Diabetes Insipidus
I wonder if this test question isn't meant to force you outside of the books, as will happen in your practice! I found this article by Googling the condition name; it's from the Nat'l Institutes of Health.
http://www.nlm.nih.gov/medlineplus/ency/article/000377.htm
Here's a partial quote:
"Central diabetes insipidus is caused by damage to the hypothalamus or pituitary gland as a result of surgery, infection, tumor, or head injury. Although rare, central DI is more common than nephrogenic DI.
"Nephrogenic DI involves a defect in the parts of the kidneys that reabsorb water back into the bloodstream. It occurs less often than central DI. Nephrogenic DI may occur as an inherited disorder in which male children receive the abnormal gene that causes the disease on the X chromosome from their mothers.
Nephrogenic DI may also be caused by diseases of the kidney (for example, polycystic kidney disease) and the effects of certain drugs (for example, lithium, amphotericin B, demeclocycline).
If thirst mechanisms are normal and adequate fluids are consumed, there are no significant effects on body fluid or salt balance. If inadequate fluids are consumed, the large amount of water lost in the urine may cause dehydration and high sodium levels in the blood."
It looks like we can guess that massage is not c/i if the condition is controlled, esp. w/doc input. If the excessive urine output due to nephrogenic DI is uncontrolled, we'd be putting a strain on the kidneys, but otherwise my guess would be request med list, request doc involvement (send doc massage-effects info), and work on client. Especially if it's treatment work rather than circulatory. But if there's a different opinion I'd like to hear it; I'm not a c/i expert and I usually try to find ways to work on people.