Endocrinology Flashcards
1
Q
What receptors on what cells lead to NO release when stimulated?
A
Muscarinic receptors on endothelial cells
2
Q
Most pituitary hormones act via cAMP-linked receptors. Which ones dont and how do they work?
A
GnRH, Oxytocin, and ADH act via IP3 system. Prolactin and GH act via JAK/STAT tyrosine kinases
3
Q
Steroid hormones bind their receptors in the cytoplasm and translocate to the nucleus. What is the exception to this?
A
Thyroid hormones bind their receptor in the nucleus
4
Q
What inhibits uptake and organification of iodide?
A
Anions (perchlorate, pertechnetate) inhibit uptake and excess iodine (Wolff-Chaikoff effect) inhibits organification
5
Q
Why are beta blockers helpful in hyperthyroidism?
A
Combat sympathetic effects (except increased o2 demand and weight loss) and they decrease peripheral T4 to T3 conversion
6
Q
Give the change in cortisol levels in the following conditions during a dexamethasone test (give low dose first then high dose): normal, ACTH-pituitary tumor, ectopic ACTH-producing tumor, cortisol-producing tumor
A
Normal - up (high dose not done). ACTH-pituitary tumor - up down. Ectopic ACTH-producing tumor - up up. Cortisol producing tumor - up up.
7
Q
Conns syndrome
A
Primary hyperaldosteronism
8
Q
Causes of waterhouse-friederichsen syndrome
A
Neisseria meningitidis septicemia, DIC, endotoxic shock
9
Q
Test of choice to diagnose pheochromocytoma
A
Urinary VMA or metanephrines
10
Q
Treatment for pheochromocytoma
A
Alpha antagonists (esp phenoxybenzamine) and surgery
11
Q
Most common extracranial neoplasm in children
A
Neuroblastoma
12
Q
Non-rhythmic eye movements with myoclonus (opsoclonus-myoclonus) in child
A
Neuroblastoma
13
Q
Test of choice for neuroblastoma
A
HVA (breakdown product of dopamine)
14
Q
What genetic change is associated with neuroblastoma
A
N-myc overexpression signals rapid tumor progression
15
Q
Spinal cord compression, pancytopenia, hepatomegaly, palpable nodules, proptosis, truncal ataxia
A
Neuroblastoma
16
Q
Hypotension, tachycardia, hypoglycemia, with existing history of vomiting abdominal pain and weight loss
A
Acute adrenal crisis (will occur in patients with adrenal insufficiency during stress)
17
Q
Increased risk of what cancer in hashimotos thyroiditis
A
Non-hodgkin lymphoma
18
Q
Histology of Hashimotos thyroiditis
A
Lymphocytic infiltrate with germinal centers with Hurthle cells. Thyroid will be moderately enlarged and nontender
19
Q
Cretinism
A
Defect in T4 formation or developmental failure in thyroid formation
20
Q
Pot-bellied, pale, puffy-faced child with protruding umbilicus and protuberant tongue
A
Cretinism
21
Q
Self-limited hypothyroidism following flulike illness
A
Subacute (de Quervain) thyroiditis. Will see granulomatous inflammtion, jaw pain, tender thyroid
22
Q
Riedels thyroiditis
A
Thyroid replaced by fibrous tissue (hypothyroid). Will find fixed, hard painless goiter
23
Q
What do you have to rule out if you suspect Riedels thyroiditis?
A
Iodine deficiency, thyroglossal duct cyst, goitrogens, Wolff-Chaikoff effect
24
Q
Treatment for Graves
A
Glucocorticoids to reduce inflammation
25
What is another name for De Quervains Thyroiditis?
Granulomatous thyroiditis. (also subacute thyroiditis)
26
Give the histology of each of the following thyroid cancers: papillary, follicular, medullary
Papillary - ground glass nuclei, psammoma bodies, nuclear grooves. Follicular - uniform follicles. Medullary - sheets of cells in amyloid stroma
27
What type of bone changes do you see in hyperparathyroidism?
Subperiosteal reabsorption with cystic degeneration
28
What is osteitis fibrosa cystica associated with?
Primary hyperparathyroidism
29
What GI abnormality is primary hyperparathyroidism associated with?
Constipation
30
What is required to diagnose complete central DI?
An increase of 50 percent or greater in urine osmolality on DDAVP administration
31
Lab findings in prolactinoma
Decreased GnRH, decreased LH, decreased testosterone
32
One difference in symptoms between pheochromocytoma and neuroblastoma
Pheochromocytoma causes episodic hypertension
33
To where do the left and right adrenal veins respectively drain?
