Treating Canine Cushing's Disease Disease

Now that we know that a diagnosis of Cushing’s disease in dogs is very serious, we also need to remember that it is treatable, thus allowing a happy life for years for most dogs if it’s caught and treated in its early stages. Dr. Vlad Kassman, DVM, in Pintler Springs, Idaho, advises, “You simply must know your dog(s). And you have to know the basic signs and symptoms of canine illness and disease so you can let us, the vets, help properly diagnose and treat conditions in their early onset.” (personal conversation)

Over the past two decades, treatment for Cushing’s disease in dogs has evolved a bit. New medications, the refinement of traditional medications, and especially the inclusion of several natural, holistic treatments, the most promising of which is lignan (flaxseed) therapy are increasing the quality of life for affected dogs, often sending them into a remission of symptoms. Thus, when we speak today of treating canine Cushing’s disease, we’re speaking of several viable options:

  • Surgery for the removal of adrenal or pituitary tumor
  • Chemotherapy to shrink tumors
  • Medications to control symptoms
  • Holistic therapy
  • Of course, dog owners need not pick only one of these options since they are almost always compatible with each other. A simple case study helps the reader understand what’s involved in treating Cushing’s:

Amber, a female Cocker Spaniel, was ten years old when she was diagnosed with Cushing’s disease. Her vigilant owners became aware that she was behaving unusually. Vienna, Amber’s “mom” noticed that she had developed a noticeable pot-belly which Vienna attributed to aging and “slowing down” a bit, being often lethargic and uninterested in running in the Maine woods and fields as she previously loved to do. Amber’s once-luxuriant coat became dry and brittle; when she came home from the groomer’s, her hair was very slow in growing back. Vienna was alarmed to notice a number of silver-dollar-size abscesses on Amber’s back, under her thin hair. Amber’s “dad,” Connor, a physician, drained and dressed these abscessed areas but they healed very slowly. Amber had little appetite but emptied her water bowl at least twice a day. Connor took note that on other days Amber seemed extremely hungry. For Vienna, the final straw came on one particular afternoon. “I was lying on the couch,” Vienna said, “and I noticed that Amber was walking strangely; she was restless, circling and seemed distressed. She jumped up onto my chest an immediately urinated profusely on me. Never had she done this, even when she was a puppy. Something was terribly wrong that we could not explain away.”

Connor and Vienna took Amber to their veterinarian – the only one in their small town in rural Maine. After listening to Connor’s and Vienna’s list of Amber’s strange symptoms and examining the dog thoroughly, Dr. Davis ordered a complete blood panel and the low dose dexamethasone suppression test. Then she told the couple that Amber had tested positive for canine Cushing’s disease – a condition with which Connor was very familiar since he had treated many patients with this autoimmune disorder. Dr. Davis explained the surgical and pharmacological treatments available for Amber, which were limited in this remote area. Lignan therapy was still unknown at this time, at least to rural vets. Dr. Davis explained surgical and medication interventions available for Amber. After consultation, Connor and Vienna elected to use a special diet for Amber but declined surgery because of the risks involved with anesthetizing a dog her age. They also declined putting her on medications that have a high potential for nasty side effects for an elderly dog. Dr. Davis prescribed a special kit with a cleansing antibiotic solution that was particularly helpful with dogs’ Cushingoid abscesses, plus an ultra-moisturizing shampoo; her dry, brittle fur was making her scratch too often. The three also discussed environmental changes to help with Amber’s urinary incontinence; when the weather is foul, Amber would be taught to use a “pee pad” in the garage. Vienna and Connor prepared to clean up after her urinary incontinence. Vienna taught Amber to wear a human baby- sized diaper to minimize accidents.

Amber lived with canine Cushing’s disease for four good, happy years. She did develop some cataract problems because of the disease, but her abscesses grew less frequent and less large. Vienna and Conner watched her closely for any type of seizures, heart congestion, and tachycardia; none of these occurred. She ate well on her special, bland diet.

When Amber was approaching her 15th birthday, one evening she had a massive stroke that paralyzed her left side. Vienna and Connor rushed her to the vet; Dr. Davis determined that Amber was also in renal failure. Gently, she informed Amber’s “people” that this was a terminal condition most likely related to her Cushing’s disease, and that she would not recover. Tearfully but resolutely, Vienna and Connor made the compassionate decision to end Amber’s suffering by euthanasia.

