Dog Falls Over:

I get a lot of 'older dogs' that are 'falling over' and there are some important questions:
1) Falls over floppy and lifeless?
2) Falls over all clenched up or paddling?
3) Falls over like, back-legs-gave-out?
4) Confused, or aware?
5) ASsociated with a yelp or howl?

There are more than four reasons for a dog to fall over.

Falling over floppy and lifeless usually means the heart stopped for a few beats. That's called "Syncope" and it costs about $1,700-$2000 to prove it. Treatment is a pacemaker. That's another many-grands. All this is done at a veterinary corporation or University of Georgia. Not here.

Flopping over tensed up, shaking, or waving all their legs (paddling) maybe even chattering chewing - is epilepsy, and what you saw was an epileptic seizure.

Flopping over like their legs gave out, is JUST that, a problem with the nerves to the legs. This is the most common cause of falling out "aware"

Conscious (aware) or unconscious is an important differentiator.

If there's a yelp or a howl, that often represents pain and is COMMON if their heart is skipping a beat. They are barely semi-aware but they may look terrified while that's happening especially if it's running in triplets. I have videos on drjohnson.com about Syncope.

MOST of the time this is a pinching nerve in the backbone. (Spine) and when they fall out, it releases. Other times it's simply 'inagility' meaning they just lost their footing which is easy for old timers. Rare on pavement, common on slick floors.

Quite often these can be separated by video provided by the owner, the physical exam, and other resources. Sometimes a treatment for one or the other most common cause brings relief and then the diagnosis is made in reverse.