(01) - Canine Hyperadrenocorticism

Question 1

Is Cushing’s Disease spontaneous or iatrogenic?

Spontaneous form is classified in what? usually seen in what dogs?

The iatrogenic form is caused by what? occurs at what age?

Many nonadrenal diseases cause clinical signs, which mimic Cushing’s. Therefore, a complete
evaluation of the patient for nonadrenal diseases is required before a diagnosis of Cushing’s is made.

Answer 1

can be either

pituitary dependent or adrenal tumor; older than 6 years

excessive/prolonged administration of exogenous glucocorticoids; any age

Question 2

1. PDC (pitutiary dependent cushing’s) accounts for what % of the spontaneous cases?
2. PDC is caused by what in most cases?
3. In either case, the final result will be excessive production of what by what? which will induce what?
4. ATs (functional adrenocortical tumor) account for what % of the spontaneous cases? usually caused by what?
5. The contralateral gland is atrophied due to what?
6. Iatrogenic Cushing’s accounts for how many cases?

Answer 2

1. 80 to 85%
2. a functional pituitary tumor (However, in some cases the pituitary negative feedback mechanism is not functioning properly)
3. ACTH by the pituitary gland; bilateral hyperplasia of the adrenal cortexes resulting in large production of cortisol
4. 15 to 20%; a unilateral adenoma or adenocarcinoma
5. feedback suppression of ACTH caused by excessive cortisol production by the tumor.
6. more than half

Question 3

1. What are the five P’s?
2. Lethargy and exercise intolerance are common complaints, and are usually associated with the muscle wastage caused by what?

3 Common dermatologic signs are symmetrical alopecia, thin skin with smooth scales, poor wound healing, prominent abdominal vasculature, easily bruised skin, dystrophic calcinosis cutis, recurrent superficial pyoderma

Answer 3

1. Polyuria, polydipsia, polyphagia, panting, potbelly (very common clinical signs)
2. the catabolic effect of glucocorticoids on proteins.

Question 4

1. The ACTH stimulation test is a quick and moderately reliable test for Cushing’s
2. It is the only reliable test to differentiate what from what?
3. The ACTH stimulation test can diagnose PDC in about what % of the cases? and AT in what % of dogs?
4. Can a diagnosis of Cushing’s should be confirmed or excluded based on the ACTH test results only?
5. Does the test differentiate dogs with PDC from those with AT?

Answer 4

2. iatrogenic Cushing’s from spontaneous Cushing’s.
3. 80%, 50-60% (False-positive results can also occur in cases of non-adrenal illnesses)
4. no (The test should be interpreted in the context of the history, physical findings, and data base results.)
5. no

Question 5

1. LDDST diagnoses PDC Cushings in about what % of the time? and AT what % of the time?
2. If a dog has either PDC or AT, the 8-hour post-dexamethasone cortisol levels should not decrease more than 1.4 mcg/dl (14 ng/ml). (this is important)

3 LDDST can distinguish PDC from AT in about what % of the cases?

4. If the 4-hour post-dexamethasone cortisol levels show less than 50% of the baseline value or the value at 8 hours, or if the 4-hour level suppresses bellow 1.0 to 1.4 mcg/dl, it indicates a case of PDC. However, if no suppression occurs at 4 hours, the case can be either PDC or AT (no differentiation can be made).

Answer 5

1. 95%, 100%

3. 40%

Question 6

1. HDDST is used to differentiate between PDC and AT?
2. It fails to differentiate PDC from AT in what % of the time?
3. If a dog has PDC (pituitary tumor), the high dose of dexamethasone will suppress the pituitary ACTH and consequently the plasma cortisol levels to a value less than 50% of the baseline value.
4. If a dog has an AT, the 8-hour post-dexamethasone cortisol concentration will not suppress more than 50% of the pre or baseline value.

Answer 6

1. HDDST

2. 15-25%

Question 7

1. Endogenous ACTH concentration is used to differentiate PDC from AT
2. An endogenous ACTH value less than 5 pg/ml is diagnostic of what? and higher than 6 pg/ml is diagnostic of what if the immunoluminometric assay is used?
3. The immunoluminometric assay is currently recommended to localize the disease if using the
   endogenous ACTH test.