Left - left renal. Right - IVC
34
What do neurophysins do and what does their deficiency cause?
Carry ADH and oxytocin from hypothalamus to posterior pituitary. Deficiency leads to central DI
35
What are the posterior and anterior pituitary respectively derived from?
Posterior (neurohypophysis) - Neuroectoderm, Anterior (adenohypophysis) - Oral ectoderm (Rathkes pouch)
36
What do the acidophils and basophils of the pituitary gland make?
Acidophils - GH, prolactin. Basophils - FSH, LH, ACTH, TSH
37
What organs dont need insulin for glucose uptake?
Brain, RBCs, Intestine, Cornea, Kidney, Liver
38
What type of transport do GLUT transporters carry out, and what is their specificity for?
Facilitated diffuse for D-glucose
39
What type of receptor is the insulin receptor?
RTK
40
What protein gets activated as a result of insulin receptor stimulation in hepatocytes?
Protein phosphatase (which phosphorylates glycogen synthase)
41
Which glucose transporter is insulin dependent?
GLUT-4
42
Give the pituitary hormones secreted or inhibited by each of the following hypothalamic secretions: TRH, Dopamine, Somatostatin, Prolactin
TRH - stim TSH and prolactin. Dopamine - inhibits prolactin. Somatostatin - inhibits GH and TSH. Prolactin - Inhibits GnRH
43
What substance acts counter to ACTH in synthesis of adrenal hormones?
Ketoconazole (inhibits cholesterol to pregenolone conversion by desmolase, which is stimulated by ACTH)
44
Metyrapol
Inhibits cortisol formation by 11B-hydroxylase. Leads to decreased cortisol and increased ACTH (reflexively)
45
Relative levels of mineralocorticoids, cortisol, and sex hormones in 17a-hydroxylase deficiency
MC - high, cortisol - low, sex hormones - low
46
Relative levels of mineralocorticoids, cortisol, and sex hormones in 21-hydroxylase deficiency
MC - low, cortisol - low, sex hormones - high
47
Relative levels of mineralocorticoids, cortisol, and sex hormones in 11b-hydroxylase deficiency
MC - Aldosterone low but 11-deoxycorticosterone high, cortisol - low, sex hormones - high
48
Hypertension, hypokalemia, male pseudohermaphroditism if XY or female with lacking secondary sex characteristics if XX
17a-hydroxylase deficiency
49
Hypotension, hyperkalemia, increased renin, volume depletion, masculinization, female pseudohermaphroditism
21-hydroxylase deficiency
50
Hypertension, masculinization
11b-hydroxylase deficiency. Contrast with 21-hydroxylase deficiency, which is masculinization with HYPOtension
51
What is the most common congenital adrenal hyperplasia?
21-hydroxylase deficiency
52
What does prolonged ACTH stimulation do to the adrenal gland histologically?
Causes hyperplasia of the fasiculata
53
Treatment of congenital adrenal hyperplasias
Suppress ACTH with exogenous corticosteroids
54
What effect does GH have on IGF-1 production?
Stimulates IGF-1 production in liver (no effect on hypothalamic activity)
55
Amenorrhea, galactorrhea, low libido, infertility
Prolactinoma (pituitary adenoma)
56
What secondary effect can a prolactinoma have in women?
Hypogonadism which leads to osteoporosis (prolactin inhibits GnRH release)
57
Medical treatment for prolactinomas
Bromocriptine or cabergoline (dopamine agonists)
58
Medical treatment for acromegaly
Octreotide
59
What factors cause increased GH release
Stress, exercise, and hypoglycemia
60
Serum sodium in DI
Greater than 142
61
Water deprivation test results in DI
Urine osmolality fails to increase (stays less than 300-500)
62
Treatment for DI
Central - desmopressin. Nephrogenic - HCTZ, indomethacin, or amilioride
63
Typically where is the dysfunction in central DI?
Hypothalamus. Usually posterior pituitary problems only cause transient DI
64
Treatment for SIADH
Demeclocycline or water restriction
65
Causes of SIADH (4)
Ectopic ADH (small cell), 2) CNS disorders/head trauma, 3) Pulmonary disease, 4) Drugs (eg cyclophosphamide)
66
Complication of pituitary adenoma
Pituitary apoplexy (bleeding into existing pituitary adenoma)
67
What type of insulin is the preferred treatment for DKA?
