Hyperpituitary Syndromes

Pituitary tumors

• Pathophysiology: adenoma — excess of ^ 1 trophic hormones (if tumor fxnal. but 30-40%

are not) and potentially deficiencies in other trophic hormones due to compression; cosecretion of PRL and growth hormone in 10% of prolactinoma

• Clinical manifestations: syndromes due to oversecretion of hormones (see below)

Anatomic consequences: headache, visual As. diploplia. cranial neuropathies

• Workup: MRI. hormone levels, consider MEN1 (see below)

Hyperprolactinemia (NEJM 2003349:2035)

• Etiology prolactinoma (50% of pituitary adenomas)

stalk compression due to nonprolactinoma -* 1 inhibitory dopamine — T PRL (mild)

• Physiology: PRL induces lactation and inhibits GnRH - I FSH & LH

• Clinical manifestations: amenorrhea, galactorrhea, infertility, I libido, impotence

• Diagnostic studies

T PRL, but elevated in many situations.r o pregnancy, hypothyroidism, psychotropic meds. antiemetics, renal failure (i clearance), cirrhosis, stress. T carb diet MRI to evaluate for tumor, visual field testing if MRI shows compression of optic chiasm

If asx (no H A or hypogonadal sx) and microadenoma (<10 mm) follow with MRI If sx or macroadenoma (s=10 mm) options include:

medical with dopamine agonist such as bromocriptine (70-100% success rate) or cabergoline (better tolerated); side effects include N V. orthostasis, nasal congestion surgtcat transsphenoidal surgery (main indications failed medical Rx. GH cosecretion.

or neurologic sx not improving); 10-20% recurrence rate radiation: if medical or surgical therapy have failed or are not tolerated

Acromegaly (T GH; 10% of adenomas)

• Physiology: stimulates secretion of insulin-like growth factor 1 (IGF-1)

• Clinical manifestations: T soft tissue, arthralgias, jaw enlargement, headache, carpal tunnel syndrome, macroglossia. hoarseness, sleep apnea, amenorrhea, impotence, diabetes mellitus. acanthosis skin tags.' sweating. HTN CMP. colonic polyps

• Diagnostic studies: no utility in checking random GH levels because of pulsatile secretion t IGF-1 (somatomedin C); - T PRL

oral glucose tolerance test — GH not suppressed to <2 ng ml by 2 h pituitary MRI to evaluate for tumor

• Treatment: surgery, octreotide (long- and short-acting preparations), dopamine agonists.

pegvisomant (GH receptor antagonist), radiation

• Prognosis: w o Rx there is 2-3 x t mortality, risk of pituitary insufficiency, colon cancer

Cushing's disease (t ACTH): 10-15% of adenomas: see "Adrenal Disorders" Central hyperthyroidism (t TSH. T alpha subunit): very rare; see "Thyroid Disorders" t FSH & LH: usually non-fxn. presents as hypopituitarism b c of compression effects

DISORDERS OF MULTIPLE ENDOCRINE SYSTEMS

Multiple Endocrine Neoplasia (MEN) Syndromes

Type 1

Parathyroid hyperplasia adenomas . hypercalcemia ( 100% penetrance) Pancreatic islet cell neoplasia (gastrin.VIP, insulin, glucagon) Pituitary adenomas

(RET proto-oncogene)

2B (RET proto-oncogene)

Medullary thyroid carcinoma (MTC) Pheochromocytoma ( 50%) Parathyroid hyperplasia — hypercalcemia (15-20%) Medullary thyroid carcinoma (MTC) Pheochromocytoma ( 50%) Mucosal and gastrointestinal neuromas

Polyglandular Autoimmune (PGA) Syndromes

Type Features

I (children) Mucocutaneous candidiasis, hypoparathyroidism, adrenal insufficiency

II (adults) Adrenal insufficiency, autoimmune thyroid disease, diabetes mellitus type 1

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