Endocrine System Flashcards
What breeds have adenohypophyseal hypoplasia as a genetic defect?
guernsey and jersey cattle
What plant causes cyclopia when ingested by pregnant sheep?
veratrum californicum (skunk plant)
Why is there prolonged gestation during fetal adenohypophyseal hypoplasia?
failure of fetus to convert pregesterone to estrogen surge
What causes pituitary cysts?
failure of rathke’s pouch to differentiate into pars distalis
What characterizes pituitary dwarfism?
slow growth, alopecia, hyperpigmentation of skin
What lesion is seen with pituitary cysts?
enlarging cyst in sella turcica and absence of adenohypophysis
What pituitary neoplasm is seen in young animals?
craniopharyngiomas
What 2 pituitary neoplams are seen in older animals?
adenomas and carcinomas
How can adenomas of the pituitary gland be distinguished from nodular hyperplasia?
large size and presence of a capsule
What is the most common pituitary neoplasm in horses?
adenomas of the pars intermedia
What are the sequlae of INACTIVE adenomas of the pars intermedia in dogs?
hypopituitarism and diabetes insipidus
What are the sequalae of ACTIVE adenomas of the pars intermedia in dogs?
cushings disease
What happens with adenomas of the pars intermedia in horses?
compression of hypothalamus –>PU/PD, hyperhidrosis, hypertrichosis (cushings)
What lesion will be seen in a dog with ACTH-secreting adenoma?
bilateral enlargement of the adrenal glands
What species have been seen with endocrinologically inactive chromophobe adenoma?
dogs, cats, rodents, parakeets
What is the sequlae of endocrinologically inactive chromophobe adenoma?
compression atrophy/space occupying lesion –> blindness
What is the sequlae of craniopharyngiomas in young animals?
failure to attain somatic maturation diabetes insipidis (no ADH) CNS dysfunction
Why do dogs with pituitary dwarfism have short life spans?
secondary endocrine dysfunction –>hypothyroidism, hypoadrenocorticocism
What pituitary neoplasm is functionally inactive but space occupying leading to panhypopituitarism in older dogs and cows?
pituitary gland carcinoma
What species get sporadic pituitary abscesses?
ruminants and swine
What is the cause of pituitary abscesses?
bacteria or mycotic agents
What form of diabetes insipidus interferes with the ADH synthesis or secretion?
hypophyseal form
What form of diabetes insipidus is a heriditary defect resulting in lack of adenylate cyclase in kidney?
nephrogenic form (cells don’t respond to ADH)
What can cause hypophyseal diabetes insipidus?
Growth disturbances that cause:
severance of infundibular stalk
or destruction of pars nervosa
When is hemorrhage of the adrenal cortex usually seen and what causes it?
newborn - trauma, severe stress, or septicemia/toxemia
What are the causes of adrenalitis?
Viruses - intranuclear inclusion bodies
Bacteria - gram negatives (myco–>granulomatous)
Fungi –> granulomatous
Parasites
What is the 2nd most common neoplasm reported in ferrets?
adrenal gland neoplasm
What is a risk factor for ferrets getting adrenal gland neoplasms? Why?
gonadectomized at an early age, chronic trophic stimulation of zona reticularis by LH
What are the 2 causes of primary hyperadrenocorticocism?
cortical neoplasm (esp. adenoma) idiopathic hyperplasia
What is the cause of secondary hyperadrenocorticism?
pituatary tumor
What can cause cushings besides primary, secondary, and iatrogenic?
ectopic cancer that produces ACTH
What is the cause of primary hypoadrenocorticism in young female dogs?
bilateral idiopathic adrenal cortical atrophy
What can cause bilateral destruction of the adrenal glands?
adrenalitis, infarction, hemorrhage, tumor
What is the pathogenesis of secondary hypoadrenocorticocism?
ACTH deficiency from pituatary lesion –> atrophyl of only the two inner zones (mineralcorticoids not affected)
What is the hallmark clinical sign of hypoadrenocorticism?
hyponatremia and hyperkalemia
What is the most common neoplasm of the adrenal medulla of animals?
pheochromocytoma
How can you diagnose a pheochromocytoma?
apply zenkers solution to freshly cut surface –> dark brown coloration after a few minutes
What animals get lymphocytic (immune mediated) thyroiditis?
dogs, obese strains of chickens, primates, buffalo rats
What are the lesions associated with lymphocytic thyroiditis?
infiltrate of lymps, plasma cells and macrophages
later replacement fibrosis, colloid vacuolated, may develop hypothyroidism
What are the causes of goiter(4)?
iodine deficient excess iodide goitrogenic compounds (brassica) genetic enzyme defects in hormone synthesis
What are the 4 morphological types of goiter?
