In this article, we will discuss Ondine’s syndrome, also known as Central Hypoventilation syndrome, along with its causes, symptoms, treatments, and diagnostic criteria.
What is Ondine’s Curse:
Ondine’s curse (also known as central hypoventilation syndrome) is the inability of the central nervous system to have control of the average breathing rate of the body while a person is asleep. However, patients don’t have any problems in involuntary breathing when they are awake as the autonomic control of respiration in sleepless hours is intact. Ondine’s curse may also cause the heart rate to be slow.
The most common type of central hypoventilation syndrome is congenital, which means the patient is born with this disease, and it is not acquired by any external factors. Inherent failure of autonomic control of breathing, idiopathic central alveolar hypoventilation, and experiencing sleep apnea along with severe hypoventilation are the main factors that distinguish between CCHS and other respiratory disorders that affect patients in their sleep.
The Legend of Ondine
The disease got its common name by an old legend of Ondine, a water spirit, who loved a knight but was unable to sleep as he was unable to breathe as soon as he fell asleep. It is a fictional tale speculated on the different medical platform as a prehistoric story for how CCHS got named as Ondine’s curse.
The interruption in oxygen supply while sleeping can cause a variable deficiency in oxygen supply to the body, but it is mostly insufficient for the patient’s organs to function normally as a specific amount of oxygen molecules are required per second by the brain. Other common names for this syndrome are Ondine’s curse, Ondine’s syndrome, Hadda syndrome, Congenital failure of autonomic control, Ondine-Hirschsprung disease, etc.
Potential Causes of Ondine’s Curse
Ondine’s curse (central hypoventilation syndrome, CHS) is a congenital respiratory disorder developed by birth in patients. However, it can be acquired later in life if there is considerable damage in the lower lateral medulla of the brain.
Every year, about 200-400 cases of such emergencies are reported. Such reports describe the acquired injury to the lateral medulla of the brain to be caused by physical conditions like strokes, tumors, etc. Scientists believe that the reason for congenital central hypoventilation syndrome can be a mutation.
Role of Genetic Mutations
In some cases of congenital hypoventilation syndrome, a variation known as the PHOX2B gene was found, but the gene was not hereditary. Therefore it seemed to be a result of gene mutation.
So far, scientists have discovered PHOX2B gene mutations of 2 types.
- Youngsters with PHOX2B gene also had neuroblastomas and Hirschprung disease. This condition is termed as syndromic congenital central hypoventilation syndrome.
- The other gene mutation for PHOX2B is a polyalanine expansion, and such type of situation is termed as isolated congenital central hypoventilation syndrome.
Congenital diseases that are not inherited are a result of autosomal gene mutations that can be caused by a few reasons, i.e., environmental factors, radiation, alcohol or drug abuse, etc.
Congenital central hypoventilation syndrome is a gene mutation that is inherited in dominant patterns. This means that one copy of the mutated gene is enough to cause the disorder as long as it is dominant in the genetic code. Most cases of PHOX2B mutation have been resulted from new mutation and sequence coding in the cell and are not a result of preexisting genetic mutations in the cell. This is why CCHS can pre-present in people who have no history of such respiratory problems in their families.
In about 10 percent of people worldwide who suffer from central hypoventilation syndrome, the inherited or altered gene of PHOX2B mutation is only able to pass down in their sex cells, i.e., sperm or egg. This is known as germline mosaicism, and a parent with mosaicism is not likely to show any symptoms of central hypoventilation disorder, but their children are likely to be born with congenital primary hypoventilation disorder if the gene mutation activates itself from the gene code during development in the uterus.
Possible Symptoms of Ondine’s Curse
Congenital central hypoventilation syndrome is present since birth in children and usually starts showing signs in the first month after birth. In rare cases, people begin experiencing symptoms much later in their life.
