Endocrinology_1 Flashcards
1
Q
Thyroid diverticulum arises from what?
A
floor of primitive pharynx–> descends into neck
2
Q
thyroid connected to tongue by what?
A
thyroglossal duct, which normally disappears but may persist as pyramidal lobe of the thyroid
3
Q
foramen cecum is what?
A
normal remnant of thyroglossal duct
4
Q
most common ectopic thyroid tissue site is where?
A
tongue
5
Q
thyroglossal duct cyst presents as what?
A
an anterior midline neck mass that moves with swallowing
6
Q
thyroglossal duct cyst must be dDx from what?
A
persistent cervical sinus leading to branchial cleft cyst in lateral neck
7
Q
fetal adrenal gland consists of what?
A
an outer adult zone and an inner active fetal zone
8
Q
features of adult zone of fetal adrenal gland?
A
dormant during early fetal life, but begins to secrete cortisol late in gestation
9
Q
control of cortisol secretion in fetus?
A
controlled by ACTH and CRH from fetal pituitary and placenta.
10
Q
role of cortisol in fetal development?
A
cortisol is responsible for fetal lung maturation and surfactant production
11
Q
adrenal cortex is derived from which germ layer?
A
mesoderm
12
Q
adrenal medulla is derived from which germ layer?
A
neural crest
13
Q
layers of adrenal gland from outer to inner?
A
Capsule –>• Zona Glomerulosa–>• Zona Fasciculata –>• Zona Reticularis–>• Medulla- Chromaffin cells
14
Q
in adrenal gland, GFR corresponds with what?
A
Salt (Na+), Sugar (glucocorticoids), Sex (androgens)• The deeper you go the sweeter it gets
15
Q
secretory product of Zona Glomerulosa of adrenal gland?
A
Aldosterone
16
Q
secretory product of Zona Fasciculata of adrenal gland?
A
cortisol, sex hormones
17
Q
secretory product of the zona reticularis of the adrenal gland?
A
Sex hormones (androgens)
18
Q
secretory products of chromaffin cells?
A
catecholamines
19
Q
Primary regulatory control of the Zona Glomerulosa?
A
Renin-Angiotensin
20
Q
primary regulatory control of the Zona Fasciculata?
A
ACTH• hypothalamic CRH
21
Q
primary regulatory control of the Zona Reticularis?
A
ACTH, hypothalamic CRH
22
Q
primary regulatory control of adrenal medulla?
A
preganglionic sympathetic fibers
23
Q
most common tumor of the adrenal medulla in adults?
A
pheochromocytoma
24
Q
most common tumor of the adrenal medulla in children?
A
neuroblastoma
25
difference in the presentation between pheochromocytoma and neuroblastoma?
pheochromocytoma causes episodic hypertension and neuroblastoma does not
26
what is the venous drainage of the left adrenal gland?
left adrenal --> left adrenal vein --> left renal vein --> IVC
27
what is the drainage of the right adrenal gland?
right adrenal --> right adrenal vein --> IVC
28
function of the posterior pituitary (neurohypophysis)?
Secretes ADH and oxytocin, made in the hypothalamus and shipped to the posterior pituitary via neurophysins (carrier proteins).
29
posterior pituitary is derived from which germ layer?
neuroectoderm
30
function of the anterior pituitary?
Secretes FSH, LH, ACTH, TSH, prolactin, GH, melanotropin (MSH)
31
anterior pituitary is derived from which germ layer?
derived from oral ectoderm (rathke's pouch)
32
α subunit is the hormone subunit common to which hormones?
TSH• LH• FSH• hCG
33
function of the β subunit of anterior pituitary hormones?
determines hormone specificity
34
acidophils of the anterior pituitary secrete what?
GH • prolactin
35
how do you remember the hormones secreted by basophils of the anterior pituitary?
B-FLAT• Basophils- FSH, LH, ACTH, TSH
36
how do you remember the hormones secreted by the anterior pituitary?
FLAT PiG: • FSH, LH, ACTH, TSH, Prolactin, GH
37
Islets of Langerhans are collections of what types of cells?
α, β, δ endocrine cells
38
Islets of Langerhans arise from what?
pancreatic buds
39
what is the position and major product of the α cells of the pancreas?
glucagon (peripheral)
40
what is the position and major product of the β cells of the pancreas?
insulin (central)• INSulin INSide
41
what is the position and major product of the δ cells of the islets of Langerhans?
somatostatin (interspersed)
42
what is the major regulator of insulin release?
glucose
43
how is insulin released?
ATP generated by glucose metabolism closes K+ channels and depolarizes β cell membrane --> opens voltage gated Ca++ channels. • Ca++ influx stimulates insulin secretion
44
does insulin cross the placenta?
no
45
what are the tissues that have insulin-dependent glucose uptake?
Brain, RBC's, Intestine, Cornea, Kidney, Liver• BRICK L
46
what are the insulin dependent glucose transporters?
GLUT-4
47
what is the bidirectional glucose transporter?
GLUT2
48
what is the distribution of GLUT-1?
RBC's Brain
49
what is the distribution of GLUT-2?
β islet cells• liver• kidney• small intestine
50
what is the distribution of GLUT-4?
adipose tissue, skeletal muscle
51
what are the anabolic effects of insulin?
