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Pathology
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289
Medical
Professional
08/10/2011

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Term
Endocrine disease stimulation tests evaluate ____________ disorders.
Definition
hypofunctioning
Term
Adrenocorticotropic hormone (ACTH) stimulation test is used in the work up of ____________.
Definition
hypocortisolism
Term
causes of hypofunctioning disorders
Definition
-autoimmune destruction
-infarction
-decreased hormone stimulation
-enzyme deficiency, infection, neoplasia, congenital disorder
Term
Endocrine disease suppression tests evaluate ______________ disorders.
Definition
hyperfunctioning
Term
Dexamethasone suppression test evaluates _______________.
Definition
hypercortisolism
Term
causes of hyperfunction
Definition
-adenoma
-acute inflammation
-hyperplasia
-cancer
Term
Secretion of hormones from the anterior pituitary is under strict control by ___________ hormones, referred to as _________ and _________ hormones.
Definition
hypothalamic
releasing; inhibiting
Term
list the anterior pituitary hormones
Definition
TSH
ACTH
FSH
LH
GH
PRL (prolactin)
endorphins
Term
list the posterior pituitary hormones
Definition
oxytocin
vasopressin (ADH)
Term
target of GHRH
Definition
anterior pituitary
Term
action of GHRH
Definition
stimulates GH secretion by stimulating the GHRH receptor
Term
target of GHIH
Definition
anterior pituitary
Term
action of GHIH
Definition
inhibits GH secretion
Term
another name for GHIH
Definition
somatostatin
Term
The actions of GHRH are opposed by ___________.
Definition
somatostatin (GHIH)
Term
target of TRH
Definition
anterior pituitary
Term
action of TRH
Definition
stimulates release of TSH and hGH
Term
target of GnRH
Definition
anterior pituitary
Term
action of GnRH
Definition
stimulates release of FSH and LH
Term
target of PRH
Definition
anterior pituitary
Term
action of PRH
Definition
stimulates release of PRL (prolactin)
Term
target of PIH (dopamine)
Definition
anterior pituitary
Term
action of PIH (dopamine)
Definition
inhibits release of PRL (prolactin)
Term
target of CRH
Definition
anterior pituitary
Term
action of CRH
Definition
stimulates release of ACTH
Term
What is the most common type of tumor that alters hypothalamic function?
Definition
pituitary adenoma (also a cause of primary pituitary disorders)
Term
slow-growing, epithelial-squamous tumor arising from remnants of the embryonic structures

causes alteration of hypothalamic function

occasionally behaves like a malignant tumor
Definition
craniopharyngioma
Term
Hypothalamic dysfunction will cause...
Definition
pituitary dysfunction
Term
clinical findings of hypothalamic dysfunction
Definition
-secondary hypopituitarism
-central diabetes insipidus
-increased prolactin
-precocious puberty
-visual field defects
-mass effects (hydrocephalus, etc.)
Term
Why does secondary hypopituitarism occur with hypothalamic dysfunction?
Definition
no releasing hormones to stimulate the anterior pituitary
Term
Why does central diabetes insipidus (CDI) occur with hypothalamic dysfunction?
Definition
antidiuretic hormone (ADH) is synthesized in the hypothalamus
Term
Why does hyperprolactinemia occur with hypothalamic dysfunction?
Definition
loss of dopamine inhibition (PIH) causes galactorrhea
Term
The visual field disturbance associated with hypothalamic dysfunction is usually ___________ ____________.
Definition
bitemporal hemianopia
Term
What mass effect is hypothalmic dysfunction associated with?
Definition
obstructive hydrocephalus
Term
What is the most common cause of hypopituitarism in adults?
Definition
non-functioning adenoma
Term
microadenoma
Definition
<10 mm
Term
macroadenoma
Definition
>10 mm
Term
What are pituitary adenomas associated with?
Definition
multiple endocrine neoplasia (MEN) syndrome
Term
Multiple endocrine neoplasia (MEN) syndromes consist of rare, autosomal _________ mutations in genes that regulate cell growth.
Definition
dominant
Term
Where do most tumors arise with MEN syndrome?
