Cushing's disease, also known as hypercortisolism, is a hormonal disorder caused by a long period of exposure to high levels of the hormone cortisol. The disease can cause fatigue, muscle weakness, high blood pressure and physical changes including upper body obesity and a protruding abdomen. In dogs, hair loss and a pot-bellied appearance due to fat shifting to the abdominal and rib areas are commonly reported symptoms.
Cushing's Disease in Humans
In humans, there is Cushing's syndrome, and then there is Cushing's disease. The syndrome is brought on by taking prednisone and other cortisonelike medications orally on a daily basis for weeks or months at a time. It should be noted that taking the same kind of medication every other day for longer periods and/or the use of inhaled asthma medications or steroid skin creams does not cause Cushing's syndrome.
Cushing's disease is a relatively rare disease, and it is caused by an actual tumor present in the pituitary gland or other areas of the body. The disease most often occurs in adults between the ages of 20 and 50. Individuals with obesity, type 2 diabetes and high blood pressure are more at risk for Cushing's disease.
Cushing's Disease in Dogs
Cushing's disease occurs when a dog's body produces too much cortisol. Too much cortisol can weaken the immune system, which can leave a dog vulnerable to other infections and diseases. In dogs, there are two types of Cushing's disease: adrenal-dependent and pituitary-dependent. Most dogs have the pituitary-dependent variety, which means that the disease is caused by a tumor on the pituitary gland. Adrenal-dependent Cushing's disease is caused by tumors being present in one or both adrenal glands. Middle-aged and older dogs are most likely to be afflicted by Cushing's disease.
Rib Cage Protrusion
One of the more noticeable traits of Cushing's syndrome or disease in humans and dogs is the tendency toward a pot-bellied appearance and rib cage protrusion. This is caused by fat deposits shifting to be stored around the abdomen, and weakened abdominal muscles being unable to adequately support the weight.
Other Symptoms of Cushing's Disease
In humans, fat deposits can form between the shoulders and around the upper back. The face may become puffy and round. Skin will become thinner and will bruise easily. Scratches, cuts, insect bites and skin infections will often take longer to heal. Depression, fatigue and weakened muscles are also reported. In women, Cushing's disease can affect the regularity of menstrual periods and can cause an increase in body hair.
In dogs, symptoms of Cushing's disease include increased appetite, thirst and urination. Excessive panting, the hallmark pot-bellied appearance, reduced activity, hair loss, thin or fragile skin and recurrent skin infections are also very common symptoms.
Diagnosis and Treatment for Humans
If Cushing's disease or syndrome is suspected, your physician will probably ask you several questions and do a physical exam. Your answers and the results of the physical exam may be able to indicate if the cause is a medication you are taking. If your physician thinks that you may have Cushing's disease or syndrome, but not because of a medication, then blood and urine tests will probably be ordered. A CT scan or MRI, which take detailed pictures of your internal body structure, may also be ordered.
Cushing's disease may be treated by removing tumors from the pituitary gland. Radiation treatments may also be recommended, and you will probably need to take some cortisonelike medications following the removal of the tumor. Your doctor will work with you to come up with an effective treatment plan.
Diagnosis and Treatment for Dogs
A diagnosis of Cushing's disease can be made using blood tests. Cushing's disease is considered to be a lifelong condition for dogs, unless the disease is adrenal-dependent. In that case, the adrenal tumor causing the disease can be removed, and if it hasn't spread to other parts of the body, the dog will be cured.
If it can't be cured, Cushing's disease is managed with medication. The Food and Drug Administration approved Vetoryl in December of 2008, and it is effective in treating both adrenal- and pituitary-dependent Cushing's by stopping the production of cortisol. Vetoryl does have some side effects, including lack of energy, vomiting, diarrhea and weight loss. Additionally, the medication should not be used in a dog that has liver or kidney disease, heart disease that is being treated by certain medications, or in a dog that is pregnant. It's important to have your dog seen regularly so that his progress and overall health can be monitored.