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VETM 425 Sys Path > Lecture 20: Endocrine 2 > Flashcards

Lecture 20: Endocrine 2 Flashcards

1
Q

What are the relevant anatomical structures near the adrenal glands

A

They are located at the cranial pole of the kidney

near the
- Ca. VC
- aorta
- the phrenicoabdominal vein runs right over top (landmark)

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2
Q

What are the parts of the adrenal gland and what do they secrete?

A

Cortex
zona glomerulosa
- mineralocorticoids: aldosterone (under control of RAAS, act on distal tubule = excrete K and resorb Na)

zona fasciculata
- glucocorticoids: cortisol release under ACTH control

zona reticularis
- androgens/progesterone/estrogen: under ACTH control

Medulla: catecholamines

cortex : medulla : cortex ratio
1 : 2 : 1

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3
Q

What is the functions of cortisol

A

spare glucose
- lipolysis
- gluconeogenesis
- protein catabolism

causes reduced:
- wound healing
- inflammation
- immunity

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4
Q

What are the 3 main disorders of the cortex

A

hypoadrenocorticism
hyperadrenocorticism
adrenal neoplasia

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5
Q

What is the common signalment of an animal with hypoadrenocorticism?

A

idiopathic adrenocortical atrophy
- young adult dog
- all breeds, esp (poodle/great dane/nova scotia duck tolling retriever)

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6
Q

What is the pathogenesis of hypoadrenocorticism

A

can affect all layers

mineralocorticoids = hyperkalemia/hyponatremia and hypochloremia = hypovolemia

glucocorticoids = GI signs/hypoglycemia/low cortisol
- no response to ACTH stimulation

reduced sex hormones

may be immune mediated

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7
Q

What are the clinical signs of hypoadrenocorticism

A

v/d/lethargy/shock

cardiovascular collapse = addisonian crisis
- hypovolemic shock
- sudden death

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8
Q

What are the gross lesions of hypoadrenocorticism? What is the mechanism of dysfunction?

A

small adrenal glands

primary hypofunction
(but for atypical addison’s it is caused by iatrogenic or secondary hypofunction)

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9
Q

What is the common signalment for hyperadrenocorticism?

A

dogs (uncommon in cats)

most common canine endocrinopathy

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10
Q

What are the 3 main mechanisms of dysfunction of hyperadrenocorticism? What gross lesions does each mechanism cause?

A

functional corticotroph adenoma in the anterior pituitary
- secondary hyperfunction
- most common 85-90%
- bilateral adrenocortical hypertrophy/hyperplasia

functional adrenal neoplasia
- primary hyperfunction
- 10-15%
- unilateral neoplasia nodule and cortical atrophy in contralateral gland

iatrogenic
- bilateral adrenocortical atrophy

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11
Q

What are the clinical signs of hyperadrenocorticism?

A

polyphagia

PU/PD
- cortisol impacts kidneys ability to recognize ADH

muscle weakness
- pot-bellied
- lordosis
- temor
- straight legged position

cutaneous lesions
- alopecia
- thin skin
- calcinosis cutis (dystrophic - no increase in blood P/Ca): causes foreign body reaction in skin = pruritus and ulceration

steroid hepatopathy + hepatomegaly
- vacuolated hepatocytes

increased secondary infection

reduced wound healing

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12
Q

What is the typical signalment of an animal presenting with adrenal neoplasia? How does signalment differ depending on lesion?

A

old dogs: adenoma > carcinoma

ferrets:
- female > male
- had early gonadectomy
- spectrum of lesions
uni or bilateral hyperplasia or carcinoma > adenoma

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13
Q

Compare adenoma and carcinomas of adrenal neoplasias causing hyperadrenocorticism

A

adenoma: common in old dogs
- usually nonfunctional but can be functional

carcinomas: uncommon
- old dogs/cattle
- functional and invasive
- often metastasize to kedneys/liver/LN/lungs

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14
Q

What is the pathogenesis of adrenal neoplasia in ferrets

A

early gonadectomy can increase the risk
- removal will impair feedback mechanisms
- increase GnRH
- increased LH/FSH
- target reticularis
- increased estradiol 17B but normal cortisol

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15
Q

What are the clinical signs of adrenal neoplasia in ferrets

A

bilateral and symmetrical alopecia

enlarged vulva (female) or enlarged prostate resulting un urethral blockage (male)

pancytopenia
- estrogen is toxic to hematopoietic precursors in bone marrow

+/- concurrent insulinoma

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16
Q

What is the main dysfunction of the adrenal medulla

A

pheochromocytoma
- benign or malignant
- come functional causing increased catecholamine/hypertension

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17
Q

What species are pheochromocytomas common in?

A

dog and bulls

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18
Q

What is a common concurrent dysfunction with pheochromocytoma

A

C tell tumors of the thyroid

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19
Q

What are the relevant structures near the thyroid?