1. increase glucose transport in skeletal muscle and adipose• 2. increase glycogen synthesis and storage• 3. increase triglyceride synthesis and storage• 4. increase Sodium retention in the kidney• 5. increase protein synthesis in the muscles• 6. increase cellular uptake of K+ and amino acids• 7. decrease glucagon release
52
which regulators lead to an increase in insulin?
hyperglycemia• GH• β2 antagonists
53
which regulators lead to a decrease in insulin?
hypoglycemia• somatostatin• α2- agonists
54
which is the insulin independent transporter?
GLUT-1
55
which tissues depend on insulin for increased glucose uptake?
resting skeletal muscle and adipose tissue (GLUT-4)
56
which tissues take up glucose independent of insulin levels?
Brain and RBC (GLUT-1)
57
Brain depends on what substances for energy?
depends on glucose for metabolism under normal circumstances and uses ketone bodies in starvation
58
RBC's depend on what substance for energy?
RBC's always depend on glucose because they have no mitochondria for aerobic metabolism
59
what is the source of glucagon?
made by α cells of the pancreas
60
what are the catabolic effects of glucagon?
glycogenolysis• gluconeogenesis• lipolysis• ketone production
61
how is glucagon regulated?
secreted in response to hypoglycemia• inhibited by insulin, hyperglycemia, and somatostatin
62
what stimulates the release of TSH and prolactin?
TRH
63
what inhibits the release of prolactin?
dopamine
64
what is the function of CRH?
stimulates the release of ACTH, MSH, β-endorphin
65
what is the function of GHRH?
stimulate the release of GH
66
what inhibits the release of GH and TSH?
somatostatin
67
what is the function of GnRH?
stimulate the release of FSH and LH
68
what inhibits the release of GnRH?
prolactin
69
what is the source of prolactin?
secreted mainly by anterior pituitary
70
what is the function of prolactin?
stimulates milk production in breast; inhibits ovulation in females and spermatogenesis in males by inhibiting GnRH synthesis and release
71
prolactin secretion from anterior pituitary is tonically inhibited by what?
dopamine from hypothalamus
72
how does prolactin inhibit its own secretion?
by increasing dopamine synthesis and secretion from hypothalamus
73
what hormone increases prolactin secretion?
TRH
74
what inhibits prolactin secretion and can be used in treatment of prolactinoma?
dopamine agonists (bromocriptine)
75
which drugs stimulate prolactin secretion?
dopamine antagonists (most antipsychotics)• estrogens (OCP's, pregnancy)
76
what is the source of growth hormone?
secreted mainly by anterior pituitary
77
what is the function of growth hormone?
stimulates linear growth and muscle mass through IGF-1/somatomedin secretion
78
what is the effect of GH on blood sugar?
increases insulin resistance (diabetogenic)
79
GH is released in pulses in response to what?
GHRH
80
when does GH secretion increase?
during exercise and sleep
81
secretion of GH is inhibited by what?
glucose and somatostatin
82
what can cause excess secretion of GH?
pituitary adenoma
83
excess secretion of GH can cause what?
acromegaly in adults or gigantism in children
84
which hormone activates cholesterol desmolase?
ACTH
85
which drug inhibits cholesterol desmolase?
ketoconazole
86
what is the function of desmolase?
converts cholesterol into pregnenolone
87
what is the function of 3β-hydroxy steroid dehydrogenase?
1. converts pregnenolone to progesterone• 2. converts 17-hydroxypregnenolone into 17-hydroxyprogesterone• 3. converts dihydroepiandosterone (DHEA) into androstenedione
88
what is the function of 17α-hydroxylase?
converts pregnenolone to 17-hydroxypregnenolone and converts progesterone into 17-hydroxyprogesterone
89
what is the function of 21-hydroxylase?
1. converts progesterone into 11-deoxycorticosterone• 2. converts 17-hydroxyprogesterone into 11-deoxycortisol
90
what is the function of 11β-hydroxylase?
1. converts 11-deoxycorticosterone into corticosterone• 2. converts 11-deoxycortisol into cortisol
91
what is the function of aldosterone synthase?
converts corticosterone into aldosterone
92
what hormone activates aldosterone synthase?
angiotensin II
93
what is the function of aromatase?
1. converts androstenedione to estrone• 2. converts testosterone to estradiol
94
what is the function of 5α-reductase?
converts testosterone into DHT
95
all congenital adrenal enzyme deficiencies are characterized by what?
enlargement of both adrenal glands due to high ACTH stimulation because of low cortisol
96
what are the hormone levels seen in 17α-hydroxylase deficiency?
high mineralocorticoids• low cortisol• low sex hormones
97
how does 17α-hydroxylase deficiency present in both sexes?
hypertension, hypokalemia
98
what are the presenting features of 17α-hydroxylase deficiency that are unique to males?
low DHT--> pseudohermaphroditism (variable, ambiguous genitalia; undescended testes)
99
what are the presenting features of 17α-hydroxylase deficiency unique to females?
external phenotypic female with normal internal sex organs, lacks 2ndary sex characteristics
100
what is the most common form of congenital bilateral adrenal hyperplasia?
