Introduction
Urinary tract infections (UTIs) are common in cats, especially as they age. They occur when bacteria enter the urinary tract and multiply. While UTIs can often be treated with antibiotics, if left untreated, they may spread to the kidneys. This can potentially lead to kidney infections, damage, and even failure. Understanding the connection between feline UTIs and kidney disease is important for preventing serious complications in cats.
What is a UTI?
A urinary tract infection (UTI) is an infection in any part of the urinary system, including the kidneys, ureters, bladder and urethra (1). UTIs occur when bacteria, often from the GI tract, travel up the urethra and into the bladder (2). Once in the bladder, the bacteria multiply rapidly in the urine, causing an infection.
In cats, UTIs are most often caused by the bacteria Escherichia coli, Staphylococcus species, and Proteus species (1). These bacteria can enter the urinary tract through the bloodstream or by traveling up the urethra. Anything that impairs the body’s natural defenses or blockages in the urinary tract can increase the risk of UTIs.
Common symptoms of UTIs in cats include (3):
- Frequent and painful urination
- Blood in the urine
- Excessive licking of the urinary opening
- Urinating outside the litter box
- Crying out while urinating
- Straining to urinate
If left untreated, UTIs in cats can spread to the kidneys and cause more serious complications like kidney infections, kidney damage or even kidney failure.
Sources:
(1) https://vcahospitals.com/know-your-pet/urinary-tract-infections-utis-in-cats
(2) https://www.webmd.com/pets/cats/cat-urinary-tract-problems
(3) https://www.fremontvetclinic.com/site/blog/2021/12/30/urinary-tract-infection-cats
Types of UTI
There are two main types of urinary tract infections (UTIs) in cats: upper urinary tract infections and lower urinary tract infections. Understanding the differences is important for diagnosis and treatment.
Upper urinary tract infections, also called pyelonephritis, affect the kidneys and ureters. These UTIs occur when bacteria travel up to the kidneys from the bladder. Upper UTIs are less common in cats but can be very serious if left untreated. They require aggressive antibiotic treatment and hospitalization in severe cases (https://vcahospitals.com/know-your-pet/urinary-tract-infections-utis-in-cats).
Lower urinary tract infections occur in the bladder and urethra. This is the most common type of UTI in cats. Lower UTIs are usually caused by bacteria like E. coli traveling up the urethra into the bladder. Cat UTIs may be acute or recurrent. Recurrent UTIs, defined as more than 3 per year, can indicate an underlying condition requiring further veterinary investigation (https://www.webmd.com/pets/cats/cat-urinary-tract-problems).
Link between UTI and Kidney Disease
UTIs, which are bacterial infections of the bladder or urethra, can spread to the kidneys and cause a more serious condition called pyelonephritis or kidney infection. When bacteria enter the urinary tract, they can travel up the ureters to infect one or both kidneys (VCA Hospitals).
Once in the kidneys, the bacteria multiply rapidly and cause inflammation and infection. This leads to swelling and damage to the kidney tissues and renal pelvis. Pyelonephritis is considered a complication of UTIs that can occur if the initial infection goes untreated and spreads (Merck Veterinary Manual).
Repeated or chronic kidney infections can permanently damage the kidneys over time, leading to impaired kidney function. Kidney damage from pyelonephritis can cause urine concentrating defects, electrolyte abnormalities, and even chronic kidney failure. Therefore, prompt treatment of UTIs is crucial to prevent kidney infection and more serious kidney complications in cats.
Symptoms
Cats with UTIs may show the following symptoms:
- Frequent and painful urination
- Blood in the urine
- Excessive licking of the genital area
- Difficulty urinating
- Crying out while urinating
- Straining to urinate
If the UTI spreads to the kidneys, additional symptoms may include:
- Vomiting
- Diarrhea
- Loss of appetite
- Lethargy
- Dehydration
- Fever
Cats with kidney infections may hide signs of illness until the infection has progressed. Early detection and treatment is key to preventing permanent kidney damage. If your cat is showing any of these symptoms, contact your veterinarian immediately.
Sources:
https://www.petmd.com/cat/conditions/urinary/kidney-infections-cats
https://www.webmd.com/pets/cats/kidney-failure-uremia-symptoms-cats
Diagnosis
There are several tests veterinarians use to diagnose UTIs and kidney issues in cats:
– Urinalysis – Checking a urine sample under a microscope can reveal bacteria, inflammatory cells, and crystals that may indicate a UTI. A urine culture can confirm infection and identify the bacteria involved.
