What Is Hypoventilation Syndrome?
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Hypoventilation Syndrome - Causes, Symptoms, Complications and Treatment

Published on Jun 16, 2022 and last reviewed on Mar 17, 2023   -  7 min read


In hypoventilation syndrome, there is too much carbon dioxide and not enough oxygen in the blood. Read below to learn more.


Hypoventilation syndrome, also known as Pickwickian syndrome or obesity hypoventilation syndrome (OHS), is a condition affecting the blood and is seen when there is not enough oxygen in the blood but there is too much carbon dioxide. Its specialty is that it is due to the presence of disordered breathing during sleep which leads to changes in the body, and the effects are long-term.

Gas exchange happens during breathing, that is, inhalation and exhalation. This exchange occurs between oxygen and carbon dioxide, and it is a normal process. This type of gas exchange is important because this maintains a good balance between the required amounts of oxygen and carbon dioxide in the blood.

One interesting feature behind the terminology of this disease is that the name Pickwickian syndrome has been derived from the character Joe from the novel The Pickwick Papers written by Charles Dickens in 1836. Joe showed similar symptoms of this disease.

The definition of OHS is described as a combination of obesity and a body mass index (BMI) greater than or equal to 30 kg/m2 with awake chronic hypercapnia (PaCO2 > 45 mm Hg). Before confirming the diagnosis, it is important to rule out other possible hypoventilation types. It has been reported that approximately 90 % of patients suffering from this condition experience obstructive sleep apnea (OSA). Studies have shown that hypoventilation worsens during rapid eye movement (REM) sleep more than during non-REM sleep.

Various other hypoventilation syndromes include the following:

1. Central alveolar hypoventilation.

2. Obesity-hypoventilation syndrome (OHS).

3. Chest wall deformities.

4. Neuromuscular disorders.

5. Chronic obstructive pulmonary disease (COPD).

What Are the Symptoms?

The symptoms are commonly associated with a lack of oxygen in the body, and thus, it can affect you when you are awake or asleep. Also, it can be associated with a stoppage of breathing for a few minutes during sleep.

Most commonly seen symptoms include the following:

  1. Breathlessness.

  2. There is a lack of energy, and the patient always feels sleepy due to the lack of oxygen supply to the brain and body tissues.

  3. Feeling of low energy in the body.

  4. Cyanosis (swelling and bluish discoloration of the skin and mucous membranes).

  5. In severe obesity hypoventilation syndrome cases, the patient loses interest in indulging in normal activities and feels upset due to extreme drowsiness. This results in depression along with suicidal thoughts.

  6. The person wakes up in the morning with a headache due to the excess amount of carbon dioxide level in the blood. They have constant low oxygen levels in the body. This condition is known as chronic hypoxia.
  7. The person makes an effort to complete one breathing cycle. It makes the patient exhausted even during the day.

Following are the more severe symptoms, and it is necessary to consult your physician as soon as possible:

  1. Cor pulmonale (tension in the heart due to less oxygen in the body).

  2. Obstructive sleep apnea.

  3. Increase in blood pressure causing vascular hypertension.

How Is It Caused?

No specific cause has been studied yet for this condition, although the following risk factors can possibly be causing it:

  1. Body Mass Index (BMI) - The first and foremost cause is excess weight. A person having a body mass index (BMI) of more than 30 is considered to be obese

  2. Brain Dysfunction - The Pickwickian syndrome occurs due to improper nerve signals in the brain. As a result, the brain fails to control the breathing muscles.

  3. Respiratory Failure - There is respiratory failure due to the excess weight covering the chest. The patient finds it difficult to inhale air with the help of the lungs.

  4. Oxygen Demand - The Pickwickian syndrome occurs if there is an oxygen deficiency in the vital organs like the lungs and brain. The metabolism of the body is interrupted due to long-term oxygen insufficiency.

  5. Osteoarthritis - It also has an association with osteoarthritis. Although the association may not be causative, it is believed that there is a link between both the diseases as both of them are primarily affected by obesity. Obesity causes hypoventilation syndrome which results in low oxygen levels in the body. Increased body weight and low oxygen levels may lead to osteoarthritis.

Are There Any Complications?

If this condition is not managed on time, it can lead to certain complications, which are as follows:

  1. Cardiac Failure - Severe obesity hypoventilation syndrome causes cardiac dysfunction and failure, particularly on the right side. This condition is known as cor pulmonale.
  2. Pulmonary Hypertension - There is increased pressure in the blood vessel of the lungs (pulmonary artery). It leads to pulmonary hypertension.
  3. Poor Sex Life - The person with Pickwickian syndrome lose interest in intimacy, and serious problems can occur in sex life.
  4. Obstructive Sleep Apnea - If the person is unable to breathe properly for a long period, especially during sleep, it results in obstructive sleep apnea.
  5. Erythrocytosis - Abnormal levels of red blood cells in the blood which is also called secondary erythrocytosis.
  6. Swelling- Build up of fluids or edema in the legs.

