A young policeman came to our center complaining of an overwhelming desire to sleep. Earlier in the month, he had been evaluated for seizures after several episodes in which he had fallen down at work and remained unresponsive for several seconds to minutes. This often occurred when he was joking around and laughing with his peers.

Unlike patients with seizures, this patient said he was completely aware of what was happening around him when the episodes occurred. He remembered hearing conversations and could repeat them without difficulty. We performed a polysomnogram and multiple sleep latency tests and diagnosed him with narcolepsy, a sleep condition I described in detail in last week’s blog.

Cataplexy is one of the cardinal symptoms of narcolepsy — as many as 70% of patients with the disorder experiencing the symptom. Cataplexy rarely occurs in anyone who does not have narcolepsy, although it may be seen in a patient with an underlying neurological disorder and is often a frightening experience for both patient and caregiver.

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Patients with cataplexy experience a sudden loss of muscle tone during wakefulness usually triggered by strong emotions, such as anger or sadness. Attacks can also be brought on by laughter, fright, shock, running, sexual activity and dancing. Mild forms of cataplexy may only cause sagging of the facial muscles, slurred speech, and weakness in the knees or the patient’s arms to drop to the sides. Episodes can last for a few seconds to greater than 30 minutes.

As with narcolepsy, cataplexy is caused by low levels of hypocretin, a chemical found in the hypothalamus. In the past, treatment was mostly with tricyclic antidepressants. Today, treatment also includes serotonin and norepinephrine reuptake inhibitors (SNRIs), such as venlafaxine, as well as sodium oxybate to help improve nighttime sleep. Patients may also try to avoid situations where they know there may be a higher risk for emotional changes.

If you suspect a patient has cataplexy, refer him or her to a qualified sleep center for appropriate testing, and offer reassurance that symptoms can be managed well with the correct treatment.

Sharon M. O’Brien, MPAS, PA-C, works at Presbyterian Sleep Health in Charlotte, N.C. Her main interest is helping patients understand the importance of sleep hygiene and the impact of sleep on health.