canine urinary tract infections

Canine Urinary Tract Infections: Symptoms and Treatment

Canine urinary tract infections (UTIs), also know as bladder infections or cystitis, are a type of bacterial infection that can be caused by a number of different bacteria. They occur when bacteria enter the urinary tract and are able to colonise a section of the tract.

Canine urinary tract infections can be uncomfortable or even painful for the patient. Urination can become especially painful, as the passing of urine becomes difficult due to the inflammation caused by bacterial colonies.

There are specific medical conditions that can increase the likelihood of canine urinary tract infections developing, but there are also other factors that can contribute to their development, such as environment, sex or age. The diagnosis of a urinary tract infection will require your vet to perform a urinalysis (where a sample of urine is taken and then tested for the presence of bacteria).

The Role of the Urinary Tractcanine urinary tract infections

The canine urinary tract can be divided in to what are essentially 4 key components, they are:

  • The Kidneys – Essentially the body’s waste filtration units, they filter the blood and remove waste compounds from it. What is excreted from the kidneys is known as urine
  • The Ureters – Connect the kidneys to the bladder
  • The Bladder – An elastic organ, which acts as a reservoir for urine
  • The Urethra – Allows urine to be excreted from the bladder

As you can see, the urinary tract is responsible for the removal of waste products from the body. Waste products are collected and stored as urine in the bladder. The kidneys are also partially responsible for the regulation of body fluids. Non-functioning or damaged kidneys can allow waste products to ‘leak’ back in to the bloodstream, posing a toxicity risk.

The Development of Canine Urinary Tract Infections

Canine urinary tract infections are typically bacterial in origin and they can occur in either the upper urinary tract (kidneys, ureters) or lower urinary tract (bladder, urethra).

Infections develop when external bacteria ascend through the urethra in to the bladder. Bacteria that remain around the external genitalia after excretion of faeces for example, could then ascend the urethra. Once these bacteria colonise the urinary tract, complications begin to arise.

The onset of infection depends on the virulence of the bacteria involved (E. coli is an example of bacteria that has strong virulence) and the effectiveness of the host’s immune system. For example, medication that decreases the immune system’s strength (immunosuppresants) would make the development of urinary tract infections more likely.

Underlying Medical Issues can Allow Canine Urinary Tract Infections to Develop

Canine urinary tract infections most commonly arise as a result of another, underlying medical condition, for example:

  • Incontinence (particularly dogs aged 7+ due to weakening of sphincter muscles)
  • Trauma (damage) to the urinary tract
  • Stress
  • Prostate disease
  • Cancer
  • Bladder stones (urolithiasis)
  • Diabetes mellitus
  • Cushing’s Syndrome (a hormonal disorder)
  • Hyperthyroidism (production of excess thyroid hormones, which are involved in metabolism)

Dog’s receiving immunosuppressant medication are also at greater risk, due to their weakened immune system. Environmental factors, such as the use of a catheter can also increase the risk.

Symptoms of Canine Urinary Tract Infections

One of the most common signs of a urinary tract infection is alteration in urination behaviour. This might be increased frequency of urination, difficulty urinating, bloody or cloudy urine, strong smelling urine and soiling in inappropriate places. Other symptoms include:

  • Fever
  • Loss of bladder control
  • Lethargy
  • Back pain
  • Polydipsia (excessive thirst)

Treating Canine Urinary Tract Infections

If your think your dog has a urinary tract infection, it could indicate a potentially dangerous underlying condition, so immediate vet assistance is recommended. After diagnosing your dog, there are a number of ways your vet can treat the infection with UTI medication:


The most common form of treatment is antibiotics, although as canine urinary tract infections usually indicate an underlying issue, your dog may require additional treatment for the underlying condition. The antibiotics will however, help alleviate the current situation. Common antibiotics used when treating urinary tract infections are:

  • Amoxycillin – A generally non-toxic, broad spectrum antibiotic
  • Cafadroxil – Has a stronger antimicrobial action against certain bacteria, although more likely to induce gastrointestinal side effects such as vomiting or diarrhoea
  • Ceftiofur – An injectable antibiotic, less effective against the majority of bacteria but strongly effective against E. Coli
  • Fluroquinolones e.g. Enrofloxacin – Spread well through the body making them good for intact males as they can penetrate effectively in to the prostate gland. Not suitable for long term treatment however
  • Tetracyclines – Another broad spectrum antimicrobial, which is excreted in to the bladder unchanged, so it retains antimicrobial activity in the urine, making it suited for lower urinary tract infections

Other Treatment Options

  • Dietary changes – Changing the diet and increasing water intake can have a positive effect on urinary tract health. For example, there are special diets such as S/O Urinary by Royal Canin that can reduce the likelihood of bladder stones developing
  • Urinary pH modifiers – Making the urine more acidic or more alkaline can help reduce the infection
  • Surgery
  • Treatment of any underlying diseases

Why not read Treating Urinary Problems for Pets, which includes some natural options for treating canine urinary infections.

Image Credit.


About James Watts

BSc Bioveterinary Science. Editor of PetSci. When I'm not writing, learning, discussing, or reading about animals, you know it's the weekend! Currently developing PetSci HealthTrak, the fast and easy way to monitor your pet's weight and calorie intake. HealthTrak offers a simple way to track your pet's progress, helping them achieve a healthy weight and a long, happy life.

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One comment

  1. I’ve noticed when my dog wees there is some blood in it, today I took her to the dog groomers to get cut and they pointed it out to me also

    I’m scared I really don’t want to lose her at all and hope its nothing serious by reading reports it sounds like a uti but then I read if she as that there will be a bigger problem.

    I’m going to book her in vets on monday but scared I really don’t want it to be bad and cost hundreds,

    She is a 10 year old shit zu

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