Cushing's dz/syndrome Flashcards Preview

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Flashcards in Cushing's dz/syndrome Deck (12):
1

Steroidogenesis

  • Adrenal cortisol synthesis begins with cholesterol
    • intermediate steps => Cortisol, aldosterone, testosterone, estradiol

2

Pathophysiologic effects of excess cortisol

Body is catabolic!

  • inc gluconeogenesis
  • proteolysis
  • bone demineralization
  • inc gastric secretion => ulcers
  • immunosuppressions
  • inc renal plasma blood flow => inc GFR
  • irritability
  • inc mature nuets, platelets, monocytes
    • dec lymphocytes, eosinophils

3

Breed/age incidence

  • common in dogs, not common in cats
  • toys and minis more prevalent
    • poodles and dashchunds
  • age 3-13 yo (ave 8 yrs)

4

Types of cushings

  • Endogenous
    • Pituitary: ACTH blood levels high
    • Adrenal: ACTH blood levels low
  • Exogenous
    • iatrogenic

5

Calcinosis cutis

  • redness and skin infection in axilla and inguinal area
    • yellowed areas of skin from mineralization of Ca deposit
      • don't give topical steroids!
  • Can happen in cushnoid dogs

6

Other clinical findings of Cushings

  • Lethargy
  • Polyphagia
  • Muscle weakness
  • Hyperpigmentation of skin and hair
  • Calcinosis
  • cutis
  • Keratin plugging of hair follicles
  • Testicular atrophy
  • Hepatomegaly
  • pulmonary calcification
  • prothrombotic tendency
  • hypertension
  • proteinuria
  • glomerulopathy (can be permanent)

7

pathologic calcification

  • can be caused by cortisol and manifests in different tissues (irreversible)

8

Endocrine DX

  1. Urine cortisol/Cr ratio
    • normal test => rules out cushings
    • not very specific
  2. ACTH stim test (w/abdominal ultrasound)
  3. Low dose dex suppression test (normal dogs suppress below 1.7)
  4. High dose dex suppression test
  5. plasma ACTH
    • high with pituitary cushings
    • low with adrenal tumor

9

Cushing's TX

  • Surgery: adrenalectomy, hypophysectomy
  • Medical:
    • OPDDD (dogs)
      • cytotoxic to Glom, Fasc, Ret
    • Trilostane (dogs and cats)
      • inhibits steroidogenesis
  • Iatrogenic: Stop the steroids

10

Lysodren objectives

  • leave a little
  • signs abate
  • ACTH stim: 2-5 mg/dL
    • if > 10 => reload

11

Side effects of OpD'D'D

  1. Drug toxicity (depression, weakness, vomiting, diarrhea, anorex)
    • stop drug until signs stop
    • restart at lower dose
  2. Addison's disease
    • discontinue OpDDD, treat new dz
  3. Pituitary tumor growth
    • Nelson's

12

Cushing's cats

  • Hi-dose dex test better than Lo-dose
  • ACTCH stim has poor sensitivity
  • Many are diabetic => treat this
  • TX
    • surgery
    • Trilostane