Hypersecretory states Flashcards
What are the two pituitary hormones that are absolutely essential for life?
Corticotropin (cortisol)
TSH (T4)
What are the two major effects that pituitary tumors can have on the endocrine system?
Hormone excess or deficiencies
Impingement of nearby structures
What is pituitary apoplexy?
Hemorrhage into the pituitary
What are the two different types of tumors that can have an effect on the HPA axis?
Hypothalamic
Pituitary
What are the major inflammatory diseases that can cause hypopituitarism?
Granulomatous diseases
Lymphocytic hypophysitis
What is lymphocytic hypophysitis?
Autoimmune attack against the pituitary, causing a variety of different symptoms
What are the granulomatous diseases that can have an effect on the pituitary? (3, two are infectious)
Sarcoid
TB
Syphilis
What is Sheehan’s postpartum necrosis?
hypopituitarism caused by ischemic necrosis due to blood loss and hypovolemic shock during and after childbirth. The pituitary is more susceptible to ischemia d/t increased lactotrophs, so hypovolemia will more often result in infarction
What are the usual first ssx of Sheehan’s syndrome?
Agalactorrhea, and amenorrhea
Aneurysm of what artery can cause pituitary damage?
Internal carotid
What are the three major infiltrative diseases that can cause pituitary dysfunction?
Hemochromatosis
Amyloidosis
Sarcoidosis
ACTH excess leads to what?
Cushings
TSH excess leads to what?
Hyperthyroidism
FSH/LH excess leads to what?
Hypogonadism
What three pituitary hormones have simple end organ feedback?
ACTH
TSH
FSH/LH
Which two anterior pituitary hormones lack a simple feedback loop?
PL
GH
PL excess leads to what?
Galactorrhea
Hypogonadism
GH excess leads to what?
Gigantism/acromegaly
What CNs can be affected with large pituitary tumors?
2, 3, 4, 5, and 6
Why is it that prolactin levels increase with otherwise panhypopituitarism?
Loss of inhibitory dopamine
What percent of the pituitary function does prolactin represent normally? What about in pregnancy?
10-25% normally
70% with prego
What is the normal serum concentration of prolactin?
2-15 ng/mL
What is prolactin inhibitory factor also known as?
Dopamine
What, besides pregnancy, stimulates the production of prolactin? (4)
Stress
Estrogens
Opiates
Diseases
What are the two main presentations of hyperprolactinemia? Why?
- Hypogonadism d/t inhibition of GnRH release
- Galactorrhea
Why is it that hyperprolactinemia is harder to detect in postmenopausal women?
They’re already hypogonadal, and do not as readily produce milk
What are the causes of hyperprolactinemia, besides a pituitary adenoma that secretes prolactin? (4)
- Stalk compression
- Decreased dop/dop inhibitory action
- Increased stimuli (e.g. estrogen excess)
- Decreased PL clearance from CKD
What are the two major types of stimuli that can cause hyperprolactinemia?
Excess estrogen
Hypothyroidism
Why can CKD cause hyperprolactinemia?
Decreased clearance of prolactin
Hyperprolactinemia with a prolactin level less than 30 is suspicious for what etiology?
Stress induce
Hyperprolactinemia with a prolactin level greater than 300 is suspicious for what etiology?
Pituitary adenoma
Hyperprolactinemia with a prolactin level greater than 100 (without pregnancy) is suspicious for what etiology?
adenoma
What is the use of ordering an hCG level with hyperprolactinemia?
prolactin levels with increase if prego
What is the use of ordering a TSH level with hyperprolactinemia?
TSH inhibits prolactin release. Thus if low, may be a secondary effect.
What are the 4 most common drugs that can cause prolactinemia?
Verapamil
Metoclopramide (Reglan)
Risperidone
Haldol
What is the most common type of functional pituitary adenoma?
Prolactinomas
True or false: the size of prolactinomas correlates well with hormonal output
True
Which is more common: micro or macro prolactinomas?
Maco
When in particular do prolactinomas usually arise?