– Blood tests – A complete blood count, biochemistry profile, and electrolyte panel can assess kidney function and pick up signs of infection like elevated white blood cells. Tests like BUN and creatinine levels show how well the kidneys are filtering waste.
– Imaging – X-rays, ultrasound, or contrast radiography can check for kidney abnormalities, stones, or obstructions. These may be consequences of chronic UTIs.
– Biopsy – Taking a kidney tissue sample for analysis can confirm damage and scarring from infections.
Early diagnosis is key to treat UTIs before they spread to the kidneys. Diagnosing kidney involvement promptly gives the best chance to halt further damage. Discuss any potential symptoms with your veterinarian so proper testing can be carried out.
Treatment
The primary treatment for UTIs that lead to kidney infections in cats is antibiotics. The specific antibiotic used will depend on identifying the bacteria causing the infection through a urine culture and determining which antibiotic that bacteria is most susceptible to. Typically the antibiotic course will need to be given for 4-8 weeks to fully clear the kidney infection. Common antibiotics used include amoxicillin, ampicillin, enrofloxacin, and cephalosporins like cefpodoxime or cefovecin (1).
It’s important to identify and address any underlying causes of the UTI as well, such as bladder stones, anatomical defects, or prostate disease in male cats. Dealing with the underlying issue can help prevent recurrence of the UTI and kidney infection (2).
Supportive care for the kidneys may also be necessary, especially if there is pre-existing kidney disease. This can include IV fluids to flush the kidneys and maintain hydration. Medications to control vomiting and encourage appetite are often used as well (3). A prescription kidney diet may be recommended to reduce strain on the kidneys.
With aggressive antibiotic treatment and addressing any underlying issues, many cats can recover fully from a kidney infection secondary to a UTI. However, if kidney damage is already present prior to the infection, the prognosis is more guarded. Close monitoring of kidney values is important even after treatment is completed.
Prevention
There are several tips and strategies cat owners can utilize to help prevent UTIs in their feline companions.
One of the most important is to encourage cats to drink more water. Increasing water consumption helps flush bacteria from the urinary tract. Provide multiple sources of fresh, clean water around the home and consider getting a cat drinking fountain, which many cats prefer over stagnant water. Wet food diets can also increase moisture intake.
It’s also critical to maintain good litter box hygiene, scooping waste at least once a day and fully cleaning the box weekly. Unsanitary litter boxes provide an environment where bacteria can thrive. Provide ample litter boxes, ideally one per cat plus an extra.
Certain supplements like D-mannose and probiotics can help prevent infections by making the urinary tract environment less hospitable to bacteria growth. Ask your vet if these may be appropriate for your cat. Avoiding stress is also key, as stress can increase UTI risk. Create a relaxing home environment for your cat.
Bringing your cat to the vet regularly and promptly treating any signs of illness are also important prevention measures. Routine vet exams allow early detection and treatment if bacteria are present.
While not always preventable, being proactive and attentive to your cat’s health can reduce the chances of painful UTIs developing.
Outlook
The prognosis for cats with UTI that leads to kidney issues can vary depending on the severity and how early it is caught and treated. Generally, the sooner pyelonephritis and kidney infection is diagnosed and treated, the better the prognosis.
For cats that develop sudden pyelonephritis but do not have pre-existing kidney disease, the prognosis is often good with appropriate antibiotic treatment, according to VCA Animal Hospitals. Most cats will recover fully if the infection is caught early.
However, cats that already have chronic kidney disease are at higher risk for more serious complications from pyelonephritis. According to a study published in the Journal of Feline Medicine and Surgery, cats with chronic kidney disease that develop pyelonephritis are more likely to suffer from worsening kidney function and progression of kidney disease. Prompt treatment is still important, but the prognosis may be more guarded in these cats.
Overall, the key factors that influence prognosis are how quickly the UTI and kidney infection are diagnosed and treated, whether kidney disease is already present, the cat’s overall health status, and response to treatment. With aggressive antibiotic therapy and supportive care, many cats can recover well, but those with chronic kidney disease need close monitoring for worsening kidney function.
Key Takeaways
Untreated UTIs can progress to kidney infections and kidney failure in cats. Cats with kidney disease often have a history of recurrent UTIs. UTI symptoms include frequent urination, blood in urine, straining to urinate, and urinary accidents. Diagnosis involves a urinalysis and urine culture. Treatment includes antibiotics and addressing predisposing factors like inappropriate litter box setup. Prevention focuses on increasing water intake, feeding wet food, and prompt treatment of UTIs. With close monitoring and care, many cats can live with chronic kidney disease for months to years.
