Kidney Disease in Cats

The kidneys are organs which maintain the balance of certain chemicals in your cat's blood, while filtering out the body's waste as urine. The kidneys also help regulate blood pressure, help regulate calcium and phosphorus metabolism, and produce a hormone that stimulates red blood-cell production called erythropoietin. As you can imagine, a malfunctioning kidney can cause many problems.

Let us picture the kidneys filtering mechanism. There are tens of thousands of microscopic funnel shaped tubes called nephrons. These tiny structures are responsible for filtering and reabsorbing the fluids that balance the body. These nephrons are susceptible to damage due to many causes such as poisons, aging, infection, trauma, cancer, auto-immune diseases, and genetic predisposition. If any of these occur the entire nephron stops functioning. Fortunately, due to both the reserve capacity of the kidney and the ability of the nephrons to grow larger, the kidney can still function. If damage to nephrons occurs gradually and the surviving nephrons have enough time to hypertrophy, a kidney can continue to function with as few as 25 percent of its original nephrons.

When the number of functioning nephrons drops below 25 percent or when damage occurs too suddenly for the remaining nephrons to compensate, kidney failure occurs. There are two types of kidney failure. Acute kidney failure is a sudden loss of function that is sometimes but not always reversible. Chronic kidney failure is an irreversible loss of function that occurs gradually over months or years.

Failing kidneys can't adequately clear the blood of certain toxins. These include urea (a nitrogen- containing byproduct of protein metabolism) and creatinine (a chemical byproduct of muscle exertion). As a result, when the kidneys fail, there is an abnormally high levels of these wastes products. Other blood components normally regulated by the kidneys - such as phosphorus, calcium, sodium, potassium, and chloride - may also rise or fall abnormally.

Failing kidneys may also produce extremely dilute urine or urine that contains too much protein. Healthy kidneys produce concentrated urine that is relatively protein-free.

To determine the prognosis of kidney disease, blood and urine tests are performed frequently during treatment to evaluate how well the kidneys are responding. A complete blood count looks at the numbers of red and white blood cells and a blood chemistry panel will examine the levels of waste products and electrolytes, indications of whether the kidneys are functioning properly. It's a good sign if test results swing back toward normal within the first 48 to 72 hours of therapy.

The blood tests will determine if your cat is suffering from anemia (a lower than normal number of red blood cells, RBC). This is significant because it often indicates a drop in erythropoietin, a hormone secreted by the kidneys that stimulates RBC production. The blood chemistries will determine levels of blood urea nitrogen (BUN) and creatinine, both are indicators of the amounts of waste products in the blood. Elevations of these levels result from kidney failure.

Urinalysis measures a number of factors, including how well the kidneys are concentrating the urine. In kidney failure, urine becomes dilute. Urine may also be checked for the presence of bacteria, protein, and blood. If the kidneys are normal urine should be concentrated and there should be no blood or protein in the urine.

X-rays, ultrasound and possible kidney biopsies are also very useful in assessing kidney disease.

Acute renal Failure:

The causes of acute renal failure are many. Toxins, antifreeze, cancer, intestinal disease and dehydration are just a few. Management of acute renal failure requires hospitalization, intravenous fluid therapy, and medications to help offset the affects of toxemia associated with renal failure. Intensive therapy is essential to attempt to reverse the process.

One hopes to see positive changes within 48-72 hours of treatment. The prognosis worsens if there is no reduction in the abnormal kidney values.

Chronic renal failure (CRF):

Chronic renal failure is the result of one of several different diseases, including chronic interstitial nephritis, glomerulonephritis, and amyloidosis. Some of these are autoimmune diseases; the body's immune system actually turns on itself and attacks organs and tissues. In addition, pyelonephritis, a bacterial infection that usually starts in the bladder, is often a complicating factor that precipitates CRF.

Other causes such as polycystic kidney disease (PKD) can affect younger cats, especially Himalayans and Persians, and also lead to CRF. Cysts develop in the kidneys and grow, destroying normal tissue.

Renal amyloidosis, is another form of hereditary kidney disease that affect Abyssinian and Somali cats, and may also lead to CRF.

There is no way to prevent or stop chronic renal failure. Cats can only live with one healthy kidney, but because CRF affects both kidneys, over time it is fatal.

