Cross your legs, folks! This article is gonna make you feel the need to pee. If your dog or cat has a sudden increased urge to urinate, he or she may have a lower urinary tract infection (UTI or bladder infection). The Meowing Vet explains the other signs of a UTI in pets and how UTIs are diagnosed, treated, and perhaps prevented.
Feel a sudden urge to “squeeze the lemon”?! Keep reading to learn more about bladder infections in pets…
How common are urinary tract infections (UTIs) in pets?
Lower urinary tract infections (or UTIs) are quite common in dogs. An estimated 14% of dogs will suffer from a UTI at some point in their life. Most UTIs are caused by bacteria (primarily E. coli) that climb up the urethra into the bladder. Most of these bacterial species arise from fecal material or due to nearby infections of the skin around the vulva or prepuce (penis sheath) in females and males, respectively. Other bacteria that can cause UTIs include Staphylococcus, Streptococcus, Enterococcus, Proteus, and Klebsiella. Fungal infections of the bladder can also uncommonly occur, and are most likely to develop as a complication of diabetic patients. Such fungal organisms include Candida and Blastomyces. Viral and parasitic UTIs (like Pearsonema) are rare.
In contrast, lower urinary tract infections are uncommon in felines. Instead, if your cat is urinating small amounts, is urinating outside the litterbox, is straining in an attempt to urinate, or has bloody urine, he or she may instead have Feline Lower Urinary Tract Disease (FLUTD). FLUTD is occasionally caused by bacterial infections but is primarily due to sterile inflammation without an infectious cause (though FLUTD can sometimes lead to a secondary bacterial UTI). You can read more about FLUTD in our article here.
What makes up the urinary tract?
To understand which organ is affected by a UTI, let’s take a moment for a basic anatomy lesson. The urinary tract can be divided into an upper and lower portion. The upper urinary tract consists of the kidneys and ureters (the tubes that carry fluid from the kidneys to the bladder). The lower urinary tract includes the urinary bladder as well as the urethra (the short tube that allows urine to be excreted from the bladder).
What keeps the urinary tract healthy in normal dogs and cats? What goes wrong to allow an infection to develop?
Your pet’s body has natural defenses to prevent bacteria and other organisms from setting up shop in the urinary tract, causing an infection. These protective mechanisms include:
- A normal anatomic structure of the urethral opening and surrounding skin as well as the bladder (i.e. no damage to this area and no malformation or tumor development)
- The urethral sphincter (a ring-shaped tough muscular “door” that closes off the urinary bladder and prevents urine leakage)
- A bladder that empties normally: some impairments of the nerves that innervate the bladder can lead to a bladder that does not fully empty, preventing pooled urine and pathogens from being excreted
- A normally functioning immune system that can fight off invading pathogens, such as bacteria and fungi
Should any of these mechanisms fail, your pet will be vulnerable to nearby bacteria that wish to colonize the urinary tract. Additionally, infections are more likely to be caused by bacteria that are present in large numbers or that are very virulent, meaning that they have factors that increase their potential danger (for example, resistance to your pet’s immune system or to certain antibiotics, special parts that allow them to attach firmly to the inner lining of the bladder, etc.).
A Girl Problem?
Females are at an increased risk of developing a UTI in comparison to males. Why? Because females have a shorter urethra than do males, and the female urethral opening is closer to the anus than is a male’s, increasing the odds that bacteria from feces has a shorter distance to travel to ascend up the urethra and into the bladder. #GirlProblems
Upper Urinary Tract Infection vs. Lower Urinary Tract Infection
The clinical signs (“symptoms”), consequences, and treatment of upper urinary tract infections differ significantly from those of the lower urinary tract. An infection of the upper urinary tract (i.e. a kidney infection) is termed pyelonephritis while a lower urinary tract infection is called urethrocystitis (typically shortened to cystitis, meaning “bladder inflammation”).
Kidney infections are overall uncommon, but can occur due to transfer of bacteria from the bloodstream (though rare), Leptospirosis infections, or an ascending infection that originated downstream in the bladder. Unlike lower urinary tract infections which only cause signs confined to the bladder (read more below), kidney infections affect the whole body.
