Kidney disease - the facts
Have you noticed you pet drinking more than normal? Off his food and losing weight? Seem a little under the weather? These are some of the typical signs of chronic kidney disease, a disease commonly seen in older cats and more sporadically in dogs.
One of the major functions of the kidneys is to filter urea (produced by protein breakdown) and to produce urine. Dogs and cats have two kidneys and each kidney has several hundred thousand tiny units called nephrons. These filter the blood, removing toxic waste products, salts and water which are then concentrated to form urine. Over time a proportion of the nephrons will disappear with age and not be replaced. Other factors such as toxins, infections or cancer may also destroy nephrons.
However, the good news is that the kidneys have excess filtering capacity with the result that, initially at least, any disease in the kidneys has little effect on their function. In fact, problems with kidney function only start to be seen when around two thirds of the nephrons have been lost. The problem with this is that once that degree of damage has occurred it can often be difficult to treat.
New treatments do offer hope for affected animals:
• Specially formulated diets (lower in salt, phosphate and protein) can help to reduce the workload of the kidneys and help reduce on-going damage
• Novel medications can be used to inhibit or block ACE (angiotensin converting enzyme) which can result in better function in the kidneys and reduce protein loss in the urine, associated with better quality of life and longevity.
If you do suspect your pet may have kidney disease, it’s always a good idea to take them to your vet for a check-up (with a urine sample if possible). Blood tests are helpful in ruling out other conditions such as diabetes mellitus and hyperthyroidism (seen in cats). A course of treatment can then be best identified going forwards.
Chris Devlin BVSc MRCVS is a Vet and Partner at Hillside Veterinary Centre in Corfe Mullen. w: www.hillsidevets.co.uk.