Answer 7

2. AT or iatrogenic Cushing’s; PDC

Question 8

1. Abdominal radiography can show calcification of the adrenal gland in cases of ATs.
2. Because adrenal calcification is rare in normal dogs and dogs wit PDC, its presence in a dog with
   Cushing’s strongly suggests what?
3. Abdominal ultrasonography may provide information that helps distinguish PDC from AT and may show abnormalities of other abdominal organs.
4. Pituitary CT and MRI scans are useful to investigate the size of the tumor and make recommendations regarding performing future scans or the need for radiatiation therapy of the brain.

Answer 8

2. AT

Question 9

1. Lysodren (o,p’-DDD) will cause what? resulting in what?
2. It rarely destroys the zona glomerulosa, so what rarely occurs?
3. The induction phase consists in giving Lysodren daily for about 7 to 10 days.
4. The maintenance phase consists in giving Lysodren how often?
5. what should always be performed before starting the maintenance phase to assess the response to the daily Lysodren administration?
6. Stop glucocorticoid therapy at what time before having an ACTH stimulation test performed?
7. Side effects associated with Lysodren therapy include lethargy, vomiting, diarrhea, weakness, anorexia, and ataxia.

Answer 9

1. necrosis and/or atrophy of the adrenal cortex; the reduction of cortisol secretion
2. mineralocorticoid deficiency (hyperkalemia and hyponatremia)
3. weekly
4. An ACTH stimulation test (An ACTH stimulation test should be performed after 1 to 2 months of the maintenance therapy and, every 6 months thereafter)
5. 24 to 48 hours

Question 10

1. Ketoconazole interferes with adrenal steroid synthesis by doing what? therefore lowering what?
2. Drawbacks of ketoconazole therapy include twice daily administration and lack of effectiveness in at least half of dogs.
3. Potential side effects include anorexia, vomiting, lightening of the hair coat and, increase in liver enzymes

Answer 10

1. blocking enzymes in the cortisol synthetic pathway; serum cortisol concentrations.

Question 11

1. Hypothalamic dopamine deficiency has been implicated in the pathogenesis of PDH in a small subset of dogs with Cushing’s disease.
2. what helps restore depleted central dopamine levels and facilitates dopaminergic transmission, increases the synthesis and release of dopamine into the synapse, and inhibits dopamine re-uptake?
3. L-deprenyl is only indicated in cases of uncomplicated what?
4. Clinical response to therapy has been disappointing.
5. Response to therapy is evaluated by history and physical examination. Is an ACTH stimulation test necessary?
6. What has been shown to be an excellent alternative to o, p’-DDD in the treatment of canine
   Cushing’s?
7. Its effect is reversible and side effects should resolve after 24 to 48 hours of drug discontinuation
8. Start with a low dose (1.8 to 2.0 mg/kg) and adjust the dose based on clinical response and ACTH stimulation test results.

Answer 11

2. L-deprenyl
3. PDC.
4. no
5. Trilostane

Question 12

1. Is Surgery curative for adrenal adenomas or small carcinomas?
2. Adrenalectomy may be associated with a high rate of what?
3. If hyperkalemia and hyponatremia occur, what is administered?
4. An ACTH stimulation test should be performed 2 to 3 days after surgery to evaluate adrenal reserve and exclude occult metastasis or incomplete resection.
5. Glucorticoid has to be administered before surgery, during surgery and after surgery until the remaining gland has regained function.

Answer 12

1. yes
2. intra-and postoperative complications, including death.
3. oral fludrocortisone

Question 13

1. The same protocol used to manage PDC can be used to manage ATs.
2. On average, the induction and maintenance dosages will be higher and the induction period longer

3.

Answer 13

d

Question 14

1. Drawbacks of ketoconazole therapy include high twice daily administration, and lack of effectiveness in at least half of dogs.

Answer 14

d