21-hydroxylase deficiency
101
what are the hormone levels seen in 21-hydroxylase deficiency?
low mineralocorticoids• low cortisol• high sex hormones
102
how does 21-hydroxylase deficiency present?
hypotension, hyperkalemia, increase renin activity, volume depletion• - masculinization, leading to pseudohermaphrodtism in females
103
what are the hormone levels seen in 11β-hydroxylase deficiency?
low aldosterone• high 11-deoxycorticosterone• low cortisol• high sex hormones
104
how does 11β-hydroxylase deficiency present?
hypertension (11-deoxycorticosterone is a mineralocorticoid and secreted in excess)• masculinization
105
what is the source of cortisol?
adrenal zona fasciculata
106
cortisol is bound to what in the blood?
corticosteroid-binding globulin
107
what are the functions of cortisol?
1. maintains blood pressure• 2. decreases bone formation• 3. anti-inflammatory/immunosuppressive• 4. increases insulin resistance• 5. increases gluconeogenesis, lipolysis, proteolysis• 6. inhibits fibroblasts
108
how does cortisol act to maintain blood pressure?
upregulates α1 receptors on arterioles --> increased sensitivity to NE and Epi
109
what are the anti-inflammatory/immunosuppressive functions of cortisol?
1. inhibits production of leukotrienes and prostaglandins• 2. inhibits leukocyte adhesion--> neutrophilia• 3. blocks histamine release from mast cells• 4. reduces eosinophils• 5. blocks IL-2 production
110
what is the effect of chronic stress on cortisol levels?
chronic stress induces prolonged secretion
111
what is the effect of CRH on cortisol?
CRH (hypothalamus) stimulates ACTH release (pituitary), causing cortisol production in adrenal zona fasciculata.
112
what is the effect of excess cortisol on the hypothalamic pituitary axis?
leads to decreased CRH, ACTH, and cortisol secretion
113
what is the source of PTH?
Chief cells of the parathyroid
114
what is the effect of PTH on serum Ca2+, PO4, and urine PO4?
increase serum Ca++• decrease serum PO4• increase urine PO4
115
what are the functions of PTH?
1. increase bone resorption of calcium and PO4• 2. increase kidney resorption of calcium in DCT• 3. decrease resorption of PO4 in PCT• 4. increase 1,25-OH2VitD production by stimulating kidney 1α-hydroxylase• 5. increase production of M-CSF and RANK-L in osteoblasts, stimulating osteoclasts
116
what is the effect of decreased serum calcium on PTH?
increase PTH secretion
117
what is the effect of decreased serum magnesium on PTH secretion?
increase PTH secretion
118
what is the effect of a dramatic decrease in serum magnesium on PTH?
decrease PTH secretion
119
what are the common causes of decreased Mg2+?
diarrhea• aminoglycosides• diuretics• alcohol abuse
120
what is the source of Vitamin D?
1. D3 from sun exposure in skin• 2. D2 ingested from plants• - Both converted to 25-OH in liver and to 1,25-(OH)2 (active form) in kidney.
121
what is 24,25-(OH)2D3?
an inactive form of vitamin D
122
Vitamin D deficiency causes what?
rickets in kids and osteomalacia in adults
123
what is the function of vitamin D?
1. increase absorption of dietary Ca and PO4• 2. increase bone resorption of Ca and PO4
124
which regulators cause an increase in 1,25-OH2 Vit D production?
1. high PTH• 2. low [Ca++]• 3. low PO4
125
what regulators cause a decrease in 1,25-OH2 Vit D production?
1,25-OH2 Vit D feedback
126
what is the difference between PTH and Vitamin D?
PTH leads to increase Ca++ reabsorption and decrease PO4 reabsorption in the kidney, whereas 1,25-OH2 Vit D leads to increased absorption of both Ca++ and PO4 in the gut.
127
what is the source of calcitonin?
parafollicular cells (C cells) of the thyroid
128
what is the function of calcitonin?
decrease bone resorption of calcium• opposes actions of PTH• not important in normal calcium homeostasis.
129
how is calcitonin regulated?
high serum calcium causes calcitonin secretion
130
which endocrine hormones act via the cAMP signaling mechanism?
FSH, LH, ACTH, TSH, CRH, hCG, ADH (V2 receptor), MSH, PTH, calcitonin, GHRH, glucagon• - FLAT ChAMP
131
which hormones act via the cGMP signaling mechanism?
ANP• NO (EDRF)• think vasodilators
132
which hormones act via the IP3 signaling mechanism?
GnRH, GHRH, Oxytocin, ADH (V1 receptor), TRH, histamine (H1), ATII, gastrin• GGOAT
133
which hormones act via the steroid receptor mechanism?
Vitamin D, Estrogen, Testosterone, T3/T4, Cortisol, Aldosterone, Progesterone• VETTT CAP
134
which hormones act via the intrinsic tyrosine kinase signaling mechanism?
insulin• IGF-1• FGF• PDGF• EGF• MAP kinase pathway• Think growth factors
135
which hormones act via the Receptor-associated tyrosine kinase signaling mechanism?