Definition
pituitary gland
pancreatic islet cells
Term
What is the most common manifestation of type 1 MEN?
Definition
hyperparathyroidism (80% of presentations)
Term
What causes the hyperparathyroidism associated with type 1 MEN?
Definition
hyperplasia of all 4 parathyroid glands
Term
What is the most common cause of hypopituitarism in children?
Definition
craniopharyngioma (benign tumor)
Term
pathophysiology of Sheehan's postpartum necrosis (cause of hypopituitarism)
Definition
-pituitary gland doubles in size during pregnancy due to the synthesis of prolactin
-hypovolemic shock during childbirth can cause pituitary infarction (not enough vascularization for increased size)
-causes sudden cessation of lactation due to loss of prolactin
Term
apoplexy
Definition
refers to a sudden onset of neurologic dysfunction
Term
What is pituitary apoplexy most often due to? (cause of hypopituitarism)
Definition
hemorrhage/infarction of pre-existing pituitary adenoma
Term
What condition can cause hypopituitarism due to pituitary infarction from vascular occlusion by misshaped cells?
Definition
sickle cell
Term
primary hypopituitarism
Definition
pituitary dysfunction
approx. 75% of gland must be destroyed
Term
secondary hypopituitarism
Definition
hypothalamic dysfunction
decreased hypothalamic releasing factors
Term
What condition can cause hypopituitarism and is diagnosed by radiologic studies showing an empty sella turcica?
Definition
empty sella syndrome
Term
When pituitary tumors enlarge, they can compress structures and cause significant neurologic deficits. The tumor may extend down into the sphenoid sinus and even erode the sphenoid bone, causing headache, epistaxis, or leakage of spinal fluid. As the tumor expands, it can invade the cavernous sinuses and surround the carotid arteries, causing double vision (CN 3,4,6) or facial pain (CN 5). If the tumor grows up, it can compress the optic nerves and chiasm, resulting in a loss of vision. The outside visual field in each eye is usually affected first (tunnel vision); this can progress to complete blindness if left unchecked.
Definition
Term
What studies are useful in the diagnosis of a pituitary adenoma?
Definition
MRI
stimulation tests for various deficiencies
Term
target of TSH
Definition
thyroid
Term
another name for TSH
Definition
thyrotropin
Term
action of TSH
Definition
stimulates secretion of T3 and T4
Term
target of ACTH
Definition
adrenal cortex
Term
action of ACTH
Definition
stimulates secretion of glucocorticoids (cortisol)
Term
target of FSH
Definition
ovary, testes
Term
action of FSH
Definition
regulates oogenesis and spermatogenesis
Term
target of LH
Definition
ovary, testes
Term
action of LH
Definition
regulates oogenesis and spermatogenesis
Term
target of PRL (prolactin)
Definition
mammary glands
Term
action of PRL (prolactin)
Definition
stimulates production of milk
Term
target of hGH
Definition
bone, muscle, etc.
Term
action of hGH
Definition
stimulates growth
Term
clinical manifestations of gonadotropin deficiency in children
Definition
delayed puberty
Term
clinical manifestations of gonadotropin deficiency in adult women
Definition
secondary amenorrhea
osteoporosis, hot flashes (lack of estrogen), decreased libido
Term
clinical manifestations of gonadotropin deficiency in adult males
Definition
impotence due to decreased libido from decreased testosterone
Term
What would GnRH stimulation test show in a patient with hypopituitarism?
Definition
no significant increase of FSH/LH
Term
What would GnRH stimulation test show in a patient with hypothalamic disease?
Definition
eventual increase of FSH/LH
Term
Decreased GH decreases synthesis and release of _____.
Definition
IGF-1
Term
clinical manifestations of GH deficiency in children
Definition
growth delay (delayed fusion of epiphyses)
bone growth does not match age of child
Term
clinical manifestations of GH deficiency in adults
Definition
hypoglycemia (decreased gluconeogenesis)
loss of muscle mass
increased adipose tissue around waist
Term
What test would you use to determine the etiology of gonadotropin deficiency?
Definition
GnRH stimulation test
Term
What tests would you use to diagnose GH deficiency?
