Infecções de bexiga em cães: sinais, tratamento e prevenção

What causes it

Most bladder infections are caused by bacteria. The most common one is E. coli, which normally lives in the gut. Bacteria from the skin around the genitals and anus travel up the urethra, the tube that carries urine out of the body, and reach the bladder. A healthy bladder usually clears them. When the body's defenses are weaker or urine does not flow normally, the bacteria can settle in and cause inflammation.

Female dogs get bladder infections more often than males, partly because their urethra is shorter. A recessed or hooded vulva, where folds of skin cover the opening, also raises the risk. So does a bladder that does not empty fully, or urine that is very dilute. Dogs with diabetes, Cushing's disease, kidney disease, bladder stones, urinary incontinence, or spinal problems that affect bladder control are more prone to infections. The same goes for dogs on long-term steroids or other medicines that weaken the immune system.

An irritated bladder is not always an infected one. Bladder stones, tumors, and inflammation without any bacteria can cause the same signs. This is one reason vets prefer to test the urine before choosing a treatment.

Sinais a observar

Some dogs with bacteria in their urine show no signs at all. When signs do appear, owners usually notice changes in how often and where the dog pees.

• Peeing more often, with only small amounts each time
• Straining, or taking a long time to finish
• Accidents in the house from a dog who was house-trained
• Blood in the urine, or urine that looks pink or red
• Urine with a strong or unusual smell
• Licking the genital area more than usual
• Seeming uncomfortable or in pain while peeing

Several other conditions look similar. Kidney disease and diabetes can make a dog drink and pee much more. In an unspayed female, discharge from the vulva together with more drinking and peeing can point to pyometra, a serious infection of the uterus that needs urgent care. In intact males, prostate problems can cause straining and blood in the urine. A vet can tell these apart with an exam and a few tests.

Quando é uma emergência

Most bladder infections are handled at a regular appointment, and it is best to book one soon after you notice signs. Contact a veterinarian right away, or an emergency clinic after hours, if you see any of these signs.

• Straining to pee with little or no urine coming out
• Crying out when peeing, or pain when the belly is touched
• Not eating, vomiting, diarrhea, or unusual tiredness along with urinary signs
• An unspayed female with vaginal discharge who seems unwell

A dog who cannot pee may have a blockage, for example from a stone stuck in the urethra. A blocked bladder is life-threatening and needs treatment without delay. Poor appetite, vomiting, and low energy can also mean the infection has spread up to the kidneys, which is a more serious illness.

How vets diagnose it

The vet will ask about your dog's drinking and peeing habits and examine the belly and genital area. The main test is a urinalysis. It checks the urine for white blood cells, red blood cells, bacteria, and crystals.

A urine culture is often recommended as well. The lab grows the bacteria from the sample and tests which antibiotics work against them. Results usually take a few days. For a culture, vets prefer urine taken straight from the bladder with a thin needle through the belly wall. This is called cystocentesis. It is quick, usually well tolerated, and avoids contamination from the skin. If you are asked to bring a sample from home, use a clean container and ask your clinic how to store it and how soon to bring it in.

If infections keep coming back, or your dog has other signs, the vet may suggest blood tests, X-rays, or an ultrasound of the bladder and kidneys. These look for stones, tumors, and other conditions that make infections more likely.

How it is treated

Bacterial bladder infections are treated with antibiotics. The vet chooses one based on the most likely bacteria and may change it once culture results arrive. For a simple, occasional infection, current international guidelines support a fairly short course. Repeat or complicated infections often need longer treatment and a closer look at the cause.

Pain relief is often given for the first few days, since an inflamed bladder is sore. When signs are mild, some vets start with pain relief alone while the culture results are pending, and add an antibiotic if it is needed.

Vets recommend giving every dose as prescribed and finishing the course, unless they advise otherwise. Stopping early, or using leftover antibiotics from another illness, can let the infection return and can help bacteria become resistant. After a simple infection, a recheck test is usually not needed if the signs go away. If signs continue or come back, or your dog has had several infections, your vet may suggest another urine test.

Treating the underlying cause matters too. A dog with bladder stones may need a special diet or surgery. Diabetes or Cushing's disease needs its own treatment. For some females with a hooded vulva, surgery to remove the extra skin fold can reduce repeat infections.

Sometimes a routine urine test finds bacteria in a dog with no signs at all. In most of these cases, current guidelines do not call for antibiotics. Your vet will explain whether treatment makes sense for your dog.

Preventing repeat infections

Many bladder infections happen even with good care, and one infection does not mean you did something wrong. Still, a few habits support a healthy bladder. Regular chances to pee during the day help, so urine does not sit in the bladder for long hours. Fresh water should be available at all times. For dogs with a history of stones or crystals, your vet may suggest wet food or other ways to increase water intake. Keeping the area around the genitals clean may also help, especially in long-haired dogs.

Cranberry products, D-mannose, and probiotics are often sold for urinary health. The evidence that they prevent bladder infections in dogs is weak, so it is best to ask your vet before adding a supplement.

Vets call infections recurrent when they come back several times in a short period, for example three or more times in twelve months. Recurrent infections usually call for a full work-up to find the cause, and treatment is often guided by a urine culture. Regular checkups also help find diabetes, kidney disease, and other conditions early.

Outros animais de estimação e pessoas

Bladder infections are generally not considered contagious between dogs. The bacteria usually come from the dog's own body. Other pets in the home only need a vet check if they show signs themselves. Washing your hands after cleaning up accidents is good practice, especially in homes with small children or anyone with a weak immune system. For cats with urinary signs, see our guide to cystitis in cats.

Newly adopted dogs

Accidents are common in the first weeks in a new home. Many come from stress, a new routine, or unfinished house-training. A nervous dog may also hold urine for a long time until it feels safe outside. Short, regular trips to a quiet spot can help. Frequent squatting with small amounts, straining, or blood in the urine can point to a medical problem. In that case, a vet visit comes before any training plan.

At Paw Squadron, the first stops after every rescue are the vet and a bath. Every animal gets a checkup, treatment, vaccinations, and a microchip before adoption. A bladder infection can still start later, after the move, as it can in any dog. If you notice changes in how your adopted dog pees, your local vet is the right first call. You can find more guides on dog health in PawPedia, and answers about adopting from us on our FAQ page.