Good Morning Rebecca and welcome. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry to hear that Poppy is having these stressful episodes.
From what you have described, Rebecca, I believe that these are Petite mal epileptic seizures. You are correct, Rebecca, that if this were a ruptured or partial ruptured disc in Poppy's back, this would not resolve so quickly.
Because of Poppy's age, I would worry that this could be due to Liver disease which causes neurologic issues or a brain tumor especially since she has had so many. Seizures do not always manifest as gran mal seizures and the ones that Poppy is having are less dramatic but still is an episode. This screaming is probably not due to pain but due to an unconcious issue. It is actually a good sign that Poppy is not having gran mal seizures since this would be more serious for her but they can move into gran mal seizures.
The best thing to do if it has not already been done is to run blood work to determine if this is due to a metabolic malfunction such as liver disease . If this is ruled out, an MRI can determine if there is Idiopathic Epilepsy which means that we do not know why this is happening or a brain tumor.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please Reply so I can clarify for you
Sincerely, XXXXX XXXXX