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Lower Urinary Tract Disease

Urinary tract disease is very common in both canine and feline species. Diseases that can affect the lower urinary tract include urinary tract infection, urinary crystals, bladder stones, and idiopathic cystitis (bladder inflammation of unkown origin). Some of these conditions can predispose to others. For example, the chronic passing of urinary crystals can cause inflammation that predisposes to urinary infections. In this article, we will discuss clinical signs of lower urinary tract disease in dogs and cats, break down the various types of diseases that occur, offer potential treatment options, as well as detail preventative measures.

Clinical Signs Of Lower Urinary Tract Disease In Dogs And Cats

Typical signs of urinary tract disease include: frequent small urinations/frequent trips to the litter box (cats), blood in the urine, straining to urinate with no success, urinary blockage/inability to pass urine (most common in male cats – a medical emergency!), vocalizing while urinating. If your pet is experiencing any of these signs, you should bring it to the vet as soon as possible. When you go to the vet, you should come prepared with a fresh urine sample in a clean container. This is much easier with dogs, since all one has to do is walk the dog, then catch a sample while the dog postures to urinate. With cats, you can call the vet beforehand and pick up some non-absorbant litter, place in the litter box and collect a sample that way. If there is going to be some lag time between the retrieval of the urine sample and the vet visit, you can store the urine in the refrigerator to keep the sample viable (for up to 6 hours).

Urinary Tract Infections

Urinary infections are most common in females, as they have a much shorter/wider urethra. However, infections still occur in males of both canine and feline species. When a urinary tract infection is suspected, a urinalysis needs to be performed to rule out other diseases of the urinary tract that may be mimicking or predisposing to urinary infections. Visualization of bacteria on the urinalysis, or other parameters that support a diagnosis of urinary tract infection, are sufficient to treat with a good broad spectrum antibiotics for two to three weeks. However, if the infection returns, a culture and sensitivity panel should be performed to identify the bacteria and determine which antibiotics are the most effective in treating. Urine to be submitted for culture and sensitivity has to be obtained by cystocentesis (a direct
intra-abdominal fine needle aspirate of the bladder) to prevent contamination of the sample.

Urinary Crystals/Bladder Stones

Urinary crystals form in the urine due to factors such as genetic predisposition, diet, and variations in urine pH. By far the most common type of urinary crystals in both dogs and cats are struvite. Struvite crystals form in alakaline urine, typically greater than 7.5. Other types of crystals are less common and include calcium oxylate and urate crystals.

The persistence of crystals in the urine can lead to inflammation of the mucus lining of the bladder and urethra. This can cause clinical signs identical to urinary tract infection, or the subsequent compromised state of the bladder mucosa can even predispose to urinary infections. Chronic urinary crystals can also form bonds with one another, leading to the formation of stones within the bladder. Stone cause severe inflammation of urinary bladder, leading to blood in the urine, pain, and chronic infections.

Treatment of urinary crystals is accomplished through prescription diets that stablize the urine pH and eliminate dietary factors that lead to crystal formation. There are a number of diets available for this purpose.

Small bladder stones can be treated by dissolution with the appropriate prescription diet. However, larger stones usually have to be removed surgically, and the patient placed on a good prescription diet to prevent their recurrence. Calcium oxylate stones cannot be dissolved with diet and have to be removed surgically. However, effective diets exist to prevent their recurrence.

* Crystal/stone dissolution/prevention diets are avilable by presciption only, and are therefore available at your vet.

Idiopathic Cystitis

Idiopathic cystitis is inflammation of the lower urinary tract of unknown origin. This disease is primarily a problem of cats. Clinical signs mimic that of urinary infections, crystals, and stones, but there is no apparent underlying cause. With no underlying cause, focusing on a treatment strategy can be extremely challenging.

Some cats affected with idiopathic cystitis respond to treatment with the tricyclic antidepressant amitriptyline, indicating that there is a psychogenic component, but results are not consistent. Other cats respond to treatment with glucosamine, but, like psychological therapy, results are also inconsistent.


FLUTD stands for feline lower urinary tract disease. It is an all encompassing term that covers all facets of urinary tract disease in cats: urinary crystals, bladder stones, urinary infections, and idiopathic cystitis. It is estimated that up to 10% of domestic cats are affected with FLUTD. FLUTD is most serious in male cats.

With their longer, narrower and more tortuous urethra, male cats are predisposed to the formation of plugs that block the passage of urine through the urethra. The plugs typically consist of matrices of mucous and crystals.

Urinary blockage is a medical emergency. Left untreated, the bladder will distend and rupture, spilling the contents of the bladder into the abdominal cavity and leading to life threatening peritonitis. If you suspect that your cat may be blocked DO NOT HESITATE to get it to the vet.

Treatment for urinary blockage consists of passing a urinary catheter and relieveing the obstruction. It is usually left in for two to three days, while measures are taken to stabilize the patient, prevent infection, and relieve the inciting causes, such as crystals. In cases where removing the inciting causes are unsuccessful and blockage recurs, then a surgical procedure called a perineal urethrostomy (PU) should be performed. The PU procedure results in a shorter/wider urethra that is much less likely to become blocked.



Roger L. Welton, DVM
Founder and Chief Editor,
President, Maybeck Animal Hospital

Founder, CEO, Dr. Roger’s Holistic Veterinary Care

Article updated 5/20/2014

17 thoughts on “Lower Urinary Tract Disease

  1. which wet food shall I feed my cats? One has struvite and one has calcium oxalate urinary issues. So, no more dry for them ? Thanks, karyl p.

  2. Judy says:

    My puppy is about 3 months old. Last few days she has peeing a lot more. Having accidents when playing etc. And today she is shaking a little more than normal. She is a Dotson and Chihuahua mix.

  3. mamtapandy says:

    I am really enjoying the design and layout of your post. It is very easy on the eyes which makes it all the more pleasant for me to come here and visit more often. Have you made your own theme because whoever made the theme here is so beautiful.

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