[09.04] Hypothalamic-Pituitary Disorders V2.pdf

Prolactin, GH, ACTH, LH, FSH, and TSH

What are the six major hormones produced by the anterior pituitary?

Trophic hormones

What is the term for pituitary hormones that elicit specific responses in peripheral target tissues?

Adrenal, thyroid, and gonads

Name three peripheral target glands regulated by pituitary trophic hormones.

Feedback control

Peripheral gland products modulate pituitary function through what mechanism?

Primary hormone excess

What condition is characterized by increased target organ hormone and decreased trophic hormone?

The target organ

In primary hormone excess, which structure is no longer responsive to regulatory function?

Secondary hormone excess

What condition is characterized by both increased trophic hormone and increased target organ hormone?

Primary hormone deficiency

What condition is characterized by decreased target organ hormone and increased trophic hormone?

Primary hormone deficiency

Which is typically more symptomatic: primary or secondary hormone deficiency?

Secondary hormone deficiency

What condition is characterized by both decreased trophic hormone and decreased target organ hormone?

Functional target organ

Why is secondary hormone deficiency often less severe than primary?

Which hormone is affected and age of onset

The presentation of a pituitary disorder depends on what two factors?

Gigantism

What syndrome results from excess growth hormone in childhood while growth plates are open?

Acromegaly

What syndrome results from excess growth hormone in adulthood after growth plates close?

Prolactin

Which hormone is hypersecreted in a lactotrope adenoma?

GH

Which hormone is hypersecreted in a somatotrope adenoma?

Cushing's syndrome

What clinical syndrome results from a corticotrope adenoma?

Thyrotoxicosis

What clinical syndrome results from a thyrotrope adenoma?

None

What hormone is secreted by a null cell adenoma?

Pituitary failure

What is the clinical syndrome associated with a null cell adenoma?

Single cell origin

Why can acidophil stem cells produce both GH and PRL?

Abrupt change

In terms of timing, what rate of onset makes symptoms more observable or worse?

Adrenal insufficiency

Name a condition mentioned where symptoms may be felt slowly over time.

Inadequately produced

Hypopituitarism occurs when pituitary hormones are what?

Inappropriately normal

What term describes a TSH value that is technically in the normal range but fails to increase despite low thyroid levels?

Transcription factor defect

Name one inherited developmental cause of hypopituitarism.

Septo-optic dysplasia, Prader-Willi, and Kallmann syndrome

Name three congenital hypothalamic disorders leading to hypopituitarism.

Traumatic

What is the most common acquired etiology of hypopituitarism?

Bleeding or infarction

Vascular causes of hypopituitarism involve what two processes?

Tuberculosis

Name an infectious cause of hypopituitarism mentioned in the source.

Lymphocytic hypophysitis

Name an inflammatory etiology of hypopituitarism.

Pituitary apoplexy

What is the term for a vascular event causing sudden pituitary dysfunction?

Postpartum necrosis

What specifically is Sheehan syndrome?

Enlargement of the gland

Why does pregnancy increase the risk of pituitary infarction?

GH > FSH > LH > TSH > ACTH

What is the specific sequence of functional loss in progressive hypopituitarism?

Growth hormone

Which hormone is the first to lose function in hypopituitarism?

TSH and ACTH

Which two hormones are the last to be affected in hypopituitarism?

Dwarfism

How does GH deficiency manifest in childhood?

Stunting of growth

What is the most observable manifestation of childhood hypopituitarism?

Pituitary irradiation

What treatment can result in long-term hypothalamic-pituitary dysfunction over 5 to 15 years?

Children and adolescents

Which age groups are most sensitive to head and neck irradiation?

Dose, time interval, and distance from energy field

What three factors influence the risk of hypopituitarism after irradiation?

Arachnoid herniation into the sella

What is the cause of primary empty sella?

Filled with CSF

How does the sella appear in empty sella syndrome?

Secondary empty sella

What term describes an empty sella resulting from adenoma infarction or surgery?

More than 90 percent

What percentage of pituitary tissue must be compressed to cause failure in empty sella?

Somatic mutation

Pituitary adenomas typically arise from what type of mutation in a progenitor cell?

Non-functioning type

What is the most common type of pituitary adenoma overall?

