Term
| Hypersecretion of the pituitary usually indicate what type of benign tumor? |
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Definition
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Term
True or False Pituitary tumors almost never metastasize. |
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Definition
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Term
True or False With the exception of ACTH and the alpha-subunit of the glycoprotein hormones, ectopic production of pituitary hormones is rare.
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Definition
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Term
| What are the top 3 most prevalent adenomas of the pituitary? |
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Definition
- Prolactinoma.
- Null-Cell Adenoma.
- Gonadotroph adenoma (FSH, alpha-subunit)
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Term
| What is the least common form of pituitary adenoma? |
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Definition
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Term
| GH excess causes two different clinical disorders in adults vs. children. What are they? |
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Definition
| Acromegaly in adults and Gigantism in children. |
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Term
True or False Gigantism is a rare disorder which should be considered in children who are >3 SD above the normal mean height for age. |
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Definition
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Term
| About one third of the pituitary tumors associated with Acromegaly are due to a mutations. Describe. |
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Definition
| About one third of the pituitary tumors associated with Acromegaly have mutations in the alpha-chain of the Gs protein complex within the GTP-binding domain. These mutations produce a constitutive increase in cAMP production in somatotrophs resulting in hyperplasia and then in adenoma formation. |
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Term
| What are two tests used for assessing Acromegaly in a patient? |
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Definition
- Serum level IGF-1
- Glucose tolerance test
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Term
| How is the glucose tolerance test effective in identifying acromegaly in patients? |
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Definition
Glucose suppresses GH secretion in normal individuals to <1 ng/ml and to < 0.3 ng/ml with the new ultrasensitive GH assay. In Acromegalics, glucose fails to suppress GH into the normal range. If GH excess is documented, a pituitary MRI should be performed.
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Term
| What kind of risk does acromegaly incurr upon patients? |
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Definition
| Epidemiological studies reveal that the mortality in Acromegaly is twice the expected rate. Significant excess morality is found in cardiovascular and cerebrovascular disease, and malignancy. There is an excess risk of colonic polyps and cancer. Mortality is significantly reduced by effective therapy. |
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Term
| What is the initial treatment of Acromegaly? |
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Definition
| transphenoidal adenomectomy. |
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Term
| What are options/drawbacks for patients who fail/refuse surgery for acromegaly macroadenoma? |
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Definition
For patients who refuse or fail surgery two options are available: irradiation and medical therapy with octreotide. The response to radiation is slow (yrs), and complications such as panhypopituitarism and impaired memory may occur. Gamma knife radiosurgery is a newer technique, which delivers a highly focussed beam of radiation to a small MR imaged focus of tumor. There is less scatter to surrounding tissue so that the side effects of memory loss and hypopituitarism are minimized. The response is generally faster with normalization of IgF-1 within 2-5 years |
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Term
| What pharmachological agents are used to inhibit GH secretions? |
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Definition
Octreotide is a somatostatin analog which is a potent inhibitor of GH secretion. Pegvisomant is a GH analog which blocks GH action by decreasing the affinity of GH for receptor 1 and through inhibition of GH receptor dimerization and signal transduction |
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Term
| How is Pegvisomant different than Octerotide in treatment of excess GH action? |
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Definition
Pegvisomant results in lowering of IGF-1 into the normal range in over 90 % of patients who receive the drug. It does not, however, result in tumor shrinkage and lowering of GH levels. Its’ advantage over octreatide, is a higher rate of symptom relief, with fewer GI side effects. However, daily injections are required and there is a slightly higher risk of tumor growth.
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Term
| what are the cardinal manifestations of hyperprolactinemia in young adult women? |
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Definition
| Inappropriate lactation, together with oligomenorrhea (irregular menses) or amenorrhea (absent menses). |
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Term
| What is the sighn of hyperprolactinemia in men? |
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Definition
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Term
| What is the effect of hyperprolactinemia on the sex hormones in men and women? |
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Definition
Hyperprolactinemia suppresses pulsatile LH secretion by decreasing GnRH gene expression. Decreased gonadotropin secretion leads to anovulation in women and suppresses testosterone production in men. Infertility occurs in both sexes. Puberty is delayed in teenagers with hyperprolactinemia.
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Term
| What diagnoses a prolactinoma? |
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Definition
if PRL level is > 200ng/ml, and usually if the level is between 100-200, too. |
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Term
| What are some reversible and common causes of hyperprolactinemia? |
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Definition
Common causes of mild hyperprolactinemia (<100) are primary hypothyroidism, perhaps because of increased TRH production, or neuroleptics which block dopamine receptors. Hypothyroidism can cause hyperplasia of lactotrophs and result in a pituitary mass which will resolve with thyroid hormone replacement. Pregnancy and neuroleptics can also be associated with reversible enlargement of the pituitary secondary to lactotroph hyperplasia. |
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Term
True or False Medical therapy for prolactinomas is more effective than surgery and often still necessary after surgery, therefore it should be given alone first, even if loss of vision has occurred.Can restore normal vision in over 90%. |
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Definition
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Term
| What is the major advantage of Bromocriptine over Cabergoline? |
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Definition
| Bromocriptine has half life of 3.3 hrs, whereas Cabergoline has a half-life of one week, so this shorter half life enables ease of discontinuation for women are trying to conceive - as soon as a missed menstral cycle. |
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Term
| What does pathological ACTH hypersecretion cause? |
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Definition
| Cushing’s syndrome. In fact, pathological ACTH hypersecretion causes 75% of all cases of Cushings. |
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Term
True or False Presentation with Cushings is classic for impaired glucose tolerance in 75%, DM 10-15%, HTN 75%, increased lipids, increased mortality 2ndary to ASHD, infections, and thromboembolism. |
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Definition
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Term
| What is the treatment of choice for Cushings Disease ? |
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Definition
| Surgery is the treatment of choice. Options for patients not cured by surgery include radation, ketoconazole and bilateral adrenalectomy. |
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Term
| High plasma gonadotropin levels usually indicate what? |
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Definition
| NOT A TUMOR, mostly gonadal failure. |
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Term
| If indeed gonadotropin hypersecretion is due to a tumor, which hormone is mostly oversecreted? |
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Definition
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Term
True or False - TSH tumors are rare of all pituitary tumors.
- Present w/goiter, hyperthyroidism, NL, up TSH, elevated T4 & T3
- Females > males 3-6 decade.
- 6 yrs average delay in diagnosis due to mistaken hyperthyroidisim
- Typically agressive 3/4 invasive
- Cosecretion of alpha-subunite, GH, PRL
- Octerotide used for treatment
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Definition
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Term
- These tumors are common, occur equally in men and women, present in middle age, usuall as macroadenomas w/hypogonadism or mass effect
- Monoclonal in origin, but heterogenous
- FSH secretion most common (20%), followed by alpha subunit (15%) and LH; can secrete beta subunit of FSH or LH.
- Can b silent and demonstrate positive hormone immunostaining w/o hormone hypersecretion.
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Definition
| Null-Cell Adenomas, or formerly known as Chromophobe adenomas. |
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