Severely affected cats may need hospitalization. They are first rehydrated. This is best done via intravenous fluids, and therefore must be done in a hospital or veterinary clinic. Some clinicians will allow cat owners to give subcutaneous fluids at home, though this is also frowned upon by others. It involves purchasing bags of sterile fluids and injecting the prescribed amount of fluid beneath the cat's skin on a regular basis.

Dietary management is also potentially helpful. A low protein diet is generally recommended. By decreasing the protein intake, waste products of protein digestion in the blood stream decrease. This reduces the work load of the kidneys. Some cats will eat this diet while others will refuse it.

These diets are also low in phosphorus, which is usually retained in the blood stream in cats with CRF. Chronic retention of phosphorus can lead to a mineral imbalance, resulting in calcium being leached out of the bones. Increases in phosphorus also cause severe irritation of the stomach, causing nausea. Decreasing the phosphate in the diet helps to prevent these problems.

Other therapies include:

Administration of antacids such as Alternagel, this acts as a phosphorus binding agent. This will also help control phosphorus levels. This product is available at most pharmacies, located where the antacids are kept.

Calcitriol at a dose of 2.5ug/kg/day is also sometimes recommended to help control phosphorous toxicity. This drug should not be administered if phosphorus levels are over 6.

If urine cultures are positive or on ultrasound there is indication of disease in the kidney pelvis, antibiotics should be administered for 4-6 weeks.

H2 blockers such as pepsid at a dose of 5mg every day, help with the nausea of kidney disease.
If hypertension (high blood pressure) develops amylodipine (Norvasc) is given at a dose of 0.625mg per day.

Epogen or Procrit is an injectable which may help replenish the loss of erythropoiten and help control the anemia. The use of these products is somewhat controversial.

Appetite stimulants-by prescription

Potassium supplements

Kidney Transplant-this procedure is available at about 10 clinics nationwide. Cornell University and the University of Pennsylvania in the East offer this procedure. Please consult with your veterinarian for a facility near you. As of this writing the cost is $4,000-$5,000. Kidney transplant recipients need to take medication daily to avoid organ rejection, and there are ethical considerations regarding the donor cat as well.

Geriatric Pets - Optimizing Health

With recent advances in disease detection and treatment, your pet’s senior years can be a healthy and happy time. By sharing life and love with you, your pet has given you a priceless gift. Now that your pet has earned senior status, you have an opportunity to give something in return: the special love and care that can make the golden years happy and healthy.

It is estimated that your pet ages five to seven years for every one of yours, which suggests that health problems in your pet can progress at a faster rate. Therefore, we recommend frequent examinations for our older pets. In this manner, we can help prevent or treat many age-related conditions and enhance your pet’s quality of life. No one knows your pet better than you do, so it’s up to you to report any and all changes to your veterinarian.

As pets age, there is a decline in organ, mental abilities, sensory function and immunity. The following is a short list of the most common problems for aging pets: heart disease, kidney disease, liver disease, osteoarthritis, hip dysplasia, dental disease (tooth loss and infections), cataracts, glaucoma, blindness, weight gain or loss, change in appetite, loss of house training, incontinence, changes in sleeping patterns, hearing loss, skin and hair coat problems, increased thirst and urination, decreased immune system, endrocrine dysfunction (thyroid), behavioral changes (due to medical problems or cognitive dysfunction), and cancer.

Physical Examination

A physical examination performed at a minimum of every six months will enable us to detect the presence of small problems or changes in your pet’s health before they can become major health problems. During this physical exam, the veterinarian assesses the following on your pet: cardiovascular system, respiratory system, gastrointestinal system, urinary and reproductive systems, central nervous system, eyes and ears, skin and coat, mouth, teeth, and gums, and a weight assessment. For some patients we will recommend a physical examination every three months.

A thorough physical exam alone is not capable of detecting all possible health problems. It is impossible to obtain and understand a complete picture without also performing other tests. Blood work gives us a means of checking your pet’s internal functions in a non-invasive manner.

Diagnostic Blood Work

Because of our strong commitment to providing the best medicine that we can for your pet, we strongly believe that regular blood testing is important in helping your pet to achieve a long and happy life. Even though our pets may appear to be healthy based on physical appearance and activity, many clinical signs of disease do not develop until late in the disease process. Pets cannot tell us when they do not feel 100% and because of their instinct to protect themselves, many animals will ‘hide’ their illness. A good example of this situation is a cat with kidney disease. This patient may be afflicted with kidney disease for months to years before developing signs of disease because a pet can lose up to 75% of kidney function before clinical signs will develop. Performing blood work will detect early changes in kidney enzymes and allow us to manage this disease process properly—allowing the patient to live a longer and healthier life.

