSRIs), including fluoxetine (Prozac, Sarafem), sertraline (Zoloft), atomoxetine (Strattera), and venlafaxine (Effexor)
• Sodium oxybate (Xyrem) (also called gamma hydroxybutyrate or GHB), a strong sedative used to treat cataplexy and excessive daytime sleepiness

Lifestyle changes that can be used along with medications to help manage narcolepsy symptoms include:

• Maintaining a regular sleep schedule
• Taking short, scheduled naps
• Getting regular exercise at least 4 to 5 hours before bedtime
• Avoiding caffeine and alcohol for several hours before bed
• Avoiding large, heavy meals before bedtime
• Not smoking
• Relaxing before bed such as with a warm bath
• Making sure the bedroom is cool and comfortable

There is no cure for narcolepsy. The goals of treatment are to reduce symptoms and to improve quality of life and patient safety.

Symptoms of narcolepsy tend to gradually worsen over time and then reach a point where they remain stable. Some symptoms, such as excessive daytime sleepiness, may on occasion worsen and require additional medication. Other symptoms may improve as patient ages. In rare instances, some patients may experience a sudden remission of symptoms. It is unknown why this occurs.