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Phase II > Endocrine > Flashcards

Endocrine Flashcards

1
Q

Describe 3 zones of adrenal gland and what they produce

A

Outer: zona glomerulosa (salt) - mineralocorticoids = aldosterone
Middle: zona fasciculata (sugar) - glucocorticoids
Inner: zona reticularis (sex + steroids) - androgens, estrogens, epinephrine / norepinephrine (from Chromatin cells)

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2
Q

What are effects of norepinephrine on alpha / beta receptors?

A

alpha - cause vasoconstriction through increased resistance - increase SAP
beta 1 - increase force contraction & increase HR

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3
Q

Describe arterial and venous supply to thyroid glands & innervation

A

Cranial thyroid a (1st off carotid) –> runs dorsal
Caudal thyroid a (brachiocephalic) –> caudal pole
– both anastomose then bifurcate and enter medial / lateral
Cranial thyroid v –> internal jugular at caudal larynx
Caudal thyroid v –> Internal jugular at caudal neck

** NO CAUDAL THYROID A IN CATS

Cranial laryngeal n. (from vagus n.)

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4
Q

What are the arterial / venous supply of adrenal glands?

A

Phrenicoabdominal a, renal a, cranial abdominal a

R adrenal v –> caudal vena cava

L adrenal vein –> Left renal vein

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5
Q

Location of external / internal parathyroids?
Vascular and nerve supply?

A

External –> cranial, not part of parenchyma
Internal –> within, at caudal pole

External - brach of cranial thyroid a
Internal - vessels surrounding parenchyma

Nerve - cranial laryngeal n.

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6
Q

Describe pathway of RAAS and how it creates aldosterone

A

Renin (juxtaglomerular apparatus kidney) –+ Angiotensinogen (from liver) –> Angiotensin I (in blood)

Angiotensive converting enzyme –+ Angiotensin I –> Angiotensin II (in pulmonary capillaries)

–> vasoconstriction + (+) aldosterone secretion (zona glomerulosa) –> Na/Cl/H2O absorption, K+ excretion by renal tubules

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7
Q

Where is PTH made, by what cell, and describe its effects to adjust Ca/P
Where is calcitonin made and what does it do?

A

PTH is synthesized by Chief cells
Bone - increases Ca/P resorption
Kidney - decreases Ca excretion, increases P excretion
Kidney - increases 1,25 dihydroxycholecalciferol from Vit D (calcitriol) –> works on Intestine - increase absorption of Ca/P

Calcitonin - made in thyroid “C” cells
- Prevents hypercalcemia, decreases bone resorption

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8
Q

Where is ectopic thyroid or parathyroid tissue found?

A

TH: trachea, thoracic inlet, mediastinum, descending aorta (thorax)
PTH: 3-6% of dogs - thymus; detected histologically in 35-50% of cats

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9
Q

Describe the effects of epinephrine on the various receptors

A

Epinephrine ~10x more potent on beta-2 receptors than norepinephrine - more important in controlling metabolism
Beta 2 - vasodilation of skeletal mm arterioles, coronary arteries, and all veins
Beta 2 - promotes glycogenolysis & gluconeogenesis (liver & skeletal mm) - forms lactate –> Increase BG concentrations

Alpha 2 - inhibits insulin secretion
Alpha 2 - stimulates glucagon secretion

Beta 1 - heart - increases force contraction & increases heart rate (shortens diastole depolarization)

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10
Q

Describe pathway to make thyroid hormone & which are biologically active

A

Thyroglobulin produced (precursors for TH)
- stored in lumen
- once iodine available –> goes into follicular cell –> hydrolyzed into thyroxine (T4) and triiodothyronine (T3) –> blood
- T4 & T3 mostly bound
- T4 major secretory; T3 major biologic activity

Hypothalamus - Thyrotropin Releasing Hormone TRH –> pituitary –TSH –> thyroid - Thyroid hormone TH

TSH secretion is inhibited by TH in negative feedback loop

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11
Q

How are catecholamines formed?
Rate of Norepi/epi in cats vs dogs?
Where are the alpha 1, alpha 2, beta 1, beta 2 receptors?