During pregnancy
Who usually has macroprolactinomas: men or women? Why?
Men
Thought is that men do not seek medical attention as quickly as women
When is it appropriate to treat a microprolactinoma? What is the treatment?
If symptomatic
Bromocriptine (dopamine agonist)
When is it appropriate to treat a macroprolactinoma? What are the two medical treatment options? Surgical?
Most always require treatment
Bromocriptine and/or tamoxifen
Transsphenoidal resection
What is the MOA of bromocriptine? Use?
Dopamine agonist for treating prolactinomas
What is the main symptom of hyperprolactinemia?
Failure to lactate
What is the major cause of hyperprolactinemia?
Sheehan syndrome
How do you diagnose Hyperprolactinemia? What is the normal response?
Stimulation test with TRH or chlorpromazine
Normal increase is 200%
What is the MOA of Chlorpromazine? Use?
Dopamine antagonist
Typical antipsychotic, but also sometimes used to treat hyperprolactinemia
GH usually accounts for what percent of anterior pituitary function? How is GH released?
50%
Pulsatile fashion
What are the two hormones that control GH release? Which does inhibition/secretion?
- GRH stimulates release
- Somatostatin inhibits release
If there is GH excess before the epiphyseal plates close, what is the outcome? After they close?
Before = gigantism After = acromegaly
What is the sleep disturbance that can happen with acromegaly d/t GH?
OSA secondary to macroglossia
What happens to the hands and feet with GH excess?
Enlargement and carpal tunnel syndrome
What can excess GH cause that causes a pt to smell?
Hyperhidrosis
What is the GI pathology that can happen with GH excess?
Colon polyps
How do you diagnose GH excess?
GH inhibition test with standard glucose load
Pts with large pituitary adenomas should always be screened for what pathology?
GH excess
What are the goal of treatment for excess GH? (3)
- Decrease GH levels back to normal
- Decrease tumor size
- Preserve normal function
What is the treatment for GH excess?
- Surgery
- Radiation
- Bromocriptine
What is the role of bromocriptine in the treatment of GH excess?
Adjunct
What are the labs that are commonly elevated with GH excess? (5)
- Hyperglycemia
- Hypercalciuria
- Hypercalcemia
- Hyperphosphatemia
- Hyperprolactinemia
What is the most common cause of GH excess?
Ptuitary adenomas (75% of the time)
What are the two rare causes of GH excess?
GRH induced
Ectopic
What is the first pituitary hormone to be lost d/t pituitary/hypothalamus problems?
GH
How do you diagnose GH deficiency?
Stimulation test for GH release
If an adult has DM, how will a GH deficiency present?
- Decreased insulin requirements
- Hypoglycemia
What percent of the anterior pituitary function is dedicated to the thyroid function?
10%
What is the normal serum concentration of TSH?
0.5 - 3.5 micro units/mL
If a patient has panhypopituitarism, will they ever have normal TSH levels? If not, what should be measured?
N
T3/T4 levels instead
What are the two secondary causes of hypothyroidism?
TSH or TRH deficiency
What are the two secondary causes of hyperthyroidism?
TSH excess
Resistance to T3/T4
What percent of the anterior pituitary function is used for ACTH secretion?
15%
What is the normal serum concentration of ACTH?
10-80 pg/mL
What is the difference between Cushing’s disease, and Cushing’s syndrome?
Disease = secondary/tertiary cause (brain)
Syndrome = primary
ACTH deficiency is also known as what?
Secondary Addison’s disease
What percent of anterior pituitary function is dedicated to gonadotrophs?
10%
What are the non-endocrine functions of the hypothalamus?
- Caloric intake
- Temp
- Sleep/wake
- memory/behavior
- thirst
- ANS
Which are more common: slow or fast growing hypothalamic tumors?
Slow
What are the usual ssx of slow growing hypothalamic tumors? (3)
Dementia
Disturbances in food intake
Endocrine dysfunction
What is the usual presentation of rapid growing hypothalamic tumors?
Coma
ANS dysfunction
