Section 6: Information that Indicates Sleep Related Hypoventilation

DSM-5-TR Code:   G47.34 Idiopathic hypoventilation

DSM-5-TR Code:   G47.35 Congenital central alveolar hypoventilation 

DSM-5-TR Code:   G47.36 Comorbid sleep-related hypoventilation

Prevalence All: Unknown

Common Specifiers:

• Severity is graded by the amount of oxygen (lower is more severe) and carbon dioxide (higher is more severe) in the bloodstream during sleep and waking hours

Can this disorder legitimately be diagnosed by a Master’s level clinician?    

No. This diagnosis requires evidence from examination of blood oxygen and carbon dioxide levels pursuant to tests administered under the supervision of a sleep specialist.

This quite rare sleep disturbance may have a number of different causative factors, all of them with medical implications. The signs and symptoms will be similar to what is seen with Sleep Apnea, since the primary effects of this condition produce a kind of apnea, where the person wakes up numerous times during the night due to insufficient oxygen.

During waking hours, people can consciously control their respiration rate, so if there is not enough oxygen - or too much carbon dioxide - in the blood stream, people can simply increase their rate of breathing. During sleep, however, when conscious control is no longer an option, people must relay on the autonomic nervous system to take over control of the rate of breathing. This disorder occurs when there are problems in how the autonomic nervous system handles this task.

With Hypoventilation Disorder, the autonomic nervous system does not adequately respond to signals about whether there is too little oxygen or too much carbon dioxide. While respiration is maintained while the person sleeps, unlike in Sleep Apnea where breathing just stops, the respiration is either too shallow or too infrequent to supply enough oxygen to operate the body. When the oxygen level gets too low or the carbon dioxide level too high, a feeling of suffocation causes the person to awake and disrupts the sleep cycle.

There are a number of factors that can contribute to the development of this disorder. With the idiopathic type of Hypoventilation Disorder, the causation factor is not known: it hasn’t been uncovered yet. Something simply goes wrong in the complex workings of the autonomic nervous system when a person is sleeping. 

With the congenital central alveolar type of this disorder, there are developmental problems due to disruptions to a specific gene that is involved in the formation of neurons, and symptoms usually appear right after birth. Children born with this disorder often have flattened facial features and a number of other physical problems related to the congenital problems that cause this disorder. This disorder is likely to be noted by the patient’s medical caretakers and treatment will often be undertaken early in the person’s life. 

With comorbid sleep-related hypoventilation, there may be a medical condition that has problematic effects on the ability to take in adequate amounts of oxygen through the lungs, such as lung disease. Or there may be contributions from medications or substances that induce central nervous system depression, slowing down the workings of the autonomic nervous system so much that it cannot respond to the need for more oxygen. Alcohol, opioids and barbiturates are substances that may produce that effect.

The comorbid type may also be seen in persons who are obese. A differential diagnosis will usually be made to rule out Sleep Apnea through examination of the level of carbon dioxide in the blood stream during waking hours. For individuals with this disorder, CO2 is significantly elevated when the person is awake, where it is not elevated for persons with sleep apnea. Clients who present with signs and symptoms of sleep deprivation and are suspected of either having Sleep Apnea or this disorder will both require referral to a sleep specialist whose role will include making these determinations.

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