A

Catecholamines from tyrosine / phenylalanine via tyrosine hydroxylase
Cats: 70% epi / 30% Norepi
Dogs: 60% epi / 40% NE

Alpha 1 - presynaptic endings
Alpha 2 - postsynaptic endings
Beta 1 - heart
Beta 2 - metabolism & smooth mm contraction

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12
Q

Name the (+) and (-) functions of glucocorticoids

A

+ hepatic gluconeogensis
+ lipolysis
+ protein catabolism
+ GFR
+ gastric acid secretion
- glucose uptake / metabolism in tissues
- protein synthesis
- vasopressin
- inflammatory response / immune system
- glucocorticoid production (negative feedback)
–> overall increases Glucose in bloodstream

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13
Q
  1. What size usually says adrenal is “too large”?
  2. What are guidelines for malignancy on CT vs US?
  3. What is accuracy of CT to ID vascular invasion?
  4. What % of Cushing’s have pituitary form?
A
  1. 1.5 cm or greater
  2. Mass size (>20 mm); invasion of mass into surrounding tissues and BVs; identification of additional mass lesions
  3. 95% accurate
  4. 80-85% (80% to 85% of dogs with naturally occurring hyperadrenocorticism have the pituitary-dependent form (pituitary-dependent hyperadrenocorticism) - excessive secretion of ACTH by the pituitary gland causes bilateral adrenal hyperplasia and excessive glucocorticoid secretion)
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14
Q
  1. Between pituitary dependent & adrenal dependent Cushing’s, which shows suppression of cortisol with LDDST?
  2. What % of pituitary do / don’t suppress?
  3. What are diagnostic tests to test for pheochromocytoma?
A
  1. Pituitary - mild to mod depression of cortisol
    Adrenal - does NOT suppress
  2. 40% fail to suppress
  3. Urine / plasma catecholamine (normetanephrine)
    Urine creatinine to normetanephrine ratio (most specific)
    Serum inhibit assay (low or undetectable with pheo)
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15
Q
  1. What are the 3 qualifiers of suppression on LDDST?
  2. Dogs with iatrogenic Cushing’s have __ ACTH and __ cortisol
  3. To prep for adrenal cortisol secreting tumor - dose trilostane and goal therapy cortisol?
  4. If increase blood pressure, what drug to give with cortisol tumor and why?
A
    • 4 hr post serum cortisol [ ] <1.5 ug/dL
      - 4 hr post cortisol [ ] <50% baseline [ ]
      - 8 hr post cortisol [ ] <50% baseline [ ]
  2. Low ACTH; subnormal baseline cortisol
  3. 1-2 mg/k PO q12 ; cortisol 2-5 ug/dL
  4. ACE inhibitor - decreases peripheral vasoconstriction and aldosterone secretion
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16
Q

With adrenal surgery, what is protocol of glucocorticoids to decrease risk of Addison’s?

A

Post-op dexamethasone (0.05-0.1 mg/kg) in IVF over 6 hours OR
ACTH stim immediately post-op and before exogenous steroids to get baseline
- if Addisonian - taper dose (decrease dose by 0.02 mg/kg/q24h) dexamethasone at 12 hour intervals until dog is given orals (24-72 h post-op)
- oral pred 0.25-0.5 mg/kg q12 tapered to 0.1 mg/kg/d by 10d
ALWAYS at 4 week - check ACTH stim before stopping GCs

