Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today.
With regards ***** ***** question, it could be but there are a number of issues that can increase thirst and urination in dogs Bruno's age. Specifically, besides kidney disease, this could also be related to liver disease, or a hormonal issue like diabetes, Cushing's disease (where the body makes too much of its natural steroids) or we can see it related to some cancers (that cause elevation in blood calcium levels). I'd also note it can sometimes also be related to bladder infections but usually they urinate more often not larger volumes.
To get to the bottom of what is triggering Bruno's signs, it would be worth having him checked by the local vet (if he is due for a vaccination soon, you could move it up a wee bit early and have him checked out at that time). The vet will be able to have a feel of him and just make sure there are no sinister lumps and bumps to blame for his signs. As well, you may consider having the vet check a blood or urine sample at this stage to give you an idea if his organs are in distress or if a hormonal issue is to blame for his signs. Now in his situation, I would say that blood sample is ideal here. It would allow you to identify any organ dysfunction and would allow you to appreciate how severe it may be. As well, hormonal diseases like Cushings can give your vet hints that they are present on routine bloods. That said, a urine sample can be an economical and non-invasive means of ruling out some of our concerns. For example, urine can be tested in-house by the vet to check for signs of diabetes (ie. sugar in the urine), urinary based infection (ie bacteria, white blood cells --which can contribute to the signs), as well as check its specific gravity (how concentrated it is) that can tell us if there are problems with his kidneys lurking. And that can be done just by taking in a fresh urine sample (even before Bruno is checked). Depending on the findings of your vet's exam and bloods/urine, you will be in a position to know which of these concerns are affecting him, how you can best address them, and what his long term prognosis may be.
Overall, I share your concern about your lad's increased thirst and urination Therefore, in this situation, it would be ideal to consider taking some steps with his vet to rule out and identify which of the above conditions are behind his abnormal signs. Because the sooner we can do so, the sooner we can manage this to reduce any further development of signs.
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