Endocrine diseases

E. Simko WCVM

Zona glomerulosa -- Aldosterone

Zona fasciculata - Cortisol …

Zona reticularis - Dihydroepiandrosterone

Adrenal medulla

Testosterone Estradiol

Endocrine diseases

Most common in dogs

Clinical signs are predominantly due to lack of

aldosterone

E. Simko WCVM

(Addison’s dz)

Glomerular filtrate

Epithelium of distal nephron

Na+ Cl- H2O

K+H+

Endocrine diseases

Most common in dogs

Clinical signs are predominantly due to lack of

aldosterone

E. Simko WCVM

(Addison’s dz)

Glomerular filtrate

Epithelium of distal nephron

Na+ Cl- H2O

K+H+

Endocrine diseases - Hypoadrenocorticism

Clinical presentation:

• Hyponatremia, hypochloremia, dehydration

• Hyperkalemia, acidosis

• Weakness, depression

• Bradycardia

• Hypovolemia, shock

• “Great pretender”

E. Simko WCVM

Endocrine diseases - Hypoadrenocorticism

Diagnosis:

• Blood chemistry: Na, Cl, K

• CBC: PCV

• ACTH stimulation – no cortisol response

• Necropsy (if animal died)

E. Simko WCVM

Endocrine diseases

E. Simko WCVM

Most common in adult catsIncreased incidence since 1970

Awareness and detection

Change in life style of feline pets Etiology:

Nodular thyroid hyperplasia

Functional thyroid adenoma

Endocrine diseases - Hyperthyroidism

• Palpable mass(es) in one or both glands

• Increased basal metabolism

• Weight loss

• Hyperactivity

• Cardiomyopathy (Usually hypertrophic)

• Tachycardia

• Weakness when stressed

Changes

E. Simko WCVM

Endocrine diseases - Hyperthyroidism

• Clinical signs

• Palpable mass(es) in one or both glands

• Increased T4 & T3 blood concentration

Diagnosis

E. Simko WCVM

Endocrine diseases

E. Simko WCVM

• Physiology and endocrinology is complex.(Independent review)

• Pathology is relatively simple resulting in:Excessive hormonal productionInsufficient hormonal production

• Most commonly these disorders are due to proliferative lesions that are:

Functional and over produce hormonesCompressive and prevent normal production of hormones

Endocrine diseases - Pituitary gland

E. Simko WCVM

• ACTH secreting - Most common in dogs – Cushing’s dz

• Adenomas of pars intermediaMost common in horsesSecond most common in dogs

Endocrinologically inactiveACTH secreting

• Endocrinologically inactive adenomasCommon in dogs, cats, and rodentsCompression Pituitary dysfunction, CNS signs

Pituitary adenomas

Endocrine diseases - Pituitary gland

E. Simko WCVM

• Pars intermedia origin• Lesions are secondary to:

Thalamic compressionProduction of beta endorphinProbably due to ACTH

Pituitary adenomas in horses

Endocrine diseases - Pituitary adenomas in horses

E. Simko WCVM

Thalamic compression results in:• Intermittent pyrexia• Hyperhidrosis (Increased sweating)• Hirtuism (hypertrichosis) • Polyphagia with huperglycemia and

glycosuria• Polyuria/polydipsia

Production of beta endorphin• Docility• Diminished responsiveness to pain

Endocrine diseases - Pituitary gland

E. Simko WCVM

• Clinical signs• Glycosuria, glycemia• ACTH / cortisol concentration• MRI

Diagnosis

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

• Parathyroid hormone• Calcitonin (Thyroid C cells)• Vitamin D

Major regulators of Ca and P:

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

• Ca reabsorption from bone• P excretion by kidney• Formation of active Vit D by kidney• Ca absorption from gut and reabsorption from renal tubules (minor)

Ca PTH promotion of:

serum Ca, serum P, renal excretion of P

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

Ca Calcitonin :

E. Simko WCVM

• Inhibition of PTH stimulated bone absorption

• Increased P excretion by kidney

serum Ca, serum P

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

• Ca and P absorption by intestines

• May facilitate PTH action

(1,25-dihydroxycholecalciferol)

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

Intestinal Lumen

Renal tubulesUrine

Extracellular fluid

Bone

P

PTH +

Vit D +PTH +Ca

Ca

Calcitonin

Ca

Vit

D +

PT

H +

P

Cal

cito

nin

PT

H +

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

• NeoplasiasLymphoma Anal apocrine gland tumor (PTH-rP)

Tumors metastatic to bone • Hyperparathyroidism

Parathyroid functional neoplasia

• Vitamin D toxicity

Major clinical conditions:

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

Major clinical conditions:

• HypoparathyroidismParathyroiditisIatrogenic – excision with thyroid glands

• Nutritional hyperphophatemia• Renal failure• Milk fever• C-cell thyroid neoplasia

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

Primary: Parathyroid tumorsSecondary:

Renal failure Nutritional imbalance

Endocrine diseases – Calcium and Phosphorus

E. Simko WCVM

Secondary hyperparathyroidism:Nutritional imbalance ( P, Ca)

Renal failure

GFRVit D

HyperphosphatemiaHypocalcemia

Parathyroid hyperplasiaIncreased production of PTH

Ca reabsorption from bone

Osteodystrophy fibrosa

• Describe basic structure, function and

response to injury of CNS and PNS

• Define nomenclature of neuropathological

terms and conditions

• Describe pathogenesis of Wallerian

degeneration and axonal regeneration

• Define terminology of CNS traumatic injury

We know NS 1:

We know NS 2:

• Cytotoxic, osmotic and vasogenic brain edema)• Thiamine-responsive polioencephalomalacia of

ruminants

• Thiamine deficiency in carnivores

• Lead Poisoning

• Salt Poisoning

• Toxin-induced vasogenic brain edema

You should be able to define, describe pathogenesis,

list lesions and know how to diagnose the following

conditions:

We know NS 3: You should be able to define, describe pathogenesis,

list lesions and know how to diagnose the following

conditions:

•Meningitis

•ITEME

•Listeriosis

•TSE

•Rabies

•Distemper

•West Nile Viral encephalitis

•Equine protozoal encephalomyelitis

Define following conditions and give examples:• Denervation atrophy• Disuse atrophy• Malnutrition atrophy• Muscular hypertrophy• Ischemic myopathy

- Occlusion of the vascular system- External pressure on a muscle- Swelling of a muscle in a non-expandable compartment

We know Muscle 1:

E. Simko WCVM

Describe mechanisms of:• Muscular regeneration• Muscular repair

We know Muscle 2:

E. Simko WCVM

You should be able to define, describe pathogenesis, list lesions and know how to diagnose the following conditions/diseases:

• Nutritional myopathy (White muscle disease)• Toxic myopathy (Monensin toxicity)• Exertional myopathy• Gas gangrene and malignant edema• Blackleg• Botulism• Tetanus• Myasthenia gravis• Masticatory muscle myositis

We know Skin dz:

E. Simko WCVM

See STUDY GUIDE FOR SKIN

We know Endocrine dz:

E. Simko WCVM

• Endocrine dermatoses – see skin guide plus Adrenal neoplasms of ferrets

• Hypoadrenocorticism• Hyperthyroidism• Pituitary tumors

ACTH secreting in CaPars intermedia in Eq

• Ca & P metabolism• Hypocalcemia and hypercalcemia• Hyperparathyroidism