I am new this forum and unfortunately have also come upon it by researching my pups nosebleeds. All the symptoms sound the same:
Pepper is a 14 year old dane/lab dame - so yes a large breed on the senior side of life.
First there were intense nosebleeds only from her right side
The vet was unable to find anything abnormal in her blood or urine.
We got some antibiotics and antiinflammatory steroid and they seemed to help. Once we stopped the treatment a little bit of blood started coming back out of her right nostril but nothing like before. Then the past two nights she could barely breathe and this morning there was still a little bit of blood again on her right side but big gobs of thick yellow discharge out out her left side.
I am not sure if that is a good sign or a bad sign. I haven't read anywhere here that your pups also had a yellow discharge. Could this possibly mean that it is an infection afterall? Our vet is putting her back on the antibiotics for now as we are waiting to hear back from the veterinary school in st. Hyacinthe which seems to be the only place that has a 3d xray scanner to set up an appointment.
Thank you very much in advance for your input! My hearts go out to all of you and your 4 legged loved ones!