Definition
arginine and sleep stimulation tests
Term
What would arginine and sleep stimulation tests show in a patient with GH deficiency?
Definition
no increase in GH or IGF-1
(normally, GH and IGF-1 are released at 5am)
Term
clinical manifestation of TSH deficiency
Definition
secondary hypothyroidism
decreased serum T4 and TSH
cold intolerance, constipation, weakness
Term
What test would you use to diagnose TSH deficiency?
Definition
TRH stimulation test
Term
What would a TRH stimulation test show in a patient with TSH deficiency?
Definition
no increase in TSH after TRF stimulation
Term
clinical manifestations of ACTH deficiency
Definition
-secondary hypocortisolism (decreased ACTH and cortisol)
-hypoglycemia (decreased gluconeogenesis)
-hyponatremia
-mild SIADH (loss of inhibitory effect of cortisol on ADH)
-weakness, fatigue
Term
What tests would you do to diagnose ACTH deficiency?
Definition
short ACTH stimulation test
prolonged ACTH stimulation test
metyropone test
Term
What would you see with the short ACTH stimulation test in a patient with ACTH deficiency?
Definition
no increase in serum cortisol over decreased baseline levels
Term
What would you see with a prolonged ACTH stimulation test in a patient with ACTH deficiency?
Definition
eventual increase in cortisol over the decreased baseline value once the adrenal gland is restimulated
Term
What would you see with a metyrapone test in a patient with ACTH deficiency?
Definition
no increase in ACTH or 11-deoxycortisol
Term
target of oxytocin (OT)
Definition
uterus, mammary glands
Term
action of oxytocin (OT)
Definition
uterine contractions
release of milk
Term
target of vasopressin (ADH)
Definition
kidney tubules
sweat glands
Term
action of vasopression (ADH)
Definition
increases water retention
Term
Presence of ADH _________ urine concentration.
Definition
increases
Term
Absence of ADH produces _________ of urine.
Definition
dilution
Term
What is the most common functioning pituitary tumor and is responsible for causing hyperpituitarism?
Definition
prolactinoma (benign adenoma)
Term
What does a prolactinoma cause in women?
Definition
secondary amenorrhea and galactorrhea
Term
Why does secondary amenorrhea occur in women and impotence occur in men with a prolactinoma?
Definition
prolactin inhibits GnRH
Term
What does a prolactinoma cause in men?
Definition
impotence due to loss of libido due to decrease in testosterone
Term
lab manifestations of prolactinoma
Definition
-elevated serum prolactin level
-decreased FSH and LH levels (due to decreased GnRH)
Term
treatment of prolactinomas
Definition
-surgery
-dopamine analogs that inhibit prolactin secretion by the tumor
Term
What type of adenoma accounts for 20% of all pituitary adenomas and can cause hyperpituitarism?
Definition
GH adenoma
Term
What studies would you use to diagnose a GH adenoma?
Definition
MRI
suppression tests
Term
What results from increased GH secretion during childhood (before puberty)?
Definition
gigantism
Term
In gigantism, the ______ bones are stimulated to grow _________.
Definition
long; disproportionately
Term
What results from overproduction of GH after puberty?
Definition
acromegaly
Term
What parts of the body is acromegaly apparent in?
Definition
hands, feet, skull, lower jaw
Term
Why does acromegaly only affect the hands, feet, skull, and lower jaw?
Definition
At puberty, the epiphyseal plates of the long bones close, so they become unresponsive to GH stimulation.
Term
Free T4 and free T3 have a __________ feedback relationship with TSH.
Definition
negative
Term
An increase in free T4/T3 should produce a _________ in TSH.
Definition
decrease
Term
A decrease in free T4/T3 should produce an __________ in TSH.
Definition
increase
Term
What does T4 and T3 bind to?
Definition
thyroid-binding globulin (TBG)
Term
How many of the TBG binding sites are normally occupied?
Definition
1/3
Term
Free T4 is a __________ and is peripherally converted to _________.
Definition
prohormone; free T3
Term
Which thyroid hormone is metabolically active?
Definition
free T3
Term
What does total serum T4 represent?
