Cushing's disease, also known as hyperadrenocorticism and Cushing's syndrome, is an endocrine disorder caused when a dog's adrenal glands produce too much of the cortisol hormone. This hormone plays a broad role in canine health, including helping to regulate body weight and fat reserves, skin health, blood sugar levels, muscle structure and autoimmunity. Because cortisol affects the functioning of numerous organs, elevated levels can cause a host of debilitating symptoms. Understanding the signs of canine Cushing's disease allows you to get your pet diagnosed more quickly so he can receive treatment and live a longer, more comfortable life.
About Cushing's Disease
The pituitary gland produces the adrenocorticotropic hormone, which causes the adrenal gland to produce cortisol. When something goes wrong in either gland, your dog has too much cortisol in his bloodstream and will develop Cushing's disease. Cushing's most commonly occurs when a tumor develops on the pituitary gland, a condition called pituitary dependent hyperadrenocorticism. Less frequently, a tumor develops on the adrenal glands and triggers adrenal dependent hyperadrenocorticism. Even less common is iatrogenic Cushing's disease, which occurs when your dog receives an excessive amount of steroids as part of a medical treatment. The different types of Cushing's disease all share the same symptoms.
Cushing's disease usually strikes dogs who are middle-aged and older. In fact, the average age of dogs at the time of diagnosis is 10 to 11 years old. Smaller dogs are more likely to develop pituitary dependent hyperadrenocorticism, while larger dogs more commonly develop adrenal gland tumors. Specific breeds seem more susceptible to Cushing's disease, including dachshunds, beagles, terriers, boxers, poodles, cocker spaniels and Jack Russells.
The most common early signs of Cushing's disease include increased appetite, water consumption and urination. High cortisol levels stimulate the appetite. Dogs with Cushing's disease often seem to be constantly ravenous, leading them to steal food from the garbage and constantly beg for treats. Cortisol also affects your dog's water balance, which makes him excessively thirsty. You'll notice that you need to fill his water bowl more often even though you haven't increased his exercise levels or made any other lifestyle changes. Excessive water intake naturally makes your dog need to urinate more frequently. Your doggy might start having accidents in the house or whine to go outside at night because he can't hold his bladder.
About 90 percent of dogs suffering from Cushing's disease develop a pot-bellied appearance. The bloated, firm belly occurs because his body fat shifts into the abdominal area stretching the abdominal wall. At the same time, the wall muscles become weaker and shrink, leading to a distended appearance. As the disease progresses, the high cortisol levels also affect normal skin functioning, leading to thin, flaky, dry, skin. Dogs become more prone to bruising and skin infections because the fragile skin doesn't heal well. Changes to the coat often go hand in hand with skin problems. Some dogs experience symmetrical hair loss on the main part of their body, but not on their legs or head. The coat might look dull or dry, or it might look oily.
Many dogs suffering with Cushing's disease suffer from behavioral changes as well as physical symptoms. The changes can be subtle at first; many owners mistake the behavior for depression or old age. Your dog might have low energy, seem lethargic or act listless. He might have no interest in his usual activities or may not respond to you in his normal manner. Weakened muscles may make him reluctant to exercise, jump on furniture, get into your car or climb stairs. As the disease progresses, some dogs experience disorientation or excessive pacing.
A Few Considerations
Adrenal and pituitary gland tumors typically grow very slowly and therefore may not threaten your dog's life. Because of the slow growth, Cushing's disease symptoms often occur gradually over time, leading to the mistaken impression that the signs are that of the normal aging process. In addition, other, less problematic health issues have similar symptoms, so many owners don't realize their dogs need medical care until the disease is quite advanced.
Consult your veterinarian if your dog exhibits any symptoms of Cushing's disease. If left untreated, the disease becomes progressively worse. Your dog will become more susceptible to heart, kidney and liver failure as well as diabetes, high blood pressure, blood clots and seizures. However, Cushing's disease is manageable, although not yet curable. With early detection, even senior dogs can live healthy and happy lives for many years after a Cushing's diagnosis.