By: Dr. Susan Wootten
Jake is a beautiful and beloved 10 ½ year old neutered male Himalayan who has been a long term patient under the care of Dr. Plankenhorn at the Animal Hospital of North Asheville. His history over the last 7 months has shown us that we can see the same kind of hormonal imbalances in cats that we commonly see in dogs and people. Endocrinopathies are diseases that affect the glandular organs of the body and can cause hormonal imbalance. These glands include the pancreas, the thyroid gland, the pituitary gland, and the adrenal gland.
Jake’s problems began when he started having inappropriate urination in October of 2012. He was drinking more water, and urinating outside of his litter pan. Blood tests and a urinalysis were consistent with early Diabetes. Diabetes mellitus (sometimes known as sugar diabetes) is a commonly diagnosed disease in cats and ultimately can affect multiple organs. It occurs due to inadequate production of insulin by the beta cells in the pancreas or a resistance by the body to insulin. Insulin is secreted directly into the circulation and enables glucose or sugar to enter the cells where it is metabolized for energy. Without insulin, the cells cannot utilize glucose and elevated blood sugar levels result. In diabetic cats, this excessive amount of glucose is eliminated by the kidneys, which results in thirst and more frequent urination.
Diagnostic testing for diabetes includes testing for hyperglycemia (elevated blood sugar levels), and glucose or sugar in the urine. Because cats can experience elevated blood sugar due to stress, we sometimes use a blood Fructosamine level to tell the difference between a stress-induced high blood glucose level and a more persistent elevation as occurs in diabetes. Fructosamine testing gives an “average” glucose reading over the previous two weeks, rather than at a single point in time.
Dietary management and daily injections of insulin help to regulate most diabetic cats. Recent research has shown that the ideal diet for diabetic cats is a high-protein, low-carbohydrate diet as cats primarily metabolize protein, not carbohydrates, for glucose. Occasionally, an overweight diabetic cat may respond to dietary management alone and not require insulin to keep the blood glucose well controlled. Jake was started on this type of diet in October when he was diagnosed, and while it worked for a while, his blood glucose levels were not well controlled and he was started on Lantus Insulin injections in February 2013. Most cats need one or two injections a day depending on the type of insulin and their blood sugar levels. Fortunately, the amounts are very small, the needles are tiny, and most cats do not react to the injections. Jake tolerates his insulin injections very well. Blood glucose tests are then utilized to track how well the cat is responding to the insulin and how much will be needed. This testing can be performed in the hospital, or families can be taught how to obtain blood samples at home (commonly doing an ear prick) and check glucose level using a home glucose monitor for pets.
Jake seemed to be responding well to the insulin over the next 3 months, however, he started developing skin irritation that we did not believe was associated with his diabetes. He was brought in for examination by Dr. Wootten and was treated symptomatically with an appropriate course of antibiotic therapy and topical medication, but the skin condition continued to worsen. Jake then started having unexplained weight loss and progression of the skin changes that included non-healing sores, seborrhea (flaking skin), patchy hair loss, and thinning of the skin. Dr. Wootten and Dr. Plankenhorn collaborated on Jake’s condition and after performing further tests diagnosed Jake with an additional endocrinopathy or glandular organ problem, hyperadrenocorticism.
Hyperadrenocorticism, or Cushing’s disease, is a disease caused by increased circulating cortisol levels in the body. The paired adrenal glands normally produce and store cortisol which is released in times of stress and allows the body to respond appropriately (“fight or flight” hormone). In a healthy pet, the pituitary gland (located at the base of the brain) secretes a hormone called ACTH that stimulates the adrenal gland to secrete normal amounts of cortisol. In Cushing’s disease, this controlling mechanism is lost because there is either increased ACTH hormone from the pituitary gland (Pituitary dependent Cushing’s disease), or excessive amounts of cortisol released from the adrenal gland (primary adrenal tumor). Excessive cortisol levels in cats can cause many symptoms including increased thirst and urination, weight loss or weight gain, enlarged liver, curled ear tips, weakness, and skin changes as we were seeing in Jake.
A complete blood count and biochemistry profile were repeated on Jake at this time. While dogs with Cushing’s disease have some characteristic abnormalities on screening blood tests, cats frequently do not. Jake’s tests were overall normal except for his diabetes, but we knew there was more wrong with him. Diagnostic imaging with ultrasound was performed next. Naturally occurring Cushing’s disease is uncommon in cats, but when it occurs, 85% will have the pituitary dependent form and a small percentage will have an adrenal tumor that secretes too much cortisol. Adrenal tumors or enlargement cannot typically be seen on radiographs. Ultrasonography by an experienced veterinarian can be used to evaluate changes in adrenal size and shape. In Jake’s case, enlargement of the right adrenal gland was found by Dr. Earley.
In order to confirm the suspected diagnosis of Cushing’s disease, additional blood testing called a Low Dose Dexamethasone Suppression test was performed. This is a common screening test for Cushing’s disease in both dogs and cats. The pet is fasted overnight, a baseline blood sample is taken, a small amount of dexamethasone is administered intravenously, and 2 additional blood samples are taken 4 and 8 hours later. In normal animals, the injection of dexamethasone tells the pituitary and adrenal glands to stop making cortisol for a while, and the blood level goes down. If the cortisol levels are not adequately suppressed on the test, it is supportive of the diagnosis. Jake’s blood test results showed no effect from the injection, which supported the diagnosis of Cushing’s. Approximately 80-90% of feline patients diagnosed with Cushing’s disease have concurrent diabetes because cortisol interferes with the effects of insulin in the body. Successful treatment of Cushing’s disease is aimed at control of the symptoms the patient has and management of the concurrent diabetes.
