What Are Urinary Tract Infections in Dogs?
Urinary Tract Infections (UTIs) in dogs typically result from bacterial presence in the urine. They manifest as either lower or upper UTIs, with lower UTIs being more prevalent. Lower UTIs primarily affect the bladder and, in male dogs, may extend to the prostate. On the other hand, upper UTIs impact the kidneys and/or ureters, which are responsible for draining urine from the kidneys to the bladder.
UTIs in dogs can be categorized as acute or chronic. Acute UTIs occur sporadically and respond well to antibiotic treatment alongside pain relief medications. Chronic UTIs, however, entail either three or more UTI occurrences within a year or two or more instances within a six-month period. A UTI is also classified as chronic if it persists despite antibiotic therapy. Chronic UTIs pose a challenge as they tend to recur even after treatment, causing frustration for both pet owners and veterinarians alike.
Symptoms
Symptoms of Urinary Tract Infections (UTIs) in dogs stem from inflammation and discomfort caused by bacterial intrusion into the bladder wall. Signs of a UTI in dogs can include:
- Inappropriate urination, such as accidents indoors or dribbling urine
- Frequent urination
- Struggling to urinate, often with only a small amount of urine produced
- Presence of blood in the urine
- Increased thirst and urination
In more serious cases, where the infection progresses to a dog’s kidneys, additional symptoms may manifest, including:
- Lethargy
- Loss of appetite
- Fever
- Vomiting
Causes
The causes of Urinary Tract Infections (UTIs) in dogs stem from the vast array of bacteria present in their environment. A dog’s external genitalia accumulate bacteria through direct contact with the surroundings, licking, and normal skin bacteria. UTIs develop when bacteria migrate from a dog’s external genitalia through the urethra and into the bladder.
Normally, a healthy bladder possesses defense mechanisms that deter bacterial infections by breaking down most types of bacteria. However, when these mechanisms falter or are compromised, bacteria can breach the bladder wall, resulting in inflammation and discomfort. Occasionally, viruses and fungi can also invade the bladder wall, leading to similar consequences.
Acute UTIs in dogs typically occur when bacteria ascend the urethra and infect the bladder. Chronic UTIs, however, may arise due to various underlying factors such as:
- Kidney disease
- Diabetes mellitus
- Bladder stones
- Vulvar malformations
- Tumors in the urinary tract
- Benign polyps in the urinary tract
- Congenital issues
- Neurological disease
- Cushing’s disease
- Urinary incontinence
- Reactions to immunosuppressive drugs
Dogs That Are Prone to UTIs
Urinary tract infections (UTIs) can affect any dog breed, but they tend to occur more frequently in female dogs. This is because male dogs have longer urethras, which means bacteria must travel a greater distance to reach the bladder. One can imagine the bacteria growing weary on their lengthy journey and either abandoning their quest or perishing before reaching their destination.
Certain dog breeds, particularly those prone to bladder stones (cystic calculi), are at a higher risk of developing UTIs, particularly chronic and recurrent ones. Bladder stones can disrupt a dog’s bladder defense mechanisms and cause inflammation by moving around in the bladder.
Breeds predisposed to chronic UTIs due to bladder stones include:
- Shih Tzus
- Bichon Frisés
- Yorkshire Terriers
- Dalmatians
- Pugs
- French Bulldogs
- Miniature Schnauzers
- Standard Schnauzers
- Miniature Poodles
Diagnosis
There are several methods veterinarians use to diagnose urinary tract infections (UTIs) in dogs and to explore the root causes of the infection. Obtaining a conclusive diagnosis is crucial whenever there are signs of urinary tract disease to prevent recurring UTIs. Below are the methods veterinarians employ to test for UTIs in dogs.
Urine Collection
Veterinarians have four methods for collecting your dog’s urine for UTI testing:
- Free catch: This involves catching the urine directly as your dog urinates.
- Tabletop: Urine is collected after your dog urinates on a surface, such as a table.
