Hi Michelle! Thanks for writing in.Stress should not cause bloody urine, nor should congestive heart failure. Bloody urine can come from the urinary tract (kidneys
, ureters, bladder, urethra) - irritation/infection, blood clotting problems, bleeding tumors or other disruptions of normal lining; or, bloody urine can be see in diseases of reproductive tract (uterus/ovaries). The latter usually happens to those that have not been spayed/neutered, but it is possible to have an infection of a uterine remnant that got left behind during a spay operation.So... In a cat with bloody urine that is 16 years of age, the most likely problems are: bladder stones, bladder cancer or urinary tract infection (this is almost never without another problem, such as kidney disease, bladder stones, cancer, etc). A wait and see approach in this case may not be the best, ***** ***** your situation, it may be the only thing to do, unfortunately. Just noticed you said that she urinated normal urine; it's a good sign, but blood may be intermittent so you may not always see it. Some cats get a condition called idiopathic renal hematuria, which is a condition in which blood comes from the kidneys but no significant cause is found; this is not as likely in an older cat, however, those conditions above are more likely.Ideally, Cleo should have blood and urine testing, as well as an abdominal x-ray; I would try to do this as soon as you are able. For now, feed her canned food
only, if she'll take it, because canned food contains much more moisture and will dilute her urine, making her urinate more frequently and in more volume, decreasing the concentration of stone forming substances and hydrating her. Other than that, there isn't much to do unfortunately...Here is some additional information: http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=612Hope this helps!