Kidney Stones in Cats: Answering All The Questions That You May Have

kidney stones in cats

If your cat is suffering from kidney stones, then it will not show symptoms right away. Most kidney stones in cats do not show any symptoms until they have grown significantly large. If left untreated, they will often lead to obstruction and serious infections. Kidneys perform the function of blood filtration and removal of wastes. Some waste products are not completely soluble, which remain inside the kidneys and lead to the formation of crystals. These crystals have the potential to develop into stones, and this process is known as nephroliths.

As a pet owner, you may have many questions, like can cats pass bladder stones, which causes kidney stones in cats, etc. Let’s try to answer some of these and help you treat your cat with kidney stones.

What is the reason for urinal stones in cats

Cats’ urine is highly acidic and concentrated, which puts them at higher risk of stone formation in the urinary tract. Abundance or deficiency of minerals or other substances can further promote stone formation. Diet, swelling, infection, and urine pH level- all these factors affect the formation of urinary stones in cats.

Veterinarians identify the different stones in cats based on their makeup. Most common stones in cats are struvite (more on that ahead) and those made of calcium oxalate. There are specific diets to control these. The exact cause behind the formation of kidney stones is unknown.

Early detection and treatment of kidney stones are critical. It can lead to problems ranging from difficulty in urinating to complete kidney failure. Vomiting, depression, dehydration, etc. are some of the signs that cats who have stones in the urinary tract exhibit. Let us look at that in greater detail before we see the possible treatment methods.  

What are the signs that my cat has urinal stones?

While kidney stones do not show symptoms until they are large, you should still be on the lookout for any symptoms. A few common signs that cats with kidney stones show:

  • Hematuria, or blood in the urine
  • Pain during urination
  • Finding it tough to urinate
  • Frequently urinating 
  • Chronic UTIs, or urinary tract infections
  • Licking of its genitals
  • Urine spraying
  • Obstruction of the urinary tract (more common in males)
  • Urinating in unusual areas

If your cat shows any of the symptoms above, then you should take it to a veterinarian on priority. 

How are kidney or bladder stones diagnosed?

The majority of the stones show up in simple radiographs. Smaller stones, however, can hide behind other contents of the intestine and not show up as readily. Certain types of stones also do not show up on radiographs, such as a urate stone. Liver disease is the main cause of urate stone. The veterinarian will require the complete history of your cat, including any recent ailments, infections, and changes to its diet. Once the veterinarian has diagnosed a stone, the next step is diagnosing what type it is. They also help to find out the possible impacts on your cat’s health. 

CBC/ Complete Blood Count

This helps to check for anemia and any infections in the kidney or urinary tract.


Urine quality helps to predict any disease in the kidney, find any bacterial infections or crystals that can help determine the type of stone.

Blood Chemistry

It helps to find out the presence of any kidney disease and the risk factor for the formation of stones. 

Blood pressure

High blood pressure is an indicator of kidney disease. 

Ultrasound of the abdomen

It is useful for finding out the location of any stones and the obstruction that they may be causing.

Abdomen x-rays

It helps to find any abnormality in the shape and size of the kidney and find urinary stones. 

Urine culture

Culture is to diagnose any bacterial infection, and the antibiotics can be used (if required). 

What are the different types of stones that a cat can have?

Stones can be of a different type, mainly divided on their location and composition. Let’s look at each of those to get a better idea.

Stones based on their location

The symptoms that your cat may show depends on where the urinary stones are. The majority of the stones in cats are either in the urethra or the bladder, with a small percent in the ureters or the kidney. Urinary stones can cause severe damage to the urinary tract lining and cause swelling. It also puts the cat at a greater risk of developing a urinary tract infection.

Some common signs that accompany bladder stones are:

  • Blood during urination
  • Urinating small amounts but with high frequency
  • Strain during urination
  • Discomfort in the abdomen

Urinary stones create urinary obstructions by blocking its flow, and these would require immediate attention and treatment. 

Signs that accompany urethral stones are:

  • Posturing or straining to urinate but no urine production 
  • Dribbling urine

If you notice any of the above signs, it is important to get your cat to a veterinarian immediately. 