Definition
T4 bound to TBG and free (unbound) T4
Term
An increase in TBG synthesis increases _______ serum T4.
Definition
total
Term
What increases the synthesis of TBG?
Definition
estrogen
Term
What conditions and/or medications could cause an increase in TBG synthesis?
Definition
pregnancy
OCP
HRT
Term
With an increase in TBG, _____ T4 increases but ______ T4 does not.
Definition
total serum T4 increases
free T4 does not
Term
With increased TBG, why is TSH normal?
Definition
because free T4 is normal
Term
Are signs of thyrotoxicosis present in a patient with increased TBG?
Definition
no
Term
A decrease in TBG synthesis decreases _________.
Definition
total serum T4
Term
What can cause a decreased TBG level?
Definition
anabolic steroids
nephrotic syndrome (urinary loss)
Term
A decreased TBG level will cause a decrease in ____________ but not in _______.
Definition
total serum T4
not free T4
Term
What happens to free T4 and TSH in a patient with a decreased TBG level?
Definition
nothing; they remain normal
Term
Are signs of hypothyroidism present in a patient with a decreased TBG level?
Definition
no
Term
What is the best overall screening test for thyroid dysfunction?
Definition
TSH
Term
What diagnosis can be given in a patient who has increased TSH?
Definition
primary hypothyroidism
Term
What is the differential for a patient that has decreased TSH?
Definition
-thyrotoxicosis (Graves' disease)
-hypopituitarism/hypothalamic dysfunction (secondary hypothyroidism)
Term
What causes the decreased TSH level in Graves' disease?
Definition
increased free T4/T3
Term
What lab findings are consistent with primary hypothyroidism?
Definition
increased TSH
normal TBG
decreased free T4
Term
What lab findings are consistent with hyperthyroidism due to Graves' disease or thyroiditis?
Definition
decreased TSH
normal TBG
increased free T4
Term
What causes 90% of hypothyroidism cases?
Definition
Hashimoto's thyroiditis
Term
cretinism
Definition
hypothyroidism in infancy or early childhood

due to maternal nutritional deficiency of iodine

causes severely stunted physical and mental growth
Term
What is an autoimmune disease that eventually leads to atrophy of the thyroid and therefore hypothyroidism?
Definition
Hashimoto's thyroiditis
Term
What antibodies are usually demonstrable in the plasma of a patient with primary hypothyroidism?
Definition
anti-microsomal
anti-peroxidase
anti-thyroglobulin
Term
What is the term for the non-pitting edema associated with severe hypothyroidism?
Definition
myxedema
Term
timeline of Hashimoto's thyroiditis
Definition
starts out as hyperthyroidism
eventually develop atrophy of thyroid
ends as either hypothyroidism or euthyroid
Term
What happens when hypothyroidism is congenital?
Definition
cretinism (impaired physical and mental development)
Term
What may result in a cretin or a mentally retarded hypothyroid dwarf?
Definition
iodide deficiency during childhood
Term
another name for T4
Definition
thyroxine
Term
What will happen if a test dose of TSH is given to a patient with primary hypothyroidism?
Definition
nothing
Term
What is the result of a radioactive iodine reuptake study in a patient with primary hypothyroidism and why?
Definition
decreased uptake of radioactive iodine because the thyroid gland is inactive and iodine is a component of thyroid hormone
Term
treatment of primary hypothyroidism
Definition
levothyroxine
Term
clinical manifestations of Graves' disease (thyrotoxicosis)
Definition
-abnormal rise in basal metabolic rate
-struma
-exopththalmos
Term
What is another cause of hyperthyroidism besides Graves' disease?
Definition
toxic nodular goiter
Term
What lab findings are consistent with hyperthyroidism?
Definition
increased serum T4
decreased TSH
TSH-receptor antibodies
Term
What would a radioactive iodine reuptake study show in a patient with hyperthyroidism?
Definition
increased uptake
Term
What does an increased serum T4, decreased serum TSH, increased 131-I uptake with a history of palpitations and weight loss with no anorexia suggest?
Definition
Graves' disease
Term
What type of hypersensitivity reaction is associated with the autoimmune response found in Graves' disease?
