LDDS Test in Dogs with PDH and Nonadrenal Illness
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Questions and Answers

What is the preferred diagnostic test for Cushing disease?

  • ACTH stimulation test
  • Urine cortisol-to-creatinine ratio
  • High-dose dexamethasone suppression test
  • Low-dose dexamethasone suppression test (correct)
  • Which of the following statements about Cushing syndrome is true?

  • Ectopic ACTH secretion in dogs is commonly associated with lung tumors
  • It refers only to pituitary-dependent hyperadrenocorticism
  • Iatrogenic hyperadrenocorticism results from insufficient steroid administration
  • Pituitary-dependent hyperadrenocorticism is less common than adrenal-dependent disease in dogs (correct)
  • What is the characteristic age range of dogs affected by Cushing disease?

  • 5-7 years old
  • 12-15 years old
  • 2-5 years old
  • 7-12 years old (correct)
  • Which term encompasses both pituitary-dependent and adrenal-dependent causes of elevated cortisol concentrations?

    <p>Cushing syndrome</p> Signup and view all the answers

    What is the most common disadvantage of the LDDS test in dogs with nonadrenal illness?

    <p>Low specificity</p> Signup and view all the answers

    What is the pattern of suppression and escape seen in 30% of dogs with PDH during an LDDS test?

    <p>Suppression at 3 or 4 hours followed by escape at 8 hours</p> Signup and view all the answers

    What diagnostic tool uses three doses of dexamethasone to measure urine cortisol in cats and dogs?

    <p>Oral LDDS test using UCCR</p> Signup and view all the answers

    What is a possible reason for negative ACTH stimulation and LDDS tests in dogs with adrenal sex steroid excess?

    <p>Excess cortisol precursors</p> Signup and view all the answers

    Why may dynamic adrenal testing be necessary for dogs with adrenal sex steroid excess?

    <p>To measure sex steroids in addition to cortisol</p> Signup and view all the answers

    Which test is the most reliable way to differentiate between PDH and adrenal tumors in dogs according to the text?

    <p>Measurement of endogenous plasma ACTH concentrations</p> Signup and view all the answers

    What is the purpose of adding the protease inhibitor aprotinin to whole blood in EDTA tubes as mentioned in the text?

    <p>To inhibit ACTH degradation</p> Signup and view all the answers

    What is a common manifestation of Cushing disease in cats?

    <p>Polydipsia and polyuria</p> Signup and view all the answers

    Why is SAP seldom increased in cats according to the text?

    <p>Because cats lack the specific hepatic isoenzyme for it</p> Signup and view all the answers

    What is the most suitable test to differentiate healthy dogs from those with hyperadrenocorticism according to the text?

    <p>Low-dose dexamethasone suppression test</p> Signup and view all the answers

    Which statement about Cushing disease manifestations in cats is false according to the text?

    <p>Hypercholesterolemia is common</p> Signup and view all the answers

    What causes polydipsia and polyuria in cats with Cushing disease?

    <p>Concurrent diabetes mellitus</p> Signup and view all the answers

    What is the cause of hyposthenuria in dogs with Cushing disease?

    <p>ADH binding interference</p> Signup and view all the answers

    Why do dogs with moderate to severe nonadrenal illness show increased UCCR ratios?

    <p>Stress of transporting to a vet hospital</p> Signup and view all the answers

    What should be done if screening test results for hyperadrenocorticism are inconclusive?

    <p>Retest the dog 3–6 months later instead of treating without a definitive diagnosis</p> Signup and view all the answers

    What should be used as the screening test of choice for canine hyperadrenocorticism according to the text?

    <p>IV low-dose dexamethasone suppression test</p> Signup and view all the answers

    What does an increased UCCR need to be confirmed by according to the text?

    <p>An IV low-dose dexamethasone suppression (LDDS) test</p> Signup and view all the answers

    What is the recommended dosage of mitotane for dogs with PDH?

    <p>25–50 mg/kg/day for 7–10 days</p> Signup and view all the answers

    What symptom should prompt discontinuation of mitotane therapy in dogs with PDH?

    <p>Anorexia, vomiting, and diarrhea</p> Signup and view all the answers

    How often should dogs on long-term treatment with mitotane have an examination and ACTH response test?

    <p>Every 3–4 months</p> Signup and view all the answers

    What is a possible adverse effect of mitotane at the recommended dosage?

    <p>Mild hypoglycemia</p> Signup and view all the answers

    Which imaging technique is stated as a more sensitive way to identify adrenal tumors?

    <p>Ultrasonography</p> Signup and view all the answers

    What is a possible consequence of administering trilostane to dogs?

    <p>Permanent adrenal insufficiency</p> Signup and view all the answers

    How often should trilostane be administered to achieve a decrease in glucocorticoid secretion?

    <p>Every 12 hours</p> Signup and view all the answers

    What should be monitored to provide an endpoint for mitotane therapy?

    <p>&lt; 60 mL/kg/day water consumption</p> Signup and view all the answers

    What symptom suggests an expanding pituitary macroadenoma after discontinuation of mitotane?

    <p>Ataxia</p> Signup and view all the answers

    What is the cortisol concentration indicating excellent control of Cushing's disease pre-trilostane?

    <p>138 nmol/L</p> Signup and view all the answers

    What is the recommended steroid dose for iatrogenic hyperadrenocorticism, as per the text?

    <p>1 mg/kg</p> Signup and view all the answers

    Which enzyme does selegiline inhibit in the context of Cushing's disease treatment?

    <p>Monoamine oxidase type B</p> Signup and view all the answers

    What is the metastatic rate at the time of surgery for adrenal tumors?

    <p>5%</p> Signup and view all the answers

    What percentage of dogs undergoing unilateral adrenalectomies experience mortality within 1 month after surgery?

    <p>~60%</p> Signup and view all the answers

    Which therapy typically follows radiation treatment of pituitary tumors in dogs and cats?

    <p>Ancillary trilostane or mitotane therapy</p> Signup and view all the answers

    What is the typical recurrence rate after hypophysectomy in dogs with PDH?

    <p>~20%</p> Signup and view all the answers

    What is the main effect of dopamine on ACTH release from the pituitary gland?

    <p>Inhibits release</p> Signup and view all the answers

    In cases of dogs with large pituitary tumors showing neurologic signs, what treatment is indicated?

    <p>Radiation therapy of the pituitary gland</p> Signup and view all the answers

    'Cyberknife' and 'gamma knife' are mentioned in relation to which medical procedure?

    <p>&quot;Newer types of radiation therapy&quot; for pituitary tumors</p> Signup and view all the answers

    What can be a complication arising from rapid reversal of hyperadrenocorticism after hypophysectomy?

    <p>Transient diabetes insipidus</p> Signup and view all the answers

    What is the median survival time for dogs with carcinomas treated with surgical excision?

    <p>778 days</p> Signup and view all the answers

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