17
Q
  1. When should you treat with mineralocorticoids and what is the treatment?
  2. What is pre-tx before surgery for Pheochromocytomas and dose?
  3. If has increased BP and tachycardia with Pheos, what is the treatment and give when?
A
  1. Na <135 mEq/L or if K > 6.5 mEq/L
    - desoxycorticoosterone pivalate
  2. ideally phenoxybenzamine 2-3 weeks before 0.5 mg/kg PO q12 OR prazosin 0.5-1 mg/kg q8h (depend size pt)
  3. Propanolol or atenolol (beta adrenergic antagonist) ONLY AFTER alpha adrenergic blockade (via phenoxy)!!!!
18
Q
  1. What % malignant thyroid tumor in dogs metastasize?
  2. What % malignant thyroid tumor in dogs are hyperthyroid?
  3. What breed of dogs are predisposed to thyroid tumors?
  4. What % specificity does CT have for ID invasion of tumor?
  5. What are benefits of scintigraphy for thyroid tumors in dogs?
A
  1. 40% detectable at presentation
  2. 10-29%
  3. Golden Rets, Beagles, Siberian Husky
  4. 100%
  5. Helps ID ectopic tissue; I131 treatment - can determine likelihood of response
19
Q
  1. What is treatment of hypothyroidism post-op thyroidectomy? Dose?
  2. MST of treatment with surgery vs untreated thyroid carcinoma?
  3. What are factors positively associated with local invasiveness?
  4. List 3 metastatic rates based on 3 volume sizes of tumors
A
  1. Levothyroxine 0.02 mg/kg POq12; max dose 0.8 mg POq12
  2. MST ~22-28 months with surgery (newer studies); w/o surgery 3 months
  3. Tumor diameter, tumor volume, tumor fixation, ectopic location, follicular cell origin
  4. 14% tumors <23 cm^3
    74% tumors 23-100 cm^3
    100% tumors >100 cm^3
20
Q
  1. List options to ID abnormal parathyroid gland intra-op
  2. What is dose of calcitriol to treat hypoCa post parathyroidectomy?
  3. What is the goal Ca range with treatment?
  4. What breed is predisposed for hyperparathyroidism
  5. What are two other treatment options for PTH tumors? MST? What is percentage of controlled hyperCa?
A
  1. Rapid chemiluminescent assay;
    methylene blue IV;
    indocyanine green near infrared fluorescent imaging
  2. 0.02-0.03 ug/kg/d POq12 2-4 days then 0.005-0.015 ug/kg/d
  3. Total 8-9.5 - iCa 0.9-1.2 mmol/L
  4. Keeshond
  5. Percutaneous ethanol (72%) MST 540 days
    Percutaneous heat ablation (90%) MST 581 days
21
Q
  1. To diagnose PTE post-op adrenal surgery, what are dx tests? Gold standard?
  2. Treatment for PTE?
A
  1. clinical signs, BW
    Blood gas: Increase pAO2 - paO2 gradient on room air (but paO2/paCO2 normal)
    Rads: interstitial infiltrates
    Pulmonary angiography - gold standard
  2. Anticoagulant
    Sildenafil
    Theophylline
    +/- mechanical vent?
22
Q
  1. Advantage of flank vs midline vs laparoscopic adrenalectomy?
  2. What % of caval invasion in adrenocortical vs pheochromocytomas
  3. What is current mortality rates for adrenalectomy?
  4. MST for not having surgery for adrenal tumors?
A
  1. Midline: easier access to CdVC
    Flank: improve exposure dorsal abdomen
    Laparoscopy: small incisions - improved visualization and exposure
  2. Adrenocortical 11-16%
    Pheochromocytomas 35-55%
  3. 4-22% mortality
  4. MST 15-17 months with medical mgmt
23
Q
  1. With cat adrenal tumors, what % are cortical? Functional?
  2. Survival rate for cats - 77% for at least two weeks, but what is MST?
  3. What are other conditions occur with ferrets with adrenal tumors?
  4. Mortality rate post-adrenalectomy for ferrets?
