- Urinary incontinence is no fun
A friend emailed me last week. Her 6-year-old spayed female shepherd mix (“Gracie”) started leaking urine three weeks before; she urinates normally but also has an almost-constant slow drip at all other times, even when she’s asleep. When her owners first noticed the problem, they started taking her out to urinate as often as they could; but this didn’t help. They had taken her for a vet visit and were waiting for results from the lab work that was submitted. Gracie is about 10% over her ideal weight but appears otherwise healthy and active. The vet mentioned that the dripping is probably due to urethral sphincter mechanism incompetence (USMI). So, my friend wrote to me to find out more.
Gracie’s problem falls under the broad category of “urinary incontinence;” but dripping urine has a very different list of possible causes than, say, a dog that empties his entire bladder on the living room rug in the middle of the night or leaves a puddle by the front door when loud Uncle Ernie comes to visit. Leaking of urine can usually be attributed to one or more of only a few causes: anatomic abnormalities of the bladder and associated structures, diseases that cause increased water consumption, decreased urethral sphincter tone, and urinary tract infection. And, while the culprit can be a spinal cord injury, other neurological problem, or trauma, these are almost always accompanied by other signs.
What’s going on in Gracie’s case? It’s easy to rule out anatomic abnormalities as a single cause: she’s 6 years old and is only now showing signs of a problem. The results of the lab tests, which became available the day after my friend’s note, ruled out a urinary tract infection, endocrine diseases like Cushing’s or hypothyroidism, and kidney failure. So, that pretty much suggests USMI.
But, what specifically is USMI? The urethra is the tube that carries urine from the urinary bladder to the outside world. The urethral sphincter is the muscle that keeps the urethra from releasing urine until the individual chooses to. If this muscle fails, so does the individual’s control over urine being released. The exact causes of USMI are not completely understood; but they are believed to be a combination of low estrogen, advancing age, genetics, and obesity. Therefore, the prime candidate for this problem is an overweight large-breed female dog that has been spayed, thus reducing the amount of circulating estrogen. And, in fact, up to 20% of female dogs are affected By USMI.
To make a precise diagnosis, there is a way to measure the pressure exerted by the urethra; it’s called a Urethral Pressure Profile test and is available at specialty clinics. But, an initial diagnosis can be made based on the history provided by the owner and ruling out the other possible causes. Then, if treatments don’t work, the diagnostic tests can be used.
Treatments for this problem range from medications to the injection of collagen to firm up the sphincter. Medications include phenylpropanolamine (PPA), which enhances sphincter control, and estrogen, which increases the pressure applied by the sphincter. These medications can be used separately or together, but are not tolerated by all dogs. PPA can cause agitation, irritability, and blood pressure changes. Too much estrogen can cause vomiting and diarrhea, as well as anemia and reduced production of white blood cells. Other medications, although used less frequently, can relax the bladder to reduce dripping. An alternative to medication is the regular injection of collagen in to the urethra in an effort to reduce urine flow; this procedure is usually repeated every six months or so.
Gracie has started PPA and, although a bit edgy, appears to be handling it well. Her urine leaking has resolved completely. Her owners are keeping their fingers crossed.
My name is Dr. Liz Stelow. I am currently a veterinary behaviorist in the UC Davis Clinical Behavior Service, treating pets for behavior problems. In 2014, I became board certified in Veterinary Behavior. Prior to that, I was a 2006 graduate of UC Davis School of Veterinary Medicine. Before starting vet school, I was the Public Relations Director at the Pasadena Humane Society & SPCA in southern California. While at PHS, I hosted a monthly cable show, wrote articles for local magazines, and answered calls from the news media and the public on countless animal topics. Before PHS, I was a docent/animal encounters volunteer at the Los Angeles Zoo and a volunteer keeper at the National Zoo in Washington, DC; both of those positions came with significant training and hands-on contact with a variety of animals.
Pet Doctor Mom 
Apr 08, 2012 @ 16:01:03
Interesting…our dog also leaks urine, but not all the time. It typically happens every couple of months or so for a few days and then it is done. She will be ten years old in a few months, she is a medium sized dog and at her ideal weight. Interestingly it is always clear and never yellow. There is no odor to it either.
Apr 26, 2012 @ 22:39:34
If your dog is drinking excessive amounts of water (due to some medical issue), she might leak little puddles because her baldder is so full – and the urine would be clear and odorless. But, if she is dripping small amounts of urine and your vet can’t find any medical reason, discuss a trial of phenylpropanolamine (PPA) to enhance the tone of her urethral sphincter muscle. It’s not uncommon for speincter mechanism incompetence to be a more occasional thing, especially early on.
Aug 01, 2012 @ 15:57:57
My dog is a female 3 year old spayed lab. She also has been leaking urine, not just small puddles but huge amounts. It’s not like she squats and pees, it just leaks out as she is laying on the floor or unfortunately it’s been our bed. It is also clear and orderless. So if I understand you correctly, you are suggest trying a PPA treatment? Thank you.
Aug 08, 2012 @ 20:42:55
Please check with you vet for a diagnosis based on bloodwork, physical exam, etc. If it’s urinary leakage from a scpincter promlem, I hope PPA will help. If the cause is something else, it likely won’t.
Sep 20, 2012 @ 18:25:01
Hi, My mix breed is also doing this, sometimes just a little and other times a huge puddle. It stops for weeks at a time. She was consuming a lot of water but now seems to not be drinking as much, in fact much less then she used to. The urine is almost always odorless and I’m worried she may have diabetes. Can heart worm cause this? or other tic or mosquito caused illness? I’m very worried about her. I was away for a few days several times and my friend took care of her. She didn’t do it for most of the trips just the last one. He said she was “leaking” and had emptied a huge puddle on his floor once. She is spayed and about 5 years old but this has started in the last 6 months and seems to have gotten worse. Going to take her to Vet but have had so many bills for my medical problems that didn’t yet. Hope my inability to pay for a Vet up until now has not caused her more harm.
Sep 22, 2012 @ 21:38:55
As I noted, there are a few reasons a dog can leak urine. I would recommend some lab work (blood and urine) to make sure she’s healthy. Then your vet can ask all about the history to determine whether PPA would be an effective treatment in her case. Check with your vet to see if you can make payments, so the up-front cost of the lab work would not be so prohibitive.
Sep 23, 2012 @ 17:29:32
Have you ever heard of this happening in a puppy? my dog is only 9 months old and she leaks while she’s sleeping, it just sort of drips out one drop at a time…Would the same possible causes apply to her?
Sep 27, 2012 @ 21:27:54
There are lots of possible causes. You should definitely discuss this problem with your vet so you can start crossing things off the list. It could be a developmental issue she may grow out of, a problem with the way her urinary tract developed (like ectopic ureters), an infection, or something else.
Dec 04, 2012 @ 08:02:02
Our 14-year-old Catahoula had this problem. She would drip like a broken faucet especially when she was laying down. She would also lick at it so her breath was smelly. We waited hoping it would correct itself, but it didn’t. The problem was fixed after 1 day on estrogen. It’s been 2 weeks without any leaks. She looks more comfortable too. The estrogen has just been reduced to once a week. My fingers are crossed.
It’s a frustrating problem. She was constantly dripping and licking, and I was constantly washing her bedding. All it took was a trip to the vet and a pill. Don’t wait to take your pet. You’ll be glad you did.