Anterior pituitary

Question 1

Normal reasons for enlarged pituitary (nonthreatening)

Answer 1

Puberty and 3rd trimester of pregnancy (prep for lactation)

Question 2

Common modes of presentation of pituitary problems

Answer 2

Incidental finding, Mass effects, Hormone excess, Hormone deficiency

Question 3

Identify two symptoms that result from pressure effects of a pituitary mass

Answer 3

Headaches (stretch the dura) and vision - From chiasmal compression, Loss of peripheral vision, tunnel vision (more severe), Pale optic disc (from ischemic). Rarer: diplopia from compression of cranial nerves, Rhinorrhea from CSF leak (surgery), Seizure, mental changes

Question 4

Table of ant pituitary hormone, target hormone, stimulatory signal from hypo and inhibition

Answer 4

Table. Dopamine is important.

Question 5

How do you measure hormone levels?

Answer 5

Basal vs. dynamic testing; Always measure target gland hormone (Cortisol, Free T4, IGF-1, Testosterone, Estradiol). In some, measure pituitary hormone (LH/FSH, PRL, TSH). In others, pituitary hormone levels highly fluctuating, often unreliable (GH, ACTH)

Question 6

DDX for pituitary mass

Answer 6

*Pituitary adenomas (most common); Meningioma; Craniopharyngioma (children); Granulomatous disease, eg. sarcoidosism; Infiltrations, eg. histiocytosis and hemochromatosis; Infections, eg. tuberculosis, abscess, syphilis; Pituitary hyperplasia (puberty, preg), Autoimmune hypophysitis

Question 7

Classification of pituitary adenoma and pathology

Answer 7

Macroadenoma: >1 cm; micro: < 1. Almost always benign. Prolactinoma most common. Can be specific for others

Question 8

List common causes of hypopituitarism

Answer 8

Starred are most common. *1. Pituitary and parapituitary tumors.*2. Radiotherapy *3.Trauma (car, sports). 4. Infarction (pituitary apoplexy). 5. Infiltrations, eg. sarcoidosis. 6. Infections, eg. tuberculosis. 7. Sheehan’s syndrome

Question 9

Describe the pathology of hypopituitarism. What are the deficiencies from most common to least?

Answer 9

3/4 of pituitary must be destroyed before endocrine deficiency becomes apparent. Acronym: Go Find The Adenoma Please: GH deficiency and hypogonadism (FSH/LH) deficiency appear early, followed by TSH and ACTH deficiency, Prolactin deficiency least common

Question 10

Manifestations of gonadotropin deficiency

Answer 10

Women (symptoms of estrogen deficiency: Amenorrhea, infertility, dyspareunia (painful intercourse), breast atrophy, loss of secondary sexual hair. Men (symptoms of testosterone deficiency): Poor libido and impotence, infertility, soft testicles, loss of secondary sexual hair

Question 11

Manifestations of GH deficiency

Answer 11

Adults: Reduced muscle mass, Abdominal obesity, Lipid disorder, Osteopenia. Children: Short stature. Metabolic effects: Abnormal lipids, more fat mass / lower muscle mass, lower bone mass

Question 12

Manifestations of TSH deficiency

Answer 12

Adults (hypothyroid symptoms): Decrease in energy, Constipation, Sensitivity to cold, Dry skin, Weight gain. Children: Growth retardation

Question 13

Manifestations of ACTH deficiency

Answer 13

Symptoms of cortisol deficiency: Weakness, Tiredness, Dizziness on standing, Pallor (not hyperpigmented), Hypoglycemia

Question 14

Describe how to investigate suspected hypopituitarism. What tests?

Answer 14

Good history (unlikely in women with normal menses); IGF-1 (commonly low); Testosterone/estradiol with FSH; normal FSH in menopausal women suggests hypopituitarism; Cortisol, may need stimulation test; Free T4 with TSH; Prolactin can be high (stalk effect). Provocative tests: GnRH stimulation, TRH stimulation, Insulin tolerance (GH, cortisol, ACTH). MRI and visual field.

Question 15

Common treatments for hypopituitary

Answer 15

Adrenal (hydrocortisone, prednisone, dexamethasone), Thyroid (thyroxine), Gonadal (testosterone/estrogen). Treat underlying disease (eg. Medical therapy for prolactinoma, transsphenoidal surgery + medical and/or radiotherapy for tumor)

Question 16

Regulation and action of GH secretion

Answer 16

Made by somatotrophs. Secretion: Pulsatile, Circadian Rhythm, Stress-induced secretion, Negative feedback by IGF-1. Picture

Question 17

What does somatomedin do? (2nd half of chart)

Answer 17

Picture

Question 18

Pathology of GH excess

Answer 18

Most are from GH secreting adenoma; Slowly progressive disease; Onset of symptoms commonly ten years earlier

Question 19

List the clinical manifestations of acromegaly

Answer 19

Gigantism in children, Acromegaly in adults: Increase in ring and shoe size. Coarse facial features, prognathism (protruding jaw) and prominent forehead. Soft tissue swelling, eg. spade-like hand, macroglossia (large tongue). Excessive sweating. Sleep apnea, snoring, daytime somnolence; Headache, Nerve entrapment, eg. peripheral neuropathy or carpal tunnel syndrome, Decreased energy, Osteoarthritis, Erectile dysfunction with decreased sex drive, Multinodular goitre, Hypertension, Diabetes or impaired glucose tolerance, colonic polyps, back pain, sciatica

Question 20

Describe the workup of a patient suspected of having acromegaly

Answer 20

Glucose tolerance test (GH normally suppressed by it), Plasma IGF-1, Prolactin: increased by stalk effect or tumor; Other pituitary hormones: may be reduced secondary to mass effect, MRI, Visual field

Question 21

Identify treatment options for acromegaly

Answer 21

Surgery (can affect other hormones tho), Analogues (sandostatin, GHr antagonist - $$), radiotherapy

Question 22

Regulation of prolactin secretion

Answer 22

Increase: TRH (thyrotropin release hormone), Stress, pregnancy, estrogen, lactation, nipple suction. Inhibit: dopamine

Question 23

Describe the clinical manifestations of hyperprolactinemia

Answer 23

Hyperprolactinemia is most common pituitary disorder. Dopamine is not inhibiting it. Female patients: Most have small tumors (microadenomas), Galactorrhea 30-80%, Menstrual irregularity and infertility, Symptoms of large tumors (less common). Male patients: Usually large tumors (macroadenomas); Impotence and reduced libido, galactorrhea not common; Symptoms of large tumors (Visual field abnormalities, headache and hypopituitarism)

Question 24

Provide a differential diagnosis for hyperprolactinemia

Answer 24

Prolactinoma or Other hypothalamic/pituitary disorders: Pituitary mass -> compression of portal tract -> stalk effect (defective dopamine delivery) or GH-secreting tumor (can co-secret prolactin or stalk effect); hypothyroid; drugs;

Question 25

List treatment options for hyperprolactinemia

Answer 25

Dopamine agonists: Cabergoline, Bromocriptine, Quinagolide