“I don’t know why Amber got canine Cushing’s,” Vienna now says. “She was not one of the “most likely” breeds and was astonishingly healthy for ten years prior. Although we elected not to use drugs and surgery for her, that was our choice and every dog owner must do what is right for themselves and their dog. The new holistic lignan therapy came too late for Amber; we definitely would have tried it with her. For any dog with Cushing’s, the worst thing to do is nothing”

Traditional medical treatments first depend upon what type of tumor is causing the disease and where it’s located. First, let’s look at pituitary gland tumors since these are the most commonly related to Cushing’s disease (85%) in dogs. This gland is located at the base of a dog’s brain. These tumors are usually small and benign, but some can be large enough to cause dangerous compression of the brain; these are called “macrotumors” and are more serious treatment issues simply because of their size. In dogs with Cushing’s, pituitary gland tumors cause the massive release of biochemicals (e.g. ACTH) that signal the adrenal gland to produce more and more cortisol. This loop is what triggers the onset of canine Cushing’s disease. The reason why pituitary (and adrenal) gland tumors occur primarily in some dog breeds and in dogs over six years old is unknown. What is known is that in humans and dogs, Cushing’s disease is neither hereditary nor contagious.

Surgery to remove pituitary gland tumors is certainly an option for dogs who can tolerate brain surgery and the effects of anesthesia. Unfortunately, this is not always the case. However, certain traditional veterinary medications usually have good results in treating canine Cushing’s disease. Like all medications, they have side effects that range from mild and tolerable to drastic and intolerable; every dog responds differently to medication and sometimes more than one is tried before a satisfactory and safe result occurs. These medications also vary in expense, and dog owners should talk this over with their veterinarian. Canine Cushing’s just isn’t an inexpensive illness!

Lysodren (generic name is mitotane) is the first-line chemotherapy-type medication for treating pituitary Cushing’s tumors in dogs. Until fairly recently, it was the only drug of its kind. Now available in generic form, it is not expensive, but like all chemotherapy drugs, it must be handled with care; dog owners should either wear gloves or wash their hands thoroughly after administering it to their dogs in pill form. Care must be taken to keep the drug out of the reach of children. Since Lysodren has been available for decades, canine vets are knowledgeable in its use and monitoring. The drug has potentially serious side effects, and vets must perform frequent blood tests on the dog to prevent and/or treat these side effects.

Lysodren works by eroding layers of the dog’s adrenal gland; while the pituitary tumor continues to send messages to this gland to secrete more cortisol, the adrenal gland is no longer able to do so. This is a tricky situation if too much of the adrenal gland layers are eroded; this requires discontinuation of the medication to allow the layers to re-grow. Lysodren can then be re-started at a lower dose. In rare, but troubling cases, the layers fail to regenerate permanently, requiring the dog to be treated life-long for cortisone deficiency. VeterinaryPartner.com notes that this side effect was the driving force to develop other drugs to treat Cushing’s disease in dogs that didn’t create this issue.

Lysodren treatment has two phases: induction and maintenance. During the induction phase, unless he or she stocks it in the clinic pharmacy, the dog owner is provided by the vet with a prescription for the medication that can be filled by a human pharmacy. The owner is also provided with the steroid prednisone that can counter any life-threatening side effects like anaphylaxis (a tight and often deadly constriction of the dog’s airway). Lysodren in pill form is given twice daily with the dog’s food to maximize absorption by the body; it should not be given to a dog with a poor appetite. After a trial period of about a week, the vet will perform an ACTH test to determine if the induction goal has been accomplished. During induction, the dog’s owner must monitor the dog vigilantly and call the vet if any of these “endpoint” signs occur:

  1. Diarrhea and/or vomiting
  2. Appetite loss
  3. Decrease in water consumption
  4. Lethargy, fatigue or listlessness

The presence of these symptoms usually indicates that the induction phase of Lysodren treatment can be discontinued. If so, and no complications are present, the dog can be entered into the life- long maintenance plan with lower doses of Lysodren twice daily. Maintenance is usually commenced after 14-16 days of induction, but again – every dog is different in response to medications. On successful maintenance, the dog usually experiences a full remittance of Cushing’s symptoms after 4-6 months, so owners must be patient and let the drug work. Owners usually first notice a decrease in water consumption and hair re-growth. Dogs can spontaneously experience symptoms of anaphylaxis, so owners should keep a supply of prednisone handy; this steroid anti-inflammatory drug works within 30 minutes.

