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DISEASES OF THE ADRENAL GLANDS
CUSHING’S DISEASE(__________________________)
ADDISON’S DISEASE(__________________________)
Physiology
• Hypothalamus – Corticotropin realeasing factor (CRF) >>> ____________________________________________________________________(ACTH)
– >>> ADRENAL CORTEX
• _________________ hormone
• __________________ hormone
• ___________________ (Androgens)
• SNS >>> ADRENAL MEDULLA >>> _____________ and ____________________
– Increase HR, Inc. BP, Dilated air passages – lungs, dec. GI function, vasoconstriction
Hyperadrenocorticism (Cushings Disease)
• Definition: Disorder caused by deleterious effects of ________________________ circulating cortisol concentrations on multiple organ systems
• Systems affected: Pansystemic disease– Renal– Skin– Cardiovascular– Respiratory– Endocrine/metabolic– Musculoskeletal– Nervous– Reproductive
Cushing’s Disease
Effects of excess glucocorticoids:1. ____________________ inflammation2. ____________________ immune system3. ___________________ cartilage growth, development,
and repairCauses: 1. ___________________________ (pituitary-dependent disease) –
85% of cases2. ____________________________ (excess cortisol secretion
independent of pituitary control) – 15-20% of cases3. Overmedication with glucocorticoids -________________
Cushing’s Disease
• signs are slow to develop and usually go unnoticed by owner
Clinical Signs:1. Some are similar to hypothyroidism2. Dog >6 yr old (most are female)3. PU/PD/PP4. Pot bellied; obese5. Muscle atrophy and weakness, lethargy, excess panting6. Bilateral symmetric alopecia; pruritis; pyoderma (↓
immune response)7. ___________________ (firm plaques of Ca++ under
skin)8. Abnormal gonadal function (lack of estrus; soft, small
testicles)
Cushing’s Disease: Calcinosis cutis
Commonly seen on the dorsal midline, ventral abdomen and inguinal region. Skin is usually thin and atrophic
Cushing’s Disease: DxChemistry Panel1. ↑ _________, _______________, _________________, _______________2. ↓ BUN3. Lipemia4. ________________ USG < 1.015, proteinuria, hematuria, pyuria, bactiuria
Urine cortisol/creatinine ratios (sample collected at home)1. Normal ratio=no Cushing’s2. Elevated ratio= __________ be Cushing’s
ACTH Stimulation test1. Normal patients show an increase of plasma cortisol2. Pituitary dependent disease (excess ACTH release) and Adrenal tumors: 60-
85% show ____________________________ cortisol response3. Does _______________________ differentiate between Pit disease and
Adrenal tumor
ACTH Stimulation for Hyperadrenocorticism
• Take a pre blood sample.
• Inject ACTH stimulation gel or liquid– Verify amounts with lab as there is
difference between amount to be injected with gel and liquid.
• Wait two hours and take a post sample
Cushing’s Disease: Dx
Low-Dose Dexamethasone Suppression Test1. Inject low dose of steroid (should suppress ant. pit [ACTH])
2. Measure plasma cortisol at 0, 4, 8 h
Interpretation:1. Normal dogs will show ________________ in plasma cortisol
2. Pituitary tumor and adrenal tumor will not show any effect at 8 h (cortisol will still be __________________)
Cushing’s Disease: Dx
High-Dose Dexamethasone Suppression Test (used to ______________________ between Pit Dis and Adrenal tumor)
1. Dosing: 0.1 mg/kg IV
2. Collect plasma cortisol at 0, 4, and 8 h
Interpretation:1. Pituitary dependent disease—70-75% will show
__________________ at 4 or 8 h
2. Adrenal tumor—__________________ change in plasma cortisol level (tumor is autonomous)
Cushing’s Disease
ACTH stimulation:Exaggerated response
High dose dexPit: Decrease 4, 8 hrsAdrenal: No change
Low dose dexNormal: reducePit/Adr tumor: high
Cushing’s Disease: Rx
_____________________ removal—1. Specialized surgery; most vets would refer surgery
2. Pituitary tumors are not surgically removed
Medical treatment
1. Lysodren (o,p,DDD)—necrosis of z fasiculata (middle), z reticularis (deep)
-repeat ACTH stimulation q 7-10 d until cortisol normal
-like chemotherapy
-excess dose affects z glomerulus (_____________________)
Cushing’s Disease: Rx
2. trilostane (Vetoryl®)—less side-effects than o,p,DDD
-interfers with cortisol production (doesn’t kill cells)
-FDA approved
Cushing’s Disease: Client info
• Serious disease; life-long treatment
• Periodic monitoring required
• Addison’s disease may result (_________, _____________, _______________)
• Prognosis: average life expectancy is 20-30 mo on therapy with frequent recurrence of clinical symptoms – varies with cause (pit vs adrenal, tumors)
HARD TIMES“In the depths of winter, I finally
learned that within me there lay an invincible summer.”