A

near
larynx
trachea
thymus
parotid salivary gland

20
Q

What is the thyroid gland made up of

A

thyroid follicular cells

C/parafollicular cells

21
Q

What is the function of thyroid follicular cells

A

makes T3/4

thyroglobin > monoiodotyrosine > diiodotyrosine > T3/T4

T3/4 has negative feedback on hypothalamus and anterior pit (TRH/TSH)

control metabolism and growth

22
Q

What is the function of C cells?

A

release calcitonin in response to hypercalcemia
- cause deposition of calcium in bone

23
Q

What is the common signalment of an animal with hypothyroidism

A

dog
- doberman
- daschund

24
Q

What are the causes of hypothyroidism

A

primary thyroid disease
- idiopathic follicular collapse
- lymphocytic thyroiditis (lymphocytic infiltration and inflammation destry the thyroid = autoimmune)

secondary disease = rare
- hypothalamic or pituitary lesion

25
Q

What are the clinical signs of hypothyroidism?

A

weight gain (reduced basal metabolic rate)

cutaneous lesions
- bilateral/symmetrical alopecia
- hyperkeratosis
- hyperpigmentation
- myxedema (accumulation of hydrophilic mucus in SC which draws fluid in)

repro

hypercholesterolemia
- atherosclerosis in coronary vessels of dogs

26
Q

What are 2 types of congenital hypothyroidism

A

goiter

congenital hypothyroidism dysmaturity syndrome (CHDS)

27
Q

What is goiter

A

non neoplastic/non inflammatory enlargement of the thyroid

thyroid follicular hyperplasia
- due reduced T3/4 synthesis and increased TSH/TRH stimulation

28
Q

What are the causes of goiter

A

iodine deficiency

goiterogenic agents (make iodine less available)

excessive iodine diets (inhibit follicular cell function)

genetic enzyme defects
- dyshormonogenic goiter

29
Q

What are the clinical signs and gross signs of goiter

A

cervical tracheal mass

alopecia

myedema

common cause for abortion in small ruminants

bilateral enlarged dark purple thyroids

30
Q

What are the clinical signs of congenital hypothyroidism dysmaturity syndrome?

A

perinantal death (soon after birth)

MSK abnormalities
- mandible prognathia
-ruptured tendons
- immature carpal and tarsal bones

  • look immature
  • sine/silky hair

prolonged gestaion

31
Q

What are the gross signs of CHDS? How to diagnose?

A

thyroid grossly normal
- NEED histo

check jaw and limb radiographs
- see the immature carpal and tarsals

32
Q

What is the cause of CHDS?

A

unknown

33
Q

What are 4 causes of thyroid hyeprfunction?

A

hyperthyroidism

nodular hyperplasia

thyroid follicular tumor

thyroid follicular carcinoma

34
Q

What lesions cause hyperthyroidism and what mechanism of dysfunction is it?

A

It is an excess of T3/4 via primary hyperfunction

multifocal nodular hyperplasia and thyroid follicular adenoma
»
thyroid follicular carcinoma

rarely dogs can get thyroid follicular carcinoma

either uni or bilateral

35
Q

How does the clinical effects of hyperthyroidism differ if it is caused by an adenoma vs a carcinoma?

A

carcinoma
- malignant and bad
- rarely develop the clinical syndrome tho because dogs have more efficient enterohepatic excretion of thyroid hormones

adenoma or hyperplasia
- weight loss
- polyphagia
- Pu/PD (due to increased blood flow to kidney = excess ultrafiltrate)
- nervous
- heat intolerance
- cardiac (tachycardia/arrhythmia/concentric hypertrophy)

the hypertrophy is NOT a primary cardiomyopathy

36
Q

What animals are most commonly affected by nodular hyperplasia

A

old cats
- usually functional

dog/horse
- usually non-functional/incidental

37
Q

What are the gross lesions associated with nodular hyperplasia

A

multiple tan/brown encapsulated nodules

38
Q

What species is benign thyroid follicular tumors common in?

A

cats

39
Q

What are the gross features of benign thyroid follicular tumors

A

single
white/tan encapsulated nodules

40
Q

What species is thyroid follicular carcinomas most common in

A

dogs

41
Q

What are the gross and clinical signs of thyroid follicular carcinoma?

A

can be found in ectopic thyroid tissue

invasive - metastasize to the lungs

clinically:
- dyspnea
- voice change

42
Q

What is the main C/parafollicular disorder?

A

C/parafollicular cell tumors
- adenoma or carcinoma

43
Q

What species do C cell tumors affect the most?

A

old bulls

44
Q

What causes C cell tumors

A

may have dietary influences
- high calcium (dairy cow) diets fed to beef cows

45
Q

What disease is often concurrent with C cell tumors

A

pheochromocytoma or pituitary tumors

VETM 425 Sys Path (21 decks)

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