Disorders of Anterior Pituitary Gland Flashcards
Cells Found in TSH
Thyrotropic cells
Cells found in Prolactin (PRL)
Mammatropic
Cells found in ACTH
Corticotropic cells
Cells found in Growth Hormone (GH)
Somatotropic cells
Cells found in LH and FSH
Gonadotropic cells
Cells found in Melanocyte-stimulating hormone (MSH)
Pars intermedia cells
TSH regulates secretion of what hormones
T3 and T4
Increased activity of the thyroid gland
Hyperthyroidism
state of thyroid hormone excess
Thyrotoxicosis
Differentiate thyrotoxicosis and hyperthyroidism
Thyrotoxicosis is defined as the state of thyroid hormone excess and is not synonymous with hyperthyroidism, which is the result of excessive thyroid function
If the problem is at the level of the pituitary gland it is considered
Secondary hyperthyroidism
Cause of Primary hyperthyroidism
Primary thyroid gland disease (Grave’s disease)
Cause of secondary hyperthyroidism
TSH secreting adenoma, Pituitary resistance to thyroid hormone
TSH level in Primary HyperT
Decreased
TSH level in secondary hyperT
Normal or elevated
In primary hyperthyroidism, why is there increased thyroid gland activity and increased thyroid hormone formation?
because there is a disease that primarily involves the thyroid gland making it produce more hormones
Most common primary thyroid gland disease
Grave’s disease
T or F TSH is responsible for the increased thyroid hormone production in Grave’s disease
False: The body produces an antibody that acts on the cells of the thyroid gland and stimulates it to produce hormones independent of the levels of the TSH
Primary hyperT due to Grave’s dse is usu associated with
Exophthalmia
Why is the bulging of the eyes found more on primary hyperT than 2nd
because it is due to stimulation by the same antibodies that stimulate the thyroid gland. It is not TSH induced but antibody induced.
Why is there bulging of the eyes in primary hyperT
There is sympathetic stimulation that causes retraction of the lids
What is the normal response of a normal pituitary gland to a high level of thyroid hormone
To decrease it, if there’s high thyroid hormone level and TSH is still normal then it means that it’s abnormal
Most common cause of central/secondary hyperthyroidism
TSH secreting adenoma
What happens if there’s TSH secreting adenoma
There’s increased TSH secretion that stimulates increase thyroid hormone production but the adenoma is abnormal
If you find normal levels of TSH but there’s high T3 and T4 what would be your diagnosis
There’s Pituitary resistance to thyroid hormone
Low thyroid hormone secretion
Hypothyroidism
Cause of primary HYPOthyroidism
Thyroiditis or autoimmune disorders
Cause of Secondary HYPOthyroidism
Lymphocytic hypophysitis, Sheehan’s syndrome
Level of TSH in primary HYPOt
Increased
Level of TSH in secondary HYPOt
Normal or low
Most common cause of primary hypothyroidism
Autoimmune Thyroiditis
inflammation that results in the destruction of the thyroid gland
Thyroiditis
Cardiac drug that may cause hypothyroidism
Amiodarone
Substrate for thyroid hormone production
Iodine
Why is there enlarged goiter in cases of primary hypothyroidism
There’s increase stimulation of the thyroid gland but no concomitant increase production of thyroid hormone production
ACTH promotes the secretion of
Cortisol
Cortisol is secreted by what cells
Zona fasciculate
Differentiate cushing’s syndrome from cushing’s disease
Cushing’s syndrome reflects a constellation of clinical features that result from chronic exposure to excess glucocorticoids of any etiology while Cushing’s Disease: increased cortisol secretion because of a problem at the level of the pituitary gland
In secondary hypercortisolism the problem is at the level of the
Pituitary gland
Cushing’s disease is primary or secondary hypercortisolism?
Secondary
Cause of primary HYPERcort
Cortisol secreting adrenal adenoma
Cause of secondary hypercortisolism
Acth-secreting adenoma
Ectopic acth is more frequently identified in M or F
M
Most common cause of cushing’s syndrome
Glucocorticoids for immunosuppression or for treatment of inflammatory d/o
This refers to cushing’s syndrome caused by a pituitary corticotrope adenoma
Cushing’s dse
T or F Cushing’s disease affects more frequently in women in all ages
False, It does affects women except in prepubertal where it’s more common in boys
Potent glucocorticoid that suppresses CRH/ACTH and endogenous cortisol
Dexamethasone
Used to rule out pseudocortisolism
Low dose dexam
Used to distinguish pituitary from adrenal
High dose dexam
Addison’s disease is considered hypo or hypercortisolism?
Primary Hypocortisolism
Hyperpigmentation can be seen in primary or sec hypocortisolism
Primary
consequence of dysfunction of the hypothalamic-pituitary component of the HPA axis
Secondary hypocortisolism
Why is there no hyperkalemia in secondary hypocortisolism
RAA controls secretion of aldosterone therefore no matter what happens at the level of pituitary, aldosterone is not affected
Hyperkalemia and hyperpigmentation is only manifested in primary or secondary Hypocortisolism?
Primary hypocortisolism
In what group of women does lymphocytic hypophysitis most often occur?
Postpartum
How does post partum hemorrhage lead to sheehan’s syndrome
The pituitary enlarges in pregnancy thus it requires more blood, if there’s hemorrhage it could lead to hypotension so it may compromise blood supply to the pituitary and can lead to necrosis
Most common manifestation of sheehan’s syndrome
Lactation failure
protein hormone of about 190 amino acids that is synthesized and secreted by cells called somatotrophs in the anterior pituitary.
Growth hormone
What are some stimulators of GH secretion
GHRH, exercise and low lvls of blood sugar
2 hormones which manage gh secretion
GHRH and somatostatin
Somatostatin inhibits gh secretion in response to lvls of
IGF-1 (insulin like growth factor 1)
hormone released when you are awake at a time when you should be sleeping. It stimulates appetite and leads to weight gain.
Ghrelin
result of excessive growth hormone secretion that begins in young children or adolescents.
Gigantism
elevated IGF-I level in a patient with appropriate clinical suspicion is almost always indicative of
Acromegaly
This procedure generally results in a rapid and substantial reduction of serum GH levels immediately
Surgical excision
Non surgical treatment for acromegaly would include
Somatostatin analogs or dopamine agonists and radiotherapy
Difference btn achrondroplastic dwarf and pituitary dwarf
In achrondroplastic dwarf, there’s no prob in GH secretion
T or F in pituitary dwarfism there’s maintenance of the symmetry of the features
True
Relatively long trunk and shortened upper parts of their arms and legs is a feature of
Achrondoplasia
T or F random lvls of GH is the gold standard for the diagnosis of GH deficiency )
False, it is not useful, the gold standard is ITOT: Insulin TOlerance Test (ITT na..hehe
If there’s severe GH deficiency, what is the peak GH response in ITT
<3mcg/L
Secretion of prolactin is regulated by
Hypothalamus, predominantly dopamine
Prolactin is secreted by
Lactorophs
What stimulates prolactin secretion
Estrogen
Why is there increased prolactin during pregnancy
Due to high lvls of estrogen
Agent of choice for prolactinoma
Bromocriptine (BEC) it’s a dopamine agonist that decreases the synthesis and secretion of PRL
Btn transphenoidal and transcranial which one is more preffered?
Thransphenoidal
