Endocrine 2 – Pituitary and Adrenal

Question 1

If have a tumor above pituitary (ex. in hypothalamus)

Answer 1

• Everything below it will be ‘stopped’/have complications
• *many effects

Question 2

GnRH to Somatotrophin: metabolic actions

Answer 2

• Protein synthesis
• Lipid metabolism
• Increased insulin resistance

Question 3

What can also stimulate somatotrophin production?

Answer 3

• Sleep stages III and IV
• Stress
• Many others

Question 4

Pituitary congenital anomalies

Answer 4

• Aplasia or hypoplasia: RARE
• Pituitary cysts
• Pituitary dwarfism

Question 5

Pituitary cysts

Answer 5

• Benign if NO changes to pituitary function
• *hard to get to cause surrounded by bone
  o Not many places it can go

Question 6

Pituitary dwarfism

Answer 6

• German shepherds
• *panhypopituitarism: effects all of the endocrine functions due to lack of signals to thyroid, adrenals and gonads
• Usually do not last to adulthood (especially in cats)

Question 7

What are the 2 forms of diabetes insipidus?

Answer 7

1. Hypophyseal form=central diabetes insipidus
2. Nephrogenic form

Question 8

Hypophyseal form (central diabetes insipidus)

Answer 8

• Any lesion that interferes with ADH synthesis OR secretion like damage to pars nervosa or hypothalamus

Question 9

Nephrogenic form (diabetes insipidus)

Answer 9

• Hereditary defects in ADH receptor or water channels in kidneys

Question 10

What does diabetes insipidus result in

Answer 10

• PU/PD
• Urine with low osmolality even after water deprivation
• *administration of exogenous ADH will lead to a rapid increase in urine osmolarity above that of plasma in hypophyseal form (BUT NOT in nephrogenic form)

Question 11

Neutrophil inflammation=abscess

Answer 11

• Sporadic in ruminants and pigs
• Bacteria
• Fugus (pyogranulomatous)

Question 12

Lymphoplasmacytic inflammation

Answer 12

• Smaller animals
• Viral or protozoan

Question 13

Pituitary hyperplasia

Answer 13

• Old sheep
• Hyperplasia of pars intermedia
  o Sometimes it may be an adenoma
• *usually no clinical signs
• Compression of adjacent tissue

Question 14

Corticotroph adenoma

Answer 14

• Pars distalis
• Secretes ACTH
• Bilateral hypertrophy of zona fasciculata (and zona reticularis) (CORTEX of adrenal glands)
• **TOO MUCH CORTISOL
• **Cushing’s disease

Question 15

Chromophobe adenoma

Answer 15

• Tumor grew upwards and compressed tissue around it
• **very little adrenal cortex (bilateral)
  o Other organs would be affected as well

Question 16

Pituitary pars intermedia dysfunction (PPID): horse

Answer 16

• PI cells produce excess POMC derived peptides
  o Varying levels of ACTH, CLIP, alpha-MSH, beta-endorphin
  o ACTH: may be biologically inactive
• Called Equine Cushing’s but it is NOT really Cushing’s
  o Horses do NOT get Cushing’s
• *it is a clinical syndrome

Question 17

**PPID: clinical syndrome

Answer 17

• PU/PD/PP
• Muscle atrophy, weakness
• Laminitis
• Hirsutism: rough hair coat
• Crested neck: altered fat deposition
• Flop sweats
• Hyperglycemia or hyper-insulinemia

Question 18

Craniopharyngioma

Answer 18

• Adenohypophysis and neurohypophysis destroyed
• Atrophy of thyroid and adrenal glands
  o Thyroid appears normal size, but is mostly colloid NOT active follicles

Question 19

Medulla : cortex ratio

Answer 19

• 1:2

Question 20

Adrenal secretions: cortex

Answer 20

• Mineralocorticoids: aldosterone (SALT)
• Glucocorticoids: cortisol (SUGAR)
• Adrenal androgens (SEX)

Question 21

Adrenal secretions: medulla

Answer 21

• catecholamines
  o NE
  o E
  o Dopamine

Question 22

Primary hypoadrenocorticism

Answer 22

• Bilateral idiopathic adrenal cortical atrophy
  o Destruction of all 3 cortical layers
• Bilateral destruction of adrenal glands

Question 23

Secondary hypoadrenocorticism

Answer 23

• Destructive pituitary lesions
• Iatrogenic
  o MOST COMMON CAUSE: sudden withdrawal of synthetic glucocorticoids treatment after prolonged usage
  o *atrophy of inner 2 zones

Question 24

What are the lesions of hypoadrenocorticism?

Answer 24

• Lethargy
• Stress intolerance
• Heart: bradycardia
• GI
• Skin: hyperpigmentation
• ***chemistry
  o Hyponatremia * hyperkalemia=hallmarks of ADDISON’S
• Metabolic: hypoglycemia, hemoconcentration

Question 25

Hyperadrenocorticism

Answer 25

• COMMON endocrinopathy in DOGS
  o Less in horses, rare in other animals
• OLDER dogs
  o Smaller with a big pot belly
• Combined gluconeogenic, lipolytic, protein catabolic and immunosuppressive effects of corticosteroids

Question 26

What are the lesions with hyperadrenocorticism?

Answer 26

• PU/PD/PP
• Hepatomegaly
• *pendulous abdomen
• Skin lesions: dermal atrophy, bilateral alopecia
• Dystrophic mineralization: lung, muscle, stomach
• Bacterial infections
• Clinical path test
  o Hypercoagulability, eosinopenia, lymphopenia

Question 27

What are the types of hyperadrenocorticisms?

Answer 27

1. Primary: 10-15%, functional cortical neoplasm or hyperplasia
2. Secondary: 80%
3. Iatrogenic: 5-10%

Question 28

Iatragenic Cushing’s

Answer 28

• Atrophy of cortex
• Long-term, daily administration of large doses of corticosteroids (exogenous)
• Decreased ACTH
• *why can get an Addisonian crisis if immediately remove the steroids=not able to function

Question 29

Glucocorticoid-induced hepatopathy

Answer 29

• Very bubbly histology
  o Glycogen being stored
• Yellow, brown liver (NOT icteric)
• Enlarged

Question 30

What is calcinosis cutis?

Answer 30

• White chalky material under the skin
• *mineral deposition

Question 31

Cortical carcinoma

Answer 31

• Atrophy of contralateral organ=due to cortical tumor producing cortisol
• *enlarged (carcinoma=looks angry)

Question 32

Pheochromocytoma

Answer 32

• Mainly in dogs, horses and cattle(seen in any species)
• Large and encapsulated
• *invades the vena cava and metastasize extensively (ex. liver cause that is where it goes first)
• Rarely functional, if so:
  o Secrete E and/or NE
  o Can cause tachycardia, edema and cardiac hypertrophy = how they present
• If hasn’t invaded vena cava and only one=can be removed and submitted for biopsy