- Cystocentesis: This method involves sterilely collecting urine using a needle, suctioning it directly from the bladder. Often, this procedure is guided by ultrasound.
- Urethral catheterization: Urine collection occurs via a catheter that is inserted sterilely into the urethra.
Cystocentesis is considered the best option because obtaining a urine sample directly from the bladder is the most sterile method. It’s important to note that since a significant number of bacteria naturally reside in the environment and on a dog’s external genitalia, tabletop and free-catch sampling may result in other bacterial contamination, making it challenging to accurately determine if a UTI is present.
Urine Testing
Veterinarians employ two primary methods to test your dog’s urine for UTIs.
1. Urinalysis
- Urinalysis serves as a crucial screening tool for dogs, whether or not a UTI is suspected. It is typically included in the routine testing conducted during your dog’s annual health examination. This comprehensive test assesses various aspects of urine, including:
- pH levels
- Specific gravity (a measure of the kidneys’ concentrating ability)
- Presence of protein
- Blood
- White blood cells
- Glucose (sugar)
- Ketones (compounds generated by fat breakdown in the body)
- Particles such as cells, bacteria, and crystals
In dogs, elevated counts of white blood cells, blood, and protein in the urine, along with a low urine specific gravity, often indicate the presence of a UTI. Notably, bacteria may not always be visible in urine samples during the initial stages of a UTI, as white blood cells can engulf them, concealing them from microscopic detection.
2. Urine Culture and Susceptibility (or Sensitivity) Test
- The urine culture and susceptibility test stands as the gold standard for diagnosing UTIs and remains the only test capable of definitively confirming a UTI in dogs. If your veterinarian suspects your dog has a UTI, they should procure a sterile urine sample via cystocentesis and send it for a culture and sensitivity test.
During this procedure, veterinarians incubate a small portion of the urine sample on a specialized medium plate and observe it for bacterial growth over a span of 1-3 days. Any bacterial growth on the medium plate serves as confirmation of a UTI.
Furthermore, culture and susceptibility tests provide insight into the type and quantity of bacteria present in the sample. Upon confirmation, your veterinarian conducts antibiotic sensitivity testing to determine the most effective antibiotics for treating the specific type of bacteria identified.
Diagnosing Acute UTIs
In cases of acute UTIs, numerous veterinarians initiate diagnosis with a urinalysis and may occasionally prescribe a broad-spectrum antibiotic for treatment. However, while a urinalysis is a common starting point, a urine culture and sensitivity test offer greater reliability. Your veterinarian should conduct this test before initiating treatment if there is any uncertainty regarding the presence of a UTI.
Administering an inappropriate antibiotic or giving your dog antibiotics without a confirmed UTI diagnosis can have adverse effects, potentially leading to antibiotic resistance in the future.
Diagnosing Chronic UTIs
- The urine culture and susceptibility test stands as the gold standard for diagnosing UTIs and remains the only test capable of definitively confirming a UTI in dogs. If your veterinarian suspects your dog has a UTI, they should procure a sterile urine sample via cystocentesis and send it for a culture and sensitivity test.
During this procedure, veterinarians incubate a small portion of the urine sample on a specialized medium plate and observe it for bacterial growth over a span of 1-3 days. Any bacterial growth on the medium plate serves as confirmation of a UTI.
Furthermore, culture and susceptibility tests provide insight into the type and quantity of bacteria present in the sample. Upon confirmation, your veterinarian conducts antibiotic sensitivity testing to determine the most effective antibiotics for treating the specific type of bacteria identified.
Treatment
Following your dog’s urine test results, your veterinarian will recommend an appropriate antibiotic for you to administer as directed.
For acute UTIs, veterinarians typically prescribe an antibiotic (most commonly a penicillin or fluoroquinolone) for 1-2 weeks. If urine culture and sensitivity testing indicate resistant bacteria, treatment will involve an antibiotic effective against that specific bacteria.
