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Flashcards in Endocrinology_1 Deck (351):
1

Thyroid diverticulum arises from what?

floor of primitive pharynx--> descends into neck

2

thyroid connected to tongue by what?

thyroglossal duct, which normally disappears but may persist as pyramidal lobe of the thyroid

3

foramen cecum is what?

normal remnant of thyroglossal duct

4

most common ectopic thyroid tissue site is where?

tongue

5

thyroglossal duct cyst presents as what?

an anterior midline neck mass that moves with swallowing

6

thyroglossal duct cyst must be dDx from what?

persistent cervical sinus leading to branchial cleft cyst in lateral neck

7

fetal adrenal gland consists of what?

an outer adult zone and an inner active fetal zone

8

features of adult zone of fetal adrenal gland?

dormant during early fetal life, but begins to secrete cortisol late in gestation

9

control of cortisol secretion in fetus?

controlled by ACTH and CRH from fetal pituitary and placenta.

10

role of cortisol in fetal development?

cortisol is responsible for fetal lung maturation and surfactant production

11

adrenal cortex is derived from which germ layer?

mesoderm

12

adrenal medulla is derived from which germ layer?

neural crest

13

layers of adrenal gland from outer to inner?

Capsule -->• Zona Glomerulosa-->• Zona Fasciculata -->• Zona Reticularis-->• Medulla- Chromaffin cells

14

in adrenal gland, GFR corresponds with what?

Salt (Na+), Sugar (glucocorticoids), Sex (androgens)• The deeper you go the sweeter it gets

15

secretory product of Zona Glomerulosa of adrenal gland?

Aldosterone

16

secretory product of Zona Fasciculata of adrenal gland?

cortisol, sex hormones

17

secretory product of the zona reticularis of the adrenal gland?

Sex hormones (androgens)

18

secretory products of chromaffin cells?

catecholamines

19

Primary regulatory control of the Zona Glomerulosa?

Renin-Angiotensin

20

primary regulatory control of the Zona Fasciculata?

ACTH• hypothalamic CRH

21

primary regulatory control of the Zona Reticularis?

ACTH, hypothalamic CRH

22

primary regulatory control of adrenal medulla?

preganglionic sympathetic fibers

23

most common tumor of the adrenal medulla in adults?

pheochromocytoma

24

most common tumor of the adrenal medulla in children?

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

256

what is the diagnosis when there is high calcium and high-normal/high PTH?

primary hyperparathyroidism (hyperplasia, adenoma, carcinoma)

257

what is the diagnosis when there is high calcium and low PTH?

PTH-independent hypercalcemia (excess calcium ingestion, cancer)

258

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

289

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

291

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

292

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

293

what are the 2 major causes of the chronic manifestations of Diabetes mellitus?

Nonenzymatic Glycosylation• Osmotic damage

294

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

298

what causes osmotic damage in chronic DM?

sorbitol accumulation in tissues with aldose reductase

299

what are the features of neuropathy caused by chronic osmotic damage in DM?

motor, sensory, and autonomic degeneration

300

what are the ophthalmic effects of chronic osmotic damage in DM?

cataracts

301

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

303

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

305

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%

310

Are DM1 and DM2 associated with the HLA system?

DM1: yes- HLA-DR3/4• DM2: No

311

what is the degree of glucose intolerance in DM1 and DM2?

DM1: severe• DM2: mild to moderate

312

what is the degree of insulin sensitivity in DM1 and DM2?

DM1: high• DM2: low

313

what is the frequency of ketoacidosis in DM1 and DM2?

DM1: common• DM2: rare

314

what are the β cell numbers in the islets in DM1 and DM2?

DM1: decreased• DM2: variable (with amyloid deposits)

315

what are the serum insulin levels in DM1 and DM2?

DM1: low• DM2: variable

316

what is the frequency of the classic symptoms of polyuria, polydipsia, polyphagia and weight loss in DM1 and DM2?

DM1: common• DM2: sometimes

317

what is the histology in DM1 and DM2?

DM1: islet leukocytic infiltrate• DM2: islet amyloid (AIAPP) deposit

318

ketoacidosis is one of the most important complications of what?

DM (usually type I)

319

diabetic ketoacidosis is usually due to what?

increased insulin requirements from increased stress

320

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

321

which are the most common ketone bodies in diabetic ketoacidosis?

β-hydoxybutyrate > acetoacetate

322

what are the signs/symptoms of diabetic ketoacidosis?

Kussmaul breathing (rapid/deep breathing), nausea/vomiting, abdominal pain, psychosis/delirium. fruity breath odor

323

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

324

what are the complications of diabetic ketoacidosis?

Life threatening mucor mycosis• Rhizopus infection• cerebral edema• cardiac arrhythmia• heart failure

325

what is the treatment for diabetic ketoacidosis?

IV fluids• IV insulin• K+ (to replete intracellular stores)• glucose if necessary to prevent hypoglycemia

326

what is carcinoid syndrome?

rare syndrome caused by carcinoid tumors (neuroendocrine cells), especially metastatic small bowel tumors which secrete high levels of serotonin

327

carcinoid syndrome is not seen if what?

the tumor is limited to GI tract (5-HT undergoes first- pass metabolism in liver)

328

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

338

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)

346

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