What causes my leg to swell up over night like pitting edema?

Pitting edema: It can come from many causes, including heart faikure, liver disease, kidney disease, excessive salt intake and fluid retension.It can also come from lacal condition involving just the affected extremitiy, like varicose veins and thrombophlebitis. You should see your doctor and have him check you.

Many possibilities: Some causes of swelling of the legs can include systemic problems such as hypertension, and problems with the kidneys and localized issues such as arthritis, infection, lymphatic obstruction, blood clots, varicose veins, trauma (fracture, sprain, tendonitis) and side effects to medication. Have it evaluated by a professional and get the appropriate treatment.