Since his diagnosis, Jake has been taking a medication called Trilostane to help manage the excessive cortisol levels in his body. The most common physical examination findings in feline patients with Cushing’s disease are skin related. One of the more serious complications includes Feline Fragile Skin Syndrome where the skin is extremely thin, and can be torn or bruised easily making them more prone to secondary skin infections. Jake has been treated with antibiotic therapy and pain management for this particular complication. He proudly wears his “muscle shirt” at home to protect his fragile skin from trauma. It may take weeks to completely respond to the medical treatment of Cushing’s disease, but he already has more energy and is gaining weight. We are all hoping that Jake has a successful outcome with treatment!
By Dr. Amy Plankenhorn
Smitty is a gorgeous big black kitty who was adopted almost three years ago. He has a great life hanging out in his apartment with his dog buddy and his mom. But one day his mom saw that Smitty wasn’t feeling well. He was withdrawn, depressed, and vomiting. She called Animal Hospital of North Asheville and got him right in to the hospital. When Smitty arrived, he was immediately examined by Dr. Amy Plankenhorn. His body temperature was low, he was dehydrated, and most importantly, his abdomen was very painful. It felt like his bladder was extremely enlarged, hard, and painful. An ultrasound examination of his bladder confirmed that it was very full, consistent with an obstruction in his urethra (the tube that carries urine out of the bladder), and that he did not have any stones in his bladder.
At Dr. Plankenhorn’s direction, our certified veterinary technicians immediately placed an intravenous catheter for IV fluids and began warming him using a Bair hugger warming blanket and micro-bags. He was given a narcotic to sedate him slightly and to treat pain, then put under emergency anesthesia. Blood tests were obtained and run in our in-house lab to assess his kidney values and his sodium, potassium, and chloride levels. Dr. Plankenhorn then carefully passed a small urinary catheter coated with a numbing lubricant gel into his urethra. The catheter did not pass easily, but with gentle flushing with saline solution and patience, she was able to relieve the blockage and get the catheter into the bladder. Once the catheter was in the bladder, urine could be removed easily.
There are several reasons that cats develop urinary obstruction. In cats under 10 years old, the most common cause is a urethral “plug,” which is typically a combination of crystals that have formed in the urine and mucous that the body makes as a response to the irritation. The crystals and the mucous join together to create a dam effect in the urethra. While female cats can develop crystals and bladder irritation, their urethra is usually wide enough to keep them from getting obstructed with plugs. Male cats have a very small urethra, so even a small amount of the crystals and mucous can start a blockage. The other cause of urinary obstruction in cats, especially those over 10 years old, is the presence of bladder stones. Very small stones can pass into the urethra and become lodged, causing blockage. Again, males are more susceptible to blockage, although male and female cats can develop stones. Stones in the bladder can be seen with ultrasound, but the tiny stones in the urethra may require detailed x-rays to find. Our digital radiography system allows us to see very fine detail, even when the picture is zoomed in.
If an animal is unable to urinate, there are many complications that can occur due to the buildup of urine in the bladder. The most obvious problem is pain which occurs in the bladder as the bladder wall becomes overly stretched and in the urethra from the blockage material and frequent straining. If an obstruction is present for 24 hours, toxins start to build up in the bloodstream. Potassium levels increase, causing potentially fatal heart rhythm abnormalities. Other waste products excreted by the kidneys also build up, causing vomiting and lethargy. If enough time elapses, the kidneys can even become damaged. The bladder muscles can become overly stretched, causing the bladder to lose tone and become unable to empty. And the urethra becomes swollen and inflamed, causing spasms and straining even after the obstruction is relieved.
The typical first signs of urinary obstruction in cats include frequent attempts to urinate, lengthy attempts to urinate, licking the genitals frequently, hiding, and abdominal discomfort. Obstructed cats will often spend a lot of time in the litter pan with nothing produced, or will even attempt to urinate in other locations besides their pan. This is the best time to intervene! The challenge is that cats can have cystitis (inflammation in the bladder) that looks very similar to urinary obstruction but is not as dangerous. If you are in doubt, we’d rather check the bladder and determine that your cat does not have a blockage rather than waiting until the problem is more severe and may become life threatening.
Unfortunately, Smitty didn’t show his mom the typical signs of obstruction. Cats have a natural instinct to hide signs of illness because if they were living in the wild, appearing ill would make them vulnerable to attack. As a result, Smitty was very sick when he arrived at the hospital. His kidney values and his potassium were elevated, although he didn’t have any heart abnormalities yet. Because he had been obstructed for enough time to make him sick, his urinary catheter was sewn into place and attached to a sterile tube and collection bag to allow his bladder to stay empty. He also received high doses of intravenous fluids to help remove the kidney toxins that had built up in his system. After a few days on IV fluids, his kidney tests were much better and his urine was no longer bloody. It was time to remove his urinary catheter to see if he could urinate on his own. Cats who have experienced a urinary obstruction are more prone to having another blockage, so we have to pay close attention to urine output in the days afterward and beyond. Smitty needed some medication to relieve urethral spasms, but was able to urinate normally within a few days.
There are many factors that lead to urethral plugs in cats, some of which are not completely understood. Many cats benefit from a special prescription diet designed to reduce the formation of crystals in the bladder. Increasing water consumption by feeding canned food and making sure there are plenty of water sources around the house is also beneficial. Stress also appears to be a major factor in causing bladder inflammation. Even a cat who has a very easy lifestyle can benefit from environmental enrichment and stress reducing measures. A great resource for more information on reducing stress in your cat’s life is the Indoor Cat Initiative: http://indoorpet.osu.edu/cats/
Smitty is at home and doing very well. His mom is watching his urination closely. He’s enjoying his canned food and the extra attention he’s getting!