Signs of a kidney (or upper urinary tract) infection include lethargy and depression, decreased appetite, dehydration, fever, abdominal pain, vomiting, weight loss (if a chronic case), and recurrent bladder infections. Additionally, kidney infections cause not only increased frequency of urination, but also an increased volume of urine produced as well as increased water consumption or thirst. This sign is known as polyuria and polydipsia (PU/PD), and typically points to a serious problem in dogs and cats. PU/PD does not occur with lower urinary tract infections, in which patients may urinate more frequently but usually in small amounts, and there is no increase in thirst with bladder infections. If you observe PU/PD in your dog or cat, contact your personal veterinarian immediately.
If left untreated, kidney infections can lead to renal failure and sometimes a systemic infection in which bacteria from the kidneys enter the bloodstream and travel to other organs. Diagnosis involves a urinalysis and bloodwork, a urine culture, and sometimes abdominal radiographs (X-rays) or ultrasound as well as a renal biopsy. Treatment includes hospitalization with IV fluid therapy and IV antibiotics. The prognosis depends on the response to treatment and the severity of complications, but may be guarded to poor.
Fortunately, lower urinary tract infections (i.e. bladder infections) are less threatening to your dog or cat’s health. Their diagnostic approach and treatment plan differ slightly, as you’ll soon find out below.
For the remainder of this article, we shall be discussing infections of the lower urinary tract (and primarily bacterial ones at that).
Learn more about Leptospirosis, a bacteria that can cause kidney and liver failure in both dogs and humans. Click here to read our article on this zoonotic disease.
Clinical Signs of a Lower Urinary Tract Infection (UTI)
The most classic signs of a bladder infection in a dog or cat are listed below. The overall behavior, appetite, and water consumption of a dog or cat with a lower UTI are not typically altered.
- Increased urge to urinate small amounts of urine (pollakiuria) without an increase in thirst
- The increased urge to pee may mean that your pet feels like he or she immediately needs to urinate, perhaps before making it outdoors, to a potty pad, or into the litterbox. Thus, small urinary accidents are common if your dog or cat has a UTI. No rolling up a newspaper to scold your pet; he or she can’t help it!
- Pain or vocalizing when attempting to urinate (stranguria): UTIs are uncomfortable. Your pet may feel a dull pain or stinging in the lower abdominal or pelvic region, especially when he or she has to tinkle.
- Bloody urine (hematuria): You may notice pink or red-tinged urine or observe a few droplets of blood after your pet urinates.
- Foul odor: In some UTI cases, the urine may have an especially unpleasant odor.
Sometimes, your pet may lift a back leg or squat down in a posture he or she assumes when urinating without actually producing any urine. With a UTI, the inflammation of the bladder lining may cause your pet to feel like he or she needs to urinate without really needing to. However, if your dog or cat makes several attempts to urinate without producing anything, and especially if he or she is straining or vocalizing in discomfort during these attempts, contact your vet without delay. Your pet may have a urethral obstruction, blocking the flow of urine from the bladder. If left untreated, such an obstruction can lead to serious damage to or rupture of the bladder as well as acute kidney failure.
Look-Alikes: Other Disorders That May Mimic the Signs of a Lower UTI
Several other disorders may have similar features to the signs of a bladder infection. Your personal vet will be able to decipher to pinpoint your pet’s problem. For instance, some look-alikes include:
- Behavioral or potty-training issues
- Normal urine marking behavior in intact (i.e. non-neutered) male dogs and tomcats
- Forgetting basic potty-training, which can be a sign of cognitive dysfunction (or “dementia”) in elderly pets
- Feline Lower Urinary Tract Disease, or FLUTD (in cats)
- Uroliths (urinary stones)
- Urinary incontinence
- For example: urethral sphincter mechanism insufficiency (a.k.a. “spay incontinence”)
- Vaginitis (in females): inflammation or infection of the vagina that can sometimes cause a feeling of a need to urinate
- Prostate disorders (in male dogs)
- Benign prostatic hyperplasia (BPH)
- Prostatitis: infection of the prostate gland
Remember, disorders that cause polyuria and polydipsia (PU/PD; increased urination and increased thirst, respectively) are different from the signs of a lower urinary tract infection.
