Obesity hypoventilation syndrome (OHS)
Pickwickian syndromeObesity hypoventilation syndrome (OHS) causes poor breathing in some people with obesity. It leads to lower oxygen and higher carbon dioxide levels in the blood.
Causes
The exact cause of OHS is not known. It is believed that OHS results from a defect in the brain's control over breathing. Excess weight against the chest wall also makes it harder for the muscles to draw in a deep breath and to breathe quickly enough. This worsens the brain's breathing control. As a result, the blood contains too much carbon dioxide and not enough oxygen.
During stable conditions, people are not acidemic as the kidneys have enough time to correct the acidity caused by the high carbon dioxide.
Symptoms
The main symptoms of OHS are due to lack of sleep and include:
- Poor sleep quality
- Sleep apnea
Sleep apnea
Obstructive sleep apnea (OSA) is a problem in which your breathing pauses during sleep. This occurs because of narrowed or blocked airways.
Read Article Now Book Mark Article - Daytime sleepiness
- Depression
Depression
Depression may be described as feeling sad, blue, unhappy, miserable, or down in the dumps. Most of us feel this way at one time or another for shor...
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- Tiredness
Symptoms of low blood oxygen level (chronic hypoxia) and high carbon dioxide can occur. Symptoms include shortness of breath or feeling tired after little effort.
Exams and Tests
People with OHS have obesity (body mass index of 30 kg/m2 or greater). A physical exam may show:
- Bluish color in the lips, fingers, toes, or skin (cyanosis)
Cyanosis
A bluish color to the skin or mucous membrane is usually due to a lack of oxygen in the blood. The medical term is cyanosis.
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- Signs of right-sided heart failure (cor pulmonale), such as swollen legs or feet, shortness of breath, or feeling tired after little effort
Cor pulmonale
Cor pulmonale is a condition that causes the right side of the heart to fail. Long-term high blood pressure in the pulmonary arteries of the lung an...
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Tests used to help diagnose OHS include:
- Arterial blood gas
Arterial blood gas
Blood gases are a measurement of how much oxygen and carbon dioxide are in your blood. They also determine the acidity (pH) of your blood.
Read Article Now Book Mark Article - Chest x-ray or CT scan of the chest to rule out other possible causes
Chest x-ray
A chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.
Read Article Now Book Mark ArticleCT scan of the chest
A chest CT (computed tomography) scan is an imaging method that uses x-rays to create cross-sectional pictures of the chest and upper abdomen....
Read Article Now Book Mark Article - Lung function tests (pulmonary function tests)
Pulmonary function tests
Pulmonary function tests are a group of tests that measure breathing and how well the lungs are functioning.
Read Article Now Book Mark Article - Sleep study (polysomnography)
Sleep study (polysomnography)
Polysomnography is a sleep study. This test records certain body functions as you sleep, or try to sleep. Polysomnography is used to diagnose sleep...
Read Article Now Book Mark Article - Echocardiogram (ultrasound of the heart)
Echocardiogram
An echocardiogram is a test that uses sound waves to create pictures of the heart. The picture and information it produces is more detailed than a s...
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Health care providers can tell OHS from obstructive sleep apnea because a person with OHS has a high carbon dioxide level in their blood when awake.
Treatment
Treatment involves breathing assistance using special machines (mechanical ventilation). Options include:
- Noninvasive mechanical ventilation such as continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) through a mask that fits tightly over the nose or nose and mouth (mainly for sleep)
Continuous positive airway pressure (CP...
Positive airway pressure (PAP) treatment uses a machine to pump air under pressure into the airway of the lungs. This helps keep the windpipe open d...
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- Breathing help through an opening in the neck (tracheostomy) for severe cases
Tracheostomy
A tracheostomy is a surgical procedure to create an opening through the neck into the trachea (windpipe). A tube is most often placed through this o...
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Treatment is started in the hospital or as an outpatient.
Other treatments are aimed at weight loss, which can reverse OHS, although it is often difficult to achieve.
Outlook (Prognosis)
Untreated, OHS can lead to serious heart and blood vessel problems, severe disability, or death.
Possible Complications
OHS complications related to a lack of sleep may include:
- Depression, agitation, irritability
- Increased risk for accidents or mistakes at work
- Problems with intimacy and sex
OHS can also cause heart problems, such as:
- High blood pressure (hypertension)
Hypertension
Blood pressure is a measurement of the force exerted against the walls of your arteries as your heart pumps blood to your body. Hypertension is the ...
Read Article Now Book Mark Article - Right-sided heart failure (cor pulmonale)
- High blood pressure in the lungs (pulmonary hypertension)
Pulmonary hypertension
Pulmonary hypertension is high blood pressure in the pulmonary arteries of the lungs. It makes the right side of the heart work harder than normal....
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When to Contact a Medical Professional
Contact your provider if you are very tired during the day or have any other symptoms that suggest OHS.
Prevention
Maintain a healthy weight. Use your CPAP or BiPAP treatment as your provider prescribed.
References
Malhotra A, Powell F. Disorders of ventilatory control. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 74.
Mokhlesi B, Tamisier R. Obesity-hypoventilation syndrome. In: Kryger M, Roth T, Goldstein CA, Dement WC, eds. Principles and Practice of Sleep Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 138.
Mokhlesi B, Masa JF, Brozek JL, et al. Evaluation and management of obesity hypoventilation syndrome. An official American Thoracic Society clinical practice guideline. Am J Respir Crit Care Med. 2019;200(3):e6-e24. PMID: 31368798 pubmed.ncbi.nlm.nih.gov/31368798/.
Respiratory system - illustration
Air is breathed in through the nasal passageways, travels through the trachea and bronchi to the lungs.
Respiratory system
illustration
Review Date: 8/13/2023
Reviewed By: Denis Hadjiliadis, MD, MHS, Paul F. Harron, Jr. Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.