M05.08.05 Narcolepsy

Narcolepsy is a chronic neurological disorder that affects the brain’s ability to regulate the sleep-wake cycle. It is classified as a REM (rapid eye movement) sleep disorder, as patients typically enter REM sleep unusually quickly, often within 10 minutes. Narcolepsy is linked to a deficiency of the neurotransmitter Hypocretin (also known as orexin), which plays a vital role in maintaining wakefulness and regulating sleep cycles.

Symptoms of Narcolepsy (Narcoleptic Tetrad)

Narcolepsy is characterized by four hallmark symptoms, collectively known as the narcoleptic tetrad:

1. Excessive Daytime Sleepiness (EDS) and Sleep Attacks

• The most common and debilitating symptom of narcolepsy.
• Patients experience overwhelming drowsiness throughout the day, often resulting in sleep attacks, where they suddenly fall asleep at inappropriate times.

2. Cataplexy

• Pathognomonic sign of narcolepsy.
• Sudden loss of muscle control ranging from mild weakness (slurred speech, drooping eyelids) to complete body collapse.
• Strong emotions such as laughter, excitement, or surprise often trigger them.

3. Hypnagogic and Hypnopompic Hallucinations

• Hypnagogic hallucinations: Occur as the patient is falling asleep.
• Hypnopompic hallucinations: Occur upon waking up.
• These vivid, often frightening, hallucinations can involve visual, auditory, or tactile experiences.

4. Sleep Paralysis

• Temporary inability to move or speak while falling asleep or upon waking.
• Can last from a few seconds to a couple of minutes.
• The person is fully conscious during the episode, which can be distressing.

Treatment Options for Narcolepsy

Management of narcolepsy focuses on symptom control, as there is no known cure for the disorder. Treatment strategies typically include:

Additional Treatments:

• Lifestyle modifications: Scheduled naps, maintaining a regular sleep schedule, and avoiding triggers such as stress or emotional outbursts.
• Sodium oxybate: Sometimes prescribed for patients with severe cataplexy and disrupted nighttime sleep.

Points to Remember

• Narcolepsy is a chronic disorder that affects sleep regulation, leading to excessive daytime sleepiness and sudden sleep attacks.
• The disorder is primarily linked to a deficiency in Hypocretin.
• Cataplexy, a hallmark symptom of narcolepsy, is often triggered by emotions and results in sudden loss of muscle tone.
• Treatment includes psychostimulants to manage daytime sleepiness and antidepressants for cataplexy.
• Lifestyle changes and scheduled naps can improve the quality of life for narcoleptic patients.

Bibliography Reference Links

• National Institute of Neurological Disorders and Stroke (NINDS): Narcolepsy Information
• Mayo Clinic: Narcolepsy Overview
• American Sleep Association: Narcolepsy Symptoms and Treatment