When a dog-owner calls and says that his dog is dribbling a little urine, you think of the usual suspects: weak bladder sphincter, bladder infection, bladder stones, neurological problems. You do NOT think of an enlarged spleen.
Max (this is his post-surgery photo) is a Mastiff mix. He's about 8 years old (a guess, as he was a stray originally), and usually weighs in the low 80's. For several days, he had been dribbling a few drops of urine after he watered the shrubbery, even though he had a good stream when he let fly. He had also leaked a puddle where he was lying down on a couple of occasions.
With that kind of history, I usually want a urine specimen first. You usually need to culture the urine, so a voided sample is not good enough for that. You just can't get an uncontaminated specimen when the dog pees in a cup. What you need to do is a cystocentesis — you lay him down on his back, do a surgical prep on his tummy, use the ultrasound to locate his bladder and insert a sterile needle. Then you withdraw some urine with a syringe and you're ready to do your culture and urinalysis. The specimen is not contaminated, and you don't have to follow the dog around the yard with a cup.
We lay Max down and scanned his bladder, and found that it was being compressed by a large mass of tissue. Further scanning showed this to be the tail of his spleen. An X-ray confirmed that his very large spleen was extending from his stomach all the way back to his bladder. It was so big and heavy that the weight of the organ was compressing the bladder and causing Max to leak urine. Sort of like a lady with an advanced pregnancy — when the baby is bouncing on your bladder, you can have an "accident".
Even in a very large dog like Max, the normal size of the spleen would be about one and one-half times the size of my hand — ten inches long and 1/2 inch thick would be a big one. This was just unreal. [It's the long, curvy red spot in the diagram.]
Your first thought would be cancer, but the ultrasound scan showed no masses or changes in texture. It just looked like a normal spleen… only huge. And… why is that? I sent out the usual panels of blood tests and they were all normal.
I spoke with an internist at the Veterinary Teaching Hospital at the University of Missouri and she said, "There is huge list of differential diagnoses." So huge, apparently, that she just listed a few for me to get started with. "Screen for tick-borne diseases". [We sent off the blood tests.]
"It could just be twisted a little, or have a partial thrombus [blood clot] in the splenic vein." [Blood can get pumped in by the arteries, but can't get out as fast, so the spleen gets gradually bigger and bigger by being inflated with blood.]
"You should still consider cancer. Try aspirating the spleen." [Stick a needle in it and see what a syringe will suck up.] Since the spleen is structurally a big sponge full of blood, we'd probably just get blood cells, but she assured me it would be safe. So I did.
"If you don't find anything on your tests, then you need to take a biopsy specimen. Well, if you're going to do that, just take out the whole spleen." [You can live without it, if you have to.]
So, no tick-borne diseases. The cytology report on my needle stick says "suspicious for lymphoma", but could just be some kind of inflammatory reaction. With a needle aspirate, you're looking at individual cells and you don't see any kind of architecture. It can be misleading. And it was.
Next step: exploratory surgery to remove the spleen.
His spleen was 28 inches long and weighed six and a half pounds. It wasn't twisted. It was a lot of work to get out. This picture reminds me of people with their trophy fish. In fact, I've seen plenty of trophy fish that weren't this big. We sent several sections to the pathologist, and it's not cancerous. It's just "severely congested" (i.e. really overfilled with blood).
It was so "over-inflated" with blood that wherever I bumped it with a finger it would break and start bleeding. I didn't lose any blood from the major vessels as I tied them off, but the rest of it was bleeding like a cartoon character shot with a shotgun. He was at no small risk of the organ rupturing and having severe internal bleeding.
The good news is that his prognosis is good. We still have to check a few things to look for reasons he might have had a blood clot in the first place, but no deal-breakers so far. The first picture in the post shows him the day after surgery and he already felt better. Nine days later he is recovering his energy level and seems to feel really good… and he's not wetting himself.