Pickwickian syndrome is named after Dickens’s The Pickwick Papers because the novel features a character who has all the classic symptoms of the condition.

Joe is obese, constantly hungry, very red in the face and is always falling asleep in the middle of tasks.

“Sleep!” said the old gentleman, ‘he’s always asleep. Goes on errands fast asleep, and snores as he waits at table.”

Obesity hypoventilation syndrome is defined as the combination of obesity (body mass index above 30 kg/m2), hypoxia (falling oxygen levels in blood) during sleep, and hypercapnia (increased blood CO2 levels) during the day, resulting from hypoventilation (excessively slow or shallow breathing). The disease has been known since the 1950s.

All patients with OHS are obese (BMI >30 kg/m2) and most have coexisting obstructive sleep apnea (OSA). The most common symptoms and signs are due to the coexisting OSA , which include excessive daytime sleepiness, loud snoring, choking during sleep, resuscitative snorting (ie, a loud snort that follows an apnea as the patient partially awakens and reopens the upper airway), fatigue, hypersomnolence , impaired concentration and memory, a small oropharynx, and a thick neck.

Other symptoms present in both conditions are depression, and hypertension (high blood pressure) that is difficult to control with medication. The high carbon dioxide (CO2) can also cause headaches, which tend to be worse in the morning.

The low oxygen level leads to excessive strain on the right side of the heart. Symptoms of this disorder occur because the heart has difficulty pumping blood from the body through the lungs. Fluid may therefore accumulate in the skin of the legs in the form of edema (swelling); decreased exercise tolerance and chest pain may occur

It is estimated that 26 percent of adults are at high risk for OSA. The prevalence of OSA in the general population is approximately 20 percent.

Clinical features of obstructive sleep apnea-hypopnea:

• Daytime sleepiness
• Non-restorative sleep
• Witnessed apneas by bed partner
• Awakening with choking
• Nocturnal restlessness
• Insomnia with frequent awakenings
• Lack of concentration
• Cognitive deficits
• Changes in mood
• Morning headaches
• Vivid, strange, or threatening dreams
• Gastroesophageal reflux
• Obesity
• Large neck circumference
• Systemic hypertension
• Hypercapnia
• Cardiovascular disease
• Cerebrovascular disease
• Cardiac dysrhythmias
• Narrow or “crowded” airway
• Pulmonary hypertension
• Cor pulmonale
• Polycythemia

DIAGNOSIS:

OHS is diagnosed when the following criteria are confirmed:

• Obesity (BMI be >30 kg/m2)
• Arterial blood (special blood draw) showing high CO2 (hypoventilation)
• A different cause of the hypoventilation cannot be identified

Additional testing is necessary to exclude other diseases that can cause hypoventilation, such as chronic obstructive pulmonary disease (COPD), restrictive disease (e.g., neuromuscular weakness, interstitial lung disease, chest wall disease), hypothyroidism, and diaphragmatic (breathing muscle) paralysis .

This generally requires the following tests:

• Thyroid function tests to look for hypothyroidism
• Pulmonary function tests, to look for evidence that COPD or a restrictive disease.
• A chest radiograph to look for lung disease, chest wall disease, signs of diaphragm paralysis, and cardiomegaly (enlarged heart).