Welcome! My name isXXXXX am a 2003 graduate from UC Davis, and currently a Medical Director of a veterinary hospital.
I am sorry to hear about this concern for Oreo.
First, I don't think this particular incident and what you observed is pain related.
It looks a lot like a seizure event. You described it quite well, even commenting on the time frame after, which suggests he was in a post-ictal period (what follows a seizure) for about 30 minutes.
Now, sometimes, a heart arrhythmia event can look a lot like a seizure, but once the heart is back to normal, there is no delay to getting normal again.
So, in consideration of it being a possible seizure, I do feel this is strongly worth a vet visit. Not necessarily to start treatment just yet, but to ensure there isn't a specific internal issue that needs to be addressed.
Seizures are generally caused by:
1. Intra-cranial disease (something inside the head including infections, inflammatory conditions, and cancer)
2. Extra-cranial disease (anything outside of the head including organ problems like liver disease, infections, electrolyte abnormalities that can be caused by endocrine disease like Addison's, cancer)
Initial testing usually includes a basic blood profile, which should be done immediately.
If a blood test does not reveal any abnormalities, additional testing would possibly include:MRICSF TAP
- to check for evidence of inflammation or infection within the spinal cord or brain.
If you would prefer to see a specialist, your primary veterinarian can refer you to a neurologist, or you can find one yourself and go without a referral by using this link:Find Various Specialists
--> Under "specialty" select SAIM = Small Animal Internal Medicine
--> Or, you can search for a Neurologist, Cardiologist or Oncologist
Now, what about your question!
When in pain?
Well, I would expect symptoms like:
1. Becoming aggressive when touched a certain way.
2. Excessive panting can be due to discomfort, although can be seen with nausea, after a seizure, and hypothyroidism (low thyroid hormone)
3. Exercise intolernace or not really wanting to walk anymore
The heart murmur is not of much concern for routine testing like a blood profile. My own Cavalier has a grade 5 to 6 out of 6 heart murmur and does quite well for blood draws.
I hope that information has been helpful.
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