By Dr. Gary A Borgman
Continuing my theme of discussing the various organ systems of our beloved pets and all that can go wrong, I will devote this article to kidney function and animal health. Pets (and people) can survive without food for days and weeks but can only live a few days without water. Healthy kidney function is so vital. Many years ago, I was taught that the kidneys have three basic functions: filtration, reabsorption, and secretion. Let me explain.
The kidneys are the filters of our body’s blood and all that it contains. Each kidney is made up of a multitude of tiny functional units called nephron units which filter the blood that passes through the kidneys. Serum, electrolytes and waste products ooze through these membranes and eventually becomes urine which is then voided from the body. Before this fluid and all it contains gets to the bladder, the kidney cells actively reabsorb things it needs to conserve (liquids and electrolytes) and actively secretes waste products it needs to get rid of. This is a delicate balancing act, dependent on hormones to control and regulate these processes. It is a fascinating subject in normal physiology and to me seems miraculous but it works well in healthy animals! So what can go wrong?
Unfortunately, much can go wrong with adverse health effects. One of the more common medical conditions we encounter is a UTI (urinary tract infection) which is usually very treatable with antibiotics. A lower UTI, involving mainly the bladder, seldom affects the kidneys. When the kidneys are infected, it is usually a more serious problem and serious kidney damage can occur. Canine Leptospirosis, can cause permanent kidney damage. This bacterial disease is most likely transmitted by wild animals, rodents and outdoor canines through the urine. We recommend vaccinating dogs to prevent Lepto. By the way, Leptospirosis is a zoonotic disease; meaning humans can also be infected.
Diabetes mellitus can definitely affect the kidneys because the excess glucose in the blood passes through the kidney membranes, resulting in reduced reabsorption of fluids, and a greatly enhanced thirst frequency and volume of urination. Fortunately diabetes is a treatable condition.
I have previously written about hormonal imbalances which affect the kidneys. Cushing’s disease (hyper-adrenocorticoism) can result in excessive thirst and urination. Diabetes insipidus is a very rare hormonal condition which also results in increased urine production. This form of diabetes is because of a lack of the ADH (anti-diuretic hormone) from the pituitary gland.
As a general rule, young healthy adult dogs and cats have five times the necessary kidney function capability that is necessary for healthy living. Infections, toxins, and aging all take their toll on the kidneys. We screen animals annually for kidney health with blood and urine tests. By the time we find abnormal kidney values in the blood tests, animals have already lost 75% to 85% of their original kidney capacity.
The treatment of advanced kidney disease usually entails hospitalization with IV fluids, antibiotics if infection is present, diet adjustments (lower protein diets) and other medications depending upon the severity of the condition. Each patient is different and the treatment recommendations must be tailored to the individual. We have some patients who have been on home administered fluid therapy for months and even years.
The doctors and staff of Kissimmee Animal Hospital (Tel 407-846-3912) and Poinciana Pet Clinic (Tel 407-518-0880) are available to answer your questions about kidney health or any other pet health issues. We are here to help and to serve