Kidney Disease

Kidney Disease

This is a disease where there is a decline in kidney function. This can sometimes happen very quickly and other times can be much more slow-onset and chronic.

Acute kidney disease is more commonly seen with a toxicity or a urinary blockage.

Chronic kidney disease is usually seen in middle age – older dogs as the kidneys deteriorate with age. The age of onset is often related to the size of the dog. For most small dogs, the early signs of kidney disease occur at about 10-14 years of age whereas large dogs tend to have a shorter life span and may undergo kidney disease as early as 7 years of age.

The kidneys are responsible for removing toxins in the blood, maintaining water and salt balance, maintaining blood pressure and producing hormones. So kidneys are an incredibly vital organ in the body.

What is kidney disease?

In acute kidney disease this is a sudden damage to the kidney tissue which impairs its ability to remove waste products from the blood. This damage can sometimes be reversible with early treatment.

Chronic kidney disease is not uncommon. This is where there is long-standing, irreversible and progressive damage to the kidneys.

It is sometimes unknown why the kidneys can deteriorate but sometimes there are underlying causes such as birth defects affecting the kidneys, polycystic kidneys, kidney tumours, infections, and glomerulonephritis.

What are the symptoms?

• Drinking a lot
• Urinating a lot
• Vomiting/nausea
• Poor appetite
• Weight loss
• Weakness
• Constipation

How can you diagnose it?

It is usually diagnosed by blood tests and urine tests.

Sometimes it is not evident that a dog has early kidney disease as early on it doesn’t necessarily show symptoms, but may show up on routine blood and urine tests. Usually, at least two thirds of the kidneys must be dysfunctional before any clinical signs are seen.

It may be necessary to x-ray or ultrasound the kidneys to look for anatomical changes such as polycystic disease, or tumours, or look for urinary stones and blockages.

What shows up on the tests?

• Blood tests can show an increase in creatinine, urea or SDMA
• Some dogs may have concurrent changes to their phosphate, calcium or potassium levels
• Urine is very dilute

How can we tell how bad it is?

The International Renal Society (IRIS) have established a staging system that helps us understand how advanced chronic kidney disease is. We often use these guidelines when diagnosing kidney disease. You can check their website on http://www.iris-kidney.com/guidelines/staging.html

Your vet will often ask for additional tests (such as a urine protein: creatinine urine test or a blood pressure check) to help stage the kidney disease.

Can we do anything to prevent it?

Nothing can be done to prevent chronic kidney disease.

Acute kidney disease can be prevented by avoiding toxins such as grapes, rasins, or overdosing on certain medications.

Can it be treated?

Acute kidney disease can sometimes be reversed with aggressive fluid therapy.

Chronic kidney disease unfortunately cannot be cured and is a progressive disease but can sometimes be managed very successfully. There are several things we can do slow the progression of the disease and keep your cat feeling as happy as possible.

1. Start a high protein, low phosphate diet. The best formulated diets we prescribe are Royal Canin Renal, Hills k/d and Purina Renal Function. These come in wet and dry preparations.
2. Provide plenty of fresh water
3. Regular blood and urine tests with your vet to check for progression of the disease
4. It may be necessary to give medications to prevent further protein loss, control high blood pressure and balance mineral and electrolytes
5. Sometimes it may be recommended to give intravenous fluids in hospital for a few days. It is also possible to give bolus fluid injections under the skin and we can help guide you on how to do this at home.
6. It is possible to manage the symptoms associated with kidney disease such as nausea and vomiting.

How do you monitor it?

As chronic disease progresses some secondary issues and complications may develop, therefore it is important to see how it is progressing to assess whether we can be doing anything else:

• Blood tests – this checks for changes in creatinine, urea, phosphate, potassium, calcium levels and anaemia
• Urine tests – check for protein loss and urinary tract infections
• Blood pressure – to check for high blood pressure

We would recommend regular testing every 3-6 months, this interval may need to be decreased if your pet is becoming more unwell.

Other diseases that can come hand in hand with chronic kidney disease (CKD)

Hypertension – high blood pressure commonly develops with CKD. Prolonged and severe high blood pressure can result in organ damage and blindness.

Hyperphosphataemia – high phosphate levels can develop, so if it does ‘phosphate binders’ may be necessary to reduce the levels

Hypokalaemia – low potassium levels can develop, this can cause muscle weakness and constipation, therefore supplementation of potassium may be necessary

Protein losing nephropathy – as CKD progresses the kidneys become more ‘leaky’ and can lose essential proteins in the body. If the kidneys do become more leaky there are medications we can give to reduce the protein loss so the essential proteins stay in the body.

Anaemia – a low number of red blood cells are common with any chronic disease. As the kidneys produce less erythropoietin hormone fewer red blood cells are produced. It is possible to supplement erythropoietin but often the anaemia isn’t severe enough to require this.

Urinary tract infections – these can be common in dogs with kidney disease as the urine is very dilute.

What to expect? How long has my pet got?

The rate at which the disease develops varies between every individual. The kidneys will eventually fail and eventually will require euthanasia but it is impossible to tell when that will be.