What Else Is It Called?
Chronic Kidney Disease can often also be referred to by the following names:
- Chronic renal failure
- Kidney disease
- Kidney failure
What Do The Kidneys Do?
In normal function kidneys remove waste and extra water from the blood to form urine. They are involved in the regulation of water balance, blood acidity, electrolytes such as calcium, phosphorus and potassium.
Kidneys also produce hormones such as Renin (helps to regulate blood pressure) and erythropoietin or EPO (induces red blood cell production in bone marrow).
The work of the kidney is carried out by functional units within it called nephrons. Each nephron includes a glomerulus and a tubule. The nephrons work through a two-step process: the glomerulus filters your blood, and the tubule returns needed substances to your blood and removes waste products which are excreted in urine.
Each kidney is made of about one million nephrons.
What is Chronic Kidney Disease (CKD)?
Chronic Kidney Disease (CKD) is the end of result of a wide range of primary disorders that cause irreversible damage to nephrons eventually leading to a reduction in the kidney’s ability to filter waste and excess water from the blood.
Is It Common?
It is estimated that about 30%of cats over the age of twelve have CKD. It is reported to be the second most common cause of death in cats over the age of five.
How Do Cats Get It?
In a minority of cases a specific underlying cause can be identified e.g. cancer, but in most cases no one primary cause can be found.
In most cases the main findings are non-specific inflammation and scar tissue replacing damaged nephrons.
Are There Any Risk Factors?
In a recent study moderate to severe dental disease has been highlighted as being associated with an increased risk of developing CKD in cats.
Periodontal disease produces chronic systemic inflammatory response as well as local inflammation.
This mirrors what is recognised in human medicine.
Why Is CKD A Problem?
Without properly functioning kidneys the body is unable to rid itself of all the waste that it creates through its normal function. This can lead to a number of changes that affect the rest of the body and the overall health and quality of life of cats.
What Are The Signs Of CKD?
Early signs of CKD can be subtle and non-specific but common signs to note are:
- Increased urination and thirst
- Dullness or lethargy
- Reduced or absent appetite
- Weight loss
- Halitosis (bad breath) in the absence of dental disease
- Poor coat quality
- Severe cases can develop oral ulceration and neurological symptoms.
How Is CKD Diagnosed?
History and clinical exam by a veterinarian will raise the suspicion for the condition.
Measurement of creatinine and urea on blood biochemistry confirms the diagnosis, however it must be noted that due to the large reserve capacity of the kidneys bloods will appear normal until about 66% of the nephrons have been destroyed.
What Else Do We Need To Know Once We Have Diagnosed CKD?
Other important factors to quantify are:
- Blood pressure
- Urinalysis – specifically to measure protein levels
- Electrolyte levels (calcium, phosphorus and potassium)
- Red blood cell count.
Are All CKDs Equal?
No! There are varying levels of severity.
We use the guidance of the International Renal Interest Society (IRIS) to determine the degree of severity as well as to guide treatment.
What Can We Do About It?
Unfortunately CKD is a progressive and irreversible condition but we can manage the symptoms and slow progression if it is diagnosed early.
In clinically affected patients supportive care in hospital includes:
- Intravenous fluid therapy is a mainstay of therapy to rehydrate and replace or maintain normal electrolyte balances
- Symptomatic treatment for other clinical signs such as anti-nausea medication and medication to regulate blood pressure if needed
- Appropriate nutrition.
How Is CKD Managed In The Long-term?
The mainstay of long-term home care revolves around dietary management.
Specialised diets have lower protein and phosphorus levels and higher potassium levels. The combination has been shown to combat the metabolic changes that cause the clinical signs of CKD.
These diets are also highly palatable which is important as cats will often have a reduced appetite.
Long-term medication is sometimes needed if they have hypertension (high blood pressure), protein in the urine or excessive levels of phosphorus in the blood.
What Can We Do To Prevent It?
It is important to realise that you cannot guarantee to prevent CKD but sometimes it is possible to reduce the risk by:
- Annual health check.
- Annual blood test for cats over the age of 8 years of age to screen for CKD.
- Carrying out dental work early and promptly when advised.