But add in a chronic condition like Parkinson's, for example, and things just got a whole lot harder.

The report cites planning strategies from advisors whose clients battle such conditions, and ways in which those advisors seek to protect their clients' most vulnerable years.

One client, diagnosed years earlier with MS, wanted to remain at home so she would be able to stay with her dogs. However, she had no family who might have been willing to provide some form of care.

Now nearly 80, the client "receives round-the-clock care from home care providers at a cost of more than $8,000 a month"—thanks to plans put in place by her advisor well ahead of time.

Family estrangement can end up costing retirees more than emotional pain, since family members and spouses are often the go-to care providers in such cases—particularly if the retiree does not have any backup plans such as a long-term care policy that can step in and provide necessary services.

In addition, waiting too long to buy either a LTC policy or disability insurance can make the point moot, since people who have already been diagnosed with a progressive disease won't qualify for either type of coverage.

And since such diseases don't necessarily follow a predetermined path of deterioration, one could find oneself living for years in relative health during retirement, with correspondingly low health care expenses, or conversely possibly spending the rest of life confined to a wheelchair or bed—sometimes for decades—and depleting any retirement savings they might have had on the high cost of care during that period.

Among the chronic diseases faced by Americans are Alzheimer's, which is estimated to affect 5.5 million people; Parkinson's, affecting 1 million; cerebral palsy, hitting an estimated 760,000; and multiple sclerosis, 400,000.

In addition to having sufficient prescience to purchase either a LTC policy or disability coverage prior to such a catastrophic diagnosis, advisors for clients facing such health issues also use variable annuities with income riders and life insurance policies with disability riders.

Sometimes adult children can be prevailed upon to pay the premiums for coverage, but of course this has to be dealt with well in advance of any diagnosis.

Other strategies advise clients to downsize and cut spending well in advance of retirement—never a bad idea anyway—and  engaging in travel, hobbies and other active retirement plans or spending time with family and grandchildren early on after a diagnosis, when such goals are still achievable and affordable.

Another major part of planning for a retirement shadowed by chronic disease is making sure that some other unpleasant details are taken care of, such as appointing a medical and legal power of attorney so that there's someone to cope with care and financial decisions once the client is no longer capable of doing so, and even setting up a trust to protect assets—something that a power of attorney by itself may not be able to do.

According to the report, concerns of elder abuse may cloud the acceptability of a power of attorney, and courts may step in to set up a guardianship over assets.

A trust with designated successor trustees can stand a better chance of being accepted by banks and other financial institutions, particularly if a power of attorney was set up years prior to its use.

In addition, wills should be made and kept up to date, particularly if younger children are involved who may need a guardian should anything happen to the healthy spouse.

And then there's that healthy spouse to provide for. And that can be no small feat, when the ill or incapacitated spouse's medical bills are soaring.

Not only should the purchase of a LTC or disability policy for the healthy spouse be considered, so that if assets are spent down during the life of the ill spouse care will still be available if needed for the survivor—but so should preservation of the residence for the healthy spouse, so that escalating medical bills don't eat up the family home along with available funds.

Planning for a retirement marked by disability isn't easy, but it's something that should be considered lest it become more of a burden than it needs to be—much less end in tragedy for the survivor.