If you have a male intact mastiff-type dog with blood in its urine, you should assume there is a bladder stone, until proven otherwise.
Veterinarians know that step one for all urinary tract issues is getting a urine sample. Oftentimes, when you see bacteria and pyuria (white blood cells) you are suspicious of a urinary tract infection. If you have a female dog, absolutely a UTI is going to be your primary concern. But there is a subset of intact male dogs that you do not want to jump to just prescribing antibiotics after you see this on your urinalysis report. Even if you do not see crystals in the urine, you cannot assume that there is no bladder stone. The majority of the time, when you have a male dog, and you are suspicious of a urinary tract infection based on your urinalysis, the pyuria and bacteriuria ends up being secondary to something else, like a stone in the bladder, or cystitis from having a stone rolling around on the bladder wall. If the signalment fits, you want to be doing x-rays or a bladder ultrasound. Or both, to be honest, because there are some uroliths that are less obvious than others. This will depend on the equipment in your clinic, and on your skillset, but you can always refer. Cystine and urate stones are sometimes described as radiolucent, or more difficult to see on x-rays. One thing to note: Do NOT assume it is struvite or calcium oxalate just because you can see it on x-rays.
So what is your signalment? A youngish (age 2-8) intact male mastiff-type breed, English and French bulldogs, occasionally pitbull type dogs.
Here are three cases that I had in the past 6 months, as well as one at a referral practice that I a shadowing.
Case 1: A 2-year-old male intact mastiff presenting for stranguria and hematuria
The first patient is a 2-year-old intact male mastiff who presented due to straining and blood in his urine.
In our patient, radiographs revealed that he had a bladder stone. We discussed that if he wasn't going to be a breeding male, that we should do a joint cystotomy (bladder surgery to remove the urolith) and castration (a preventive measure - to prevent future uroliths from forming). All of non-breeding males should be castrated. The owner, however, declined the castration, against medical recommendations.
So what do you do when your client declines castration? Well, you need to send the stone off for analysis. If the stone comes back as a cystine or urate based stone, you're going to discuss a long term low purine diet; if it comes back as a struvite or calcium oxalate stone, then the standard urinary s/o indexed foods should suffice.
This stone came back as a cystine based stone, and the owner struggled to try to get the dog on the low purine diet. Maybe they don't taste as good because they are low protein, not that I have tried them.
Case 2: A 3-year-old male intact French Bull Dog presented to a referral practice with the inability to urinate
This 3-yo Frenchie presented for an inability to urinate. Any patient that cannot urinate is considered an emergency. We see a lot more blocked cats than blocked canines. But, it does happen! The first thing to do is pass a urinary catheter to relieve the obstruction. If they are still urinating, then getting an x-ray may be the first thing you do, but in this case, since our little patient couldn't urinate, in went a catheter.
A little tip for when passing a catheter in a male dog. You can have an assistant use digital rectal pressure to guide the catheter around the pelvic brim, so when you are passing the catheter around this sharp angle of the urethra, it will be guided more easily.
Treatment for our little Frenchie was placing him on IV fluids and a urinary catheter placement for the night with some pain medication and prepare him for a cystotomy and castration procedure the next morning.
Case 3: A 20 month-old male intact South African Boerboel
My patient had been experiencing intermittent hematuria (blood in the urine) for the last year. Six months prior to presentation to my hospital he had a visit with his regular veterinary clinic and x-rays had not shown any uroliths. His urinalysis showed bacteriuria and pyuria with no crystals. He was put on antibiotics. While on antibiotics, the blood would resolve, but then a few weeks later it would happen again. On presentation to me, there appeared to be no straining, but blood at the end of urination.
I took one look at him, not familiar with the exact breed, but saw a very large mastiff-type dog, and because I had done a lot of research on our previous intact mastiff, the alarm bells went ding ding! I told the owner he has a cystine stone until proven otherwise. It turns out the South African Boerboel's are predisposed to cystine stones.
Again, not all uroliths will show up on x-rays. Even when a stone is radio-opaque, sometimes they can be difficult to see. Since nothing showed up on x-rays at the previous clinic, I offered a fast ultrasound of the bladder.
In the ultrasound image below, my patient is laying in right lateral recumbency, and I am sending the ultrasound beam from his left side towards the right side. On the far side or gravity dependent side of the bladder you can see a hyperechoic (bright white) round structure that is casting a dark shadow, within the anechoic (fluid filled or black) bladder.
Using the measurement tool on the ultrasound machine, the stone measures approximately 1.2 cm in diameter.
If your patient is stressed and will not lay down, that's ok! You can image from ventral to dorsal, panning the ultrasound probe back and forth looking for artifact shadows.
In this image, you can see that the stone is on the gravity dependent side of the bladder - which is the ventral aspect - after you do your mental gymnastic while imaging.
