Rep. Jesse Jackson Jr. (D-IL) talks to constituents following a town hall meeting on health care reform at the Sheldon Heights Church of Christ August 18, 2009 in Chicago, Illinois.(Photo by Scott Olson/Getty Images)

CHICAGO – Wednesday’s disclosure that Congressman Jesse Jackson Jr. is being treated for an undisclosed “mood disorder” left numerous unanswered questions for his constituents in Chicago. It could also potentially lead to a messy situation in the midst of a re-election campaign if he is unable to continue due to his treatment.

“I know a lot of people are saying when is he going to get back to work, he should get back to work — why would he go back to work to a Congress that does no work,” said Chicago Mayor Rahm Emanuel, a former Congressman, in the Chicago Tribune. “Why rush? Take care of your health. Guess what? Congress is going to be there.”

Jackson has been away from Congress since June 10, initially citing exhaustion. Earlier this year, he defeated former Illinois State Rep. Debbie Halvorson in a hotly-contested primary and has been the subject of an ongoing House ethics investigation into his dealings with former Illinois Gov. Rod Blagojevich.

Raghuveer Nayak, Jackson’s longtime friend and fundraiser, was arrested on June 20 by federal agents and faces a 19-count indictment which includes 10 counts of mail fraud, 5 counts of racketeering, and 4 counts of filing false income tax returns from 2005-2008. During Blagojevich’s 2010 corruption trial, Jackson was accused of instructing Nayak to raise money for Blagojevich in exchange for President Obama’s U.S. Senate seat.

“If testimony came out that Congressman Jackson was much more involved in offering the bribe to Gov. Blagojevich, that would be damaging,” said Dick Simpson, a professor and head of Political Science at the University of Illinois-Chicago. Jackson could face censure or even removal from Congress if found to have bribed Blagojevich, but Simpson said that removal was highly unlikely.

Since Jackson went on leave, he has missed 90 House votes, including Wednesday’s latest Republican effort to repeal the Affordable Health Care Act. His absence – and relative low profile –  drew the ire of his constituents and fellow congressmen alike, as he had told no one of his illness and gave no timetable for his return.

“I think Congressman Jackson and his office and his family would be well advised to advise the constituents of his condition,” said House Minority Whip Steny Hoyer, D-Maryland. “He’s obviously facing a health problem. We have many members who are out right now.”

One member is Republican Illinois Senator Mark Kirk, who suffered a stroke in January and disclosed it publicly just two days later. He has since released videos of his rehab and recovery.

“This is not an unusual circumstance,” Hoyer said. “People get sick, and when people get sick, they miss work. Everybody in America understands that. But I think the family would be well advised to give his constituents as much information as is appropriate.”

The lack of information led to speculation and innuendo about Jackson’s condition, including unsubstantiated rumors about drug use. Jackson’s father and his wife, Chicago Alderman Sandi Jackson, shared little in terms of updates. An NBC News report on Wednesday initially said that Jackson was being treated for alcoholism at an Arizona rehab facility, but Jackson’s camp quashed that report.