Trilostane (brand name is Vetoryl) is one of the new generation of treatment for Cushing’s disease in canines caused by a pituitary tumor; it was approved by the FDA in 2009 for veterinary use. It’s often used with dogs who can’t tolerate Lysodren side effects. Plus, it does

not erode the adrenal layers as Lysodren does. However, Trilostane does have its own set of problems, including:

  1. A standard dosing protocol for dogs does not yet exist
  2. Lysodren costs less because it’s been around longer and is given to the dog less frequently than Trilostane.
  3. Because the drug is so new, many vets have little or no experience in giving it; dog owners will need to discuss this with their vet.

The discovery of treating Cushing’s disease in dogs with Ketoconazole was quite accidental! This drug was originally used in humans to treat dangerous systemic infections, but was causing disruption of male hormone production through a steroid-like action. Ketoconazole was studied in the 1980’s by veterinarians as an alternate medication for canine Cushing’s disease with positive effects. Compared to Lysodren, this drug has some significant problems:

  1. It’s a very expensive drug and most veterinarians have little experience in using it since its price usually exceeds the dog owner’s budget.
  2. It requires more monitoring tests – incurring even greater expense.
  3. Ketoconazole is given to the dog more often than Lysodren; an inconvenience for most dog owners.

Anipryl (generic name is L-Deprenyl) is another drug developed to improve canine Cushing’s symptoms without the problems of Lysodren. Anipryl uses a very different approach to pituitary tumors by targeting them directly, with no involvement by the adrenal gland. Better still, Anipryl has a minor side effect profile compared with Lysodren. Only 1 of 5 dogs experienced reduced hearing, nausea and restlessness. Thus, dogs who are elderly and cannot tolerate surgery or Lysodren, Anipryl could be the best choice to treat their Cushing’s disease.

An adrenal tumor can be either benign or malignant; either type causes symptoms of canine Cushing’s disease. Veterinarians use imaging, chest radiographs, or nuclear medicine scanning to determine the site and type of the adrenal tumor. If it’s benign and surgically removed, the dog has an excellent chance to make a symptom-free recovery.

If the tumor is malignant, as most are, and is not rapidly spreading, veterinarians sometimes opt for Lysodren instead of surgery. However, if there is conclusive evidence that the tumor is spreading, surgery is considered to be the best option as long as the dog isn’t too old or ill. This type of surgery is risky and should only be performed by a board-certified veterinary surgeon. Even then the dog remains at risk because:

  1. The adrenal gland is located between the aorta, renal artery and the phrenicoabdominal artery. To remove a dog’s adrenal tumor without nicking the heart, kidney or abdominal wall is considered to be one of the most difficult veterinary surgeries.
  2. Malignant adrenal tumors cause a high risk of severe bleeding.
  3. Dogs with Cushing’s have poor wound healing, a risk for recovering well from surgery.
  4. According to veterinarypartner.com, 63 dogs were monitored in a study; 6% of dogs undergoing adrenal gland surgery had inoperable tumors and were euthanized on the table. 29% died during surgery or shortly afterwards because of recovery complications.
  5. The average life span for dogs after this surgery was only 36 months.

For dog owners who are distressed about euthanasia, chemotherapy or surgery for their beloved dog, there is some very exciting news about treating canine Cushing’s disease in a holistic, natural way through diet, homeopathic medicine, and certain herbal remedies.