Negative regulatory feedback

Unlike other cell lines, lactotrophs are usually in what state?

Breastfeeding

What is the primary function of lactotroph cells?

Inhibit reproduction and suppress sexual drive

Besides milk production, what are two functions of prolactin?

Dopamine

Which substance provides normal inhibitory control of lactotroph cells?

D2 receptors

Dopamine inhibits prolactin by stimulating which specific receptors?

Tuberoinfundibular and tubulohypophyseal systems

Dopamine comes from which two systems in the brain?

Lactotrophs go free

What happens to prolactin levels if the connection between the hypothalamus and pituitary is severed?

Pregnancy and lactation

Name two physiologic states where prolactin is elevated.

Chest wall stimulation, sleep, and stress

Name three non-reproductive physiologic causes of elevated prolactin.

Dopamine receptor blockers

What class of drugs, including Haloperidol and Metoclopramide, causes hyperprolactinemia?

Estrogen

Which hormone can stimulate the formation of lactotroph cells and prolactin production?

Prolactinoma

What is the pathologic term for a pituitary adenoma hypersecreting prolactin?

Primary hypothyroidism

Which thyroid condition can lead to pathologic hyperprolactinemia?

TRH

In hypothyroidism, low thyroid levels trigger the release of what, which then stimulates prolactin?

End stage renal disease and cirrhosis

Name two conditions where prolactin accumulates because it isn't broken down.

Galactorrhea

What is the term for spontaneous milk production in hyperprolactinemia?

Amenorrhea or oligomenorrhea

How does hyperprolactinemia affect the menstrual cycle?

Low libido and impotence

Name two reproductive symptoms of hyperprolactinemia in males?

Hot flashes and osteopenia

Name two menopause-like symptoms caused by hyperprolactinemia.

Prolactinoma

What is the most common hypersecretory pituitary tumor?

Microadenoma

What is the term for a prolactinoma less than 1 cm?

Macroadenoma

What is the term for a prolactinoma 1 cm or larger?

20 to 1

What is the female to male ratio for microadenomas?

Males

Which gender more commonly presents with macroadenomas?

Blindness

What severe symptom might a male with a macroadenoma present with due to mass effect?

Stimulates growth

What is the basic function of Growth Hormone?

Lipolysis

GH promotes the metabolism of what?

Protein anabolism

What effect does GH have on protein?

Antagonize insulin action

How does GH affect insulin?

Prognathism

What is the term for the protruding jaw seen in acromegaly?

Macroglossia

What is the term for the enlarged tongue in GH hypersecretion?

Frontal bone hypertrophy

What is "frontal bossing" in acromegaly called in the source?

Spade-like hands

How are the hands of an acromegaly patient described?

Reduced joint space

Why do GH excess patients suffer from arthralgia and arthritis?

Hyperhidrosis

What is the term for excessive sweating in acromegaly?

Coarse, rough, warm, and moist

Describe the skin of a patient with acromegaly.

Sleep apnea and airway obstruction

What are two respiratory complications of GH hypersecretion?

Cardiomegaly and thyromegaly

Name two examples of organomegaly caused by GH excess.

Cardiovascular mortality

What is the highest cause of death for both GH hyposecretion and hypersecretion?

Loss of lean bone mass

What is a primary effect of GH hyposecretion in adults?

Visceral obesity

What type of fat deposition is seen in adult GH deficiency?

Hypoglycemia

GH deficiency creates a propensity for what blood sugar abnormality?

40 to 45 years

What is the mean age at diagnosis for GH-secreting adenomas?

Macroadenomas

More than 65 percent of GH-secreting adenomas are what size at diagnosis?

Promote adipogenesis

How does ACTH/Cortisol affect fat cells?

Buffalo hump

What is the common term for the fat pad on the back of the neck in Cushing's?

Inhibit epidermal cell division and reduce collagen

Why does excess cortisol lead to thin skin?

Facial plethora

What is the term for the "slapped cheek" appearance in Cushing's?

Broad and violaceous

Describe the characteristic striae in Cushing's syndrome.

Cortisol increases conversion of estrogen and testosterone

Why does acne occur in Cushing's?

Hirsutism

What is the term for male-pattern hair growth in women?

Ferriman-Gallwey score

What tool is used to evaluate hirsutism?