Prolactin, Immunomodulators (cytokines, IL2, IL6, IL8, IFN), GH• JAK/STAT pathway• Think acidophiles and cytokines
136
what is the effect of high sex hormone-binding globulin in men?
lowers free testosterone--> gynecomastia
137
what is the effect of low SHBG in women?
raises free testosterone--> hirsutism
138
when do SHBG levels increase in women?
during pregnancy
139
what are T3/T4?
iodine- containing hormones that control the body's metabolic rate
140
what is the source of T3/T4?
follicles of thyroid. most T3 formed in target tissues
141
what is the function of T3/T4?
1. bone growth (synergism with GH)• 2. CNS maturation• 3. increase β1 receptors in heart--> high CO, HR, SV, contractility• 4. increase basal metabolic rate via high Na/K ATPase activity = high O2 consumption, RR, body temperature• 5. increases glycogenolysis, gluconeogenesis, lipolysis
142
what binds thyroid hormones?
thyroxine binding globulin binds most T3/T4 in blood; only free hormone is active
143
when is TBG low?
hepatic failure
144
when is TBG high?
pregnancy/OCP• estrogen increases TBG
145
what is the major thyroid product?
T4 is major thyroid product
146
how is T3 made?
T4 is converted to T3 in peripheral tissue by 5'-deiodinase
147
which thyroid hormone has the higher receptor affinity?
T3>T4
148
thyroid peroxidase is responsible for what?
oxidation and organification of iodide as well as coupling of MIT and DIT
149
propylthiouracil inhibits what?
both peroxidase and 5'-deiodinase
150
methimazole inhibits what?
peroxidase
151
what are the functions of T3
4B's• Brain Maturation• Bone growth• Beta-adrenergic effects• Basal metabolic rate
152
function of TBG?
binds most T3/T4 in blood; only free hormone is active
153
what is cushings syndrome?
high cortisol due to a variety of causes
154
what is the #1 cause of Cushings syndrome?
exogenous (iatrogenic) steroids• (presents with low ACTH)
155
what are the endogenous causes of Cushing's syndrome?
1. Cushing's disease• 2. Ectopic ACTH• 3. Adrenal adenoma
156
what fraction of endogenous Cushing's syndrome is caused by ACTH secretion from pituitary adenoma?
70%
157
what fraction of endogenous Cushing's syndrome is caused by ectopic ACTH from nonpituitary tissue making ACTH?
15%
158
what fraction of endogenous Cushing's syndrome is caused by adrenal adenoma, carcinoma, nodular adrenal hyperplasia?
15%
159
ACTH level in Cushings disease?
high
160
ACTH level in Cushings syndrome from small cell lung cancer or bronchial carcinoids?
high
161
ACTH level in Cushing's syndrome caused by adrenal adenoma, carcinoma, nodular adrenal hyperplasia?
low
162
what are the findings in Cushing's syndrome?
1. HTN• 2. weight gain• 3. moon facies• 4. truncal obesity• 5. buffalo hump• 6. hyperglycemia• 7. skin changes• 8. osteoporosis• 9. amenorrhea• 10. immunosuppresion
163
what is the effect of dexamethasone suppression test on cortisol in a normal individual?
1. Low dose= suppressed• 2. high dose= suppressed
164
what is the effect of the dexamethasone suppression test on cortisol in individuals with ACTH-pituitary tumor?
1. low= remains elevated• 2. high= suppressed
165
what is the effect of the dexamethasone suppression test on cortisol in an individual with ectopic ACTH producing tumor?
1. low= remains elevated• 2. high= remains elevated
166
what is the effect of the dexamethasone suppression test on cortisol in an individual with cortisol-producing tumor?
1. low= remains elevated• 2. high= remains elevated
167
primary hyperaldosteronism is caused by what?
adrenal hyperplasia or an aldosterone-secreting adrenal adenoma (Conn's syndrome) • - may be bilateral or unilateral
168
primary hyperaldosteronism results in what?
hypertension• hypokalemia• metabolic acidosis• low plasma renin
169
what is the treatment for primary hyperaldosteronism?
surgery to remove the tumor and/or spironolactone, a K+ sparing diuretic that works by acting as an aldosterone antagonist
170
what happens in secondary hyperaldosteronism?
renal perception of low intravascular volume results in an overactive renin-angiotensin system.
171
what causes secondary hyperaldosteronism?
renal artery stenosis• chronic renal failure• CHF• cirrhosis• nephrotic syndrome
172
what is the renin level in secondary hyperaldosteronism?
high
173
what is the treatment for secondary hyperaldosteronism?
spironolactone
174
what is Addison's disease?
Chronic primary adrenal insufficiency due to adrenal atrophy or destruction by disease (autoimmune, TB, metastasis)--> deficiency of aldosterone and cortisol
175
deficiency of aldosterone and cortisol in Addison's causes what?
hypotension (hyponatremic volume contraction)• hyperkalemia• acidosis• skin hyperpigmentation
176
why is there hyperpigmentation in Addison's?
MSH, a by-product of high ACTH production from POMC
177
Addison's involves which parts of the adrenals?
all 3 cortical divisions• medulla spared
178
Addison's must be distinguished from what?
secondary adrenal insufficiency (low pituitary ACTH production), which has no skin hyperpigmentation and no hyperkalemia
179
what is Waterhouse-Friderichsen syndrome?