In addressing chronic UTIs, treatment focuses on tackling the underlying cause. Antibiotics are usually prescribed for 4-8 weeks and are selected based on urine culture and sensitivity results to prevent antibiotic resistance. In rare cases of chronic UTIs, your veterinarian may advise a lifelong antibiotic regimen for your dog’s comfort.
Additionally, your veterinarian may prescribe pain medications, anti-inflammatories, and probiotic supplements to aid in treating and resolving the infections.
Recovery and Management
Your veterinarian should conduct urine testing for your dog following antibiotic therapy for both acute and chronic UTIs. In cases of chronic UTIs, urine testing may occur during treatment as well as after treatment to evaluate bacterial levels.
Once urine testing confirms resolution of a UTI, dogs with acute UTIs typically require no further treatment. For dogs with chronic UTIs, maintaining urinary tract supplements and probiotics may help prevent recurrence.
If an underlying medical condition is diagnosed by your veterinarian, treatment will focus on managing it to prevent recurrent UTIs. Below are examples of potential underlying issues and their respective treatments:
- Diabetes mellitus: insulin therapy and dietary adjustments
- Kidney disease: dietary modifications, blood pressure regulation, and fluid therapy depending on disease stage
- Abnormal vulvar conformation: surgical correction and/or daily perivulvar region cleaning
- Urinary crystals: increased water intake, urinary tract supplements, and sometimes a dissolution diet
- Bladder stones: surgical removal via cystotomy or dissolution diet
- Urinary tract masses: surgical removal and/or chemotherapy
Each dog with a UTI requires individual evaluation since multiple factors can contribute to pain and inflammation.
UTIs in Dogs FAQs
How do veterinarians test for UTIs in dogs?
Testing for UTIs in dogs involves urinalysis and urine culture with sensitivity. If veterinarians suspect underlying medical conditions are causing chronic UTIs, dogs may undergo full bloodwork, abdominal radiographs (x-rays), and abdominal ultrasound and/or cystoscopy.
How long does it take for antibiotics to work for UTIs in dogs?
Typically, dogs begin to show improvement within 48-72 hours of starting appropriate antibiotic therapy. Pain medication can alleviate discomfort and straining almost immediately.
How are UTIs treated in dogs?
UTIs in dogs are treated with antibiotics, pain medications, and probiotics. Veterinarians prescribe antibiotics based on urine testing results to achieve optimal outcomes and avoid antibiotic resistance. Additionally, addressing the underlying cause is essential for treating chronic UTIs in dogs.
Can food cause UTIs in dogs?
Food itself does not cause UTIs in dogs. However, certain foods can alter urine pH and predispose dogs to urinary crystal or bladder stone formation. These crystals and stones can lead to bladder inflammation, eventually resulting in UTIs.
What causes UTIs in male dogs?
Male neutered dogs rarely develop UTIs. Male intact dogs are at risk for prostate issues, which can contribute to UTIs. Underlying conditions such as diabetes mellitus, kidney disease, Cushing’s disease, neurological issues, bladder stones, and bladder masses increase the risk of UTIs in male dogs.
What is the most effective antibiotic for UTIs in dogs?
The most effective antibiotic for UTIs in dogs depends on urine culture and sensitivity results. Commonly used antibiotics include amoxicillin, Clavamox®, trimethoprim sulfa, and enrofloxacin.
What leads to frequent UTIs in dogs?
Frequent (chronic) UTIs in dogs are typically caused by underlying medical issues. These may include kidney disease, diabetes mellitus, bladder stones, vulvar malformations, urinary tract tumors, benign polyps, congenital issues, fecal and urinary incontinence, neurologic diseases affecting bladder emptying, Cushing’s disease, reactions to immunosuppressive drugs, and urinary incontinence issues.
Can stress trigger UTIs in dogs?
Stress is not commonly considered a direct cause of UTIs in dogs. While severe stress might potentially lower the immune system’s function or cause urinary retention, scientific evidence supporting stress as a direct cause of UTIs in dogs is lacking.