A
  1. 91% cortical; 76% functional
  2. 50 weeks
  3. Splenomegaly (87%)
    Insulinoma (27%)
    Cardiomyopathy (10%)
  4. <2% mortality
24
Q
  1. Between dogs/cats with thyroid nodules on PE, what % are malignant?
  2. For cat thyroid tumors, what % are bilateral?
  3. What is best approach to evaluate renal disease w thyroid cats?
  4. What % hyperTH cats had chronic renal disease?
  5. What % hyperTH cats had hypokalemia; what is the clinical sign?
A
  1. Cats <1-4% malignant; Dogs >90%
  2. 70-91% bilateral
  3. Trial course with methimazole and effects reversible when discontinued (monitor chem with tx)
  4. 40% had CRD
  5. 32% hypoK - neck ventroflexion
25
Q
  1. What % cats with hyperTH have palpable nodule?
  2. Tx options to make euthyroid pre-op for cats?
  3. What condition is it not recommended to do sx for feline hyperthyroid?
  4. List sx approaches to removal thyroid gland
  5. With parathyroid autotransplantation, what is timeline it starts to function?
A
  1. > 90%
  2. Propylthiouracil and methimazole (1.25-2.5 mg BID)
  3. If azotemia with euthyroid state -> surgery not OK, do methimazole
  4. Modified extracapsular
    Modified intracapsular
    Intracapsular
    Extracapsular
    - also can do staged
  5. 7-21 days
26
Q
  1. Prognosis thyroidectomy cats
  2. Complications of thyroidectomy in cats
  3. What % cats get significant hypoCa post-op?
  4. List tx options and doses for hypoCa post-op
A
  1. Excellent - low mortality rate
  2. Hemorrhage
    Lar par
    Dyspnea
    Horner’s
    HypoTH
    HypoPTH
    Recurrent hypoTH
  3. <6%
  4. 10% Ca gluconate IV 0.25-1.5 mL/kg slowly (over 10-20 min) to effect or CRI at 5-15 mg/kg/h IV.
    Ca lactate or carbonate 0.5-1 g of calcium/cat/d orally.
    Oral vitamin D can be in the form of either dihydrotachysterol or calcitriol
    Calcitriol 0.02 to 0.03 µg/kg/d for 2 to 4 days then 0.005 to 0.015 µg/kg/d
    Dihydrotachysterol 0.03 mg/kg once daily for 1 to 7 days, then 0.02 mg/kg/d
27
Q
  1. What % cats recur with hyperTH?
  2. What is prognosis for I131 for hyperTH?
  3. Of all thyroid tumors in dogs, what % benign? Of those felt on PE, what % benign?
  4. What % canine malignant tumors are bilateral?
  5. Where are ectopic thyroid noted in dog?
A
  1. 5-11% recur
  2. Single dose cures most
  3. ~30-50% adenoma; <10% malignant
  4. 25-47% bilateral
  5. Base of tongue, cranial mediastinum, ventral neck, heart base
28
Q
  1. Canine thyroid tumors - I131 MST? (W vs W/O mets?)
  2. Canine thyroid tumors - RT MST?
  3. With partial hyoidectomy for sublingual ectopic thyroid tumors - what should you protect?
  4. What are primary, secondary, tertiary hypothyroidism dogs?
A
  1. W/O 839 days; W mets 366 days
  2. Mean progression free survival 45 months; 3 year PFS 75%; others ~24 months
  3. Hypoglossal and recurrent laryngeal n
  4. Primary: disease of thyroid gland
    Secondary: problem with pituitary gland
    Tertiary: hypothalamus unable to produce enough TRH
29
Q
  1. For the list of diseases, say if PTH, PTHrp, iCa, and vitamin D? ⬆️⬇️
    Primary hyperPTH
    LSA
    CRF
    AGASACA
    Hypervitaminosis D
A

Primary hyperPTH: PTH ⬆️; PTHrp ⬇️; iCa ⬆️; Vit D ⬆️
LSA: PTH ⬇️; PTHrp ⬆️; iCa ⬆️; Vit D ⬇️
CRF: PTH ⬆️; PTHrp ⬆️; iCa ⬇️; Vit D ⬇️
AGASACA: PTH ⬇️; PTHrp ⬆️; iCa ⬆️; Vit D ⬆️
HyperVit D: PTH ⬇️; PTHrp ⬇️; iCa ⬆️ Vit D ⬆️

Phase II (4 decks)

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