3.7 Pathology Of The Endocrine System

Front 1

Endocrine glands synthesize, store, & directly release their secretory products into the ___, resulting in physiological effects on target cells.

Back 1

Blood stream

Front 2

The ___ → anterior pituitary gland → releases TROPHIC hormones → specific endocrine glands → release hormones → exert ultimate actions on downstream tissues.

Back 2

Hypothalamus

Front 3

The pars ___ is the largest portion and produces most hormones.

Back 3

Distalis

Front 4

1. The Anterior pituitary is composed of:
2. The Posterior pituitary is composed of:
3. The pituitary gland is located in the ___ of sphenoid bone.

Back 4

1. Pars distalis, Pars intermedia, Pars tuberalis
2. Pars nervosa, Infundibular stalk
3. Sella turcica

Front 5

Cyst from failure of differentiation of oropharyngeal ectoderm of Rathke's pouch → complete or partial abscence of pars distalis & compression of neurohypophysis
Dx:

Back 5

Pituitary cyst of Rathke's pouch

Front 6

Pituitary cyst of Rathke's pouch → ___ (which is more COMMON in German Shepherds)

Back 6

Pituitary dwarfism (Juvenile panhypopituitarism)

Front 7

Identify the lesion and what does it lead to?
Lesion:
Causes:

Back 7

Lesion: Pituitary cyst
Causes: Pituitary dwarfism (Juvenile Panhypopituitarism)

Front 8

Both shepherds are of same age but the one in the foreground is developing abnormally.
Dx:

Back 8

Dx: Pituitary dwarfism (Juvenile Panhypopituitarism); will see stunted growth with partial alopecia

Front 9

5-month old German Shepherd dog with areas of alopecia.
Dx:

Back 9

Dx: Pituitary dwarfism (Panhypopituitarism)

Front 10

What is the lesion?

Back 10

Pituitary abscess

Front 11

How does a pituitary abscess originate?

Back 11

Bacteria/mycotic agent (secondary to hematogenous spread)

Front 12

The pituitary gland is notably enlarged because of an ___ of the ___ in horses. This neoplasm is associated with failure of hair shedding also known as ___.

Back 12

Adenoma/pars intermedia/Hirsuitism

Front 13

This horse is experiencing HIRSUITISM due to to an ___ of the ___.

Back 13

Adenoma/pars intermedia

Front 14

Horses affected with pituitary adenomas of the pars intermedia also present with...

Back 14

Polyphagia (affects satiety center)
Hyperadrenocorticism (Equine Cushings Disease)
PU/PD (no absorption of osmoles)
Laminitis

Front 15

Hyperadrenocorticism in dogs is caused by a pituitary ___ of the ___.

Back 15

Adenoma/pars distalis (Functional Chromophobe ("Corticotroph") Adenoma in Pars Distalis)

Front 16

Identify the lesion.
Lesion:

Back 16

Lesion: Pituitary adenoma

Front 17

What is the result of compression/destruction of the pars nervosa, infundibular stalk or supraoptic nucleus of the hypothalamus?

Back 17

Central (Hypophyseal form) Diabetes Insipidus

Front 18

What type of diabetes develops when target cells in the kidney LACK the biochemical pathways necessary to respond to ADH?

Back 18

Nephrogenic Diabetes Insipidus

Front 19

What hormone regulates the retention of water → ↑[urine] & reducing urine output?

Back 19

ADH aka vasopressin

Front 20

1. Administer ADH → ↑[urine], then Dx:
2. Administer ADH → NO ↑[urine], then Dx:

Back 20

1. Central Diabetes Insipidus
2. Nephrogenic Diabetes Insipidus (Defects in ADH receptors)

Front 21

Mnemonic to remember layers of adrenal glands and what they produce:

Back 21

Front 22

What cells of the adrenal medulla synthesize catecholamines, epinephrine & norepinephrine?