- Hypoventilation: People with CCHS hypoventilate and take shallow breaths mostly in their sleep. This can cause a significant drop in gaseous transport in the body and result in an increased amount of carbon dioxide and decreases the amount of oxygen. Patients experience shallow breathing in the non-REM sleep cycle or when fully awake.
- Cognitive Deficits: Patients show active signs of learning disabilities, fainting, thermoregulatory problems, seizures, pneumonia, etc.
- Darkening of Skin: An insufficient amount of oxygen can also cause dark skin and difficulty swallowing.
- Neural Degeneration: The human brain even loses its neurons if a fixed amount of oxygen is not provided to it every minute. After 7 minutes of oxygen delay, the brain starts losing its neurons, which is an irreversible process. It means that even if a doctor can bring back a patient from an episode of sleep apnea or central hypoventilation, he or she will not be able to reverse the brain damage that may have been caused by the event.
- Vasoconstriction: Low concentration of oxygen in red blood cells also contributes to vasoconstriction in blood vessels, causing the blood flow to be altered and slowed down in many parts of the body.
- Suppressed Thermoregulation: Vasoconstriction can also cause overheating in the body, and heat loss is stopped causing a drop in thermoregulation. This can lead to a further decrease in the breathing rate of the patient.
- Other Symptoms: Patients suffering from Ondine’s curse also experience other symptoms of CCHS, including physical pain, vomiting, difficulty in swallowing, dysgeusia, nausea, poor GI motility, and acid reflux. They may also experience depression, generalized anxiety or exhaustion and loneliness.
Diagnostic Aspects of Ondine’s Curse
As PHOX2B gene mutation has been identified to cause congenital hypoventilation syndrome (CCHS), such genetic disorders can be detected in utero. CVS tests are recommended by doctors to all pregnant women, in which doctors take a part of the placenta in the 14th week of pregnancy and test it for genetic disorders in the baby’s genetic code such as down’s syndrome, turner’s syndrome, etc.
The sequencing of the PHOX2B gene mostly results in mutations when it is a case of CCHS. In cases of patients acquiring central hypoventilation syndrome by damage to their lateral medullary brain stem, the doctors might not be aware of this situation instantly.
Congenital disorders start showing their symptoms in the first few months of the baby’s life. Doctors evaluate the child for brain lesions, hypercapnia (Building up of carbon dioxide in the patient’s body), hypoxia (oxygen circulation being decreased in patient’s body), and other stimuli that can increase breathing rate. Polysomnography (an instrument used to monitor wave patterns during sleep) shows that patients suffer from hypoventilation in the slow-wave sleep cycle.
In many severe cases of congenital central hypoventilation syndrome, patients experience hypoventilation in the non-REM period of their sleep. Doctors also can for malignant tumors in chest and neuroblastomas in respiratory tracts of the patient. CCHS is a sporadic disease; therefore, health care professionals observe different breathing patterns of breathing and sleep apnea in children.
Treatment Options for Ondine’s Curse
A single treatment is not available for CCHS, but doctors put together different courses of surgeries for the symptoms present in the patient they are treating. Doctors use a ventilator with a tracheostomy cut into the patient’s throat by their neck. The ventilator is used to control the average breathing rate when the patient is sleeping.
This is important as patients with CCHS have a risk of dying by falling asleep. The nature of this treatment is very hectic, and people close to the patient have to get used to all the equipment and extra care. Acid reflux and GI problems are treated with medications and proper diets.
Health care professionals also suggest changing eating and sleeping schedules altogether for patients with CCHS Oxygen therapy is a potential treatment for Ondine’s curse.
Diaphragm pacing is an alternate treatment in which the machine provides other electrical impulses to the diaphragm in cases of sleep apnea or hypoventilation syndrome. Doctors also prescribe stimulating medications for the respiratory system. Using ventilators for a long time can cause other health issues in patients, such as infections and pneumonia.
Most people do not survive more than 2-3 years unless they have a late-onset for this disease. Patients with families who are extra cautious and caring when it comes to following the doctor’s instructions can help in developing a better lifestyle for the patient.