Diffuse hyperplastic goiter
colloid goiter
multifocal nodular hyperplasia
congenital dyshormonogenetic goiter
What is the phase of goiter once hyperplastic goiter has been treated with iodide?
colloid goiter
What happens in colloid goiter that still causes it to be enlarged?
decreased endocytosis of colloid from lumen
Which species is multifocal nodular hyperplasia functional?
cats, the rest are nonfunctional
What kind of animals is multifocal nodular hyperplasia usually seen?
older animals
What molecule can’t be synthesized in congenital dyshormonogenetic goiter?
thyroglobulin
What species get follicular cell adenoma?
more common in cats than dogs and horses
What species commonly gets follicular cell carcinoma of the thyroid?
dogs
Where may follicular cell carcinomas arrise from in dogs
accessory thyroids - between base of tongue and cr. mediastinum
What is the cause of hyperthyroidism in dogs?
thyroid neoplasms
What is the cause of hyperthyroidism in cats?
many different lesions (adenomas and multinodular hyperplasia)
What are some of the symptoms of hyperthyroidism in cats?
restlessness, polyphagia, 2ry hypertrophic cardiomyopathy
What are the 2 causes of hypothyroidism in dog?
idiopathic follicular collapse/atrophy
lymphocytic thyroiditis
What are some of the CS associated with hypothyroidism?
hyperkeratosis, alopecia, myxedema, infertility
What can lead to arthrosclerosis in hypothyroidism?
hypercholesterolemia (decreased lipid metabolism)
What breeds get lymphocytic parathyroiditis?
adult dogs - schnauzers and terriers
What is thought to be the cause of lymphocytic parathyroiditis?
immune mediated
What are the 2 forms of hypoparathyroidism?
lymphocytic parathyroiditis
parturient paresis
What is the cause of parturient paresis?
fed high calcium diet before parturition
anorexia from estrogen
What are symptoms of dogs with lymphocytic parathyroiditis?
neuromuscular excitiabilty, blood P are increased (reabsorbed from tubules)
What are the lesions associated with lymphocytic parathyroiditis?
extensive degeneration of chief cells and replacement fibrosis
What are the 3 causes of primary hyperparathyroidism?
parathyroid hyperplasia
parathyroid adenomas
parathyroid carcinomas
What cells does primary hyperparathyroidism effect?
functional neoplasms of CHIEF cells
What are the sequlae of primary hyperparathyroidism?
excess PTH –> osteolytic/clastic bone resorption –>fibrous osteodystrophy
How is primary hyperparathyroidism diagnosed?
total blood calcium and phosphorus, circulating PTH
What are the 2 types of secondary hyperparathyroidism?
secondary to nutrition
secondary to renal disease
What causes nutritional secondary hyperparathyroidism?
generally low calcium, high phosphorus diets (bran, meat)
What species get hyperparathyroidism due to renal disease?
cats and dogs
What are the lesions associated with secondary renal hyperparathyroidism?
bilateral enlargement of parathyroids
big head in horses, rubber jaws in dogs and cats
How can renal disease causes secondary hyperparathyroidism?
decreased renal degradation of PTH resulting in less Ca uptake in intestine (from renal disease)
What causes hypercalcemia and hypophosphatemia in pseudohyperparathyroidism?
imbalance of Ca released from bones, Ca excreted by kidneys, or Ca absorbed from GI
What are the 3 mechanisms that can cause pseudohyperparathyroidism?
humoral hypercalcemia of malignancy (humoral factors) (HHM)
metastases of solid neoplasms to bone (local bone resorption)
hematologic malignancies (lymphosarcoma, multiple myeloma)
What causes hypercalcemia in lymphosarcomas in dogs and cats?
production by neoplastic cells of humoral substances
What kind of dogs is adenocarcinomas of apocine glands of anal sacs seen? (causes pseudohyperparathyrodism)
female dogs
What cells of the pancreas produce somatostatin?
delta cells
Does diabetes cause acidosis or alkalosis?
acidosis
What virus can cause diabetes in cattle?
FMD
What is type 1 diabetes caused by?
destruction of beta cells -> progressive loss of insulin
What is the pathogenesis of type 2 diabetes?
insulin resistance
What is the cause of secondary diabetes melitus?
antagonism in peripheral tissues between insulin and other hormones
What hormones can cause secondary diabetes?
glucagon, growth hormone, glucocorticoids
What type of diabetes mellitus do dogs get?
type 1
What happens to the islets of the pancreas of type 2 diabetes in cats?
amyloidosis of islets
severe vaculoation of islet beta cells –> exhaustion
what is hepatocutaneous syndrome associated with?
glucagonomas
What is another name for chemoreceptor organs?
nonchromaffin paraganglia
In animals, are aortic body tumors or carotid body tumors more common?
aortic body tumors
How do aortic body tumors cause damage?
space occupying in pericardium
What should aortic bodies be differentiated from as a heart base tumor?
tumor of ectopic thyroid
Are carotid body tumors unilateral or bilateral usually?
unilateral
How many “heart base tumors” are from ectopic thyroid gland tissue?
5 to 10%
How do ectopic thyroid gland tumors cause damage?
compress or invade cr. mediastinum near base of heart
What are the 3 diseases associated with adenohypophyseal hyperfunction?
cushings
hyperthyroidism
gigantism/acromegaly
What are 3 diseases that are from adenohypophyseal hypofunction?
addisons hypothyroidism dwarfism anestrus ovarian follicular cysts
What is a disease associated with neurohypophyseal hypofunction?
diabetes insipidus