Predisposing causes of a Lower UTI
As discussed previously, your dog or cat’s body has natural protective factors to aid in the prevention of a bladder infection. However, certain disorders can impair these natural defenses, making your pet more susceptible to developing a UTI. Concurrent disorders or other issues that can predispose your pet to a bladder infection include:
- Decreased water consumption due to decreased availability of fresh water supply: “The solution to pollution is dilution.” Ensuring that your pet intakes an adequate amount of water will help produce more dilute urine to flush bacteria out of the bladder and urethra before they have a chance to amount an infection. So don’t forget to fill your pet’s water bowl!
- Waiting too long to urinate: Don’t make your dog hold his or her bladder all day long while you’re at work! Hire a dog walker or take your pup to a doggie daycare to ensure that your dog can empty a full bladder mid-day. while you’re gone
- Spinal cord disorders (such as intervertebral disc disease, spinal tumor, etc.) that cause impairment to the nerves that supply the bladder, preventing it from emptying properly
- Obesity: Excessive fat rolls around the urethral opening can trap moisture and bacteria, which can travel to the urinary tract. Overweight animals may also have difficulty in cleaning their rear ends, and fecal matter can accumulate, serving as a potential source of a bacterial UTI of the bladder.
- Urinary stones (uroliths): Urinary stones can irritate the lining of the bladder and serve as a structure for bacteria to latch onto, increasing the risk of contributing to a secondary bacterial infection of the lower urinary tract.
- Anatomic abnormalities
- Urinary fistula
Recessed or hooded vulva (in female dogs): Sometimes with age, a spayed female dog’s vulva may slightly sag inward, causing it to be “recessed” or “hooded.” Obesity can also create extra folds around the vulva, also causing a “hooded” vulva. These anatomic structural changes can trap moisture and bacteria, increasing the odds of a bladder infection to develop. Treatment of this vulva abnormality often involves a simple “nip-tuck” surgical procedure called an episoplasty performed by your vet.
- Urinary obstruction (for instance, a urethral plug or stricture, a urethral stone, a prostatic cyst, or a mass inside the abdomen that compresses the bladder or urethra)
- Injury to the urinary tract (such as via a dog fight or by being hit by a car)
- Recent urethral catheterization
- Bladder surgery that could introduce bacteria into the bladder or other abdominal surgery that can lead to inadvertent injury to the urinary tract
Bladder tumor (most commonly, transitional cell carcinoma, or TCC)- A compromised immune system due to disease or certain medications
- Disease processes
- Chronic kidney failure
- Hyperadrenocorticism (Cushing’s disease)
- Diabetes mellitus: When your pet’s blood sugar becomes high enough, excess glucose (or sugar) will seep out of the bloodstream and enter the urinary tract to be excreted in urine. When glucose is in the urine (termed glucosuria), it provides the perfect food source for certain bacteria and fungal organisms (such as Candida, the same fungal species that causes thrush). This increases the risk of a UTI development. Additionally, diabetic patients often have impaired immune system function as well, complicating UTI formation and treatment.
- Medications: chemotherapy drugs or other immunosuppressants, such as high-dose prednisone
- Disease processes
- Presence of a bacterial population resistant to both your pet’s immune system defenses and to antibiotic usage
Diagnosis of a Lower UTI
Based on your dog or cat’s clinical signs of increased urgecy to urinate (urinating small amounts frequently), discomfort upon urinating, and blood in the urine, a lower urinary tract infection is going to be on the forefront of your vet’s mind. Your vet will require a urine sample to confirm this diagnosis. He or she may either collect a sample via free-catch (in which urine is collected in a container as your dog or cat is urinating or after your cat has peed on non-absorbent cat litter), catheterization (in which a catheter, or sterile tube, is placed up your pet’s urethra into the bladder), or by cystocentesis (in which a needle is placed through the skin of the belly directly into the bladder for sampling).
A complete urinalysis will be performed. If your pet has a UTI, his or her urine will typically display evidence of bacteria (seen on microscopic examination), inflammation (the presence of white blood cells, known as pyuria), and blood (hematuria). The diagnosis is made. Depending on your individual pet’s medical history regarding bladder infections, his or her case may be deemed an uncomplicated vs. a complicated UTI, a persistent infection vs. a recurrent infection. Further diagnostic steps and more advanced treatments are necessary for complicated cases and persistent or recurrent infections.
