Kidney disease in dogs

Kidney disease is less common in dogs than cats, but it is still a condition that is important to recognise. The kidneys perform a vital role in keeping our canine companions healthy and happy, so if they become diseased or damaged, the consequences can be serious.
 
While your vet is always there to answer questions about your dog’s condition, we are here to provide additional information and help support you with those conversations. Read on to find out more about kidney disease in dogs.

What do healthy kidneys do?

The kidneys do a variety of jobs in the body, including –

• Removing toxins from the blood and excreting them in the urine
• Managing the balance of water and electrolytes in the blood, including sodium, potassium, calcium and phosphorus
• Maintaining the correct blood pH through acid-base regulation
• Helping regulate blood pressure
• Producing hormones, such as erythropoietin, which is involved in red blood cell production
  

What is kidney disease in dogs?

Any condition that affects the way the kidneys perform may be referred to as kidney or renal disease. This can vary considerably, depending on whether part of the kidney tissue is affected or whether the kidneys have stopped functioning properly altogether.

Kidney disease can be divided into two main categories –

Acute kidney disease (or acute kidney injury)

Eating something nephrotoxic like human medication, grapes, or antifreeze (ethylene glycol) could cause sudden-onset kidney damage. However, acute kidney disease can also occur secondary to infection, urinary stones, trauma, or a sudden drop in blood pressure due to shock or haemorrhage elsewhere in the body.
 
If treated quickly and aggressively enough, acute kidney disease may be treatable, though this will depend on the degree of damage and underlying cause. However, despite everyone’s best efforts, acute kidney disease can be fatal.

Chronic kidney disease  

Chronic kidney disease in dogs appears more slowly. Over time, the kidneys gradually become less effective, and their function deteriorates. This type of kidney disease is more common in older pets. It also may have a hereditary element, as some breeds seem more prone to it than others, such as Bull Terriers, Cocker Spaniels and Beagles.

A previous history of acute kidney injury, such as toxin ingestion or infection, could play a role. However, in many cases the cause of chronic kidney disease is unknown, and it is often put down to age-related ‘wear and tear’.

Dogs with chronic kidney disease are less able to filter the blood and allow too much water to pass through into the bladder, meaning affected dogs often urinate more than usual.  

Chronic kidney disease can’t be cured, but it can be managed to help improve symptoms and slow progression.

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What are the symptoms of kidney disease in dogs?

In the early stages of chronic kidney disease, there may be no symptoms at all, as there is still enough kidney tissue available to function reasonably. However, as things progress, you may start to notice the following –

• Increased thirst
• Increased urination
• Weight loss
• Reduced appetite
• Vomiting or nausea
• Lethargy
• Constipation
• Halitosis (uraemic breath)
  

In the late stages of kidney failure, additional symptoms may be seen such as –

• Severe dehydration (sunken eyes, skin tenting, collapse)
• Mouth ulceration
• Issues with muscle twitching or weakness
• Anaemia (low red blood cells, causing pale gums, elevated heart rate and collapse)
  

Dogs that have acute kidney disease will have a much more rapid progression of some of the listed symptoms than dogs with chronic kidney disease. Additionally, they may have abdominal pain, seizures, and no urine output.  

How is kidney disease diagnosed in dogs?

Your vet will start by examining your dog and discussing their symptoms with you. They will want to know whether your dog could have encountered something toxic and if they are up to date with their vaccinations.

Depending on their findings, they may recommend the following tests –

• Blood samples – these will check your dog’s kidney values, but also other parameters like red and white blood cell levels, liver values, blood sugar and electrolytes. This helps to assess the severity of the problem but also rule out other disease processes.
• A urine sample – looking at the concentration of your pet’s urine and whether there are other abnormalities like proteins or bacteria, will help to confirm kidney disease. Samples may need to go to an external lab for additional tests.
• Blood pressure – Measuring your pet’s blood pressure will help your vet to stage the severity of your pet’s kidney disease and inform their treatment plan.
• Diagnostic imaging – X-rays, ultrasound and CT scans can help to look for the cause of your dog’s kidney disease. These are particularly useful if urinary stones or tumours are suspected.
• Fine needle aspirates or biopsies – Sometimes samples of cells or tissues are needed to work out the underlying cause of the kidney disease.
  

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What are the treatment options for canine kidney disease?

Treatment will depend on the severity of your pet’s kidney disease, the underlying cause, and whether they are suffering from acute or chronic kidney disease. It may involve the following –

Acute kidney disease

Treatment will mean hospitalization to reduce and prevent further damage to your pet’s kidneys.
 
This will usually involve trying to reduce circulating toxins and supporting kidney function through intravenous fluids (a drip). For ingestion of poisonous substances, your vet may induce vomiting and administer activated charcoal to prevent further toxin absorption. Your pet could need help with their electrolyte balance and may require additional medications to support blood pressure, treat infections or manage any nausea and diarrhoea.
 
The prognosis depends on the amount of kidney damage that has occurred. With the right care, many patients are successfully discharged and have a relatively good long-term outcome, according to a study in 2022.

Chronic kidney disease

It’s not possible to reverse the damage that has already occurred to the kidneys, so this condition is unfortunately not curable. However, it can often be managed, and disease progression slowed through the following treatments –

• Feeding a vet-approved kidney diet – Special kidney diets are formulated to have the right levels of protein and electrolytes to support these pets. Changes in diet should be done gradually, so that your pet accepts the new food.
• Supporting fluid intake – Make sure your pet has plenty of clean, fresh drinking water. This should always be available. You can also add water to your pet’s food. If your pet is unwell or dehydrated when they are first diagnosed, they may require intravenous fluids initially.
• Medications – Your pet may need to take medication if their blood pressure is too high, or if they are suffering from anaemia, nausea and stomach upsets.
• Supplements – Vitamin or electrolyte supplements can further support your dog with their condition.
• Regular monitoring – Your dog will need regular vet check-ups, which may include blood pressure monitoring, blood tests and urine samples. This will allow your vet to track the progression of your pet’s condition and ensure they are receiving the best treatment.
  

If your dog is very unwell when first diagnosed, their long-term prognosis is much poorer. As with all diseases, the earlier this condition is detected and managed, the better, so make sure to speak with your vet as soon as you notice any symptoms.

Some vets offer routine blood and urine screening in older patients to help detect problems earlier, so it is worth considering this if you have a senior pet.

Many pets can live for months to years if their condition can be well managed. However, because this chronic kidney disease is progressive and cannot be cured, symptoms may get worse over time. Sometimes euthanasia is discussed, especially if your pet’s quality of life is affected.

Summary

The kidneys carry out many essential roles in the body. If they become damaged, then your pet can become very unwell. Symptoms of acute kidney disease often appear more rapidly than those of chronic kidney disease, which is a more gradual process.

If your dog is showing any signs of kidney disease such as increased thirst, excessive urination and weight loss, then get them checked out sooner rather than later.