What are the other Names for this Condition (Also known as/Synonyms)

• OHS (Obesity Hypoventilation Syndrome)
• Pickwickian Syndrome

What is Obesity Hypoventilation Syndrome? (Definition/Background Information)

• Obesity Hypoventilation Syndrome (OHS) is a condition affecting individuals who are obese. In this condition, there is reduced oxygen and elevated carbon-dioxide in blood, due to a breathing abnormality
• The increased concentration of carbon-dioxide in blood occurs from poor breathing and inadequate ventilation, termed hypoventilation. The body is also slow to respond to correct the defect, causing progressive drop in oxygen levels in blood
• Commonly, this breathing abnormality occurs from obstructive sleep apnea, a sleeping disorder causing intermittent airway block during sleep. Besides this, individuals with very high body mass index (BMI of 40 and over) have an increased risk for Obesity Hypoventilation Syndrome
• The condition can result in symptoms that involve both the heart and lung. Obesity Hypoventilation Syndrome may cause daytime sleepiness, sensation of choking during sleep, morning headaches, and depression. It may also cause severe complications such as pulmonary hypertension and enlargement of a part of the heart
• The treatment of Obesity Hypoventilation Syndrome may involve positive airway pressure therapy and ventilation support, if needed. Individuals, who are obese, need to undertake weight loss measures including dieting and exercising. The prognosis of individuals with OHS is based on the severity of the condition and any associated complications

Who gets Obesity Hypoventilation Syndrome? (Age and Sex Distribution)

• Obesity Hypoventilation Syndrome may be observed in individuals of a wide age group; but most cases are observed in middle-age adults, belonging to the fourth and fifth decade (between ages 40 and 60)
• Both males and females are affected, although studies indicate that the condition is more often observed in males
• No racial or ethnic group predilection is observed and the condition is observed worldwide

What are the Risk Factors for Obesity Hypoventilation Syndrome? (Predisposing Factors)

The risk factors for Obesity Hypoventilation Syndrome may include:

• High value of body mass index (BMI): Individuals, with a BMI value of 40 or over, have a very high risk for OHS
• Obesity causing the buildup of excess body fat around the belly/abdomen rather than around the hips or thighs
• Any individual who is obese (i.e., BMI over 30) is at risk for OHS; individuals with necks that are unusually large have an even greater risk
• Obstructive sleep apnea, a sleeping disorder, is associated with OHS in many cases

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Obesity Hypoventilation Syndrome? (Etiology)

• The exact mechanism of development of Obesity Hypoventilation Syndrome (OHS) is not well-understood, since not all individuals who are obese have OHS
• Due to abnormalities in breathing, the exchange of oxygen and carbon-dioxide in the air sacs of lungs is disrupted. Consequently, the symptoms of OHS develop due to decreased levels of oxygen and increased levels of carbon-dioxide in blood
• This breathing disorder may develop from a combination of factors that include obesity, obstructive sleep apnea, and certain other factors involving the respiratory system

What are the Signs and Symptoms of Obesity Hypoventilation Syndrome?

The signs and symptoms of Obesity Hypoventilation Syndrome (OHS) may vary from one individual to another. The signs and symptoms may be mild or severe and include:

• Continuous snoring while sleeping; the snoring may be very loud
• Feeling a sensation of choking/gasping during snoring intervals
• Other symptoms of associated obstructive sleep apnea that may include:
  • Daytime sleepiness; continually falling asleep while engaged in other activities such as watching television or driving
  • Daytime fatigue
  • Morning headaches and moodiness
  • Unable to focus during the day; memory and concentration lapses
  • Frequently waking up at night for urination
  • Depression
• Presence of shallow breathing; breathing in short bursts

How is Obesity Hypoventilation Syndrome Diagnosed?