If a complicating factor such as uroliths (bladder stones), a bladder tumor, or chronic pyelonephritis is suspected, your vet may also wish to perform imaging: abdominal radiographs (X-rays) and ultrasound (sonogram) of the urinary tract. Your veterinarian may also require a urine culture to grow the specific bacteria causing your pet’s UTI in order to identify it to determine which antibiotic is best to treat it. Such samples should be collected via catheterization or cystocentesis to prevent contamination. If bladder or prostate cancer is suspected in your dog, your vet may consider the noninvasive CADET® BRAF gene test.
Click here to learn how to decipher your pet’s urinalysis.
Treatment of a Lower UTI: What Your Vet NEEDS You to Do
What kills bad bacteria? Antibiotics! One of the most important things that every veterinarian desperately needs pet owners to realize is the vital importance of giving their dog or cat an antibiotic exactly as prescribed for the entire duration that is instructed! Most cases of unresolved (i.e. persistent) bladder infections arise from failure to give an antibiotic as it is intended to be given. Multidrug-resistant bacteria can also evolve due to failure of not administering appropriate antibiotics to a patient for their full course. So do your vet (and, more importantly, your pet) a favor by ensuring that you give your pet the full dose of a prescribed antibiotic correctly as frequently as prescribed for as long as intended. This also means that your doggie or kitty doesn’t spit out or vomit up the pill. No missed doses!
If your pet has a simple (uncomplicated) UTI, and especially if this is his or her first bladder infection, a simple course of oral antibiotics (commonly penicillin drugs) for 10-14 days will be prescribed. Depending on the level of your pet’s discomfort, some vets may also give some anti-inflammatory medications to reduce swelling of the bladder lining and subsequent pain. In 7-10 days after the antibiotic regimen is completed, your vet will likely wish you to provide a urine sample from your pet to run a basic urinalysis once more. Re-checks are very important. But why would you need to do this after all the trouble of giving your pet antibiotics for two weeks? Your vet wants to ensure that the infection has been fully cleared to prevent a persistent infectious state, which would require another round of antibiotics and likely other treatments. So please be compliant to avoid unnecessary expenses and work for yourself later on.
If your dog or cat has a complicated UTI (due to concurrent health problems or anatomical disorders predisposing him or her to the development of a urinary tract infection) or a persistent or recurrent infection, your vet will likely choose a stronger antibiotic based on the results of the urine culture that should be performed in such cases. When UTIs such as these are difficult to treat, your vet will instruct you to give your pet the antibiotics either for 4-6 weeks or for 2 weeks after your pet’s clinical signs resolve. Another urinalysis and urine culture are recommended 5-7 days after the antibiotics are started and again in 7-10 days after they are completed.
In addition to antibiotics, the underlying issue predisposing your pet to a complicated UTI must also be addressed: concurrent diseases must be treated, anatomic defects and injury must be corrected, and any tumors or bladder stones must be managed. Antibiotics alone will not be the sole solution to treating the complicated UTI; without addressing the other issues, the UTI will either not be resolved or shall recur. Moreover, most feline UTI cases are automatically deemed “complicated” since bladder infections in cats are largely uncommon and typically stem from another problem.
If UTIs recur or persist even after appropriate treatment is completed and predisposing factors (such as bladder stones) are treated, your vet may recommend one of the following options:
- Chronic antibiotic therapy using either one-third dose of an antibiotic for 6 months or else only dose at nighttime for 6 months (pets don’t tend to urinate while they’re sleeping, allowing time for the antibiotic to concentrate in the bladder)
- Flush the bladder with formaldehyde
Why are UTIs so important to treat?
Not only do we want to improve your pet’s comfort, but we also want to treat a lower UTI as early as possible to prevent three potential complications:
- An ascending infection from the bladder up the ureters into the kidneys can lead to pyelonephritis, or a kidney infection, a serious medical emergency (as explained above).
- Bacteria from the bladder can migrate to the vertebrae that encase the spinal cord, causing diskospondylitis (or “disko” for short). Diskospondylitis causes severe back pain and damage to the vertebral end plates. It must be promptly treated with antibiotics.