Definition
type II hypersensitivity reaction
Term
Why does the radioactive iodine uptake increase in a patient with Graves' disease?
Definition
because the gland requires more iodine to keep pace with the synthesis of thyroid hormone
Term
serum T4 in Graves' disease
Definition
increased
Term
free T4 in Graves' disease
Definition
increased
Term
serum TSH in Graves' disease
Definition
decreased
Term
serum T4 in a patient taking excess hormone
Definition
increased
Term
free T4 in a patient taking excess hormone
Definition
increased
Term
serum TSH in a patient taking excess hormone
Definition
decreased
Term
serum T4 in the initial phase of thyroiditis
Definition
increased
Term
free T4 in the initial phase of thyroiditis
Definition
increased
Term
serum TSH in the initial phase of thyroiditis
Definition
decreased
Term
serum T4 in primary hypothyroidism
Definition
decreased
Term
free T4 in primary hypothyroidism
Definition
decreased
Term
serum TSH in primary hypothyroidism
Definition
increased
Term
serum T4 in secondary hypothyroidism (hypopituitarism)
Definition
decreased
Term
free T4 in secondary hypothyroidism (hypopituitarism)
Definition
decreased
Term
serum TSH in secondary hypothyroidism (hypopituitarism)
Definition
decreased
Term
serum T4 in a patient with increased TBG (excess estrogen)
Definition
increased
Term
free T4 in a patient with increased TBG (excess estrogen)
Definition
normal
Term
serum TSH in a patient with increased TBG (excess estrogen)
Definition
normal
Term
serum T4 in a patient with decreased TBG (anabolic steroids)
Definition
decreased
Term
free T4 in a patient with decreased TBG (anabolic steroids)
Definition
normal
Term
serum TSH in a patient with decreased TBG (anabolic steroids)
Definition
normal
Term
______ _________ and _______ ________ __________ cells secrete thyroid hormone without inhibition from the hypothalamo-pituitary axis.
Definition
toxic goiter; toxic solitary adenoma
Term
PTH _________ calcium reabsorption in the early distal tubule.
Definition
increases
Term
PTH _________ bicarbonate reclamation in the proximal tubule.
Definition
decreases
Term
PTH ___________ phosphorus reabsorption in the proximal tubule.
Definition
decreases
Term
PTH _______ ionized calcium level in the blood.
Definition
maintains
Term
PTH __________ bone resorption and renal reabsorption of calcium.
Definition
increases
Term
What is the most important endocrine regulator of calcium and phosphorus concentration in extracellular fluid?
Definition
PTH
Term
targets of PTH
Definition
bone
kidneys
Term
What is PTH stimulated by?
Definition
hypocalcemia
hyperphosphatemia
Term
What is PTH suppressed by?
Definition
hypercalcemia
hypophosphatemia
Term
Hypofunction of the parathyroid glands leads to __________.
Definition
hypocalcemia
Term
What are the 3 possible causes of hypoparathyrodism?
Definition
autoimmune (most common)
previous thyroid surgery
DiGeorge syndrome
Term
What is the most common cause of hypoparathyroidism?
Definition
autoimmune
Term
DiGeorge syndrome
Definition
-failure of descent of 3rd/4th pharyngeal pouches
-absent parathyroids and thymus
-causes hypoparathyroidism
Term
What lab findings are consistent with hypoparathyroidism?
Definition
hypocalcemia
hyperphosphatemia
decreased PTH
Term
What is the only syndrome associated with absence of the thymus, hypocalcemia, and cyanotic congenital heart disease?
Definition
DiGeorge syndrome
Term
Hypocalcemia causes __________, which in newborns is manifested by jitteriness, repetitive blinding, and stridor.
Definition
tetany
Term
What controls the release of PTH?
Definition
ionized calcium level in the blood (negative feedback system)
Term
Binding of PTH to its receptor stimulates _____ and __________ _________.
Definition
cAMP; phosphatidylinositol diphosphate
Term
What are the 5 major actions of PTH?
