ABC News' Lindsey Ellerson reports: After taking a fall on Monday evening, U.S. Senator Frank Lautenberg, D-N.J., has been diagnosed with a bleeding ulcer, according to an aide to the senator. The 86-year old Democrat underwent an endoscopy procedure this morning and is expected to make a full recovery. “After becoming lightheaded and taking a fall as a result of the condition, the Senator sought medical attention last night,” said Communications Director Caley Gray in a written statement. “The Senator is expected to make a full recovery and will be back to work soon.” Lautenberg was transported from his New Jersey home by ambulance to the hospital Monday night. He had recently returned from Haiti with a congressional delegation and was planning to discuss the details of the trip at a news conference today. Serving the Senate since 1982, Lautenberg is the first New Jersey senator to be elected to five terms and is the second oldest senator next to Sen. Robert Byrd, D-W.Va.