4 year old cats are worrying me

I have two cats aged 4 they are litter mates. Been together since day 1. They have a couple chronic medical issues that i can deal with but lately my boy has been feeling like he's losing weight except when i weight him he weighs 10 lbs which the vet says he should weigh around that. But I'm starting to be able to feel his spine and ribs and hips. And he can't jump onto the low windowsill like normal. He came running out at me meowing with a hoarse voice like he was in pain. And my girl wasn't able to jump onto the couch which has never been an issue before. And when she lays down it looks like she's favoring her hips and back legs. Like they are paining her. They are going to the vet on wed. But i just don't know what to do about them now. They both act like they are in bad pain. They always show me when they are hurting or sick and after taking care of so many cats i know how to handle just about anything that can run my way with them but I've never seen this before and i don't know how to handle it. Any on else see something like this? Anyone know what i can do to help them?

Do they have any other symptoms? What chronic issues do they have? How long have you noticed these new issues?

I noticed last night my boy looks like he isn't bathing but i have seen him bathing himself. His fur looks like he hasn't bathed in a week. They have chronic upper respiratory infections that won't go away. It will with antibiotics but as soon as they are done it comes right back like almost instantly. The vet says as long as they are doing ok she won't put them on antibiotics. When it acts up and they get lethargic and feverish then they'll get antibiotics. My boy also has an issue with one of his eyes but its not causing any problems so far. They also have malabsorbtion issues but i put probiotics on their food and that takes care of that. This morning my girl was looking like she doesn't want to get up. She will if she has to but its like its really hard for her. She slept on the floor where i could touch her next to the bed all night so i know she's not feeling good she does that only when she's sick. I tried to get them into the vet this morning but they didnt have any appointments for today.

Oh and i started noticing all these new things around sunday night. By monday night i started getting concerned that's when i saw my girl not be able to jump on the couch.

I would be suspicious of Calicivirus as some strains can cause muscular pain. It's more common in kittens and is known as "limping kitten syndrome". But, your cats are immunocompromised and could certainly have this.

Calicivirus is a virus that causes upper respiratory issues.

I wonder if your cats suffer from chronic Calicivirus or feline herpes.

Have you ever tried them on L-Lysine (a supplement)? What about Famcyclovir (an antiviral medication)?

There is a fairly new treatment protocol out for feline herpes that I have had success with for those cats that have chronic flare-ups.

I haven't tried either of those i haven't heard of this before. Ill have to ask the vet when they go in. My girl does have an issue with one of her eyes that the vet said was a type of herpes. She said it was kennel herpes is what she called it but she's never been in a kennel so we don't know where she got it. The vet said its common and happens mainly in shelter cats but my babies weren't shelter cats. I got them right from the lady who rescued them. She's gotten ointment for it before but it didnt do much. I've been trying to find something else to try.

So i wanted to update. They went to the vet yesterday. my boy seems fine he hasnt lost any weight so the vets not concerned about him looking skinny. hes exactly where he should be. but my girl concerned him. she jumped off the vet table and her back legs buckled under her she fell to the floor. she hasnt been able to jump up so this was the first ive seen her jump down. she got right back up and walked around but the fall was concerning. the vet did mention the two things above and suggests i get them on l-lysine. im going to get some tomorrow when i get paid. vet took all my money. she got blood drawn and they said she was really dehydrated tho i know shes been drinking a lot. so they put fluid under the skin to help. they had me get a urine sample out of her. which when i got it it had blood in it. the vet called today with the results and says her levels are crazy off and there was bacteria in the urine and she shows muscle trauma consistent with getting hit by a car. shes indoor only never been outside a day in her life. she doesnt even go onto the balcony. the only thing she gets is tackled by her brother. she wants to get her on antibiotics even tho her white blood cell count is normal. she thinks its a kidney problem. shes sending the work to another lab to get them to analyze it. shes going to try and rule out a kidney issue if she can. my girl hasnt gotten any better. shes lethargic and just lays on the floor all day. she was walking this morning and her back end fell into the wall. she gets up and gets food and water but i have yet to see her use the litter box and she gets up only to follow me and my husband when we move around. she wants to be close at all times. my boy stays close to her knowing his sister is sick. im so worried my stomach is in knots and i started crying when i got off the phone. i cant lose my baby girl. shes too young i cant handle that.

I am so sorry to hear about your girl. Hopefully with antibiotics on board she will start to feel better.

Do your cats like wet food? Giving this with a few extra tablespoons of warm water or low sodium chicken broth is a good way to get extra fluids into a cat. Tuna water is another.

Let us know what you find out with the other lab work.