It is important to contact your physician as soon as possible in case you develop any of these symptoms.

How Can It Be Diagnosed?

Initially, when you visit your physician, you will be asked about your signs and symptoms along with your medical and personal history, followed by measuring your height and weight to calculate your BMI. Also, your waist and neck circumferences will be measured. Certain other tests that your doctor may perform include pulmonary function tests, X-ray of the chest, gas level in the arterial blood, serum bicarbonate test, etc. Certain other blood tests may also be performed. If you are going ahead with surgery, you will be monitored regularly before, during, and immediately post-surgery.

The tests that are used to investigate the oxygen and carbon dioxide level are described below:

  • Arterial Blood Gas - The blood from the artery is used to check the acidity level and gases like oxygen and carbon dioxide level. It is used to evaluate breathing conditions. The impaired acid or base balance reveals improper functioning of the lungs and the airways (bronchial tubes). It is also used to assess the body's metabolism.

  • Pulmonary Function Test - It is used to inspect the abnormal functions of the lungs. The rate of air inhaled and exhaled is measured using a lung function test. It follows a forceful exhalation after a deep breath. It is used to estimate the oxygen level in the bloodstream. The obesity hypoventilation syndrome leads to scarring of the lungs due to inadequate breathing. Abnormal results indicate the weakness of the breathing muscles.

  • Polysomnography - Since obesity hypoventilation syndrome affects sleep, polysomnography is used to record the sleep cycle. This test is conducted during the night. It is used to measure the time taken to fall asleep or to attain deep sleep. It also records the airflow in the lungs during sleep. The breathing effort during sleep is observed.

Certain other conditions may show similar signs and symptoms, which are as follows:

  • ALA Dehydratase Deficiency Porphyria.

  • Botulism.

  • Diaphragm Disorders (Diaphragmatic Dysfunction).

  • Bronchitis.

  • Diaphragmatic Paralysis.

  • Disorders associated with usage of Sedative, Hypnotic, Anxiolytic.

  • Respiratory Acidosis.

  • Emphysema.

  • Obesity.

  • Chronic Obstructive Pulmonary Disease (COPD).

  • Opioid Abuse.

How Can It Be Treated?

There are many ways to treat this condition, and they are mentioned below:

1) Loss of Weight: If obesity is the cause of this condition, then losing weight is the first line of treatment.

2) PAP (CPAP) Therapy: Positive airway pressure (PAP) therapy is a common treatment followed to manage this condition. This machine helps in providing a constant flow of oxygen with the help of a motor into a tube which is connected to a mask worn over the mouth and nose.

3) Ventilator Machine: This helps in maintaining a constant flow of oxygen. This includes two techniques: continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BiPAP).

  • In both the techniques,the patient wears a facemask either in a sitting or lying position and receives the air supply. Both these techniques are concerned with delivering oxygen. But the only difference is the change in pressure.

  • Continuous positive airway pressure (CPAP) is used to supply air to the bronchial tubes (airways) present in the lungs. It prevents respiratory failure and saves the patient from lung collapse. In bilevel positive airway pressure (BiPAP), the air pressure is delivered from the tube connected to a machine during inhalation and exhalation.

4) Tracheostomy: This is done in case you are not responding to other treatments. This will help to get a patent airway by making a hole in the neck into the trachea. It is used to open the airway and remove secretions around the lungs. It is inserted into the windpipe (trachea). While using tracheostomy, the patient with Pickwickian syndrome can breathe without any obstruction. It is done under general anesthesia.

5) Surgery to Lose Weight: Surgery done to lose weight is called bariatric surgery.

6) Other Treatment Options: Medroxyprogesterone can be used to manage the symptoms of Pickwickian Syndrome. This is known to cause certain side effects like erectile dysfunction in men and uterus bleeding in women. Hence, it is necessary to consult your physician before consuming it.

How Can It Be Prevented?

There are certain ways to prevent this condition and also to limit the complications or severity of symptoms, and they are as follows:

1. Manage or maintain weight.

2. Consume a healthy balanced diet along with exercising.

3. Use CPAP machines properly.


Hypoventilation syndrome can cause some serious complications if it is chronic in nature. Thus, it is essential to contact a physician or specialist to know more about it in detail and get it diagnosed and managed early. Consulting a specialist has been made easy with online medical platforms. To get more details on this topic, you can consult a physician or specialist online.

Last reviewed at:
17 Mar 2023  -  7 min read




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