Back 22

Pheochromocytes (chromaffin cells)

Front 23

A common endocrinopathy in dogs with clinical signs associated with ↓corticosteroids (salt, sweet, sexy) including:
Hyperkalemia
↓gluconeogenesis
↑sensitivity to insulin

Back 23

Hypoadrenocorticism

Front 24

Rare adrenocortical hemorrhage as a consequence of overwhelming sepsis in horses.

Back 24

Waterhouse-Friderichsen syndrome

Front 25

The result of ischemia & fibrosis of Waterhouse-Friderichsen syndrome is ___ in horses.

Back 25

Hypoadrenocorticisim

Front 26

1. What agent is the most common cause of embolic suppurative nephritis/glomerulitis in foals?
2. In foals, adrenal hemorrhage is often a complication of bacterial sepsis, ___.

Back 26

1. Actinobacillus equuli
2. Waterhouse-Friderichsen syndrome

Front 27

A common endocrinopathy in ADULT/AGED dogs and infrequent in cats most commonly associated with a FUNCTIONAL CORTICOTROPH (ACTH-producing) PITUITARY ADENOMA.

Back 27

Hyperadrenocorticism

Front 28

In dogs, the pituitary adenoma is found in the pars ___, while in equine it is found in the pars ___.

Back 28

Distalis/Intermedia

Front 29

This dog presented with the following clinical signs:
Lordosis
Bilateral alopecia
PU/PD
Dx:

Back 29

Dx: Hyperadrenocorticism

Front 30

Why do dogs with Cushing's disease develop PU/PD?

Back 30

Cortisol interferes with the release of ADH.

Front 31

Pendulous abdomen ("potbelly appearance")
Cause?

Back 31

Cause: Hyperadrenocorticism→
↑Cortisol → Hyperglycemia (↓Glu intake) → Mobilization of fat/ **Muscle asthenia & Wasting** → **Hepatomegaly** & obesity

Front 32

Edx:
Cause?

Back 32

Edx: Steroid hepatopathy
Cause: Cushing's disease

Front 33

What are some immunosuppressive effects that arise from excessive cortisol?

Back 33

・↓inflammatory mediators
・Inhibition of inflammatory cell migration
・Promotion of APOPTOSIS in leukocytes
・Inhibition of fibroblasts (affecting wound healing)

Front 34

Non-pruritic bilateral symmetrical alopecia
Pendulous abdomen
Dermatitis
Dx:

Back 34

Dx: Hyperadrenocorticism/Cushion's disease with atrophic dermatopathy

Front 35

1. In approximately 30% of patients with hyperadrenocorticism may develop gritty & firm lesions. Name this condition.
2. What stain is used to confirm this?

Back 35

1. Name: Calcinosis Cutis (idiopathic)
2. Von Kossa stain

Front 36

Calcinosis cutis is diagnostic for...

Back 36

Hyperadrenocorticism

Front 37

What is the result of
・↓synthesis of vasodilator prostaglandins
・↑secretion of aldosterone
in animals with hyperadrenocorticism?

Back 37

Hypertension → CHF, glomerulopathy, IO hemorrhage with retinal detachment

Front 38

A complication arising due to a change in coagulable state (Hypertension → glomerulopathy)?

Back 38

Pulmonary thrombosis

Front 39

Cause of hyperadrenalcorticism in this dog?
Mdx:

Back 39

Cause: Since both are enlarged, we suspect
・PITUITARY ADENOMA
・IDIOPATHIC HYPERPLASIA
Mdx: Bilateral adrenal hyperplasia

Front 40

Cause of hyperadrenalcorticism in this dog?

Back 40

Cause: Since both are enlarged, we suspect
・PITUITARY ADENOMA
(ACTH-secreting Chromophobe Pituitary Adenoma)

Front 41

Tumor arising from adrenal cortex with ATROPH of the unaffected contra-lateral gland.
Dx:

Back 41

Dx: Adrenocortical adenoma

Front 42

Tumor arising from adrenal cortex with ATROPHY of the unaffected contra-lateral gland.
Name this lesion.

Back 42

Adrenocortical carcinoma

Front 43

Hyperplastic a adrenal cortex with NORMAL contra-lateral gland.
Name this lesion & significance.