Lignans.net cites a recent report by Dr. Jack Oliver, DVM, Ph.D., a professor of veterinary medicine, that recommends flax seed lignans and melatonin (the body’s natural sedative) as a frontline treatment for dogs with Cushing’s disease. The complete report is available on lignans.net. Lignans are bunches of chemical compounds found in the brain; in particular, they are phytoestrogens as well as antioxidants. They’re also found in flax seed hulls and in spruce tree knots. Dr. Oliver’s report doesn’t refer to a cure for Cushing’s disease in dogs because none is known. The report does emphasize how well the symptoms can be managed by lignan therapy. When combined with melatonin, flaxseed lignans for dogs have been found to significantly ease their symptoms and discomfort. The results of lignan therapy are so helpful for the dog that it’s often used in conjunction with medication and/or surgery. An increasing number of veterinarians are using lignan therapy as a stand-alone treatment for canine Cushing’s, especially with dogs that can’t tolerate chemotherapy and are poor surgical candidates. Lignan treatment has no side effects and several studies indicate that it may actually shrink tumors. Lignans are found in most all-natural stores and on the Internet and are drastically less expensive than medication and/or surgery.

It’s important for vets and dog owners to keep in mind that they should use flax hull lignans (SDG) or HMR lignans. A dog should never be given flax seed oil since the lignan content is very low and it increases triglycerides.

According to eHow.com, the Endocrinology Department of the University of Tennessee’s College of Veterinary Medicine recommends that dogs with Cushing’s disease be given a combination of flax seed lignans and melatonin to reduce the alopecia (hair loss) which is actually not only unsightly but very uncomfortable for the dog. The College associates flax seed hulls for dogs with the alpha-linoleic acid that supports their internal organs; their plant hormones stimulate hair re-growth.

Could modifying your dog’s diet minimize his canine Cushing’s symptoms? According to Small Animal Clinic as cited by eHow.com it certainly can! Dogs with Cushing’s disease should be fed a diet high in protein but low in fat, fiber and purines. Purines are by-products from some foods including organ meats like liver, wild game, shellfish, beans and peanuts; these contain high amounts of purine and should be avoided. Dairy products, cooked eggs, whole grain cereal and nuts are low-purine foods that are good for easing your dog’s Cushing’s symptoms. In limited amounts, feed him foods with moderate purine levels like cooked poultry, lamb, beef and pork.

It’s difficult to find a commercial food for dogs with Cushing’s disease, so most owners make their own mixture of 3⁄4 low purine and 1⁄4 moderate purine. Adding a spoonful of powdered Vitamins C and E and selenium creates a meal high in beneficial antioxidants. While some animal nutritionists say that Cushingoid dogs’ symptoms can also be relieved by eating raw meat and vegetables, they are in the minority to experts who recommend well-cooked meat. Vegetables seem to be the only versatile ingredient here, either cooked or raw.

Dogs with Cushing’s disease may also benefit from some herbal remedies that function similarly to the way they do with humans. As cited on Pinit.blogspot, Dr. Andrew Jones, DVM, says that Ginkgo Biloba can reduce cortisol production, thus easing the discomfort of affected dogs; it also helps destroy tumors on the adrenal gland. Since dogs with Cushing’s often feel restless, anxious and agitated, Valerian root, a natural sedative, eases these symptoms.

Other herbs that are said to be helpful in relieving Cushing’s symptoms are:

  • Dandelion
  • Burdock root
  • Nettle
  • Garlic
  • Astralagus
  • Siberian ginseng
  • Seaweed powder

In a 2001 UK study, 41 horses and dogs with Cushing’s disease were treated with a homeopathic mixture of ACTH 30C and Quercus 30C; the study found that 81% of these animals showed a significant decrease in their symptoms. (The term 30C refers to the strength of the preparation) Other preparations to ease Cushing’s symptoms are:

  • Arsenicum 30C for excessive thirst and urination
  • Hepar Sulph 30C for skin irritation and abscesses
  • Mercurius 30C for thirst, bladder irritation and diarrhea
  • Sulphur 30C for thirst, skin problems and indigestion

Regardless of the choices you make on behalf of your wonderful dog with Cushing’s disease, it’s always best to discuss all your options with a veterinarian and then let him or her update your dog’s records. Some dogs experience a crisis such as seizures; your vet needs to know all about his diet, lignan therapy, herbal and homeopathic treatment to help him or even save his life.

Hyperadrenocorticism is the scientific word for Cushing's Disease in dogs. Hyperadrenocorticism is defined as: a glandular disorder caused by excessive cortisol