It's a surprisingly tough call when more testing/imaging is actually beneficial, and it's constantly up for debate in medicine.
This is tough for folks who aren't medically trained.
Very interesting, and actually kinda reassuring to hear.
During the final 8 hours of our beloved cat's life, the vet at the emergency clinic suggested that they keep him for the next 24-48 hours to stabilize him (IV fluids, enema, antibiotics, bone marrow biopsy, and probably some other stuff I don't remember) and then re-evaluate. Cost estimate: $3500. Of course we were in an agony of indecision, grief, and tears, and hope is a powerful motivator. But I asked her if those 48 hours would result in concrete answers as to whether the chemo treatments were working -- he had GI lymphoma, which is very aggressive, and it had relapsed. She said "it might. Hopefully." My thought, despite our grief, was "$3500 and the result is a *maybe*?!?" I realize the vet could not give us guarantees, but she also didn't really suggest euthanasia as an option. And yeah, her job is to give us options and of course it's not their decision to euthanize. But he was 16-17 yrs old, and even if the chemo did work, we'd have weeks left, maybe a month or two if we were very lucky. More importantly, his last 48-ish hours had not been good for him. A bone marrow biopsy sounds painful, and he was already miserable in the clinic. Why put him through another 2 days for a "maybe"? So we said goodbye, even though the vet was suggesting further treatment. My heart still holds a tiny bit of resentment toward her, though I know logically it's probably just a reflection of my grief and guilt.
Anyway, that was a long story to say that I didn't realize there were debates going on in medical circles about whether more testing/imaging is beneficial to the patient. I had just assumed my indecision was emotional.
Oh indeed.
Here, let me give you a human example.
I get a certain treatment for my spine. I initially went to the US because there was only one clinic I could get in to during the pandemic. They did thousands of dollars in tests to justify the treatment.
Two years later I got in to see an MD in Canada who was trained by the exact same expert as the clinic in the US. He did NONE of the initial tests and didn't even bother looking at the ones that the US doctor did, because they don't change the indication or the outcome of treatment. In fact, the imaging the US doctor did is banned in Canada because it isn't useful or worth the risk of the exposure and the fear created by incidental findings.
I personally have been sales pitched just about every single modern diagnostic imaging tool in existence, and have never once felt there was enough benefit to justify their frequent use for my particular area of expertise, which tends to very commonly use expensive imaging as part of their profit driver AND as a major treatment justification tool. Advanced imaging is useful for other areas, just not mine.
It's A LOT easier to get someone to spend thousands of dollars on treatment when you can find something on an image and say "see! this is what's wrong." Except the relationship of findings on imaging to actual diagnostic fact are nowhere near as one-to-one as people are led to believe.
Did my US doctor find stuff on imaging? Yep
Does it explain my symptoms? According to him, it does, and he's very convincing
Does it have any impact on my recommended treatment? No, he was going to recommend the same treatment regardless of what the tests show, they're just a way for him to make more money and make his recommendation more compelling at the same time
Does he 100% believe that his testing is necessary and beneficial? Oh you bet, with a fervour that borders on religious conviction
Another example is that even regular mammograms are hotly debated as to whether they help more or harm more.
Every single test we order has to be analyzed in terms of the risks and benefits. More testing is not fundamentally better, but there is little agreement between professionals as to where the line is, especially when there are professionals whose beliefs are heavily influenced by their own self interest.
As for your specific example, my vet always offers euthanasia when a very old animal presents with extreme pain. The probability of the animal surviving in great shape should be assessed before subjecting a likely dying animal to more pain and indignity away from their family.
I will personally never again let a vet take an animal away from me for a few days of observation and testing if there's a good chance the animal will die. I wouldn't want that for myself, a million times over I would rather the risk of dying a bit prematurely than spending my last days alone, scared, not knowing what's happening, and being tortured by scary doctors who I can't communicate with who are motivated by money to keep torturing me.
People reading my journal know that my little dog had a health crisis last year and I wouldn't let the vet take him overnight, his symptoms were too vague to have a clear indication of what was happening. He needed fluids, so I asked for fluids and syringes to do sub-Q injections myself. If he was dying, he was going to die at home, curled up with me while we waited for test results, not alone in a cage, abandoned by his family to people who hurt him. It turned out he had pancreatitis, which could only be managed by watchful waiting and fluids anyway.
Will my approach one day result in the death of an animal who *maybe* could be saved by timely, heroic, advanced medical intervention? Yep, very possible. But it's guaranteed to prevent a lot of my critters from spending their last, painful days feeling terrified and abandoned.
If I thought spending 5-10K had ever made the death of one of my animals better, I would think differently. But I'm someone who has dealt with A LOT of animal death because I've adopted so many very old and sick rescue dogs, so I've had an animal die every year or so for a very long time. After the 5th or 6th time I went through the expensive vet hospital horror show, I stopped being willing to play along.
I took my 17 year old long-spine/short legs dog to a vet hospital a few years ago only because he woke up screaming at 2am after jumping off the bed and my vet wasn't open and I needed pain killers for him immediately. I ended up in a screaming fight with the vet who tried to tell me that he should be kept for a few days for a cardiology consult for the murmur he had had his whole life, and a dental consult for the canine that had been broken for a decade. My dog could barely walk and they were offering literally no treatment for what was obviously a spinal problem because it wasn't showing up on the xray, and there really isn't a treatment for a long dog whose spine is fucked.
They didn't want to keep him because of the pain that was making him scream. They were using his pain as an opportunity to keep him and guilt me into a bunch of treatment that wouldn't even help his pain. But they kept saying that since the xray didn't show anything, they couldn't rule out that his other issues weren't the source of the problem and he "really did deserve thorough testing because he's obviously such a good dog."
When I insisted he couldn't live with his current level of pain, they offered NSAIDs. Fucking NSAIDs!
I have a spinal injury, NSAIDs aren't going to cut it.
When I heard him screaming in the back room as they tried to get a urine sample from him while lying him on his injured spine, and were telling me that NSAIDs would manage him just fine, that's when I broached the subject of euthanasia and they aggressively shamed me. I snapped and went into full on fucking beast mode, which I've been told is abjectly terrifying.
By that point, my vet's office was open and his regular vet agreed it was likely his spine, that even if surgery was an option, with his age and heart condition, it wouldn't even be worth trying. The only meds strong enough to make him comfortable were strong opioids, so that's what we dosed him with until his vet could make time to put him down at the end of the day. He spent the rest of his last day high as a kite, surrounded by everyone who loved him, and he got a cheeseburger, which is our family tradition.
My vet even says "I think we need to consider a cheeseburger as a reasonable treatment" because we've been through this so many times.