Introduction
Urinary tract infections (UTIs) are a common medical issue in cats, with studies estimating the prevalence between 3.5-10% in cats with lower urinary tract signs [1]. Bacterial UTIs refer to the presence of bacteria in the bladder (cystitis) or kidneys (pyelonephritis), and can be subcategorized as clinical or subclinical. Clinical UTIs cause noticeable symptoms, while subclinical UTIs may not have overt symptoms. UTIs are more common in certain populations, such as diabetic cats where prevalence reaches 11-13% [2]. Understanding the prevalence and risks of feline UTIs can help cat owners and vets provide prompt diagnosis and treatment.
Symptoms
Cats with urinary tract infections often exhibit the following symptoms:
- Straining to urinate – Cats may frequently attempt to urinate but only pass small amounts of urine each time. They will often assume the urinating position and strain visibly.
- Frequent urination – Cats will feel the urge to urinate more often than usual but will only pass small amounts of urine when they try.
- Crying out when urinating – Some cats will cry out in pain when trying to urinate due to the burning sensation caused by the infection.
- Blood in urine – Bloody urine is a common symptom, though not always present. The blood is caused by inflammation and irritation of the urinary tract.
- Urinating outside litter box – Cats may associate the litter box with painful urination and begin eliminating elsewhere in the home.
Other potential symptoms include lack of appetite, lethargy, and vomiting. Symptoms may persist and worsen without proper treatment. If a urinary tract infection is suspected, a veterinary examination is recommended.
Underlying Causes
There are several underlying causes that can lead to urinary tract infections in cats:
Bacterial Infection: The most common cause of UTIs in cats is a bacterial infection, usually from Escherichia coli bacteria found in feces. Bacteria can enter the urinary tract and multiply, leading to an infection (Source).
Bladder Stones: Bladder stones, also called uroliths or calculi, are rock-like formations of minerals that can irritate the bladder wall and block the flow of urine. This creates an environment ripe for bacterial growth. Struvite and calcium oxalate stones are most common in cats (Source).
Tumors: Tumors in the urinary tract, especially the bladder, can obstruct urine flow and cause infection. These are seen more often in older cats.
Anatomical Defects: Birth defects affecting the urinary tract like kidney dysplasia, ureteral strictures, and bladder extrophy can predispose cats to UTIs.
Diagnostic Tests
If a urinary tract infection is suspected, the vet will perform several tests to confirm the diagnosis. Some of the main diagnostic tests include:
Urinalysis
A urinalysis is one of the most important initial tests for diagnosing a UTI. It evaluates the chemical properties, cells, crystals, bacteria, and other contents in a urine sample. Changes and abnormalities can indicate infection or inflammation. For example, the presence of bacteria, increased white blood cells, and high protein levels often point to a UTI (VCA Animal Hospitals).
Urine Culture
While a urinalysis can suggest a UTI, a urine culture is needed to confirm it. This test grows and identifies the specific bacteria present to determine the appropriate antibiotic treatment (Bond Vet). The bacteria count also helps assess the severity of the infection.
Imaging Tests
Imaging such as x-rays or ultrasound may be used to check for stones, tumors, or other structural issues that could be causing or contributing to the infection.
Bloodwork
A complete blood count and blood chemistry panel can identify conditions like kidney disease that may make a cat prone to UTIs. Bloodwork also helps assess the cat’s overall health status (Merck Veterinary Manual).
Urinalysis
One of the first diagnostic tests vets perform to check for urinary tract infections in cats is a urinalysis. Urinalysis is a routine test that analyzes the physical and chemical properties of a cat’s urine [1]. It provides important information about the health of the kidneys and urinary system.
There are several components vets look for in a urinalysis to diagnose a UTI:
- Color – Dark or bloody urine may indicate infection or inflammation
- Clarity – Cloudy or opaque urine can signify increased cellular material or crystals
- pH – Abnormal pH can indicate infection or metabolic disorders
- Glucose – Glucose in the urine can be a sign of diabetes
- Protein – Excess protein suggests kidney damage or dysfunction
- Red blood cells – Higher than normal levels can indicate inflammation, trauma or cancer
- White blood cells – Elevated levels often mean infection
- Crystals – Crystals may be indicative of stone formation
- Bacteria – The presence of bacteria confirms a urinary tract infection
By examining all these elements, vets can determine if a UTI is present and pick the appropriate treatment.
Urine Culture
A urine culture is a test that aims to grow and identify bacteria from a urine sample in order to diagnose a urinary tract infection (UTI). According to research, the reported prevalence of positive urine cultures in cats with ureteral obstructions before surgery is 2-33%.
