Just for curiosity's sake, one of my clients, a cocker spaniel, came in a couple of weeks ago. She's not the best cared for bless her, usually has a few fleas and knots, and the father-in-law who has her on the day and brings her over said she had suddenly started limping when he'd got her out from under a chair or something to bring her to me (she's not keen on getting in the car or going to be groomed so was hiding). She had a tick on her face I removed, and also a grass seed in the paw of the foot she was limping on which I managed to pull out and she seemed a little happier. When the owner picked her up she was startled by the limping as she hadn't been doing it that morning, and I told them about the grass seed and suggested they take her to the vet in a day or two if it was no better as she might have another grass seed or an infection in the foot, or perhaps a pulled muscle. I was startled today to be told by the grown up son who I work with that the vet had diagnosed a pyo and said if she'd gone in a day later she would have died!! I've never heard of a bad limp as being a symptom of this, was it just a very lucky coincidence or could the pain of the infected womb have made her limp?? She was barely touching foot to ground.

We didn't have a limp with a pyo, just a bitch who slowly became unwell until she was barely eating & lethargic........

I've never had experience of a pyo but Marianne would be able to give you info.  Hopefully she will see your post.

Now I think of it, Barbara has spoken of pyometra too.

Well I've never heard anything like it but can't help wondering if the leg was incidental and not actually part of it, and the vet spotted more common symptoms of pyometra when seeing the dog and questioning the owner perhaps.

That's what I wondered - I wouldn't have noticed her being lethargic as she's always depressed about coming to me to be groomed poor girl. And any odd smells I would have put down to her manky ears, general grubbiness, or an infection from the grass seed in the foot. Oh well, sounds like she was a lucky girl!!

This was, presumably, a closed Pyo - no nasty discharge?    I too have been lucky not to have experienced one in all our bitches (and I have a theory, probably wrong! that as we never took our bitches in season off our property, they didn't squat in the wrong place .... Bassets are low to the ground and those part almost always touch with ground to some extent when they 'go') but I'd question the lame and a pyo.   Lethargic for sure so maybe limping was part of that?   Interesting but the vet did a good job of spotting this before the worst happened.

I didn't see any discharge myself, and the son probably wouldn't know (he's moved out now so doesn't have regular contact with dog or parents), he just said infection in the womb. I guess the vet spotted either a discharge or a tenderness in the area while checking out the leg problem. Phew!

I wonder if it was referred pain from womb swelling triggering a nerve. I know one of the symptoms of ectopic pregnancy in humans is shoulder tip pain. Seems bizarre but it's caused by nerve pressure from the fallopian tube.