I had a discussion with the owner about castration and cystotomy, versus trying low purine diet since he was presenting for blood in the urine and not yet obstructed. The owner was warned that if he did get obstructed he should get a cystotomy.
Within two weeks he was in due to the inability to urinate. He went in for a cystotomy with my colleague and below are the stones that they pulled out.
Those stones went out for calculus analysis which I told the doctor where going to be cystine based on the breed. They had put him on the urinary s/o diet after surgery. Well, we just got the results back from: 100% Cystine. Guess who is getting another diet change.
Case 4: A 3-year-old intact male pitbull mix presenting for straining to urinate
About a month after case 3 presented, I had another intact male dog straining to urinate put on my schedule. A new graduate was hanging about and I said, intact male, straining to urinate - it's bladder stones.
How do I know?
When it is an intact male that is straining to urinate, it's a bladder stone until proven otherwise.
The patient was sweet, but leaking urine and urinating on everywhere! On the floor, on us. I just had to laugh as I'm trying to do my exam and he's peeing on my shoe! I threw a dipstick on the urine and it was high with leukocytes and had moderate blood.
I told the owner we should do an x-ray to check for bladder stones.
This owner had no plans to breed his pup and I discussed that castration during the same anesthetic procedure is the most cost effective means of treatment and prevention. Fortunately for this pup the owner was up for my recommendation! As you can see, a urinary catheter was placed for overnight care and he went for surgery the next morning.
Management and Prevention
#1 castration. Maybe it's just me, but I have seen a growing trend to not castrate male dogs. Part of it will stem from male owners feeling bad about castration, because they put themselves in their pup's paws. The female owners don't really care too much, except when they have a breeder contract that says they need to keep their male intact for 18 months, or something like that.
The other hesitation to castration is that some breeds are predisposed to orthopedic issues, which is thought to be related to castration prior to the growth plates being closed. Larger breed dogs take longer to mature, while smaller breed dogs are ready for breeding at 6 months of age. Castration tends to prolong the time to closure of these growth plates and is thought to cause issues like cranial cruciate ligament tear and hip dysplasia. However, hip dysplasia has a genetic predisposition, and also a dietary component. Additionally, large breed dogs are not being fed like large breed dogs (see my previous post on what you should feed your dog). What we do typically see is that neutered animals tend to gain excessive body weight. Excessive body weight worsens CCL tear and hip dysplasia. So, sadly, you cannot have a cause-effect relationship with castration alone.
The bigger question is: If your male dog has a bladder stone that is there because he is intact, and he is not a breeding male, do you want to anesthetize him every few years to have a stone removed? I didn't think so.
#2 breed predisposition. Breeders should be aware if their line of males is predisposed, since there are types of cystine stones that are genetically passed on to offspring. If you're a breeder, please educate your purchasers on the condition in your breed of dogs. There are three known types of Cystine stones. Type I: a recessive gene found in Newfoundland dogs, Landseers, Labrador retrievers and their mixes Labradoodles. Type II: a dominant gene found in Australian cattle dogs and possibly min-pins. Type III: the genetic abnormality is not yet determined, but found in the mastiff types (including the South African Boerboel discussed above), English bulldogs and French Bulldogs and only occurs in intact male dogs. Do your research before you purchase, and if you're breeding your male, be sure to see #3 below!
#3 is diet. The cystine and urate crystals in the urine are formed when there is a high purine level in the diet. When we start talking purines and pyrimidines, I am sure everyone has a glazed look in their eyes. Ok, maybe not everyone, because there are some people that love biochemistry. Not me. I had a panic attack after my undergrad biochem midterm *shudder* So, what do we need to know about purines? Purines are the nitrogenous bases adenine (A) and guanine (G) that make up DNA, in somewhat simplistic terms. A low purine diet is essentially a lower protein diet. Because of the way that base pairs work, you always get a pyrimidine (T or C in DNA) that matches up with a purine (A or G). Anyway, there are two prescription diets for dogs that are low in purines (again, I do not benefit from these recommendations!). If you can afford the canned diets, this would be ideal to help dilute the solids that make crystals form. Hill's u/d and Royal Canin Urinary UC.
As you may know from my previous post on diets, I will give my clients the option to balance a homemade diet. You can balance a low purine diet through BalanceIT.com, but similar to other prescription diets, you will need your veterinarian's approval. I also always encourage pet owners to read the reviews on the product website for all diets.
For those of you with intact male dogs, if you feel like having your dog on antibiotics several times a year has not gotten rid of that pesky blood in the urine, please consider an x-ray of the bladder and/or a bladder ultrasound! Also, consider castration. It's ok to wait until they are fully grown at a year old, but you do not need to wait until they are 3 years to neuter them after they develop a bladder stone. I can guarantee that undergoing an elective surgery for castration with adequate pain management is much less painful than trying to pee out a 1.2 cm stone!