Change in older dogs behaviour

Question
Hi
Tommy our almost 12 year old mini-poodle, has come with issues that we've learned to deal with over the years. We got him when he was a year and a half old from the SPCA - he only spent one night there -but we do know that the couple who returned him did so because they felt bad leaving him alone for 12 hours a day. He was so sweet and wonderful for the first month - we never heard him bark - ever! But once he got used to things - he got into his own routine. He has separation anxiety - follows us around if he senses we are leaving - he rarely is not in the same room as me if I'm home. He's barked and urinated when we've left him, and when he was younger would destroy things too if and when we left him..
He'd also be overly protective in his barking- we live in a 4-plex - and he'd bark at any noise outside our door - i.e. any time anyone else comes up or down the stairs - rather than just when someone is at our door.

This is all stuff we've grown used to - and he's been on Clomicalm for years now. This has helped somewhat - but as I said - we've had him for almost 10 years now and we know that he's got special needs and have learned to live with them.

The problem is that recently - he's become quite aggressive when we wake him at night to take him out. Originally he'd just growl or groan - but he'd let us put his leash on and take him. Lately it's become worse - he's growling, snarling and biting. My reaction at first is to say no - then back off and leave the room (he's still into following me) and when he's awake and no longer in la la land - he lets us put his collar on and off he goes for the nightly "drag"... He still does everything that he has to - so it's not a matter of not "needing" to go to the bathroom. Thing is my husband wants to show him that he's not the boss of us and will fight back - which of course never comes to a positive ending.

I have an appointment with the vet in a week (he's out of town) - but in the meantime - I'd love some advice if anyone has seen a change in behavior before like this and if you have any suggestions.
Thanks!
Diane

Answer
Well this does sound like it could in fact be a medical issue,and is a symptom of many hormonal issues,such as hypothyroidism,cushing's disease or addison's disease,all common in older dogs and poodles are esp prone to cushing's-but all these disorders can be easily controlled with daily medication

It could also be a problem with his joints,which again is common in older dogs

It might also be that he has decided he wants to be in charge,and in this case spraying him with water will often work and saying 'no' loud and firm-but it will be best to see the vet first,because if it's a medical problem,correcting him might make it worse