Term
| What portion of the adrenal cortex produces aldosterone? |
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Definition
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Term
| What portion of the adrenal cortex produces cortisol? |
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Definition
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Term
| What portion of the adrenal cortex produces sex hormones? |
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Definition
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Term
| What are the five most common types of canine cushing's? |
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Definition
-Pituitary dependent(PDH): most common
-Adrenal dependent (FAT): second most common
-Ectopic ACTH non-pituitary tumor: rare
-Food dependent hypercortisolemia: very rare
-iatrogenic (due to exogenous GCs |
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Term
| What are the three types of pituitary dependent? |
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Definition
1. Microadenomma (<3mm): most common
2. Adenoma: 3-10 mm
3. MAcroadenoma > 10mm |
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Term
| Out of the three types of pituitary dependent hyperadrenocorticism has neuro signs? |
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Definition
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Term
| Is adrenal dependent hyperadrenocorticism responsive to ACTH? |
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Definition
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Term
| Is adrenal dependent hyperadrenocorticism most commonly bilateral or unilatera? |
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Definition
| -most commonly unilateral |
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Term
| What percentage of adrenal dependent hyperadrenocorticism is malignant? |
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Definition
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Term
| Is iatrogenic HAC common or rare in dogs? What causes it? |
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Definition
-relatively common
-caused by administration of glucocorticoids |
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Term
| What is the typical signalment of pituiary-dependent HAC? |
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Definition
-most < 20kg
-female = male
-most > 9y
-Breeds: Dachshund, Poodle, Boxer, Terrier |
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Term
| What is the typical signalment of adrenal-dependent HAC? |
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Definition
- most > 20kg
-females > males
-most > 9y |
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Term
| What are the common clinical signs seen with HAC? |
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Definition
-polyphagia
-PU/PD
-pot bellu
-symmetric alopecia |
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Term
| What causes the PU/PD seen with HAC? |
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Definition
-cortisol interferes w/ ADH = free water oss
-nephrogenic DI
-patning |
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Term
| What causes the pot bely seen with HAC? |
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Definition
-redistribution of fat
-abdominal muscle weakness
-hepaomegaly
-full urinary bladder |
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Term
| What causes the panting we see with HAC? |
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Definition
-weak resp mm
-inc abdominal fat/ hepatomegaly
-direct stimulation of resp center
-pulmonary thromboemboli and mineralization |
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Term
| What musculoskeletal changes do we see due to HAC? |
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Definition
-weakness due to muscle wasting
-lameness due toruptured CCL
-gait abnormalities due to myotonia (rare) |
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Term
| What are the derm signs we see with HAC? |
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Definition
-alopecia
-truncal
-non-pruritic
-slow hair growth
-hyperpigmentation
-thin skin
-atrophy of dermis
-loss of elasticity
-non-healing wouns
-comedones
-calcinosis cutis
-dorsal midline
-ventrum
-inguinal
-seborrhea sicca
-pyoderma
-bruising |
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Term
| What are the four common sequelae of HAC? |
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Definition
-trhomboembolism
-renal disease
-diabetes mellitus
-dystrophic caclification |
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Term
| Explain the physiology of thromboembolism seen with HAC? |
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Definition
| -thrombocytosis and activated platelets => protein-losing nephropathy = dec antithrombin & inc hematocrit |
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Term
| What do we see with renal disease with HAC? |
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Definition
-proteinuria
-systemic hypertension |
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Term
| What do we see on CBC with HAC? |
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Definition
-stress leukogram
-mild polycythemia
-thrombocytosis |
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Term
| What do we see on biochem panel with HAC? |
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Definition
-inc ALP & cholesterol
-mild inc glucose & ALT |
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Term
| What do we see on UA with HAC? |
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Definition
-dec USG
-proteinuria (renal failure issues)
0UTI: may have inactive sediment |
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Term
| What do we see on rads with HAC? |
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Definition
-hepatomegaly
-distended urinary bladdeer
-excellent serosal detail
-FAT => mineralized mass cranial to kidney
-dystrophic calcification: lungs/ stomach/ kidney & calcinosis cutis |
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Term
| What are our confirmatory tests to diagnose HAC? |
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Definition
-ACTH stim test
-Low dose dexamethasone supprpession test (LDDS) |
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Term
| What do we use as a screening test for HAC? |
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Definition
| -urine cortisol:creatinine |
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Term
| Is urine cortisol:creatinine a rule in or rule out test for HAC? |
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Definition
-rule out test only (high sensitivity but low specificity)
-expensive |
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Term
| What does an ACTH stim test evaluate? What is it commonly used for in addition to diagnosis? |
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Definition
-exaggerated response to synthetic ACTH
-used for monitoring therapy |
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Term
| What will HAC look like of LDDS? |
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Definition
| -fails to suppress at 8h cortisol readings |
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Term
| What are the advantages, disadvantages, and uses of ACTH Stim Test for HAC? |
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Definition
-Advantages: only 1h, more specific, can diagnose IH
-Disadvantages: more expensive, less sensitive, not sensitive for FAT
-Uses: diagnosis & monitoring |
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Term
| What are the advantages, disadvantages, and uses of LDDS for HAC? |
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Definition
-Advantages: less expensive, more sensitive, better for FAT, lesss expensive