Outlook and Additional Precautions
People with Central Hypoventilation syndrome usually develop it as a result of gene mutation. Most children do not survive past the age of infancy, and the ones that do are bound to ventilators and tracheal machines their whole life. Patients are unable to sleep well their entire life due to the danger of dying in their sleep.
Physical injuries and traumas also cause damage to the medullary lobe responsible for involuntary actions like breathing, which causes some people to develop respiratory disorders and fatal conditions such as sleep apnea and CHS. These people can get cyanosis as a result of low oxygen, causing their limbs and body to turn blue. In layman terms, cyanosis is also known as blue babies.
Cyanosis is one of the main onsets for CHS. Patients start facing difficulties in regulating their heart rate and have a shallow perception of pain, sweating, thermoregulation, and other involuntarily controlled functions and responses of the brain. People should also be on the outlook of having heart rate problems and have difficulties regulating their heart rhythm to a healthy range.
Patients should get themselves checked for neuroblastoma, ganglio-neuroblastomas, ganglioneuromas, and other tumors in their chest and respiratory tract if they start facing such symptoms and difficulties in their daily life. For people who suffer from central hypoventilation syndrome, their life expectancy is directly proportional to the severity of their disease.
Some Helpful Resources
- “The Sleep Solution: Why Your Sleep is Broken and How to Fix It” is a comprehensive book detailing strategies to improve your sleep quality.
- You can also use the journaling technique to monitor overall sleep pattern and quality, by using “Sleep Monitor Journal”
- Another great book is “The Effortless Sleep Method”
- “Treating Sleep Problems: A Transdiagnostic Approach” addresses sleep disturbances in adults and adolescents, both.
- You may also be interested in reading, “What you should know about sleep apnea”
Doctors can diagnose it right and be successful in their treatments of the illness, and it can still be fatal if the condition isn’t caught in time. Central hypoventilation syndrome is a hazardous disorder and can cause several difficulties in daily life and neurological functioning of the patient. There are many support groups active that can help patients and families connect.
Many of these active organizations contribute to several types of research throughout the world and try looking for better cures and treatments for such fatal diseases. Many advisors also provide a list of specialist health care professionals who can offer a further better guide and lead the patient to a better place.
Frequently Asked Questions
Q1. Why is it called the Ondine curse?
It is named after an ancient legend and a novel in which a character named Ondine, curses her husband that he would never be able to sleep well. According to that legend, the husband died as soon as he fell asleep due to breathlessness.
Q2. What causes someone to forget to breathe?
Breathing is an involuntary function, and if a person is having a problem remembering to breathe or need to do it voluntarily, then there may be a problem in the brain’s functioning and signalling when it comes to their respiratory system.
Q3. Who coined the term ‘Ondine’s curse’?
Ondine’s curse was a term coined by Severinghaus and Mitchell when they were describing three patients who had the disease.
Q4. Can a person forget to breathe while awake?
People who have hypoventilation conditions take very shallow breaths and can have breathing problems while they are either awake or asleep, and it can cause them to stop breathing.
Q5. Can anxiety make you forget to breathe?
No, shortness of breath and breathing difficulties are common occurrences with people who suffer from anxiety, but it is not directly associated with anxiety and isn’t caused by it. However, shortness of breath can create anxiety in patients.
Q6. What causes someone to forget to breathe?
The interruption in breathing is an indication of alteration of the brain’s functioning when it comes to involuntary functions, such as breathing. Such problems are documented in diseases like sleep apnea and central hypoventilation syndrome.
- Ondine’s Curse: A mythical tale and a deadly sleep disorder
- Ondine’s Curse: Causes, Symptoms and Treatment
- What is Ondine’s Curse
- Congenital Central Hypoventilation Syndrome
- All about Ondine’s Curse
- Ondine’s curse: A discussion about five cases