Acute primary adrenal insufficiency due to adrenal hemorrhage associated with Neisseria meningitidis septicemia, DIC, and endotoxic shock
180
what is the most common tumor of the adrenal medulla in adults?
pheochromocytoma
181
pheochromocytoma is derived from what?
chromaffin cells (arise from neural crest)
182
what is the rule of 10's for pheochromocytoma?
10% malignant• 10% blateral• 10% extra-adrenal• 10% calcify• 10% kids
183
most pheochromocytomas secrete what?
Epi• NE• dopamine• which can cause episodic hypertension
184
lab findings in pheochromocytoma?
Urinary VMA and plasma catecholamines are elevated
185
pheochromocytoma is associated with which conditions?
NF1• MEN2A• MEN2B
186
what is the treatment for pheochromocytoma?
tumor surgically removed only after effective α and β blockade is achieved:• irreversible α-antagonists (phenoxybenzamine) must be given first to avoid a hypertensive crisis. β blockers are then given to slow the heart rate
187
what are the episodic hyperadrenergic symptoms of pheochromocytoma?
5 P's:• Pressure• Pain• Perspiration• Palpitations• Pallor
188
what is the most common tumor of the adrenal medulla in children?
neuroblastoma
189
where can neuroblastoma occur?
anywhere along the sympathetic chain
190
lab values for neuroblastoma?
elevated urine homovanillic acid (HVA)
191
which out of the common tumors of the adrenal medulla is more likely to cause hypertension?
pheochromocytoma > neuroblastoma
192
what is associated with rapid tumor progression in neuroblastoma?
overexpression of N-myc oncogene
193
signs/symptoms of hypothyroidism?
1. Cold intolerance (low heat production)• 2. Weight gain, decreased appetite• 3. hypoactivity, lethargy, fatigue, weakness• 4. constipation• 5. decreased reflexes• 6. myxedema (facial/periorbital)• 7. dry cool skin; coarse brittle hair• 8. bradycardia, dyspnea on exertion
194
signs/symptoms of hyperthyroidism?
1. heat intolerance (high heat production)• 2. weight loss, increased appetite• 3. hyperactivity• 4. diarrhea• 5. high reflexes• 6. pretibial myxedema (Graves)• 7. warm moist skin; fine hair• 8. chest pain, palpitations, arrhythmias, increased β-adrenergic receptors
195
lab findings in hypothyroidism?
high TSH• low free T4
196
lab findings in hyperthyroidism?
low TSH• high free or total T4• high free or total T3
197
what is the most common cause of hypothyroidism?
Hashimoto's thyroiditis
198
what are the autoantibodies in Hashimoto's thyroiditis directed at?
thyroid peroxidase• antithyroglobulin
199
Hashimoto thyroiditis is associated with which haplotype?
HLA-DR5
200
people with hashimoto thyroiditis have an increased risk of what?
Hodgkin's lymphoma
201
what is the histology seen in Hashimoto thyroiditis?
Hurthle cells• lymphocytic infiltrate with germinal centers
202
what are the PE findings in Hashimoto thyroiditis?
moderately enlarged nontender thyroid
203
when can Hashimoto thyroiditis present as hyperthyroidism?
early in the course
204
what causes hyperthyroid Hashimoto thyroiditis?
thyrotoxicosis during follicular rupture
205
Cretinism happens due to what?
severe fetal hypothyroidism
206
where does endemic cretinism occur?
where ever endemic goiter is prevalent
207
sporadic cretinism is caused by what?
defect in T4 formation or developmental failure in thyroid formation
208
what are the PE findings in cretinism?
5P's:• Pot belly• Pale• Puffy faced child• Protruding umbilicus• Protuberant tongue
209
what is subacute thyroiditis (de Quervain's)?
self limited hypothyroidism often following a flu like illness
210
what is the histology seen in de Quervan's thyroiditis?
granulomatous inflammation
211
what are the findings in de Quervain's thyroiditis?
high ESR• jaw pain• early inflammation• very tender thyroid
212
what is Riedel's thyroiditis?
thyroid replaced by fibrous tissue
213
Riedel's thyroiditis is considered a menifestation of what?
IgG4 related systemic disease
214
what are the findings in Riedel's thyroiditis?
fixed hard painless goiter
215
what are the other causes of hypothyroidism?
congenital hypothyroidism• iodine deficiency• goitrogens• Wolff-Chaikoff effect• painless thyroiditis
216
what happens in toxic multinodular goiter?
focal patches of hyperfunctioning follicular cells working independently of TSH due to mutation in TSH receptor-->• increased release of T3/T4
217
which type of thyroid nodules are less likely to be malignant?
hot nodules
218
what is the Jod-Basedow phenomenon?
thyrotoxicosis if a patient with iodine deficiency goiter is made iodine replete
219
what is Grave's disease?
an autoimmune hyperthyroidism with thyroid-stimulating immunoglobulins
220
findings in Grave's disease?
Ophthalmopathy (proptosis, EOM swelling)• pretibial myxedema• increase in connective tissue deposition• diffuse goiter
221
Grave's disease often presents when?
during stress (child birth)
222
what is thyroid storm?
stress-induced catecholamine surge leading to death by arrhythmia.
