Why are my cat's creatinine levels high after a UTI or cystitis?

This does indicate kidney disease but not necessarily permanent. Cystitis can cause improper emptying of the bladder. If the bladder gets backed up, it affects the kidneys and can spread the infection there. Clearing the infection and getting the bladder emptying properly can resolve those values. You can switch him to a kidney diet and make sure he gets plenty of water. I would recheck the blood work in 1-2 weeks and see how the numbers compare. If they are worse, then you likely have kidney disease and he may benefit from IV or SQ fluids. If they improve, then it may have been a result of the cystitis and medicines

Creatinine of 8.8 is very high and indicates kidney disease/failure. This can be due to a back of urine from the bladder into the kidneys if he had a urinary blockage. Typically this is irreversible damage but only time will tell. Dehydration would not affect the creatinine to that degree. He should be put on anti-nausea medications which may help his appetite.

Every lab has different reference ranges, so according to the lab that your cats blood was run in, the BUN and CREA are considered to be mildly elevated. However, unless your cat has a low specific gravity (concentrating ability of the kidneys), we have to assume that the BUN and CREA levels are not indicating any kind of kidney failure. In other words, if the kidneys are concentrating normally, and the pet is asymptomatic, then the BUN and CREA levels should simply be rechecked at a later date or another more sensitive test called the SDMA test should be done to clarify what is really going on with your pets kidneys. So based on the information you have provided we cannot say if Frodo has true kidney disease, but if his urine test was negative for bacteria then no infection is present. Ask your vet about Frodo's specific gravity and if that was normal or not. If it was normal, then go forward with the SDMA test to confirm that the kidneys are ok. If you need further help regarding your pet Frodo's case, since this can be a bit complicated to explain on the forum, please feel free to request a private consultation with either myself or another expert here and we will be more than happy to assist you further. I hope that this helps and best wishes with your pet Frodo moving forward! Take care: )

She probably has cystitis and not a UTI. It is not impossible that she has a UTI concurrently but I think cystitis is more likely. Antibiotics will not help that. She needs to be on pain meds and you need to de-stress the environment. This article has more in-depth information: https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951488 I strongly recommend you put some Feliway diffusers in your house and do some environmental enrichment for her. Usually these two things help too. https://worldtails.securevetsource.com/itemView/view/198944_HomeDelivery.pml?productId=117324 thedrakecenter.com/materials/environmental-enrichment-indoor-cats  https://www.youtube.com/watch?v=AejmrLa_Cs4

Yes this is normal. Most urinary tract "infections" in non-geriatric cats are not caused by bacteria (antibiotics kill bacteria) but inflammation caused by stress. This is called Feline Idiopathic Cystitis. So Prednisone does two things: It takes the inflammation whch in turn takes the pain, and it is also a diuretic which helps flush the bladder. Male cats also seldom have a bacterial cystitis as the urethra is much longer than a female's urethra and therefore bacteria would have to travel much farther to get into the bladder.

Elevated BUN (uraemia) in itself is associated with nausea and vomiting and the underlying cause should be investigated. Dehydration as a result of vomiting, intestinal bleeding, obstructive bladder stones, fever, diabetes and kidney disease can all contribute - a thorough urine analysis would be recommended. Fluid therapy would be advised as soon as a urine sample has been obtained in order to try and reduce levels but urine production must be monitored closely to prevent overhydration if kidneys are not able to function well

It is difficult to tell anything from the picture of the x-ray however, the urinalysis shows that there is a urinary tract infection which could account for the difficulty urinating. I am also concerned about the high levels of protein in the urine and a urine protein:creatinine ratio should be requested to assess kidney function. It is a good thing that the CRT is decreasing, however in order to properly evaluate kidney function the BUN levels are needed as well. Speak to your veterinarian about their suspected diagnosis/diagnoses and recommended treatments to get Tittie feeling better soon.