ENDO Flashcards
(291 cards)
The 2 hormones stored in the posterior lobe are
ADH (antidiuretic hormone or vasopressin) and oxytocin
Microadenomas are defined as tumors ____ in diameter
<1 cm
Pituitary Adenomas by Function
Prolactin_____
Growth hormone (GH) _____
ACTH_____
Gonadotroph ____
50–60%
15–20%
10–15%
10–15%
Excess prolactin secretion is a common clinical problem in women and causes the syndrome of
galactorrhea-amenorrhea
Why is there amenorrhea in Prolactinemia
The amenorrhea appears to be caused by inhibition
of hypothalamic release of gonadotropin-releasing hormone (GnRH) with a decrease in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion. Prolactin inhibits the LH surge that causes ovulation.
Prolactinemia
The most common presenting symptom in men is
erectile dysfunction and decreased libido.
Hyperprolactinemia can be seen in natural physiologic states such as
pregnancy, early nursing, hypoglycemia, seizure, exercise, stress, sleep, cirrhosis, nipple stimulation, and
chronic renal failure (due to PRL clearance).
Prolactinemia
They are usually _____ when they occur in women and ______ in men, usually presenting with visual field deficits, etc.
microadenomas
macroadenomas
Macroadenomas can obstruct the pituitary stalk, increasing prolactin release by
blocking dopamine transport from hypothalamus (stalk effect)
Hyperprolactinemia can also occur with decreased inhibitory action of dopamine.
This occurs with the use of drugs that
block dopamine synthesis (phenothiazines, metoclopramide) and dopamine-depleting agents (α-methyldopa, reserpine).
Always check _____in patients with elevated prolactin
TSH
Always exclude states such as_______
before starting the work-up of hyperprolactinemia
pregnancy, lactation, hypothyroidism and medications
Prolactinomas may co-secrete
growth hormone (GH)
Prolactin levels >100 ng/mL suggest probable
pituitary adenoma
For prolactinomas, initially treat with _____ both of which reduce prolactin levels in almost all hyperprolactinemic patients.
cabergoline or bromocriptine (a dopamine
agonist),
Surgery is reserved only for adenomas
not responsive to cabergoline or bromocriptine, or if the tumor is associated with significant compressive
neurologic effects.
T or F
Surgery is more effective for microadenomas than macroadenomas
T
About _____of patients treated with cabergoline have a drop in prolactin to <10% of pretreatment levels
90%
______ is used if drug therapy and surgery are ineffective in reducing tumor size and prolactin levels
Radiation therapy
______ is a syndrome of excessive secretion of growth hormone. In children this is called____
Acromegaly
gigantism
______ is an insidious, chronic debilitating disease associated with bony and soft tissue overgrowth, and increased mortality
Acromegaly
Acromegaly is caused by
pituitary adenomas, usually a macroadenoma in 75% of
the cases that produce growth hormone
Other SSX associated with acromegaly
Obstructive sleep apnea can also develop.
Interstitial edema, osteoarthritis, and entrapment neuropathy (carpal tunnel syndrome)
are seen
About 10-20% of patients develop cardiac anomalies such as hypertension, arrhythmias, hypertrophic cardiomyopathy, and accelerated atherosclerosis.
Metabolic changes asstd with acromegaly
impaired glucose tolerance (80%) and diabetes (13–20%).