"Pyelonephritis in dogs - A bacterial infection of the kidneys

"Pyelonephritis in dogs - A bacterial infection of the kidneys

Health & Safety

When dogs are fully grown and have reached adulthood, their bodies are really good at fighting off and avoiding opportune infections such as virus and bacteria, due to a combination of their standard vaccination protection and the development of their own full adult immune systems.

This means that dogs who are grown up and generally healthy will tend to stay healthy and not be plagued by a lot of minor ills, or a propensity to develop infections – because even if they are exposed to bacteria or viruses for many common and often serious diseases, their bodies have developed protections against them.

However, this does not mean that a generally healthy adult dog will never get sick of course, and for dogs that have weak or compromised immune systems, picking up otherwise innocuous pathogens can quickly lead to ill health. Dogs come into contact with a wide range of different viruses and bacteria simply going about their daily lives and when out on walks, usually with no ill effects – but any dog, just like any human, can potentially pick up something that their body cannot eliminate quickly, and become sick.

One common type of infection that dogs can develop over the course of their lives is pyelonephritis, which is a type of bacterial infection that affects the kidneys, and that left untreated, can potentially make your dog very ill. Dogs that tend to suffer from urinary tract problems and/or kidney stones tend to be more prone to contracting pyelonephritis infections than other dogs, because anything that compromised the normal functions of the kidneys or urinary tract makes dogs more vulnerable to opportunistic infections too.

In this article, we will look at pyelonephritis in dogs in more detail, including how dogs catch it, how to spot the symptoms of it, and what can be done to treat it. Read on to learn more.

What is pyelonephritis?

Pyelonephritis is a type of bacterial infection that affects a specific part of the dog’s kidney, which is called the renal pelvis. However, pyelonephritis refers to the type of infection caused rather than the specific bacterial strain that causes it, and various different types of bacteria including E. coli and Staph infections can all lead to the condition developing.

In some cases, the infection may begin to develop lower down in the dog’s urinary tract, and progress upwards to the kidneys. Pyelonephritis is rare in otherwise healthy dogs, and it is generally considered to be an opportune infection, which enters and affects the body due to a separate underlying issue, such as existing kidney problems, persistent UTI infections, or kidney stones or crystals.

How do dogs catch it?

As mentioned, bacteria of a huge range of different types are naturally present in out environments at all times, including some potentially nasty strains like E.coli and Staphylococcus aureus. If such bacteria are able to enter your dog’s body and your dog’s immune system fails to fight them off – such as if your dog already has an infection or their immune system is compromised or already working to fight off another problem – the bacteria in question can lead to pyelonephritis developing.

The symptoms of pyelonephritis in dogs

A range of generalised kidney-related symptoms usually present in dogs with pyelonephritis, which like any internal problem or health condition, can make getting to the bottom of the symptoms and identifying their root cause challenging.

If your dog already has kidney problems or is prone to flare-ups of kidney stones or urinary infections, this can help to point your vet in the right direction for diagnosis; and some of the main symptoms that accompany pyelonephritis in dogs include:

  • Bloody urine, or urine that is orange looking or darker than usual.
  • Very strong-smelling urine.
  • Difficulty or pain when urinating, which may manifest as the need to pass water very often, and appearing to strain or be uncomfortable when trying to do so.
  • Increased thirst levels.
  • Pain in the kidneys themselves, which can lead to your dog being reluctant to allow you to touch their lower flanks and back, or lead to pain and pain responses when you do touch them.
  • A dog fighting a kidney infection will tend to feel quite under the weather and unwell, and may go off their food and be lethargic and reluctant to exercise.


If you spot any of the above symptoms in your dog, it is important to take your dog to the vet promptly, so that they can formally diagnose the problem and rule out any other conditions that may present with similar symptoms. Left unchecked, pyelonephritis can make your dog very ill, impair their kidney functions, and potentially lead to permanent damage, and the longer an infection is left, the harder it will be to treat.

However, accurate diagnosis and prompt intervention means that a bout of pyelonephritis can usually be cleared up with antibiotics, although this can be challenging in some cases if the bacteria in question is an antibiotic resistant strain, or the wrong type of antibiotics are prescribed for the specific type of infection present.

Any underlying issue that contributes to the development of pyelonephritis must of course also be resolved in order to prevent future flare-ups and further opportune infections, which may require laser or surgical intervention to remove kidney stones, or a special diet to reduce urinary crystal formation.

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