Definition
1. activates and increases the number of osteoclasts, which mobilizes calcium from bone
2. increases renal tubular reabsorption of calcium
3. increases conversion of vitamin D to active dihydroxy form in kidneys
4. increases urinary phosphate excretion, which reduces calcium loss
5. increases GI calcium absorption
Term
What does hyperparathyroidism cause?
Definition
bone resorption
hypercalcemia
hypercalciuria
renal stone formation
bone lesions
metastatic calcification
hypophosphatemia
hyperphosphaturia
elevated plasma PTH
Term
What is the most common cause of primary hyperparathyroidism?
Definition
adenoma (80% of cases)
Term
What are the other causes of primary hyperparathyroidism besides adenoma?
Definition
primary hyperplasia (20% of cases)
carcinoma (uncommon)
Term
What lab findings are consistent with primary hyperparathyroidism?
Definition
hypercalcemia
hypercalciuria
hypophosphatemia
hyperphosphaturia
increased serum PTH
Term
What is the best initial screening tests for primary hyperparathyroidism?
Definition
intact serum PTH (iPTH)
Term
Why is an intact serum PTH test the best initial screen for primary hyperparathyroidism?
Definition
distinguishes it from hypercalcemia related to a malignancy
Term
What else might cause hypercalcemia besides hyperparathyroidism?
Definition
cancer with bone metastases
malignant tumors producing PTH
Term
What is the most common cause of hypercalcemia in the hospital?
Definition
malignancy
Term
Serum PTH is _____ in primary hyperparathyroidism whereas it is _________ due to a malignancy.
Definition
increased; decreased
Term
Hypercalcemia due to a malignancy is a ___________ syndrome.
Definition
paraneoplastic
Term
Secondary hyperparathyroidism is a compensation for ___________.
Definition
hypocalcemia
Term
What undergoes hyperplasia in secondary hyperparathyroidism?
Definition
all four parathyroid glands
Term
What might cause the hypocalcemia that leads to secondary hyperparathyroidism?
Definition
inadequate vitamin D due to renal failure and malabsorption
Term
What lab findings are consistent with secondary hyperparathyroidism?
Definition
hypocalcemia
increased PTH
Term
A patient with secondary hyperparathyroidism may develop...
Definition
tertiary hyperparathyroidism
Term
tertiary hyperparathyroidism
Definition
glands become autonomous regardless of calcium level

may bring serum calcium into a normal or increased range
Term
What is the most likely cause of hypoparathyroidism?
Definition
prior thyroidectomy or parathyroidectomy
Term
What is an extremely rare autoimmune disease that can cause hypoparathyroidism and is often found in combination with other autoimmune disorders?
Definition
primary idiopathic hypoparathyroidism
Term
What are the layers of the adrenal cortex from outermost to innermost?
Definition
glomerulosa
fasciculata
reticularis
Term
What does the zona glomerulosa of the adrenal cortex produce?
Definition
mineralocorticoids (aldosterone)
Term
What does the zona fasciculata of the adrenal cortex produce?
Definition
glucocorticoids (cortisol)
Term
What does the zona reticularis of the adrenal cortex produce?
Definition
sex hormones (testosterone)
Term
What are the potential causes of acute adrenocortical insufficiency?
Definition
abrupt withdrawal of corticosteroids
Waterhouse-Friderichsen syndrome
Term
What is the most common cause of acute adrenocortical insufficiency?
Definition
abrupt withdrawal of corticosteroids
Term
What organism usually causes the septicemia associated with Waterhouse-Friderichsen syndrome?
Definition
Neisseria meningitidis
Term
What happens in Waterhouse-Friderichsen syndrome?
Definition
N. meningitidis endotoxic sepsis --> DIC --> bilateral adrenal hemorrhage
Term
What condition causes chronic adrenal insufficiency?
Definition
Addison's disease
Term
What is the most common cause of Addison's disease in the U.S.?
Definition
autoimmune disease
Term
What is the most common cause of Addison's disease in developing countries?
Definition
miliary TB
Term
What type of cancer most commonly results in Addison's disease?
Definition
primary lung cancer
(often metastasizes to the adrenals)
Term
What clinical findings are consistent with Addison's disease?