-Disadvantages: 8h, needs additional blood draw, less specific, cannot diagnose IH
-Uses: confirms ACTH Stim Test findings |
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Term
| What diagnostic methods do we use to localize HAC? |
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Definition
-LDDS
-high dose dex suppression test
-endogenous plasma ACTH
-abdominal imaging: abdominal US, CT, or MR |
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Term
| How do we administer a HDDS test? How do PDH dogs respond? How do FAT dogs respond? |
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Definition
-Dex SP IV
-15-50% PDH dogs fail to suppress
-FAT will NEVER suppress |
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Term
| If cortisol is suppressed with HDDS test, what is the diagnosis? |
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Definition
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Term
| If cortisol was not suppressed with HDDS test, what is the diagnosis? |
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Definition
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Term
| How will a PDH dog respond to testing endogenous ACTH? |
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Definition
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Term
| How wil a FAT dog respond to testing endogenous ACTH? |
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Definition
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Term
| What do we do if testing the endogenous ACTH is not conclusive? |
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Definition
| -use another differentiation test or repeat endogenous ACTH |
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Term
| Describe the specific collection and handling of endogenous ACTH. |
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Definition
-Aprotinn as protease inhibitor (preservative)
-EDTA blood
-centrifuged immediately
-plasma in plastic tube
-immediately frozen
-shipped on dry ice: overnight |
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Term
| HOw does FAT HAC appear on adrenal US? |
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Definition
-one large and irregular adrenal gland
-contralateral gland atrophy |
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Term
| How does PDH HAC appear on adrenal US? |
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Definition
-bilaterally symmetric; normal-sized or enlarged
-nodular hyperplasia may cause asymmetry |
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Term
| How does iatrogenic HAC appear on adrenal US? |
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Definition
| -bilaterally small adrenal glands |
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Term
| Where would we look if we have neuro signs with HAC using MR or CT? |
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Definition
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Term
| What do we use MR and CT for in cases of HAC? |
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Definition
-ID pituitary mass
-pre-surgical planning for adrenalectomy |
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Term
| What are our three methods of PDH treatment? |
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Definition
1. inhibit synthesis of cortisol: Trilostane or KEtoconazole
2. Necrosis of adrenal cortex: Mitotane
3. Surgically remobe pituitary mass |
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Term
| What is the MOA of Trilostane and what does it do to treat PDH? |
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Definition
-MOA: competitively inh 3-beta-hydroxysteroid DH
-inh syntehsis of cortisol |
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Term
| What are the common side effects of Trilostane? |
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Definition
-Hyperkalemia
-Steroid withdrawal: bomiting, diarrhea, lethargy
-Transient hypoA: dec trilostane and admin steroids
-permanent hypoA
-acute death |
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Term
| How do we monitor Trilostane? |
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Definition
-2w: biochem and CBC
-4w: biochem, CBC, and ACTH |
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Term
| If we have normal [cortisol] after ACTH stim with Trilostane how do we alter drug dosage? |
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Definition
-if clinical signs improving: keep same dose
-if no improvement of clinical signs: inc to q12h dosing |
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Term
| If our [cortisol] is high after ACTH stim with Trilostane management, how do we alter drug dosage? |
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Definition
| -inc dose by 20-25% and recheck in 4w |
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Term
| If our [cortisol] is low after ACTH stim with Trilostane management, how do we alter drug dosage? |
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Definition
-stop
-if ill adminsiter corticosteroids
-repeat ACTH stim if clinical signs return (reinstitute trilostane at half original dose) |
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Term
| How do we utilize ACTH stim monitoring for trilostane administration for HAC? |
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Definition
-always 2-4h after trilostane admin
-recheck 4w after each dosage change
-one on maintenance rechck q3-6m
-recheck any time dog is ill |
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Term
| How does Mitotane work to treat HAC? |
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Definition
-adrenocorticolytic with irect cytotoxic effect (primarily zona fasciculata and reticularis)
-off-label use in animals |
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Term
| When would we discontinue mitotane to treat HAC? |
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Definition
-dog acts lethargic
-stops or slows eating
-water soncumption drops
-vomiting or diarrhea |
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Term
| What is the major downside to using Mitotane to treat HAC? |
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Definition
| -70& will relapse with signs w/in 12m: msut repeat induction and inc maintenance dose by 25-50% |
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Term
| What are the common side effects of Mitotane? |
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Definition
-GI upset
-Over treatment: lethargy, weakeness/tremors/collapse, anorexia, vomiting, diarrhea
-send home pred with owners |
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Term
| What is the MOA of Ketoconazole in the treatment of HAC? |
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Definition
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Term
| What are the side effects of Ketoconazole when treating AHC? |
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Definition
-anorexia
-vomiting
-diarrhea
-hepatotoxicity |
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Term
| What is the major downfall to treating HAC with Ketoconazole? |
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Definition
| -not effective in up to 33% of dogs |
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Term
| What do we use L-deprenyl for in HAC cases? MOA? Is it recommended? |
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Definition
-used for cognitive dysfunction in dogs
-inh MOA type B
-not recommended b/c not effective in msot dogs |
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Term
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Definition
-unilateral adrenalectomy + mineralocorticoid and glucocorticoid supplementation
-Mitotane: higher dosages required = inc side-effects and may cause tumor necrosis
-Trilostane: no effect on tumor growth |
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