I wanted to add a couple of things that I left out of my first post.
First of all, you mentioned that his body was flopping. In all likelihood that was from damage to a nerve when he hit the ground. If he landed on his head it could have been a seizure. If the vet does MRI he'll be able to tell if it was a seizure or nerve damage.
I have to agree with you that these days it seems that too many vets are in the business to make money rather than to help animals. True enough, there ARE, unfortunately, many people who just NEVER pay their bills but there are more who DO, and it's sad and frustrating for those of us who DO pay what and when we are supposed to that we are forced to "pay up or get out" because of those who don't. This, to me, is why it is extremely important to develop a good rapport with your vet, because if a situation like this (in terms of large amounts of money needing to be put out) arises, if you have a good relationship with your vet and they know you as a person and not just as a client who comes in once a year for shots, they are more likely to just begin treating the animal and worry about the money later.
In terms of money in this case, however, it's a bit of a different situation because this is an Emergency Vet and not your regular vet. Emergency vet clinics ALWAYS charge an arm and a leg because the vets and technicians who man them are doing extra hours. These clinics usually don't have a regular staff, they are manned by vets and technicians from several local animal hospitals who make their services available on a rotating basis. Normally there are 10 or 11 clinics (sometimes more) who make up the staff of emergency vet clinics. The emergency clinics open at 8:00 pm (usually) after the normal hospitals and clinics close for the day. They usually remain open until 7 in the morning, when the regular clinics and hospitals open for the day. Some of these people work 3 and 4 straight shifts between their regular hospitals and the emergency clinics. There ARE cases that come in that are not truly emergencies, they are instances of owners panicking and being afraid to wait until morning, but for the most part, the cases that they DO see in these places are very serious. Lots of traumatic injuries, hit-by-cars, dogs with bloat (need immediate surgery or dog will die), etc. These cases require a LOT of manpower to treat and CONSTANT vigilance. The crew can't just pop the animal into a cage and sit and watch infomercials until morning. So I CAN see a certain amount of those high charges being justified. But some of them are double and triple what you would be charged at your regular vet, and those are the ones I think are very unfair. The vet's first concern should be to help to relieve the animal of its suffering, but I have seen people with badly hurt animals turned away by these places because they did not have the money when they brought the animal in. Shame on those vets! Even if they told them "I'm really sorry, but if you can't pay, all I can do is euthanize your (dog, cat, whatever) to relieve it of its suffering" that would be better than having the person take the physically traumatized pet back home wrapped in the same bloody blanket it was carried in on just because of money. Let me stop before I get on my soapbox over this.
Ghilly
I have to say that NO, you are NOT going overboard on the vet! Chihuahua puppies are EXTREMELY fragile and even though most of the posts here that were about chihuahuas being dropped didn't say that they were hospitalized or even that they took them to the vet, they SHOULD have ALL been taken to the vet IMMEDIATELY after their falls.
Chihuahuas are the only breed of dog that have a molera. The molera is a soft spot in the skull, comparable to the human baby's fontanelle, the difference being that the fontanelle closes as the child grows, the chihuahua puppy's molera stays open for its whole life. Brain injuries are common in chihuahua puppies for this reason. Too many people do not take these injuries seriously enough and even though their puppies may SEEM to be OK after their falls, these injuries can lead to all manner of problems down the road. They can even lead to sudden death.
By allowing the vets to do the diagnostics they are doing, you are eliminating these possible problems and making sure your puppy will make a full, uneventful recovery. Please don't beat yourself up over this. It was an accident. You quite obviously adore your dogs and this puppy in particular and I very much doubt that you would have intentionally done anything to put him in danger. Puppies are unpredictable, they're little wiggle worms, and sometimes they do things unexpectedly and don't leave us any time in which to react.
IF, as the vet seems to think, he has a fractured vertebra, then staying at the vet's is the best possible thing for him. A fractured vertebra that is left undiagnosed or untreated can lead to seizures, paralysis or even death. Don't take any chances. I realize it's a whole lot of money, but if you want to save the puppy it's something that needs to be done.
Please keep us updated on his progress. You are in my thoughts.
Ghilly