Question about my 16 year old cat’s urinary problem

Lately, my cat has good days and bad days. On the bad days she walks back and forth for hours on end, seeking for a place to urinate. When she finds the place, she sits at it for a few moments before getting up having left a few drops of urine behind.
What is causing this and can I treat her at home without having to take her to the vet(not that it would be easy to capture her if I needed to. She’s semi-feral and when she doesn’t feel well, she runs away from me)?

What would cause her the least amount of stress and possible harm, waiting out her symptoms in the quiet and safety of her home, or whatever procedures veterinary treatment would entail? Until now the answer was always clear, but now that she appears to be in distress, I’m no longer sure what’s the best thing to do for her. Can you please advise?

 

Answer from Dr. Gaylord Brown:
The symptoms you describe are likely to be associated with a urinary track infection. At the very least antibiotics will be required to treat the problem. At worst this may be a tumor of the bladder. Diagnostic test would include a urinalysis, radio-graphs, and possibly an ultrasound of the bladder. Your description that she is in distress makes your course of action clear. she needs to be examined by a veterinarian.