A diagnosis of Obesity Hypoventilation Syndrome may involve the following tests and exams:

• Complete physical examination with comprehensive evaluation of medical history: A general head and neck physical exam may help the physician diagnose sleep apnea. Individuals may be questioned about their sleep habits and relevant history. They are recommended to maintain a ‘sleep diary’, which may help the physician evaluate if there is a sleep disorder
• Assessment of the presenting signs and symptoms
• Polysomnography (sleep study) may be considered in all those who are suspected of having obstructive sleep apnea, in order to verify the presence of the disorder and determine its severity
• Blood tests that include:
  • Complete blood count
  • Blood gas analysis, to check for the level of oxygen and carbon-dioxide in blood
  • Bicarbonate blood test
  • Pulse oximetry, to determine the level of oxygen in blood
  • Emergency and overdose drug testing (toxicology screen), if needed
• Electrocardiogram, to assess the activity of the heart
• Imaging studies that include X-ray of chest
• Pulmonary function tests: In this test, the physician assesses the current status of lung function

Note: It is reported that a diagnosis of Obesity Hypoventilation Syndrome is usually delayed or missed; also, the chances of a misdiagnosis is high.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Obesity Hypoventilation Syndrome?

The complications of Obesity Hypoventilation Syndrome may include:

• Diminished quality of life; stress and depression
• The affected individuals are higher prone to error during work; accidents
• Pulmonary hypertension: High blood pressure in the (main artery of the) lungs
• Pedal edema: A condition where the legs are swollen due to fluid buildup
• Heart abnormalities that include enlargement of a side of the heart (cor pulmonale) and heart failure (that may occur due to sleep apnea)
• OHS can cause an increase in the number of red blood cells (RBCs) in the body

How is Obesity Hypoventilation Syndrome Treated?

A multidisciplinary approach with a team of healthcare specialists and experts from various medical fields, such as pulmonologists, sleep specialists, critical care specialists, bariatric surgeons, nutritionists, and fitness trainers, may be necessary to treat Obesity Hypoventilation Syndrome.

The treatment measures may include the following:

• Administration of prescription medication, in some cases
• Positive airway pressure therapy to help maintain the levels of oxygen and carbon-dioxide in blood
• Continuous positive airway pressure (CPAP): It helps provide positive pressure to the airway through a device worn on the face. CPAP keeps the upper airway passages open, preventing apnea
• Bilevel positive airway pressure (BPAP): It can be used for those who are unable to adapt to CPAP. BPAP provides more pressure during inhalation and less during exhalation
• Individuals with severe OHS may require oxygen/ventilator support, placement of endotracheal tube, or a tracheostomy
• Weight loss: Individuals are encouraged to lose weight, if they are obese. Weight loss can help reduce the bulk of tissues in the neck that may narrow the airway, thereby reducing airway collapse
• Weight-loss surgery, if needed
• Modification of lifestyle, to include exercise and diet (healthy eating) into one’s daily regimen

How can Obesity Hypoventilation Syndrome be Prevented?

The following steps may be taken to help prevent Obesity Hypoventilation Syndrome:

• Weight loss, if one is obese or overweight, which can help improve overall health, decrease the apnea, and improve the overall quality of life
  • Healthy dieting
  • Increased physical activity/exercising
• Individuals are advised to maintain regular sleep hours and avoid alcohol, sedatives, sleeping pills, before bedtime
• Avoid working on or using bright screens (laptops, mobiles) before bedtime

Some of the above factors may prevent aggravation of the condition.

What is the Prognosis of Obesity Hypoventilation Syndrome? (Outcomes/Resolutions)

• The prognosis of Obesity Hypoventilation Syndrome depends on the severity of the signs and symptoms, overall health of the individual, and his/her response to treatment
• Delayed treatment of the condition may result in severe complications and health issues, since it is a progressive condition. In some cases, mortalities have been observed
• Also, the presence of certain underlying conditions, such as asthma or diabetes, can worsen the prognosis

Additional and Relevant Useful Information for Obesity Hypoventilation Syndrome:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/healthy-living/wellness-center/