My roommate's cocker spaniel is about 5 or 6, and generally in good health. but for the last year, he has had sporadic episodes that occur as follows:
one minute, everything is fine. the next, he starts to scream, loses bladder and sometimes bowel control, and runs almost blindly until he finds a safe spot to hide, normally under furniture. then the screaming stops, but he starts to quiver and pant heavily for at least half an hour.