Endocrine System Pathology 2

Question 1

What is primary hyperthyroidism caused by?

Answer 1

Functional nodular hyperplasia or neoplasia of one or both thyroids

Question 2

In feline hyperthyroidism, what proportion of cats have bilateral disease?

Answer 2

<70% of cases

Question 3

What are the most common types of thyroid neoplasias in dogs?

Answer 3

Carcinomas are much more common than adenomas

Question 4

What is the main species affected by hyperthyroidism?

Answer 4

Cats

Question 5

What are the two main causes of primary hypothyroidism in dogs?

Answer 5

Lymphocytic thyroiditis
Idiopathic follicular atrophy

Question 6

What is lymphocytic thyroiditis?

Answer 6

Autoantibodies against thyroid follicular cell antigens

Question 7

List and briefly describe the uncommon mechanisms of hypothyroidism in dogs

Answer 7

Destruction of the thyroid glands - bilateral thyroid neoplastic disease
Secondary hypothyroidism - pituitary lesions causing insufficient release of TSH

Question 8

What is the main species of hypothyroidism?

Answer 8

Dog

Question 9

What is the normal biological action of parathyroid hormone in the kidney, bone and GI tract?

Answer 9

Kidney - increases calcium reabsorption and decreases phosphorus reabsorption. Actiavtion of calcitriol synthesis.
Bone - resorption by osteoclasts, mobilisation of calcium.
GI tract - promotes absorption of calcium

Question 10

What are the four mechanisms of hyperparathyroidism?

Answer 10

Primary hyperparathyroidism
Parathyroid hormone-related protein production by neoplasms
Hyperparathyroidism secondary to chronic kidney disease
Hyperparathyroidism secondary to nutritional imbalances

Question 11

What causes primary hyperparathyroidism?

Answer 11

Functional chief cell adenoma or focal/multifocal nodular hyperplasia or chief cell carcinoma

Question 12

What is the cause of pituitary pars intermedia dysfunction? (PPID)

Answer 12

Pars intermedia hyperplasia and adenoma formation follwoing decreased dominergic inhibition.
Increased production of POMC-derived hormones/compressive or destructive effects on the pituitary and the hypothalamus

Question 13

What is diabetes insipidus?

Answer 13

Inability of the kidneys to concentrate urine due to loss of functional effects of antidieuretic hormone.

Question 14

What are the two mechanisms of diabetes insipidus?

Answer 14

Insufficient ADH production or release from the hypothalamus/pituitary (central diabetes insipidus)
Renal tubules insensitive to ADH (nephrogenic diabetes insipidus)

Question 15

What causes central diebetes insipidus?

Answer 15

Injury/destruction of the hypothalamus or pituiatry

Question 16

What is acromegaly caused by?

Answer 16

Growth hormone (somatotropin) secretion by a functional pituitary tumour, usually an adenoma.

Question 17

What is the main species affected by acromegaly?

Answer 17

Cat