To perform a urine culture, the veterinarian will obtain a sterile urine sample from the cat. This is often done by cystocentesis, where a needle is inserted through the skin directly into the bladder to obtain urine. The sample is then incubated in a laboratory to allow any bacteria present to multiply. If bacteria grow, they can then be identified.
A urine culture allows the vet to determine the specific type of bacteria causing an infection, as well as test the susceptibility of the bacteria to different antibiotics. This helps guide treatment recommendations. A positive culture indicates there are significant bacteria present in the urinary tract.
However, according to Glencoe Animal Hospital, some cats with UTIs may have a negative culture, especially if antibiotics were already started. Therefore, a urine culture is just one diagnostic tool vets use to check for a UTI in cats.
Imaging Tests
Veterinarians may use various imaging tests to get a closer look at a cat’s urinary tract and identify potential causes of infection or obstruction. Common imaging tests include:
X-rays: Abdominal X-rays can detect bladder stones and sometimes masses or other abnormalities. X-rays provide a noninvasive way to get an overview of the urinary tract.[1]
Ultrasound: An ultrasound uses sound waves to create images of the bladder and kidneys. It allows a veterinarian to see stones, masses, and structural problems that might not show up on X-rays.[2]
Contrast radiography: In this imaging technique, a contrast dye is injected into the bladder or urethra before taking X-rays. The dye highlights the urinary tract, allowing veterinarians to see stones, tumors, and anatomical defects in detail.[1]
These imaging tests help veterinarians pinpoint the cause of a UTI or obstruction in cats. They are an important diagnostic tool when evaluating urinary tract health.
Bloodwork
Veterinarians will often run bloodwork as part of the diagnostic process for a suspected urinary tract infection in cats. There are two main components of a blood panel that provide helpful information:
A complete blood count (CBC) checks for anemia and elevations in white blood cell counts, which can indicate inflammation or infection. As noted by The Drake Center, the CBC provides an overview of your cat’s general health status. Significant abnormalities may prompt further testing.
Blood chemistry tests assess kidney and liver function, electrolyte levels, and more. According to VCA Animal Hospitals, bloodwork helps rule out concomitant issues that could complicate treatment of the UTI. For example, chronic kidney disease is common in older cats and makes them more prone to UTIs. The blood chemistry can detect kidney problems.
While not diagnostic for UTIs specifically, blood tests allow veterinarians to check for other health issues and gauge the cat’s overall condition before determining the appropriate treatment plan. Bloodwork also establishes a baseline for comparison if the cat develops recurrent UTIs.
Citations:
https://www.thedrakecenter.com/services/cats/blood-tests-for-cats
https://vcahospitals.com/know-your-pet/urinary-tract-infections-utis-in-cats
Treatment
The main treatment for urinary tract infections in cats is antibiotics. Vets will usually prescribe a broad-spectrum antibiotic that treats common bacteria like [1]. Some commonly used antibiotics include amoxicillin, cephalexin, trimethoprim-sulfa combinations, and enrofloxacin. The antibiotic course is usually 2-4 weeks. It’s important to give the full course as prescribed, even if symptoms improve, to fully eliminate the infection.
In addition to antibiotics, vets may recommend addressing any underlying causes or risk factors. This may include changing to a urinary diet, increasing water consumption, adding supplements, or addressing stressors. Providing supportive care like pain medication is also important.
If the cat has a urethral obstruction, that will need to be addressed first before antibiotics. Blockages are emergencies that require sedation, catheterization or surgery to open up the urethra and allow normal urination.
[1] https://vcahospitals.com/know-your-pet/urinary-tract-infections-utis-in-cats
Prevention
There are several ways cat owners can help prevent UTIs in their cats, according to experts. One of the most important is to ensure the cat is drinking plenty of water, as increased water intake can help flush bacteria from the urinary tract (source). Provide fresh, clean water at all times and consider getting a cat water fountain if your cat does not drink enough. You can also add more moisture to your cat’s diet by feeding wet food.
Feeding a urinary health diet designed to support urinary tract health may also help prevent UTIs, as these foods are formulated to increase urine volume and dilute out bacteria (source). Ask your veterinarian for diet recommendations.
Since stress can be a contributing factor to UTIs, taking steps to reduce your cat’s stress levels can be beneficial. Provide a clean, comfortable litter box, limit changes to their routine, use pheromone diffusers and make sure they have access to quiet, low-traffic areas (source). Monitoring for any urinary issues and bringing your cat to the vet promptly can also help prevent infections from worsening.