Stones can be there in the ureter too. The ureter is the part of the tract that takes urine from the kidneys to the bladder. Such an obstruction can lead to serious damage to the kidneys. Symptoms that accompany ureteral stones are:

  • Blood during urination 
  • Decrease in appetite
  • Vomiting
  • Lethargy
  • Discomfort in abdomen

Stones based on their composition

Struvite Stones

30% of the stones found in cats are generally struvite stones. These are mostly the result of urinary tract infections. Some bacteria increase the urine’s pH, which decreases the possibility of these stones dissolution in the urine.

Calcium Oxalate Stones

Over 60% of the stones found in cats are of calcium oxalate. These are prevalent in the ureters or kidneys, making up 70% of the stones found there. Himalayan, Persian and Burmese cats are among the ones most diagnosed with these stones. There is no confirmed cause of these stones yet. There is some indication that a decreased concentration of crystal formation inhibitors in the urine, as well as a high intake of dietary oxalate, can promote the formation of these stones.

Cystine Stones

These stones are mostly caused due to excessive removal of cystine in the urine. A high amount of cystine inside a primarily acidic environment promotes the formation of these stones. Cystine stones are not visible on x-rays easily but can be better found through ultrasound. 

Silicate Stones

Silicate stones may correlate with excess intake of silica acid and magnesium silicate. Common foods that include these are soybean and corn glutens. 

What is the treatment for a cat with kidney stones?

The vet needs to diagnose the type and size of stones before any form of treatment is started. Mostly there are no natural ways to dissolve bladder stones in cats, and you will help of a veterinary to treat those. However, there are many different medical (non-surgical) and surgical treatment options available for stones in cats.


Medication is most useful in cases where the stones are not stopping the urine flow. Numerous medications can be used in such a case. These medications dissolve the stones, and then the cat can easily pass those with urine. The urine is then cultured to test for any infection, after which the veterinarian will prescribe antibiotics. 

Fluid Therapy

Intravenous fluids will be given to cats that have been dehydrated. During this fluid therapy, the vet will also check the heart and kidney to ensure that the fluid is being received properly. 


Any stones that are obstructing urine flow need immediate removal, as it could otherwise lead to kidney failure. ESWL, Extracorporeal shock wave lithotripsy, is used to remove kidney stones. It is a non-invasive procedure and among the most preferred ones.

kidney stones in cats

Surgical Treatments

If the stones are becoming an emergency and ESWL is not possible, then surgical intervention is an option. The veterinarian makes a small incision to access the kidneys, using an ultrasound for guidance. Any stones that are obstructing urine flow needs surgical removal. Sutures are made use of for closure of the incision, and the cat may be under hospital observation for a while. With surgical intervention, there is a greater risk of kidney damage and infection. It is generally the last treatment option if nothing else works.


There are special prescription diets that have a formulation for cats suffering from kidney stones. These are low-protein and have wet canned food that increases the water intake. There are many popular prescription foods that you can get from a veterinary or even online. 

OTC Diets for Stones

Quite a few cat owners ask about using over the counter diets that are sold for cats’ urinary health. However, these have not undergone extensive testing. They majorly focus on just a small subset of factors, such as struvite stones. They do not have any thorough testing done for any other type of stone. Such diets can be an additional risk factor if taken without a vet’s advice.

How safe are therapeutic diets?

Therapeutic diets are gaining popularity for treating cats with kidney stones. You should only use those diets that are tested and have demonstrated success in the reduction of stone development. You mustn’t put your cat on any such diet before consulting a veterinarian. 

Supplements and Treats

There are several dietary supplements such as Vitamins C and D to increase the acidity of the urine. These supplements have shown positive results in dissolving kidney stones. However, do take your vet’s guidance before putting your cat any of those.

Any therapeutic diets undergo testing with cats that ate only those diets, and nothing else. Adding any extra treats or supplements may decrease the effectiveness of those diets. If your cat refuses to take such diets as is, consult with the veterinary before making any changes. 

What are some other things that I should be careful about?

As a pet parent, having adequate knowledge before making any decision to treat your cat is vital. With so much information around us, you should weigh each decision and do thorough research. Any medication should be only come from a veterinarian’s recommendation. 

Stones may not seem to be causing problems at first. However, they could cause more complications as time passes. Regular blood and urine analysis help to monitor the situation. There are a lot of resources and help available for pet parents dealing with such a situation. Do not let it overwhelm you. With the right steps and early treatment, cats with kidneys stones have chances of a healthy life. Trust your veterinarian and take the right steps towards a healthy life for your cat!