- The development of struvite-type bladder stones can occur in dogs secondary to a bacterial infection of the lower urinary tract. Clumps of bacteria and debris inside an infected bladder can form a nidus, or center upon which mineral deposits take hold, growing and growing outward to form a hard bladder stone. In addition to treating the underlying UTI with appropriate antibiotics, your veterinarian may suggest one of two options to rid your pet of its struvite stones. Depending on the size of the stones, your vet may recommend direct removal of the stones; this may be performed either by surgical removal (via bladder surgery, or cystotomy) or via laser ablation (or lithotripsy) in which smaller stones are blasted apart by a laser and removed via a minimally-invasive scoping technique. Alternatively, your vet may prescribe a special prescription diet to help dissolve your pet’s bladder stones over time. Such diets include Hill’s® s/d and Purina® SO. (Fun Fact: Struvite stones in cats are thought to be caused by dietary mineral sources rather than bacterial infections of the bladder.)
[EDIT: This article was updated on 9/25/17 to add information about diskospondylitis.]
What about natural treatments?
Yogurt? Cranberries? These make for a yummy snack but not a very good UTI treatment for doggies and kitties. Yogurt and probiotic supplements contain a high amount of “good bacteria” that theoretically help fight infections by “bad bacteria”. However, at this point in time, research regarding the effectiveness of yogurt and similar products in helping treat and prevent bladder infections is lacking.
Though it can’t take the place of an antibiotic prescribed by your vet to treat your pet’s UTI, cranberry extract may have a bit more credibility than yogurt. Cranberry extract may help decrease the ability of E. coli bacteria from sticking to the lining of your pet’s bladder, thus decreasing its chances of colonizing it and causing an infection. However, its effectiveness is still not fully known, so it can’t replace your pet’s antibiotic quite yet. However, cranberry extract may help prevent recurrent UTIs in some patients. D-mannose powder may act similarly to cranberry extract at inhibiting E. coli.
Bottom line: Consult with your vet about your pet’s health; don’t take it upon yourself to treat without veterinary advice. And always ask your vet’s advice before giving your dog or cat any supplement.
Can a lower urinary tract infection be prevented?
Sometimes no matter how amazing a pet owner we are, our pet can develop a bladder infection. However, there are a few things that you can do to help prevent this risk:
- Provide your pet with easy access to plenty of fresh, clean water.
- Allow your dog to go out to potty regularly (ideally, 3-4 times daily). Fully emptying the bladder allows bacteria that may enter up the urethra to be excreted from the body.
- Keep your cat’s litterbox clean, and learn how to reduce your cat’s chances of developing Feline Lower Urinary Tract Disease (FLUTD).
Ensure that your pet has good hygiene “down there”. If your dog is overweight**, excess skin folds can trap moisture and become wet with urine when your pet relieves herself. This allows for the perfect breeding ground for a skin infection, which can lead to a secondary UTI if bacteria from the skin enters the urethra and bladder. Keep your dog or cat clean and dry. Chlorhexidine wipes contain a gentle antiseptic that may help reduce infection. Ask your vet about the best and safest way to clean. The same advice holds true if your pet has diarrhea, which can stain the rear end and contaminate the urethral opening. Keep your dog or cat’s tush clean and dry.- **Help your dog to maintain a healthy weight. Since obesity can lead to a plethora of health problems, including urinary tract disorders and potential bladder infections, be your pet’s personal trainer by helping him or her fight the battle of the bulge. Click here for our tips on how to safely aid your pet in losing weight.
- If your pet has been treated for a spinal disorder causing disruption to the nerves of the back legs and urinary bladder, make sure to follow your vet’s advice on how to properly manually express your pet’s bladder to allow proper emptying.
- If your veterinarian prescribes an antibiotic to treat an existing UTI, please, please, PLEASE follow the instructions implicitly and give your pet the full dose for the entire duration that it is prescribed! As we’ve already discussed, this is one of the best ways to help prevent a persisting or relapsing bladder infection.
And the best tip is always this: if you have concerns about your dog or cat’s health, be it urinary tract-related or otherwise, ask your vet for his or her advice. As a team, we can work together to improve your pet’s health and quality of life.
The Meowing Vet hopes that your dog or kitty gets some much needed relief following the detection and treatment of his or her urinary tract infection! Contact your local veterinarian if you suspect that your pet has a UTI.
– Maranda Elswick, DVM
