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Obesity Hypoventilation Syndrome

Obesity Hypoventilation syndrome is an uncommon sleep and breathing disorder. It is also known as Central Alveolar Hypoventilation syndrome. Patients with the syndrome are obese, usually snore loudly, may stop breathing at night for brief periods, may have swelling in their legs from fluid accumulation, and complain of daytime tiredness and sleepiness.

An insufficient level of breathing primarily a night but which eventually extends into the day characterizes the syndrome. The insufficient breathing is a subconscious event. The cause is unknown. Almost all adults with the disease are obese. Therefore, obesity clearly plays a role in the development of the syndrome. Most likely, extra chest wall and abdominal weight cause the breathing muscles to fatigue and result in an inability to breath sufficiently. In other words patient's with the syndrome "can't breath". Additionally, the breathing center in the brain likely sends inadequate signals to the breathing muscles resulting in insufficient breathing as well. In other words, patient's with the syndrome "won't breath". Finally, the majority of patients with the syndrome also have Obstructive Sleep Apnea, which can itself result in insufficient nocturnal breathing.

The insufficient breathing results in progressive respiratory failure. The carbon dioxide level in the blood rises and the oxygen level in the blood falls. In fact, the disease is usually first detected by measuring the level of these two substances in the arterial blood. Eventually, untreated patients may develop severe heart failure and severe respiratory failure from high levels of carbon dioxide and low levels of oxygen.

The diagnosis and treatment are usually straight forward. Usually a patient will have an arterial blood gas, pulmonary function tests, a chest x-ray, and a sleep study. If the diagnosis is confirmed, the treatment consists primarily of weight loss, supplemental oxygen during the day and night, treatment of coexisting sleep apnea, and a fluid pill to control the fluid accumulation in the legs. A respiratory stimulant is sometimes tried as well but generally is inadequate treatment. If the syndrome progresses, sometimes tracheostomy and mechanical ventilation are need. Consequently, close follow-up with a physician who specializes in sleep and breathing disorders is important.

PCCAB has a dedicated web site related to our Sleep Services. Please click the link below to learn more about this division of our services.

Sleep Medicine Associates of Maryland

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