223
thyroid storm is seen as a complication of what?
Grave's and other hyperthyroid disorders
224
what lab level may be seen in Grave's disease?
high ALP due to high bone turn over
225
what is the most common thyroid cancer?
papillary carcinoma
226
prognosis for papillary carcinoma thyroid is what?
excellent
227
what are the histologic features of papillary carcinoma of thyroid?
empty appearing nuclei (Orphan Annie's eyes) psammoma bodies, nuclear grooves
228
increased risk of papillary carcinoma of thyroid is associated with what?
childhood irradiation
229
what is the prognosis associated with follicular carcinoma of the thyroid?
GOOD
230
how does follicular carcinoma of the thyroid appear histologically?
uniform follicles
231
cellular origin of medullary carcinoma of thyroid?
from parafollicular C cells
232
medullary carcinoma of thyroid produces what?
calcitonin
233
histologic appearance of medullary carcinoma of thyroid?
sheets of cells in amyloid stroma
234
medullary carcinoma of the thyroid is associated with which conditions?
MEN types 2A and 2B
235
features of anaplastic undifferentiated carcinoma of thyroid?
- older patients• - very poor prognosis
236
thyroid lymphoma is associated with what condition?
Hashimoto's thyroiditis
237
primary hyperparathyroidism is usuallly caused by what?
usually an adenoma
238
findings in primary hyperparathyroidism?
1. hypercalcemia• 2. hypercalciuria (renal stones)• 3. hypophosphatemia• 4. high PTH• 5. high ALP• 6. high cAMP in urine
239
clinical presentation of primary hyperparathyroidism?
often asymptomatic, or may present with weakness and constipation
240
what is the skeletal complication of primary hyperparathyroidism?
Osteitis fibrosa cystica
241
what causes secondary hyperparathyroidism?
secondary hyperplasia due to decreased gut Ca++ absorption and increased phosphate, most often in chronic renal disease
242
how does chronic renal disease cause secondary hyperparathyroidism?
causes hypovitaminosis D --> low Ca++ absorption
243
what are the findings in secondary hyperparathyroidism?
hypocalcemia, hyperphosphatemia in chronic renal failure (hypophosphatemia in most other causes), high ALP, high PTH
244
what is the skeletal complication associated with secondary or tertiary hyperparathyroidism?
Renal osteodystrophy
245
what is seen in osteitis fibrosa cystica?
cystic bone spaces filled with brown fibrous tissue (bone pain)
246
what is renal osteodystrophy?
bone lesions due to secondary or tertiary hyperparathyroidism due in turn to renal disease
247
what is tertiary hyperparathyroidism?
refractory (autonomous) hyperparathyroidism resulting from chronic renal disease
248
findings in tertiary hyperparathyroidism?
very high PTH• high Ca++
249
hypoparathyroidism is due to what?
accidental surgical excision, autoimmune destruction, or DiGeorge syndrome
250
what are the findings in hypoparathyroidism?
hypocalcemia• tetany
251
what is Chvostek's sign?
tapping of facial nerve --> contraction of facial muscles
252
what is Trousseau's sign?
occlusion of brachial artery with BP cuff--> carpal spasm
253
what is the eponym of pseudohypoparathyroidism?
(Albright's hereditary osteodystrophy)
254
what is pseudohypoparathyroidism?
autosomal dominant kidney unresponsiveness to PTH
255
what are the findings in pseudohypoparathyroidism?
hypocalcemia• shortened 4th/5th digits• short stature
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what is the diagnosis when there is high calcium and high-normal/high PTH?
primary hyperparathyroidism (hyperplasia, adenoma, carcinoma)
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what is the diagnosis when there is high calcium and low PTH?
PTH-independent hypercalcemia (excess calcium ingestion, cancer)
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what is the diagnosis when there is low calcium and high-normal/high PTH?
secondary hyperparathyroidism (chronic renal failure)
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what is the diagnosis when there is low calcium and low PTH?
hypoparathyroidism (surgical removal, autoimmune destruction)
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pituitary adenomas are most commonly what?
prolactinoma
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what are the findings in prolactinoma?
amenorrhea, galactorrhea, low libido, infertility (low GnRH).
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prolactinoma can impinge on what structure?
optic chiasm--> bitemporal hemianopsia
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what is the treatment for prolactinoma?
dopamine agonists (bromocriptine or cabergoline) cause shrinkage of prolactinoma
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what causes acromegaly?
excess GH in adults
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excess GH in adults is typically caused by what?
pituitary adenoma
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findings in acromegaly?
large tongue with deep furrows• deep voice• large hands and feet• coarse facial features• impaired glucose tolerance
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increased GH in children leads to what?
gigantism ( increased linear bone growth)
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how is acromegaly diagnosed?
high serum IGF-1• failure to suppress serum GH following oral glucose tolerance test• pituitary mass seen on MRI
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what is the treatment for acromegaly?
pituitary adenoma resection followed by somatostatin analog if not cured
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Diabetes insipidus is characterized by what?
intense thirst and polyuria together with an inability to concentrate urine owing to lack of ADH or to a lack of renal response to ADH
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what causes central DI?
lack of ADH• - pituitary tumor• - trauma• - surgery• - histiocytosis X
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what causes nephrogenic DI?
hereditary• or• secondary to hypercalcemia, lithium, demeclocycline
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what is demeclocycline?