Back 43

Name: Adrenocortical hyperplasia
Significance: Age-related

Front 44

1. This tumor is more common in cattle & dogs and develop concurrently with calcitonin-secreting thyroid C-cell tumors.
2. What diagnostic feature will help us conclusively diagnose it?

Tumor name (in adrenal medulla):
Diagnostic feature:

Back 44

Tumor name (in adrenal medulla): Pheochromocytoma
Diagnostic feature: It has a tendency to invade the CAUDAL VENA CAVA

Front 45

Dx:
Diagnostic feature:

Back 45

Dx: Pheochromocytoma
Diagnostic feature: It has invaded the CVC

Front 46

Functional pheochromocytomas (RARE) produce what clinical features?

Back 46

Tachycardia
Cardiac hypertrophy
Hypertension

Front 47

Non-pruritic bilateral symmetrical alopecia
Lethargy
Weight gain
***Myxedema (accumulation of glycosaminoglycans (GAGs (thyroid hormone inhibits GAG accumulation)) = "Tragic" Facial Expression*** = diagnostic
Dx:

Back 47

Hypothyroidism

Front 48

___ is associated with ___.

Back 48

Coronary atherosclerosis/Hypothyroidism

Front 49

Lesion:
Dx:

Back 49

Lesion: Coronary atherosclerosis
Dx: Hypothyroidism

Front 50

What are the MOST COMMON causes of hypothyroidism in dogs?

Back 50

· Idiopathic Follicular (produce TGB) atrophy
· Lymphocytic (immune-mediated) Thyroiditis

Front 51

___ is the prominent skin folding over the eyes resulting from the accumulation of glycosaminoglycans (GAGs) (thyroid hormone inhibits GAG accumulation) & hyaluronic acid. This is diagnostic for ____.
Name:
Diagnostic for:

Back 51

Name: Myxdema/"Tragic" Face
Diagnostic for: Hypothyroidism

Front 52

Histological findings: Thyroglobulin replaced by lymphocytes & adipose tissue. This leads us to suspect ___ leading to ___.

Back 52

***Lymphocytic (immune-mediated) Thyroiditis*** (probably most common cause of hypothyroism in dogs)/Hypothyroidism

Front 53

What should we examine closely for subtle changes during necropsy that will CONFIRM hypothyroidism?

Back 53

Coronary atherosclerosis

Front 54

Define goiter:

Back 54

Benign conditions in which the thyroid gland enlarges and swells.

Front 55

NON-NEOPLASTIC & NON-INFLAMMATORY enlargement of the thyroid gland (can be secondary to ↓iodine in mother's feed).
Dx:

Back 55

CONGENITAL Goiter (Goats)
Thyroid Hyperplasia Secondary to CONGENITAL Iodine Deficiency (Bovine)
(↓T3/T4 = ↑TSH)

Front 56

Findings at necropsy: Active/Inactive in the following,
Cats:
Dogs, Horses,:
Mdx:

Back 56

Cats: Active (→ hyperthyroidism)
Dogs, Horses,: Incidental
Mdx: Bilateral thyroid hyperplasia

Front 57

Name 2 causes of hyperthyroidism in cats:

Back 57

· Thyroid Adenoma
· Nodular Thyroid Hyperplasia (type of goiter but ASYMMETRICAL)

Front 58

1. Hyperthyroidism is associated with ___ in cats.
2. What clinical signs are associated with hyperthyroidism in cats?

Back 58

1. Hypertrophic Cardiomyopathy (HCM)
2. PU/PD, weakness, ↑rate of BASAL metabolism, ↑appetite but losing weight.

Front 59

Post-mortem finding in the thyroid glands of a horse.
Mdx:
Functional/Non-functional?

Back 59

Mdx: Thyroid Adenoma (well-demarcated)
Functional/Non-functional? Non-functional (functional only in cat)

Front 60

Post-mortem finding in the thyroid glands of a horse.
Mdx:

Back 60

Mdx: Thyroid Carcinoma (Invasive & non-functional)

Front 61

Thyroid carcinomas tend to metastisize to the ___.

