Definition, Symptoms, Causes, and Risk Factors of Obesity Hypoventilation Syndrome
- Obesity hypoventilation syndrome (OHS) is a condition characterised by a combination of obesity and hypoventilation.
- It is defined as an increase in arterial carbon dioxide levels (hypercapnia) during wakefulness in obese individuals.
- Symptoms of OHS include excessive daytime sleepiness, morning headaches, difficulty breathing during sleep, fatigue, loud snoring, and morning dry mouth.
- The main cause of OHS is obesity, particularly central obesity (abdominal fat).
- Other risk factors for OHS include a sedentary lifestyle, genetic predisposition, and certain medical conditions such as hypothyroidism and polycystic ovary syndrome.
- OHS is more common in middle-aged individuals and is more prevalent in males than females.
- The prevalence of OHS increases with the degree of obesity.

Diagnosis and Evaluation of Obesity Hypoventilation Syndrome
- The diagnosis of OHS is based on clinical evaluation, including a thorough medical history and physical examination.
- Pulmonary function tests, such as spirometry and arterial blood gas analysis, are used to assess lung function and measure carbon dioxide levels.
- Polysomnography (sleep study) is essential to evaluate sleep-related breathing disorders, including OHS.
- Imaging studies, such as chest X-rays and CT scans, may be performed to assess lung and airway abnormalities.
- Evaluation for underlying medical conditions, such as hypothyroidism and hormonal imbalances, is also important.

Treatment and Management of Obesity Hypoventilation Syndrome
- The primary treatment for OHS is weight loss through lifestyle modifications, including diet and exercise.
- Continuous positive airway pressure (CPAP) therapy is often used to treat sleep-related breathing disorders associated with OHS, such as obstructive sleep apnea.
- Noninvasive positive pressure ventilation (NPPV) is a common treatment option for OHS, which provides mechanical support to help improve breathing during sleep.
- Supplemental oxygen therapy may be necessary in some cases to improve oxygen levels in the blood.
- Regular follow-up and monitoring of weight, lung function, and symptoms are crucial in the management of OHS.

Prognosis and Complications of Obesity Hypoventilation Syndrome
- Without proper treatment, OHS can lead to serious complications, including pulmonary hypertension, heart failure, and respiratory failure.
- The prognosis of OHS improves with weight loss and adherence to treatment.
- Long-term management of OHS is essential to prevent complications and improve quality of life.
- Comorbidities associated with obesity, such as diabetes and hypertension, should also be addressed and managed.
- OHS is a chronic condition that requires ongoing care and support from a multidisciplinary healthcare team.

Epidemiology and Statistics of Obesity Hypoventilation Syndrome
- The exact prevalence of OHS is unknown, and many people with symptoms may be undiagnosed.
- About a third of people with morbid obesity have elevated carbon dioxide levels in the blood.
- OHS is more common in those with severe obesity and is twice as common in men compared to women.
- The average age at diagnosis is 52, and it is more commonly reported in the United States due to higher obesity rates.
- Obese Asians are more likely to have OHS at a lower BMI due to physical characteristics.

Obesity hypoventilation syndrome (Wikipedia)

Obesity hypoventilation syndrome (OHS) is a condition in which severely overweight people fail to breathe rapidly or deeply enough, resulting in low oxygen levels and high blood carbon dioxide (CO₂) levels. The syndrome is often associated with obstructive sleep apnea (OSA), which causes periods of absent or reduced breathing in sleep, resulting in many partial awakenings during the night and sleepiness during the day. The disease puts strain on the heart, which may lead to heart failure and leg swelling.

Obesity hypoventilation syndrome
Other names	Pickwickian syndrome
Obesity hypoventilation syndrome often improves with positive airway pressure treatment administered overnight by a machine such as this device.
Specialty	Respirology
Risk factors	Obesity

Obesity hypoventilation syndrome is defined as the combination of obesity and an increased blood carbon dioxide level during the day that is not attributable to another cause of excessively slow or shallow breathing.

The most effective treatment is weight loss, but this may require bariatric surgery to achieve. Weight loss of 25 to 30% is usually required to resolve the disorder. The other first-line treatment is non-invasive positive airway pressure (PAP), usually in the form of continuous positive airway pressure (CPAP) at night. The disease was known initially in the 1950s, as "Pickwickian syndrome" in reference to a Dickensian character.