ADH antagonist
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what are the findings in diabetes insipidus?
urine specific gravity <1.006; serum osmolality >290 mOsm/L
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how is diabetes insipidus diagnosed?
Water deprivation test- urine osmolality doesn't increase.• Response to desmopressin distinguishes central DI from nephrogenic DI
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what is the treatment for central DI?
1. adequate fluid intake• 2. intranasal desmopressin (ADH analog)
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what is the treatment for nephrogenic DI?
HCTZ/• Indomethacin/• amiloride/
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what are the findings in SIADH?
- excessive water retention• - hyponatremia with continued urinary Na+ excretion• - urine osmolarity > serum osmolarity
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how does the body respond to SIADH?
decrease aldosterone (hyponatremia) to maintain near normal volume status
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very low sodium levels in SIADH can lead to what?
seizures (correct slowly)
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causes of SIADH include what?
1. Ectopic ADH (small cell lung cancer)• 2. CNS disorder/head trauma• 3. pulmonary disease• 4. drugs like cyclophosphamide
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what is the treatment for SIADH?
fluid restriction• IV saline• conivaptan• tolvaptan• demeclocycline
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hypopituitarism is what?
undersecretion of pituitary hormones
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undersecretion of pituitary hormones can be due to what?
1. nonsecreting pituitary adenoma, craniopharyngioma• 2. Sheehan's syndrome• 3. Empty sella syndrome• 4. brain injury; hemorrhage• 5. radiation
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what is the treatment for hypopituitarism?
substitution therapy (corticosteroids, thyroxine, sex steroids, human growth hormone)
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what is Sheehan's syndrome?
ischemic infarct of pituitary following postpartum bleeding; usually presents with failure to lactate
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what is Empty sella syndrome?
atrophy or compression of pituitary, often idiopathic, common in obese women
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what are the acute manifestations of diabetes mellitus?
1. polydipsia• 2. polyuria• 3. polyphagia• 4. weight loss• 5. DKA (type 1), hyperosmolar coma (type 2)• 6. unopposed secretion of GH and epinephrine (exacerbating hyperglycemia
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in the acute manifestations of diabetes mellitus, insulin deficiency and glucagon excess lead to what?
1. decreased glucose uptake• 2. increased protein catabolism• 3. increased lipolysis
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in the acute manifestations of diabetes mellitus, decreased glucose uptake leads to what?
1. hyperglycemia• 2. glycosuria• 3. osmotic diuresis• 4. electrolyte depletion• -->dehydration, acidosis• --> coma, death
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in the acute manifestations of diabetes mellitus increased protein catabolism leads to what?
increased plasma amino acids, nitrogen loss in the urine• -->• 1. hyperglycemia• 2. glycosuria• 3. osmotic diuresis• 4. electrolyte depletion• -->dehydration, acidosis• --> coma, death
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in the acute manifestations of Diabetes mellitus, increased lipolysis leads to what?
1. increased plasma FFA's• 2. ketogenesis• 3. ketonuria• 4. ketonemia• -->dehydration, acidosis• --> coma, death
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what are the 2 major causes of the chronic manifestations of Diabetes mellitus?
Nonenzymatic Glycosylation• Osmotic damage
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what happens in small vessel disease caused by nonenzymatic glycosylation in DM?
diffuse thickening of basement membrane --> retinopathy, glaucoma, nephropathy
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what are the features of DM retinopathy that occurs as a result of nonenzymatic glycosylation in small vessels?
hemorrhage, exudates, microaneurysms, vessel proliferation
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what are the features of DM nephropathy caused by nonenzymatic glycosylation of small vessels?
nodular sclerosis• progressive proteinuria• chronic renal failure• arteriosclerosis leading to hypertension• Kimmelstiel-Wilson nodules
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what are the chronic effects of nonenzymatic glycosylation of large vessels in DM?
large vessel atherosclerosis• CAD• peripheral vascular occlusive disease• gangrene • --> limbloss, cerebrovascular disease
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what causes osmotic damage in chronic DM?
sorbitol accumulation in tissues with aldose reductase
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what are the features of neuropathy caused by chronic osmotic damage in DM?
motor, sensory, and autonomic degeneration
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what are the ophthalmic effects of chronic osmotic damage in DM?
cataracts
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what are the tests to monitor chronic diabetes?
fasting serum glucose• oral glucose tolerance test• HbA1C
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HbA1C reflects what?
average blood glucose over prior 3 months
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what is the primary defect in DM1 vs. DM2?
DM1: autoimmune destruction of β cells• DM2: increased resistance to insulin, progressive pancreatic β cell failure
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is insulin necessary in treatment of DM1 and DM2?
DM1: always• DM2: sometimes
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what is the age of onset of DM1 vs. DM2?
DM1: <30• DM2: >40
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do DM1 and DM2 have an association with obesity?
DM1: no• DM2: yes
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are DM1 and DM2 associated with a genetic predisposition?