Definition
-weakness and hypotension
-diffuse hyperpigmentation
Term
What does a patient with Addison's disease have weakness and hypotension?
Definition
due to sodium loss from mineralocorticoid and glucocorticoid deficiency
Term
Why does a patient with Addison's disease have diffuse hyperpigmentation?
Definition
increased plasma ACTH stimulates melanocytes
Term
What areas is the diffuse hyperpigmentation most apparent in a patient with Addison's disease?
Definition
buccal mucosa
skin
skin creases
Term
What lab findings are consistent with Addison's disease?
Definition
decreased serum sodium, cortisol, bicarb
increased serum potassium, ACTH
Term
What electrolyte findings are consistent with Addison's disease?
Definition
hyponatremia
hyperkalemia
metabolic acidosis
Term
Why would a patient with Addison's disease be hypoglycemic?
Definition
decrease in cortisol (cortisol is gluconeogenic)
Term
What results in Cushing's syndrome?
Definition
excess cortisol secretion
Term
What are the potential etiologies of Cushing's syndrome?
Definition
-primary abnormality in the steroid hormone production by the adrenal cortex
-result of overproduction of ACTH by the pituitary resulting in excessive stimulation of the adrenal cortex
Term
Cushing's disease
Definition
pituitary disorder with increased secretion of pituitary ACTH
Term
Cushing's syndrome
Definition
term for all clinical cases of abnormally high glucocorticoid concentration (cortisol) in the plasma
Term
What type of Cushing's is caused either by pituitary disorder or by an ectopic ACTH-producing tumor?
Definition
ACTH-dependent Cushing's
Term
What is the ACTH concentration in the plasma of a patient with ACTH-dependent Cushings?
Definition
high
Term
What type of Cushing's is caused by glucocorticoid administration for long periods or an adrenal tumor that is producing excess glucocorticoid?
Definition
non-ACTH-dependent Cushing's
Term
What is the ACTH concentration in the plasma of a patient with non-ACTH-dependent Cushing's?
Definition
suppressed
Term
What is the most common pathologic cause of Cushing disease?
Definition
pituitary adenoma
Term
What lab findings are consistent with Cushing disease?
Definition
increased ACTH
increased cortisol
Term
What is the most common cause of adrenal Cushing syndrome?
Definition
adrenal adenoma
Term
What lab findings are consistent with adrenal Cushing syndrome?
Definition
decreased ACTH
increased cortisol
Term
What is the most common cause of ectopic Cushing syndrome?
Definition
small cell carcinoma of the lung
Term
What lab findings are consistent with ectopic Cushing syndrome?
Definition
markedly increased ACTH
increased cortisol
Term
What result would you get with a 24 hr urine free cortisol in a patient with Cushing's?
Definition
high
Term
What result would you get with a 48 hr dexamethasone test in a patient with Cushing's?
Definition
fail to suppress cortisol levels
Term
What finding related to the circadian rhythm would you find in a patient with Cushing's?
Definition
abnormally high evening cortisol level
Term
What would you find with an insulin tolerance test in a patient with Cushing's?
Definition
no cortisol rise with hypoglycemia
Term
What type of Cushing's could a high-dose dexamethasone suppression test suppress cortisol?
Definition
pituitary Cushing syndrome (but not any other types)
Term
iatrogenic Cushing's syndrome
Definition
caused by long-term use of corticosteroids (prednisone)
Term
What is a normal response to dexamethasone?
Definition
suppression of ACTH
decrease in cortisol production
Term
Cortisol enhances _______________ and stimulates the release of _________.
Definition
gluconeogenesis; insulin
Term
Why might a patient with Cushing's be in hypokalemic metabolic alkalosis?
