Expiratory Apneas With or Without Catathrenia Presenting As Central Apneas

Here’s an interesting poster that I presented at last week’s SLEEP meeting in Boston: Expiratory Apneas With or Without Catathrenia Presenting As Central Apneas. To explain the terminology, catathrenia is a rare condition where one groans or moans while sleeping. Central sleep apneas occur when your brain doesn’t send signals to your lungs to breathe. It’s more commonly seen in patients with heart failure or neurologic conditions. Apneas are commonly thought to occur during inhalation, with a collapse of your throat tissues while you inhale.

However, in some patients, the obstruction happens during mid-nasal exhalation. The history is very unique: The person begins a normal nasal exhale, but during mid-exhalation, you hear a sudden occlusion or closure, with breath holding for a few seconds to well over 15 seconds. This breath holding is terminated by an arousal or complete oral exhale and then a few deep breaths, with the cycle happening all over again. In some patients, there will be moaning or groaning during the breath-holding portion.

I was able to find a patient that could replicate this finding while awake on his back (see poster). What you see is that during mid-nasal exhalation, the redundant uvula flaps back up into the nasopharnx, blocking nasal exhalation completely. During this event, you can either hold your breath, like straining lightly during a bowel movement, or vocalize continuously, leading to moans. Coincidentally, my wife also had this exact phenomenon during the last trimester of her last pregnancy.

If you look at the sleep study tracings during these episodes, it may seem like a central apnea, since there’s no nasal air flow and there are no chest or abdominal movements. But if you look closer, sounds are being made, and there’s air coming out of the mouth (due to moaning). These events classically occur during REM sleep, in the early morning hours, when muscles are most relaxed. In the American Academy of Sleep Medicine’s International Classification of Sleep Disorders -2, catathrenia is classified as a parasomnia. However, it’s clear from this observation and a handful of other studies that suggest that catathrenia should be classified as a variation of obstructive sleep apnea. Guillminault published a paper a while back showing that all his catathrenia patients were cured with either CPAP or uvulopalatopharyngoplasty.

I’ve had a number of these patients (mostly young and thin) who were diagnosed with central sleep apnea. You can imagine the anxiety that’s created when they find out that they have central sleep apnea, with no plausible explanation.

Do you either moan in the night, or stop breathing suddenly during exhalation while sleeping?