Canine Cushing Syndrome

Glands near the kidneys produce cortisone necessary for health.  Unbalanced levels are unhealthy and can cause illness and even death.  Too little and sudden death can occur, too much results in Cushing syndrome.  Too much cortisone over a long period of time can also result in death.  Too much cortisone is a relatively common problem for older dogs.  However, it is uncommon in cats.

The disease was named after Dr. Harvey Cushing, a physician and pathologist that initially discovered the clinical condition.  It was originally described in people and since has been identified in animal species.

Cushing’s syndrome does not produce the same symptoms for all dogs, however there are common abnormalities.  Vomiting and diarrhea are rarely seen.

1. Many of the Cushing’s syndrome dogs urinate more frequently and for long time period due to excess urine volume.
2. House broken pets may begin to urinate in the house, or begin to have leakage.
3. Excessive thirst is commonly observed in Cushing’s syndrome dogs.
4. Loss of hair is common along the back, tail and rear legs. A thinning coat or complete hair loss, except for the heads and feat occurs.
5. Dogs with Cushing’s syndrome commonly develop muscle weakness. They begin to demonstrate difficulty doing ordinary feats such as, rising for lying down, climbing of stairs, jumping onto the couch, or inability to get into the car.
6. Muscle weakness may cause the animal to gain a pot belly.
7. Cushing’s syndrome commonly causes a ravenous appetite.
8. Cushing’s syndrome can cause excessive panting.

An excess or cortisone can occur for a variety of reasons.

1. A pet can be given cortisone in excess amounts by pill, injection, topical or even eye medication to treat disease.  In this case, treatment is discontinuation of the medication.
2. Prednisone
3. Prednisolone
4. Methylprednisolone
5. Triamcinolone
6. Dexamethasone
7. Cushing’s syndrome can occur naturally.

A small percentage of dogs and cats present a tumor in one of the adrenal glands, causing Cushing’s syndrome.  When natural levels of cortisone are in excess of 85% to 90%, most animals have a small tumor in the pituitary gland.  The tumors persistently send a protein message called “ACTH” asking for cortisone to be released into the blood stream.

The message sent does the following;

1. ACTH does not turn off.
2. ACTH is produced in an excess amount.
3. ACTH causes the adrenal glands to grow larger.
4. ACTH causes the glands to produce cortisone excessively without stopping.
5. ACTH causes Cushing syndrome.

What a Veterinarian will look for when looking for additional problems.

1. Large liver on abdominal palpation
2. Skin infections on the dog
3. Muscle atrophy
4. Thinner looking skin
5. Urinary tract infections are common with an enlarged liver.
6. High blood cholesterol concentration
7. High blood pressure

Tests

1. A routine blood and urine test can check for abnormalities.
2. Radiographs of the chest to check for abnormalities with the lungs
3. Radiographs to heck for adrenal tumors
4. Ultrasound to look for adrenal tumors
5. Ultrasound or radiographs for an abdominal examination to assess the liver size, fat accumulation and other problems
6. Hormone testing to verify the diagnosis; ACTH stimulation test and the urine cortisol creatinine test, low dose dexamethasone test (LDDST)
7. Other tests to discriminate dogs with the pituitary and adrenal form of the disease

Treatment

Treating an animal will help alleviate weakness, addiction to food and water, and the ability to live a happier, more active life.  Correction of the condition is usually recommended.

A veterinarian may suggest surgery or oral medications to treat natural Cushing’s syndrome.  Successfully managed dogs far exceed treatment failures.