When a top management official at the Treasury Department told coworkers that he had Acquired Immune Deficiency Syndrome (AIDS), they were afraid and cautious. He had always been well-liked at work, but colleagues began to avoid him. He felt all the more frightened and alone.

When four restaurant employes died of AIDS within eight months, the restaurant's manager conceded: "When someone gets AIDS, he takes a leave of absence and gets put on disability . . . And that's it. We don't see them again; we just hear what happens through the grapevine . . . It's just all pushed underneath the surface."

The ordeal of AIDS in the workplace is raising questions that are agonizing and, sometimes, unanswerable. What happens when an employe gets AIDS? What is a fair and humane response by employers? What are the legal rights of the afflicted employe? Of coworkers?

"The typical reaction of many companies is to say, 'We don't have a problem with AIDS,' " says Thomas R. Horton, president and chief executive officer of the American Management Association (AMA).

"It's a taboo subject. There is very little knowledge about it at most companies. How they're handling it is analagous to going to the doctor and saying, 'Doc, I've got a friend who has this problem.' "

Horton contends that what has become the health crisis of the '80s is also a pressing challenge for American management. With the number of new cases of AIDS expected this year to reach levels comparable to the once-feared polio epidemic, and some medical authorities predicting that in five to 10 years the number doomed to die of AIDS could jump to 1 million, the American workplace is hardly immune.

Most companies appear to be taking a wait-and-see approach which, Horton says, is tantamount to no policy and certainly inadequate once an employe is diagnosed as having AIDS.

When the AMA decided last year to publish management-minded guidelines to help corporate America develop sensitive and legal policies toward incidents of AIDS, the 92,000-member, not-for-profit education organization headquartered in New York heard some criticism. "This is a gay plague, a gay fight, and an organization like the AMA should not be in it," was the typical complaint, said one AMA source who asked not to be identified.

Since its publication last month, however, "AIDS: The Workplace Issues" has drawn virtually no negative comment, says Don Bohl, AMA's managing editor of membership publications. Bohl has received corporate requests for the booklet -- some from as far away as northern Canada, many from companies, he says, that have been struck by "some rumors, some disruption from AIDS."

While the AMA doesn't pretend to have all the answers, its nationwide research and interviewing succeeded, at least, in clarifying what has and hasn't worked so far when confronting AIDS in the workplace. The restaurant manager who lost four employes to AIDS, for instance, told AMA researchers, " . . . if someone decided to come out with it, that they had AIDS, I think we'd have to force them to leave."

The Treasury Department, on the other hand, took a more positive approach, according to the AMA investigation. Twenty-five coworkers met with a counselor specializing in life-threatening illnesses. Medical issues were discussed; no documented cases of AIDS have been transmitted in the workplace, or through casual contact, they were told.

"We've gone through the first wave of fear and I think the panic is starting to subside," says Bohl. "Now the issue is to focus on policy."

Among the AMA's recommendations to employers:

*Don't wait for the first AIDS incident. Prepare.

*Offer the afflicted worker support.

*Clear the air of misconceptions with education programs that provide employes with up-to-date facts. Distribute literature. One corporation set up an AIDS information booth. As Jackson Peyton of the AIDS Foundation told the AMA, "There are no dumb questions about AIDS. People's concerns have to be addressed with care and understanding."

*If current disability policy is adequate, say so. If additional policy on AIDS is made, tell employes.

*Safeguard the worker's right to confidentiality.

*Make reasonable accommodations that would be normal for any seriously ill employe.

Horton adds that one difficulty confronting AIDS in the work environment is diffusing rumor and innuendo. "You can't do a lot about it," he says, advising managers to tell the person who is the subject of the gossip that there are rumors circulating that are detrimental to him, and then offer help.

Copies of "AIDS: The Workplace Issues" are available for $7.50 (AMA members), $10 (nonmembers) and $3.75 (students) from the American Management Association, 135 W. 50th St., New York, N.Y. 10020. Of Work and Life Skills

What are your marketable skills? Prince George's Community College is now registering for its "Career Decision Making and Life Planning" course -- 10 Friday sessions, starting Feb. 28, designed to help you identify your job and personal skills. $100 for county residents. (301) 322-0886. Job Searching

The Northern Virginia Community College, Alexandria campus, is offering no-fee, no-registration classes in its Career and Life Assessment Skills series. Among the two-hour sessions: Re'sume' and Interviewing Techniques (tomorrow) and Adult Transitions (Feb. 11). (703) 845-6301. Job Changing

An evening workshop assisting Fairfax County residents in sizing up new careers begins Feb. 18 for six Tuesdays at the Re-entry Women's Employment Center in Annandale. Fee based on income. (703) 750-0633.