Back 61

Lungs

Front 62

Post-mortem finding.
Mdx:

Back 62

Thyroid carcinoma with pulmonary metastases

Front 63

Name 2 causes of hypoparathyroidism in dogs (particularly in smaller breeds):

Back 63

· ***Lymphocytic parathyroiditis*** (Thyroid: Lymphocytic thyroiditis)
· Accidental removal of PT glands during thyroid SX.

Front 64

What clinical signs are associated with hypoparathyroidism in dogs?

Back 64

· ↑NM excitability, tremors, & tetany
· Generalized tetany
· HYPOCALCEMIA ([L] of PTH) & HYPERPHOSPHATEMIA (↑renal tubular reabsorption of P)

Front 65

Post-mortem finding around the thyroid glands of a dog. What can this lead to?
Dx:

Back 65

Dx: Parathyroid adenoma → Primary Hyperparathyroidism → Fibrous osteodystrophy [R] (↑osteoclast activity → loss of bone → replacement by fibrous connective tissue)

Front 66

What may cause BILATERAL enlargement of the PT glands?

Back 66

Secondary Hyperparathyroidism
1. Low Ca/ High P DIETS (→ ↑PTH secretion)
2. Renal dz (→ ↑P → ↑PTH secretion → ↑Ca)

Front 67

Describe the pathogenesis of humoral hypercalcemia of MALIGNANCY:

Back 67

Anal sac apocrine gland carcinoma/lymphosarcoma → PTHrp → ↑Ca (PSEUDOHYPERPARATHYROISM/paraneoplastic hypercacemia)

Front 68

Bone metastases → ↑Ca
Is this considered a paraneoplastic syndrome?

Back 68

No

Front 69

Overstimulation/exhaustion of β CELLS →

Back 69

Hydropic degeneration w/ glycogen accumulation (Vacuolar degeneration) of pancreatic islets → DM

Front 70

Name the 2 types of primary diabetes:
Name 2 ways secondary diabetes can arise:

Back 70

1. Type I (IDDM) (insulin deficient)
Type II (NIDDM) (insulin resistant) = more common
2. Infectious diseases (pancreatitis, destruction of islets), Gestational diabetes

Front 71

Persistent hyperglycemia & formation of ADVANCED GLYCOSYLATION END PRODUCTS → vascular injury

Back 71

Glomerulosclerosis (diabetic nephropathy)

Front 72

Glucose metabolized in the lens → accumulation of large amounts of sugar alcohols (GLYCOSYLATION END PRODUCTS) → hypertonicity & opacity of lens

Back 72

Diabetic cataracts

Front 73

Obese rats → mutation in leptin receptor gene (stimulates satiety) →

Back 73

Abnormal food intake → Hepatic lipidosis

Front 74

DM in dogs is often the sequel of ___.

Back 74

Pancreatitis (enough damage to pancreatic islets → DM)

Front 75

What lesions are typically see in diabetic cases?

Back 75

· Cataracts (bilateral)
· Chronic renal disease (pyelonephritis, renal papillary necrosis, glomerulosclerosis = diabetic nephropathy)
· Pancreatitis (necrotizing, acute-chronic) → pancreatic atrophy
· Coronary atherosclerosis

Front 76

___ is a protein normally produced in the beta cells of the pancreas along with insulin, as a response to high blood sugar. The high blood sugar temporarily suppresses beta cell insulin production, so that little insulin is made, but this substance continues to be produced building up and accumulating in the pancreas.

Back 76

Islet amyloid polypeptide (IAPP)

Front 77

Build up of glucose → microvascular damage → demylination due to ↓perfusion → plantigrade stance in cats.
Dx:

Back 77

Diabetic neuropathy

Front 78

Neoplasm arising from β cells & benign → hypoglycemia.
Dx:

Back 78

Insulinoma (functional tumor)

Front 79

Neoplasm found at base of heart:
Significance?

Back 79

Neoplasm: Chemodectoma (neoplasm on RA = HSA)
Significance: Incidental finding