-Albert Camus
Addison’s Disease (Hypoadrenocorticism)
• Definition: Disorder caused by _________________ production of glucocorticoids (cortisol) or mineralocorticoids (aldosterone) or both
• Secondary disease caused by chronic administration of _______________________
Addison’s Disease (Hypoadrenocorticism)
• Not as common as Cushing’s Disease; rarely seen in cats
• Deficiency of Glucocorticoids and Mineralocordicoids
• Clinical signs due to Mineralocorticoid (____________________) deficiency
Clinical Signs:1. lethargy, weakness, anorexia, wt loss
2. Vomiting/Diarrhea
3. PU/PD, dehydration
4. _________________________________________
Addison’s Disease
• Pathophysiology– Decreased aldosterone => Increased ____
and decreased _________________– => decreased volume =>_______________,
hypotension, dehydration, weakness, depression
– Hyper K => heart (____________________)– Glucocorticoid deficiency => vomiting,
diarrhea, melena, lethargy, wt loss, hypoglycemia (less common than expected)
Addison’s Disease: Dx
Chem Panel
Na:K ratio <___________________ !!!(normal=27:1 to 40:1)
↑ BUN, Creatinine, Ca++
↓ blood glucose, albumin (less common)
ACTH Stimulation test (________________________ test)
normal dog= ↑ cortisol
hypoadrenocorticism dog= _______________ , unchanged cortisol level
Endogenous ACTH will be increased (1º hypoadrenocorticism; lack of neg feedback)
What is your Dx?
Chem Panel (What is not normal?)
Parameter Value Normal valueBUN 81 mg/dl 7-27 mg/dlCreatinine 2.1 mg/dl 0.4-1.8 mg/dlSodium 131 meq/L 141-156 meq/LPotassium 6.5 meq/L 4.0-5.6 meq/LNa:K ratio 20 27-40
What is your Dx?
ACTH Stimulation Test ResultsValue Normal
Plasma Cortisol
Pre-ACTH 0.2 2-6 Post-ACTH 0.3 6-18
Addison’s Disease: RxAcute Crisis (may be life-threatening situation)1. Normal saline IV (low _____________ is hallmark finding of Addison’s)
2. Glucorticoid replacement(cortisol will also be low)a. Dexamethasone or Prednisone (IV or IM)
3. Mineralocorcorticoid replacementa. ____________________ (fludrocortisone acetate)—po
b. _____________________-V (desoxycorticosterone pivalate) injection
Chronic Management1. Glucocorticoid replacement
a. Prednisone
b. Prenisolone
2. Mineralocorcorticoid replacementa. Florinef® (fludrocortisone acetate)—po daily (not cheap; 50¢/tab)
b. Percortin-V (desoxycorticosterone pivalate)—inj ~monthly (expensive)
3. Monitor electrolytes, BUN/Creatinine, clinical signs
Addison’s disease: Client info
1. Mineralocorticoid deficiency is life-threatening
2. Animal requires periodic blood tests
3. Glucocorticoids needed in times of stress
4. Always remind attending vet of pet’s condition
5. Hormone replacement therapy continued for life of pet
6. Prognosis: Good to excellent after stabilization and treatment
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