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Client Library Article
HYPERADRENOCORTICISM = CUSHING’S DISEASE
| Cushing's Disease |
| Cushing’s disease is another name for hyperadrenocorticism,
an endocrine disorder where too much cortisol, a type of steroid, is released from
the adrenal gland. either by a productive adrenal gland tumor, or by a productive
tumor of the pituitary gland in the brain which releases a substance that then
over stimulates the adrenal to release excess cortisol. Cortisol is a type
of steroid, similar to prednisone, that affects carbohydrate, protein, and
fat metabolism in the body. Persistent high levels of cortisol in
the body can cause a
wide variety of problems such as hypertension (high blood pressure), hair
loss, increased thirst & urination, decreases immunity to disease, slower
healing, and persistent heavy panting. Occasionally, animals placed on
steroids such as prednisone for a long period of time will develop symptoms
of Cushing’s disease (iatrogenic Cushing's). Once these dogs are weaned off of steroids, the signs
will resolve. |
| Symptoms of Cushing's
Disease |
- Increased water consumption ( polydypsia)
- Frequent urination (polyuria)
- Increased appetite (polyphagia)
- Pot-belly abdomen
- Muscle loss and weakness
- Prolonged wound healing, frequent infections
- Symmetrical hair loss on trunk (alopecia)
- Dark or black skin, can be mineralized
- Persistent panting
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| Diagnosis |
- Cushing’s is suspected based on history and clinical symptoms
- Blood work shows an elevation in the liver enzymes, cholesterol, and
sometimes blood sugar. ( secondary diabetes).
- Urinalysis shows dilute urine and dogs with a high level of cortisol.
Also Cushing’s patients frequently develop urinary tract infections.
- Cushing’s is diagnosed using high and low dose dexamethasone
suppression tests which measure the response of the adrenal glands to
administration of calculated doses of external steroids, and by ACTH stim
test- also a hormone response test.
- These test are also used to distinguish between Cushing’s caused by a
pituitary tumor in the brain and that of a primary adrenal tumor.
- Ultrasound is used to measure the size of the adrenal glands.
With adrenal tumors, one gland will be much larger than the other.
With pituitary dependent Cushing's, both glands will be uniformly
enlarged. .
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| Therapy |
- If the Cushing’s disease is caused by a tumor of the pituitary gland
in the brain, a drug called lysodren is used. Lysodren
selectively kills part of the adrenal gland so it can only produce a certain
amount of cortisol. The dose of lysodren is adjusted so that the amount of
cortisol produced is equal to that of a normal dog. Careful monitoring is
required when using lysodren, and the dose often needs to be frequently
adjusted. If too much lysodren is given, the dog can develop signs of Addisons
disease. Lysodren therapy is required for life.
- If the Cushing’s is caused by an adrenal tumor, surgery will be the
treatment of choice- removing the tumorous gland & preserving the normal
gland.
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| Prognosis |
| Prognosis depends on proper diagnosis and owner compliance
for life long treatment. Careful attention must be paid during the
initial loading phase with lysoden and clinical signs monitored throughout
the pets life. |
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