Shortly before Christmas my cat experienced a spasmodic urethra. Basically it's when a cat's urethra has muscle spasms and is usually related to stress. This can be an acute or chronic condition. It leads to a blocked urethra meaning the cat cannot empty his bladder. Vets consider this a life threatening emergency. It only take 24 to 48 hours for this to lead to devastating complications such as kidney failure and sepsis. Neutered males are at higher risk of developing a blockage as their urethras are very narrow.
So Dave spent 3 days at an emergency veterinary hospital. A catheter was placed into his urethra to empty his bladder. He was given antispasmodic medications to calm his urethra down and a pain killer for discomfort. Poor Dave! He was very mad and spent his 3 days and nights trying to attack any nurse or vets that went near him. He HATES people he isn't exposed to on a regular basis. 
Dave is home and high as a kite: 
Dave is missing a square (IV shave): 
Which brings me to the reason for this occurrence. Due to his behavior toward people he doesn't live with - aggression, it was determined that he suffers from fear aggression and stress. This led to a physical manifestation of that stress in the form of urethral spasms, which in turn caused his urethra to clench shut.
The treatment to try and prevent this from recurring is to keep his stress under control. Enter kitty Prozac and a supplement called Zylkene. Zylkene is powdered milk casein, which is a naturally occurring protein in dairy. It is known to have a calming effect on cats and dogs. This product can be bought without a prescription online or at a Petco location. The lowest price I have found was on https://www.amazon.com/s/ref=nb_sb_noss/141-3039164-0644702?url=search-alias%3Daps&field-keywords=zylkene.
Additional measures to manage stress are daily playtimes, which helps to relieve stress and excess energy. Play is very important for all domestic animals and should be a part of their daily routine. A clean litter box is very important as well. Cats can be very particular about their litter boxes and can easily become stressed when it is not clean enough. It is important to remove waste daily and change out the litter weekly.
If this condition becomes chronic you may want to consider having the cats penis removed. Yes, you heard me right. Removing the penis eliminates the urethra thus eliminating the problem. This surgery should only performed by a vet who specializes in this. The cat's penis is removed and a small opening is created for urine to pass through. In essence, a sex change operation.
Well so far so good for Dave. He hasn't had a recurrence and is much calmer and less prone to aggression. My sister is no longer getting attacked when she comes to visit. Keeping my fingers crossed that it continues!
“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” ― Mahatma Gandhi
Cat's urine glows under a black light.
Quickest and easiest way to find out where your cats been peeing - hand held black light.
If your cat snores, or rolls over on his back to expose his belly, it means he trusts you.