What makes Joan Rivers unique...in court

Joan Rivers was unique. That's what virtually all of the obituaries said in one way or another. The write-ups mostly focused on the uniqueness of her lacerating, celebrity-seeking missile of a wit. The commentators also focused on the unique way she often turned that wit on herself. And then there was her unusual, if not unique, half-century in the public eye.

But Joan Rivers was also unusual because, at the age of 81, an age when most people are long retired, Ms. Rivers was still working. She was not only working, she was earning an enormous income from working. One web site pegged her annual wages at $5 million.

Read MoreComedian and entertainer Joan Rivers dies at 81

It is that aspect of what made Ms. Rivers so unusual — and not so much the other qualities that made her death such big news — that may be the focus of any legal action that results from the circumstances of her death.

Of course, it is far too soon to conclude that Ms. Rivers' death was caused by any errors or omissions on the part of her health-care providers. She was, after all, 81 years-old.

Read MoreGoodbye, Captain: Robin Williams' 5 best roles

Still, it at least raises questions when someone goes into cardiac arrest and then dies after what was described as minor, outpatient throat surgery. According to a Wharton online life-expectancy calculator, an 81-year-old woman may expect to live until the age of 93. Such sudden, unexpected death has to rank among a Baby Boomer's worst nightmare as we watch our parents age.

Joan Rivers in 2012
Getty Images
Joan Rivers in 2012

All of that explains why both the New York Department of Health and the Office of the New York Medical Examiner are investigating the circumstances Ms. Rivers' death. All of that also explains why there is talk of a potential wrongful death civil action by her heirs.

A court will, of course, consider the tremendous pain Joan Rivers' death is sure to have caused her surviving daughter and grandson. But in a medical-malpractice action, a court considers the age and earnings capacity of the deceased in evaluating damages.

Read MoreWhy women should say 'No!' more often

When Ms. Rivers died, she was in reasonably heavy demand as an entertainer. The New York Times obituary for her explained that, after her late-night television show on the then-budding Fox network was canceled in 1987, her bookings declined sharply as did, presumably, her earnings. But she recovered — and that will matter if any legal action is taken.

Commentary by Dan Eaton, a partner with the San Diego law firm of Seltzer Caplan McMahon Vitek where his practice focuses on defending and advising employers. He also is a professor at the San Diego State University College of Business Administration where he teaches classes in business ethics and employment law. Follow him on Twitter @DanEatonlaw.