10yo dog defecating and urinating in the house every night

Our 10 year old Pointer x Staffy has been both defecating and urinating in the house every night for the past 8 months. We have been back and forth to the vet for multiple inconclusive examinations. About 8 months ago, he was given a venison ear as a treat which upset his stomach and resulted in a bad bout of diarrhoea. Since that day he has both defecated and urinated in the house every night, sometimes up to 2-3 times a night. We have done urine testing, tried a behavioural medication (Fluoxetine) and most recently a stomach ultrasound to ensure there was nothing leaning on the bladder. All of his tests have come back fine. He eats drinks and he’s happy to exercise as he usually would. He is able to hold his urine in the day and isn’t incontinent or leaking. The vet is now looking at DISHAA as a possible option but we just wanted to see if anybody had had a similar experience or any insight.

Hello - It's great that your vet has ruled out a lot of problems already.  This may still have a medical or behavioural cause.  Sometimes animals avoid going outside because it hurts to get up, so they tend to delay doing so and then accidentally leave it too late.  It stands to reason that you might have become aware of this when your dog had diarrhoea, which is often quite urgent,  but it could be that there is an underlying issue such subtle arthritis, which is not always found on a clinical exam.  If your vet thinks that this might still be a possibility then a pain-relief trial may be worthwhile. There may also be behavioural reasons.  For example, a dogs' nose is many times more sensitive than a human nose.  If a human nose is picking faeces up, owners tend to clean like crazy until they can no longer smell it.  However, dogs sometimes continue to smell faeces and convince themselves that the site of a previous indiscretion is a viable toileting site.  Furthermore, they may have become a little concerned by something in the garden - a visiting fox for example - and be avoiding going outside or urinating / defecating in its territory. It is interesting that defecation and urination are both affected; for me, this makes e.g. a specific bladder or a specific bowel problem less likely.  However, confusion or cognitive dysfunction may be an issue and many early signs of it can be subtle and difficult to pinpoint.  There are questionnaires designed as a tool for picking up early cognitive dysfunction - perhaps your vet could access one for you?