We feel that blood work is the most important diagnostic test that we can perform on our older pets. Yes, we do not like to admit it, but most of our pets are senior citizens at seven years of age. Giant breed dogs attain senior citizen status at five to six years of age. Because of rapid aging changes at this stage of your pet’s life, we highly recommend blood work on an annual basis. We can compare current and previous blood results in order to evaluate the process of a disease and its response to therapy. Common diseases include heart disease, liver and kidney disease, arthritis, diabetes, thyroid disease, and dental (tooth) disease.

A normal result on blood work is great! You have not wasted your money. We now have a baseline for how your pet is doing at this time. If future blood work reveals changes then we can tell how long there has been a problem and are assured that we are indeed catching the problem early. Normal blood work results give both of us peace of mind that your pet is doing well.

A CBC (Complete Blood Cell Count) and Comprehensive Blood Serum Chemistry are good screening tests to help detect health problems for your pet.

Complete Blood Cell Count

This test provides information about the various types of blood cells. Red blood cells carry oxygen to tissues. White blood cells are the body’s primary defense against infection. Platelets are involved in the clotting process. Abnormalities with any of these values help to potentially detect anemia, inflammation, acute or chronic infection, bleeding disorders, blood parasites, dehydration and autoimmune diseases.

Comprehensive Blood Serum Chemistry

This is a series of individual tests that analyzed together give us valuable information concerning the kidneys, liver, pancreas, intestinal tract, and endocrine diseases.

BUN, CREATININE, and PHOSPHORUS—kidney
ALT, ALKALINE PHOSPHATASE, and BILIRUBIN—liver
AMYLASE and LIPASE--pancreas
TOTAL PROTEIN and GLOBULIN—immune system, dehydration
GLUCOSE—diabetes, insulin tumor
CHOLESTEROL—hypothyroidism, cushings disease, pancreatitis
CALCIUM—kidney disease, hyperparathyroidism, some tumors
ELECTROLYTES—endocrine diseases, kidney and dehydration

Sometimes other diagnostics may be recommended based upon these results. Some of these involve specialized tests at outside laboratories. Some of the more common diagnostics involve:

Thyroid: Hyperthyroidism is extremely common in older cats. It can cause hypertension, heart disease, and weight loss. Dogs tend to get hypothyroidism which causes weight gain, problems with the hair coat, and other problems.

Urinalysis: This is a common test that will help to detect kidney disease, diabetes, infection, inflammation, and metabolic disorders. Kidney disease is first evident here.

ECG (Electrocardiogram): This enables us to see the electrical activity of the heart. Abnormalities may indicate a serious problem and a chest x-ray or a cardiac ultrasound may be recommended to further diagnose heart disease.

Ultrasound: This is a specialized piece of equipment that allows us to obtain a three dimensional image of your pet’s organs. We can visualize the heart, liver, spleen, kidneys, stomach, intestines, pancreas, adrenal glands and bladder. When diseases of the liver or kidney are detected, the ultrasound can give us a look at the internal structure of these organs and allow for ultrasound guided biopsies to help further identify the cause of the disease. We strongly recommend an ultrasound on all of our cardiac patients, especially cats. Older cats are prone to HCM—Hypertrophic Cardiomyopathy. This is a disease in which the heart muscle hypertrophies, decreasing the available volume of blood to be moved through the heart. Radiographs will not diagnose this disease; it can only be diagnosed via ultrasound. This disease is fatal without specific and appropriate medical management.

Blood Pressure: Many older cats and dogs become hypertensive, especially with hyperthyroidism and/or kidney disease. This machine works much like the blood pressure monitors in human medicine. The test is quite simple and easy to perform.

X-Rays (Radiographs): These can help to detect problems with the heart, lungs, kidneys, liver, bones, soft tissue and intestinal tract. They are used to identify disease and also to monitor progress/response to therapy. X-rays are an essential component in the work up of heart patients.

Glaucoma testing using the Tonopen: Many older pets can have problems with increased intraocular pressure (glaucoma) same as people do. Increases in pressure in the eye will cause pain and also lead to blindness if not detected early and treated appropriately.

