Exam 2 -- Endocrine -- Everything but DM Flashcards
What percentage of pituitary tumors secrete prolactin?
60%
What are some physiologic causes of hyperprolactinemia?
Pregnancy and stress (stress doesn’t cause very much prolactin increase)
What are some pathologic causes of hyperprolactinemia?
Prolactinoma, damage to hypothalamus or pituitary stalk (loss of dopamine inhibition of prolactin release), hypothyroidism (low TH increases TRH from hypothalamus, which increases TSH and prolactin from pituitary), dopamine antagonists (antipsychotics, verapamil, cimetidine)
What percentage of clinically recognized pituitary tumors are prolactinomas?
30-40%
True or false: prolactinomas are more common in women than in men
True.
What are the clinical features of hyperprolactinemia?
Oligomenorrhea or amenorrhea, galactorrhea (in men and women), and loss of libido. VF defects and HA can occur if the hyperprolactinemia is caused by a prolactinoma.
What is the treatment of choice for prolactinoma?
Dopamine agonists (cabergoline and bromocriptine) work rather well to decrease prolactin secretion and can actually shrink the size of the tumor.
Patients on dopamine agonists for treatment of prolactinoma have what procedure done every two years?
Cardiac ultrasound due to possibility of valvular disease.
Of the dopamine agonists used to treat prolactinoma, which is more efficacious? Which might be better for a woman who wishes to get pregnant?
Cabergoline is more efficacious and bromocriptine might be better for the woman who wishes to get pregnant.
After how long of dopamine agonist use can reduction of dosage begin? How long until complete drug cessation is possible?
1 year for reduction and 2 years for cessation
When might transsphenoidal adenectomy and/or raditherapy be considered in treatment of a prolactinoma?
If medical therapy fails, or if the tumor is larger than 3cm and the woman wishes to get pregnant
Excessive growth hormone causes growth of what types of tissue?
Soft tissue, increased bone density
What are the clinical features of acromegaly?
Headache, enlargement of jaw and separation of teeth, hand and feet enlargement, osteoarthritis, entrapment neuropathies, abnormal glucose tolerance, and heart failure
What percentage of deaths of patients with acromegaly are due to heart failure?
60%
What percentage of patients with acromegaly are cured through transsphenoidal adenectomy?
60-90% (if the tumor is small))
True or false: medical therapy for acromegaly is as effective as transsphenoidal adenectomy
False.
What types of medications can be used for management of acromegaly?
Somatostatin analogues (inhibitors of growth hormone) octreotide and lanreotide, GH receptor antagonist pegvisomant, dopamine agonist cabergoline.
Use of dopamine agonists to treat acromegaly is most effective in what type of tumors?
Tumors that secrete GH and prolactin
True or false: if surgery or medical therapy fail in treatment of acromegaly, radiotherapy may be used
True.
How long can radiotherapy take to normalize GH levels in the treatment of acromegaly?
3-10 years
Which hormones are secreted by the adrenal cortex?
Glucocorticoids (cortisol), mineralocorticoids (aldosterone), adrenocortico androgens (testosterone)
What is the most common cause of Cushing’s syndrome?
Administration of exogenous steroids (iatrogenic)
What would be the levels of ACTH and cortisol in a patient with Cushing’s syndrome due to exogenous steroids?
Low ACTH and low cortisol (the exogenous steroids resemble cortisol enough that the hypothalamus tells pituitary to stop releasing ACTH)
What is the most common cause of endogenous Cushing’s syndrome?
Cushing’s disease (usually small ACTH-secreting pituitary adenoma, though could be a hypothalamic adenoma) accounts for more than half of endogenous Cushing’s syndrome
True or false: males are more affected by Cushing’s disease than females, and the incidence is normally in the third to fourth decade
True and false: females (not males) are the more affected gender, but the peak incidence is indeed in the third to fourth decades
What would be the levels of ACTH and cortisol in a patient with Cushing’s disease?
High ACTH and high cortisol (the pituitary releases ACTH, which stimulates adrenal cortex to release cortisol)
Which endogenous cause of Cushing’s syndrome is considered ACTH-independent, and why?
Primary adrenocortical hyperplasia or neoplasm (neoplasm more commonly). The hyperplasia or neoplasm would release excess cortisol regardless of ACTH presence.
What percentage of endogenous Cushing’s syndrome is caused by adrenocortical hyperplasia or neoplasm?
15-30%
What would be the levels of ACTH and cortisol in a patient with Cushing’s syndrome due to adrenocortical hyperplasia or neoplasm?
Low ACTH and high cortisol (hyperplasia or neoplasm releases excess cortisol, which signals to hypothalamus to tell pituitary to decrease ACTH release)
Ectopic ACTH secretion can be a cause of endogenous Cushing’s syndrome. What type of tumor is commonly the cause of the secretion?
Small cell carcinoma of the lung.
What would be the levels of ACTH and cortisol in a patient with Cushing’s syndrome due to ectopic ACTH secretion?
High ACTH and high cortisol (ectopic tumor releases ACTH, which stimulates release of cortisol; though hypothalamus is stimulated to tell pituitary to decrease ACTH release, the ectopic tumor isn’t under hypothalamic control)
What are the early manifestations of Cushing’s syndrome?
HTN and weight gain
What are later findings of Cushing’s syndrome?
Truncal obesity, moon face, buffalo hump, decreased muscle mass/weakness, hyperglycemia, glucosuria, polydipsia, thinning of skin, acne, easy bruising, osteoporosis, hyperpigmentation (only if ACTH-dependent Cushing’s), increased risk for infection, mental disturbances, hirsutism, cataracts
What percentage of Cushing’s syndrome patients also have diabetes mellitus?
20%
What test can be used to differentiate the two ACTH-dependent Cushing’s syndrome causes (i.e., pituitary ACTH tumor from ectopic ACTH tumor)? What would this test show in a non-Cushing’s patient? In a Cushing’s disease patient? In an ectopic ACTH patient?
Dexamethasone suppression test; in a non-Cushing’s patient, cortisol levels would be low; in a Cushing’s disease patient, cortisol levels would drop slightly; in an ectopic ACTH patient, cortisol levels would not drop at all.
What is the treatment of choice for Cushing’s disease?
Transsphenoidal adenectomy
Besides the treatment of choice, what other treatment options are available for a patient with Cushing’s disease?
Pituitary irradiation, adrenalectomy, pasireotide (somatostatin analog)
Adrenalectomy is one of the treatment options for Cushing’s disease. What are some of the significant side effects?
Addison’s disease (adrenal insufficiency), possible Nelson’s syndrome (rapid tumor growth)
True or false: adrenal carcinomas are usually inoperable due to metastasis
True.
What is the most common cause of primary hyperaldosteronism? What is the cause of most other cases of primary hyperalldosteronism?
Idiopathic bilateral hyperplasia is the most common cause, followed by unilateral aldosterone-secreting adenoma
What is another name for an aldosterone-secreting adenoma?
Conn’s syndrome
Why does hyperaldosteronism cause hypertension and hypokalemia?
Aldosterone causes sodium (and hence water) retention, increasing blood pressure. Whenever more sodium is retanied, less potassium is kept.
Hypertension caused by _____________ and ______________ is curable by surgery. (Name the two conditions.)
Primary hyperaldosteronism; pheochromocytoma
Which gender has a higher prevalence for primary hyperaldosteronism, and at what age?
Female (2:1) middle age