DM1: relatively weak, polygenic• DM2: relatively strong, poly genic
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what is the concordance between identical twins for DM1?
50%
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what is the concordance between identical twins for DM2?
90%
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Are DM1 and DM2 associated with the HLA system?
DM1: yes- HLA-DR3/4• DM2: No
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what is the degree of glucose intolerance in DM1 and DM2?
DM1: severe• DM2: mild to moderate
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what is the degree of insulin sensitivity in DM1 and DM2?
DM1: high• DM2: low
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what is the frequency of ketoacidosis in DM1 and DM2?
DM1: common• DM2: rare
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what are the β cell numbers in the islets in DM1 and DM2?
DM1: decreased• DM2: variable (with amyloid deposits)
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what are the serum insulin levels in DM1 and DM2?
DM1: low• DM2: variable
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what is the frequency of the classic symptoms of polyuria, polydipsia, polyphagia and weight loss in DM1 and DM2?
DM1: common• DM2: sometimes
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what is the histology in DM1 and DM2?
DM1: islet leukocytic infiltrate• DM2: islet amyloid (AIAPP) deposit
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ketoacidosis is one of the most important complications of what?
DM (usually type I)
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diabetic ketoacidosis is usually due to what?
increased insulin requirements from increased stress
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what is the biochemical basis of diabetic ketoacidosis?
excess fat break down and increased ketogenesis from increased free fatty acids, which are then made into ketone bodies
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which are the most common ketone bodies in diabetic ketoacidosis?
β-hydoxybutyrate > acetoacetate
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what are the signs/symptoms of diabetic ketoacidosis?
Kussmaul breathing (rapid/deep breathing), nausea/vomiting, abdominal pain, psychosis/delirium. fruity breath odor
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what are the lab values seen in diabetic ketoacidosis?
1. hyperglycemia• 2. high H+• 3. low HCO3- (anion gap metabolic acidosis)• 4. high blood ketone levels• 5. leukocytosis• 6. hyperkalemia, but depleted intracellular K+ due to transcellular shift from decreased insulin
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what are the complications of diabetic ketoacidosis?
Life threatening mucor mycosis• Rhizopus infection• cerebral edema• cardiac arrhythmia• heart failure
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what is the treatment for diabetic ketoacidosis?
IV fluids• IV insulin• K+ (to replete intracellular stores)• glucose if necessary to prevent hypoglycemia
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what is carcinoid syndrome?
rare syndrome caused by carcinoid tumors (neuroendocrine cells), especially metastatic small bowel tumors which secrete high levels of serotonin
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carcinoid syndrome is not seen if what?
the tumor is limited to GI tract (5-HT undergoes first- pass metabolism in liver)
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carcinoid syndrome results in what?
recurrent diarrhea, cutaneous flushing, asthmatic wheezing, and right sided valvular disease
329
what are the lab values seen in carcinoid syndrome?
high 5-HIAA in urine• niacin deficiency
330
what is the treatment for carcinoid syndrome?
somatostatin analog (octreotide)
331
what is the rule of 1/3's for carcinoid syndrome?
1/3 metastasize• 1/3 present with second malignancy• 1/3 multiple
332
what is the most common tumor of the appendix?
carcinoid
333
what causes Zollinger-Ellison syndrome?
Gastrin secreting tumor of pancreas or duodenum
334
what does the stomach look like in ZES?
stomach shows rugal thickening with acid hypersecretion
335
ZES causes what?
recurrent ulcers
336
ZES may be associated with what?
MEN type 1
337
what are the characteristic tumors seen in MEN 1 (Wermer's syndrome)?
1. Parathyroid tumors• 2. Pituitary tumors• 3. Pancreatic endocrine tumors
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what are the pituitary tumors seen in MEN1?
prolactin or GH secreting
339
what are the pancreatic endocrine tumors associated with MEN1?
ZES• insulinoma• VIPomas• glucagonomas (rare)
340
MEN1 commonly presents with what?
kidney stones and stomach ulcers
341
what are the tumors seen in MEN 2A (Sipple's syndrome)?
1. Medullary thyroid carcinoma• 2. Pheochromocytoma• 3. Parathyroid tumors
342
medullary thyroid tumors in MEN2A/B secrete what?
calcitonin
343
what tumors are characteristic MEN2B?
1. medullary thyroid• 2. pheochromocytoma• 3. oral/intestinal ganglioneuromatosis
344
oral/intestinal ganglioneuromatosis in MEN2B is associated with what?
marfanoid habitus
345
what is the mnemonic for MEN1?
3P's• Pituitary• Parathyroid• Pancreas• (diamond)
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what is the mnemonic for MEN2A?
2 P's• Parathyroids• Pheochromocytomas• (square)
347
what is the mnemonic for MEN2B?
1P• Pheochromocytoma• (triangle)
348
what is the inheritance of all MEN syndromes?
autosomal dominant
349
MEN is associated with which gene mutation?
MEN2A and MEN2B are associated with ret gene mutation
350
what is the treatment strategy for DM1?
low sugar diet, insulin replacement
351
what is the treatment strategy for DM2?
dietary modification and exercise for weight loss; oral hypoglycemics and insulin replacement