Definition
due to increased weak mineralocorticoids
Term
serum cortisol in pituitary Cushing's
Definition
high
Term
serum cortisol in adrenal Cushing's
Definition
high
Term
serum cortisol in ectopic Cushing's
Definition
high
Term
urine free cortisol in pituitary Cushing's
Definition
high
Term
urine free cortisol in adrenal Cushing's
Definition
high
Term
urine free cortisol in ectopic Cushing's
Definition
high
Term
low-dose dexamethasone test in pituitary Cushing's
Definition
cortisol not suppressed
Term
low-dose dexamethasone test in adrenal Cushing's
Definition
cortisol not suppressed
Term
low-dose dexamethasone test in ectopic Cushing's
Definition
cortisol not suppressed
Term
high-dose dexamethasone test in pituitary Cushing's
Definition
cortisol suppressed
Term
high-dose dexamethasone test in adrenal Cushing's
Definition
cortisol not suppressed
Term
high-dose dexamethasone test in ectopic Cushing's
Definition
cortisol not suppressed
Term
plasma ACTH in pituitary Cushing's
Definition
normal to high
Term
plasma ACTH in adrenal Cushing's
Definition
low
Term
plasma ACTH in ectopic Cushing's
Definition
markedly high
Term
What is a malignant tumor of the alpha-islet pancreatic cells that causes hyperglycemia?
Definition
glucagonoma
Term
clinical manifestation of a glucagonoma
Definition
hyperglycemia
Term
What is a benign tumor of the beta-islet pancreatic cells?
Definition
insulinoma
Term
What is the most common islet cell tumor?
Definition
insulinoma
Term
clinical manifestation of an insulinoma
Definition
fasting hypoglycemia causing mental status abnormalities
Term
What lab findings are consistent with an insulinoma?
Definition
fasting hypoglycemia
increased serum insulin
increased C-peptide
Term
What is a malignant tumor of the alpha-islet pancreatic cells that causes achlorhydira, cholelithiasis, steatorrhea, and diabetes mellitus?
Definition
somatostatinoma
Term
What is a malignant tumor with excessive secretion of vasoactive intestinal peptide (VIP)?
Definition
VIPoma (pancreatic cholera)
Term
clinical manifestations of VIPoma (pancreatic cholera)
Definition
secretory diarrhea
achlorhydria
Term
What is a malignant islet cell tumor that secretes gastrin producing hyperacidity and has a MEN type 1 association?
Definition
Zollinger-Ellison syndrome
(usually gastrinoma)
Term
clinical manifestations of Zollinger-Ellison syndrome
Definition
peptic ulceration
diarrhea
maldigestion of food
Term
What lab finding is consistent with Zollinger-Ellison syndrome?
Definition
serum gastrin >1000 pg/mL
Term
What are the acute regulators of blood glucose concentration?
Definition
insulin and glucagon
Term
What is the key factor that produces organ damage in diabetes mellitus?
Definition
hyperglycemia
Term
What lab findings are consistent with diabetes mellitus?
Definition
hyperglycemia
increased HbA1c (>6%)
Term
diagnostic criteria for DM
Definition
-random plasma glucose >199 plus classic symptoms
-fasting plasma glucose >125
-2 hr glucose level after 75-g glucose challenge >199
-one of these 3 criteria must be present on a subsequent day to confirm the diagnosis
Term
HbA1c
Definition
-glycosylated hemoglobin
-evaluates long-term glycemic control
-represents mean glucose value for preceding 8-12 weeks
-goal is <7% (some use 6.5%)
Term
What causes the glucose intolerance during pregnancy in gestational diabetes?
Definition
anti-insulin effect of human placental lactogen (HPL), cortisol, and progesterone
Term
When should a pregnant woman be screened for gestational diabetes?
Definition
24-28 weeks
Term
What is a positive screen for a 1-hr glucose tolerance test during pregnancy?
Definition
>140
Term
How is a positive 1-hr glucose tolerance test confirmed?
Definition
with a 3-hr GTT
Term
Wermer syndrome
Definition
MEN-1
rare heritable disorder
Term
What endocrine tissues are affected by MEN-1?
Definition
parathyroid
pancreas
pituitary
Term
Sipple syndrome
Definition
MEN-2a
Term
What type of tumors are associated with MEN-2a?
Definition
pheochromocytoma
medullary carcinoma
parathyroid hyperplasia
Term
What type of tumors are associated with MEN-2b?
Definition
medullary thyroid coarcinoma
pheochromocytoma
neuroma
ganglioneuroma
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