a complex of respiratory and circulatory symptoms associated with extreme obesity. The name originates from the fat boy depicted in Charles Dickens (Dickens, Charles)'s The Pickwick Papers, who showed some of the same traits. (By some definitions, to be obese is to exceed one's ideal weight by 20 percent or more; an extremely obese person would exceed the optimum weight by a much larger percentage.) This condition often occurs in association with sleep apnea, which is another common complication of obesity.

In pickwickian syndrome the rate of breathing is chronically decreased below the normal level. Because of inadequate removal of carbon dioxide by the lungs (lung), levels of carbon dioxide in the blood increase, leading to respiratory acidosis. In more severe instances, oxygen in the blood is also significantly reduced.

Individuals who have pickwickian syndrome often complain of slow thinking, drowsiness, and fatigue. Low blood oxygen causes the small blood vessels (blood vessel) entering the lungs to constrict, thus increasing pressure in the vessels that supply the lungs. The elevated pressure stresses the right ventricle of the heart, ultimately causing right heart failure. Finally, excessive fluid accumulates throughout the body (peripheral edema), especially beneath the skin of the lower legs.