Other Considerations

Advances in medical diagnostics and treatment enable us to help your pet be more comfortable and also to prolong his/her life. You and your veterinarian can form a partnership whose goal is to maintain an improved quality of life for your pet as long as we can.

Many older pets suffer from arthritis. This may be presented as lameness, difficulty getting up or climbing stairs, increased irritability, decreased appetite, and overall decrease in activity. New pain management medications help pets with chronic pain have a better quality of life. Nutritional supplements containing Glucosamine and Chondroitin Sulfate help with joint maintenance and repair and are good to use in conjunction with other anti-inflammatory medications. The medication that is best for your individual pet’s needs will be chosen after discussion between you and your veterinarian. Acupuncture is another option for pets with arthritis.

In addition to medications, appropriate nutrition for your pet’s condition will also prolong his/her lifespan. All veterinarians agree that older pets need to be on a high quality diet. Most older pets suffer from obesity. These pets would benefit from increased dietary fiber. Other pets with kidney problems or heart disease may need specialized diets restricting sodium and protein. Skin problems can often be improved by adding omega 3 fatty acids to your pet’s diet. Immunomodulators and antioxidants will often help immune compromised and cancer patients. Some older pets will actually do better with a diet high in carbohydrates and increased protein. Together you and your veterinarian will decide upon an appropriate diet based upon your pet’s individual needs.

Many older pets will suffer from various dental problems: tooth decay and loss, gingivitis, infection and oral tumors. Pain caused by a tooth abscess can cause your pet to have a decreased appetite, be more irritable, and also lead to infection elsewhere in the body. These problems can be treated with antibiotics, anti-inflammatories, teeth cleaning and oral rinses.
Behavioral changes may be an early signal of various medical problems. Many of these can be related to pain from arthritis, dental disease, etc. Cognitive dysfuntion is due to age related changes in the brain. Some symptoms of this are confusion and disorientation, decline in social interactions, changes in the sleep-wake cycle and house soiling.

With detailed information obtained through a physical examination and diagnostics, you and your veterinarian can formulate a plan for keeping your senior pet as healthy as possible. This overall patient assessment will include diet, exercise, and treatment recommendations. Certain medical, nutritional, and behavioral changes could signal a need for special care and diagnostics. With your love and dedication, these can be your best years together!

This article was donated by the Claws & Paws Veterinart Hospital, http:www.cpvh.com

Televets is a new free online pet Q&A service. Visit them today and ask your question!
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Heat Stroke in Dogs

Dogs don’t sweat the way people do in order to cool the body down during extreme temperatures. They cool off by panting; the air cools the mucous membranes and blood vessels in their mouth and tongue. Extreme cases of heat stroke lead to the disruption of the dog’s internal cooling mechanism, and they quickly go into cardiovascular shock, which is life-threatening.

Cars are the worst culprit. Even windows left open do not always provide the air flow needed, and the hothouse effect is very rapid! If you absolutely must leave your dog in the car, park only in the shade with windows open (so that they cannot jump out), and NEVER for more than 7 - 10 minutes. They must have access to cool, clean water at all times and be able to avoid direct heat by providing shade if outdoors, or a fan if left in an apartment during the hottest part of the day.

Puppies and older dogs are more susceptible to heat stroke. If you suspect your pet has heat stroke, this is an emergency situation and should be treated by your veterinarian immediately.

Some of the signs to watch for include:

1) unusual sluggishness or unresponsiveness
2) pale or dark red gums, sometimes with a dry feel
3) erratic breathing

Treatment:

NEVER ICE YOUR PET. THIS WILL CAUSE THE BLOOD VESSELS IN THE BODY TO CONSTRICT TOO FAST AND AFFECT BLOOD FLOW IN THE BODY

Immediate correction of hyperthermia:

Monitor your pets temperature with a rectal thermometer. The normal temperature for a dog is around 38.5°C or 101°F. Dogs suffering from heat stroke often present with body temperatures around 105ºF.

Spray with water or immerse in water before transporting to veterinary facility.

Stop cooling procedures when temperature reaches 103°F, to avoid hypothermia.

Give artificial respiration support if required.

Don't let a fear of heat stroke stop you from enjoying the great outdoors with your pet, but please be aware of the danger. A little caution goes a long way, even just providing access to water and shade at all times will prevent your pet from developing this condition.

This article was donated by the Columbia Animal Hospital. For further information visit http://www.petshealth.com

Televets is a free online pet Q&A service. Visit them today at http://www.televets.com to ask your question!