Cat with labored breathing and overnight care at the vet

My cat was admitted for overnight care on friday, after a few days of labored breathing. Let's start from the beginning aka around 3 weeks ago when I noticed my cat (11F, European short hair) was going to pee every 5 minutes. My other cat died last year because of a bladder tumor and this is exactly how it started so off to the vet we go. They take her urine and send it off to a lab for culture, blood values are good, she's very overweight but healthy otherwise. They take an ultrasound, no liquid in her lungs. We go home with a prescription of cystophan, metacam and a few days later when the lab gets back to them we pick up antibiotics for a 5 days cycle. Everything looks good Last week same cat had a ecocardiogram cause she has had an hear rumor since she was a baby, it never closed and it was really loud so vet got scared and wanted us to see a specialist. Turns out it's a 3 mm hole between the left and right chamber, louder sound in this case is good. But lose weight and check it every 2 to 3 years. Ok good, we do it. On Tuesday the current nightmare began, she stopped eating. Sometimes she does that, we weren't too worried cause it usually means she ate something she shouldn't have and she'll either vomit it or poop it. Happened 2 other times already. On Wednesday she vomited at 5 am and then started peeing blood. I know what bloody urine looks like, remember cat with bladder cancer, but what she was expelling was looking like little blood cloths every couple of seconds. At the beginning she peed well a good amount with some blood, then she started going every 5 minutes or so and peed very little (her bladder was empty so duh) then she left gave up and just plopped down and would stand up and try to pee on the spot or she would have what I later found out were urethral spasms. On the same day I made a vet appointment. We went and checked: blood, all values are normal except her calcium iirc which she didn't eat so it most likely was because of it and not a deficiency cause 3 weeks ago it was normal. Kidney values normal. X rays showed her stomach was empty so they said an ultrasound wasn't really needed. I let them give her an infusion to fill her bladder and take a urine sample and they did. Bacterial culture hasn't come back yet but they found blood traces and some very few crystals but the doc suspicion is that the blood causes the crystal and not the opposite. We took her home with prescription metacam for 5 days, cystophan, zylkene and appetite stimulant. On thursday her breathing get worse, we decide to wait. We bring her in for a check on friday, as I said at the beginning, because her breathing overnight got heavier. The vet immediately told us they would need to admit her for overnight care, she got started with antipyretic cause she had extremely high fever, and a double antibiotic to cover most bacteria. Because it's the weekend, no labor is open so blood culture is out of the question until monday. Xray showed a thickening of her lungs, that's why she breathes so heavily, she (vet) told us she's gonna call us this morning. She called us this morning and told us that her breathing got heavier during the night but remained otherwise stable, fever got better even without antipyretic. She would have to keep her under observation, labor got back to them for the urine culture, it's ecoli. The antibiotic she's already giving her work against it so its fine. A couple of minutes ago vet calls again, her breathing got worse, xray shows further thickening, vet says it shouldnt be reason for her to breath so badly though, even though the walls got thicker. She says she saw something in her stomach but would have to check with the ultrasound specialist on TUESDAY. Something in stomach = how can it relate to the lungs? No fluids around her lungs, she will repeat the blood tests tomorrow and see what they say. I am honestly shaking, I had 3 cats at the beginning of 2023, 2 at the beginning of 2024, I don't wanna end up with 0 in 2026. Is there anyone out here who can help me???? They are not an er hospital, I asked whether it would be a good idea to bring her, she told me since it's the weekend night it's mostly students anyway and she's not sure how well they would be able to diagnose her since the big bosses are mostly not there on the weekend. Idk what to do, what to say, what to ask, I just want some answers.

Hello - and I'm so sorry to hear about all that is going on with your cat.  What a puzzle!  Getting up to urinate every few minutes might indicate bladder cancer, especially in an older cat.  However this is rare and there are plenty other possibilities.  Your vet will have ruled a lot of common problems out by now. Most commonly, the urinary symptom is reported with cystitis, inflammation of the bladder, which is not usually bacterial but brought on by stress, often in combination with other lifestyle factors.  If your cat was already suffering from an underlying illness at that time, this may have added to the stress (from your point of view, the problems occurred the other way around - but cats are masters when it comes to hiding illness).  Cats can also become stressed by everyday things that humans would never perceive as stressful - so it can be difficult to pinpoint. In this case it sounds as though your vet feels that a bacterial infection may have been involved.  I haven't seen the evidence for this but a lab pathologist or even a specialist who can see your vets work-up, could comment on this.   I am at a loss regarding the 'thickening' of the lungs but again, it sounds as though your vet is seeking advice.  Sometimes it can be related to the speed of fluid delivery; your vet may be able to rule this in or out.  There are worms and other illnesses that can cause this. It does sound to be a puzzle at this stage, with the bladder, the lungs and the gastro-intestinal tract (ie. vomiting) all affected.   Other things that I wondered about are pancreatitis, a hidden disease that causes pain (thereby stress) and only occasionally presents with vomiting.  It sounds as though your vet is concerned about and treating for widespread bacterial infection; viral infections may also be on the list.  Your vet will have a problem list and be slowly ruling illnesses out, starting with either the most likely, the most urgent or the easiest to rule out - until they get to the bottom of it. Meanwhile, there is a job even more important that diagnosing your cat - and that is looking after her - balancing the multiple symptoms and making sure that she is well in herself i.e. has fluid as necessary and drugs as appropriate to treat any symptoms.  Regular assessments of the case, in person or by phone, may help with this. Good questions for your vet may be, 'What has been ruled out so far?' and 'What could still be causing this?'  'Have your ruled out pancreatitis in this case?'  'What other differentials (possible diagnoses) are you concerned about,' 'What is the simplest explanation for the problems your have seen' and 'What do you think we should do if we can't pin-point the answer?'  I hope that they are able to reassure you a little in this complex case.  'Would referral to a specialist be a good idea' is another possible question. Please will you come back and let us know how you get on?