Regular (not short acting)
68
What factors tend to increase or decrease blood glucose in type 1 diabetics?
Infection, pain, and sleep deprivation tend to increase blood glucose. Exercise decreases blood glucose
69
What compounds are central in the pathogenesis of T2DM?
FFAs and serum TGs
70
What are the tests of choice for T1DM, T2DM, and gestational diabetes respectively?
T1 and T2 DM - fasting blood sugar (in the US). Gestational - OGTT
71
What are potassium levels like in DKA?
Hyperkalemia is present, but intracellular levels of K are very low due to transcellular shift from decreased insulin
72
What is your first step in management if you suspect mucormycosis in a DKA patient?
Biopsy and look at it under the microscope
73
Pathogenesis of fetal macrosomia in gestational diabetes
Maternal glucose crosses placenta, hyperplasia of fetal islets, fetal hyperinsulinemia followed by fetal hypoglycemia, fetal macrosomia
74
Rule of thirds for carcinoid
One third metastasize, One third present with second malignancy, one third present as multiple
75
Treatment for carcinoid syndrome
Octreotide
76
Test of choice for Zollinger-Ellison
Infusion of secretin (will see increased gastrin secretion in Z-E syndrome)
77
MEN 1
Pituitary (prolactin or GH), Parathyroid, Pancreas (ZES, insulinoma, VIPoma, glucagonoma). Kidney stones and stomach ulcers. Draw a diamond
78
MEN 2A
Medullary thyroid carcinoma (calcitonin), Pheochromocytoma, Parathyroid tumors. Draw a square
79
MEN 2B
Medullary thyroid carcinoma (calcitonin), pheochromocytoma, oral/intestinal ganglioneuromatosis (neuromas). Marfinoid habitus. Draw a triangle.
80
How does pheochromocytoma often present
Headache
81
Genetic mutation associated with MEN 2A and 2B
Ret mutation
82
List the insulins and include their duration of action
Rapid - lispro and aspart. Short acting - insulin. Intermediate - NPH. Long-acting - Glargine and detemir
83
Treatment for gestational diabetes
Insulin
84
Tolbutamide
Sulfonylurea (first generation)
85
Chlorpropamide
Sulfonylurea (first generation)
86
Glyburide
Sulfonylurea (second generation)
87
Glimepiride
Sulfonylurea (second generation)
88
Glipizide
Sulfonylurea (second generation)
89
Metformin
Biguanide
90
Pioglitazone
Glitazone (aka thiazolidinedione)
91
Rosiglitazone
Glitazone (aka thiazolidinedione)
92
Acarbose
Alpha-glucosidase inhibitor
93
Miglitol
Alpha-glucosidase inhibitor
94
Pramlinitide
Mimetic (diabetes drug)
95
Exenatide
GLP-1 Analog
96
Sulfonylurea mechanism
Closes K channel in beta cell membrane, triggering insulin release via increased Ca influx
97
Mechanism of biguanides (metformin)
Unknown. Decreased gluconeogenesis, increased glycolysis, increased peripheral insulin sensitivity
98
Mechanism of Glitazones/Thiazolidinediones
Increased insulin sensitivity via PPAR-gamma binding
99
Alpha-glucosidase inhibitor mechanism
Inhibits intestinal brush border alpha-glucosidases leading to decreased glucose absorption
100
Mimetics (pramlinitide) action
Amylin analogue. Leads to decreased glucagon secretion and delayed gastric emptying and promotes satiety
101
Exenatide (GLP-1 analog) effects
Increased insulin, decreased glucagon release
102
What does activation of PPAR-gamma do and what drugs activate it?
Increases insulin sensitivity and levels of adiponectin. Glitazones/thiazolidinediones
103
Contraindications of metformin
Renal failure (can cause lactic acidosis)
104
Toxicities of glitazones/thiazolidinediones
Weight gain, edema, hepatotoxicity, heart failure
105
PTU and methimazole
Block peroxidase and inhibit iodide organification. PTU also blocks 5-deiodinase (decreasing peripheral conversion of T4 to T3).
106
Toxicities of PTU and methimazole
Rash, agranulocytosis, aplastic anemia, hepatotoxicity (PTU), teratogen (methimazole)
107
Necrolytic migratory erythema, elevated erethematous rash on groin, hyperglycemia, stomatitis, cheilosis, abdominal pain, anemia
Glucagonoma
108
Uses of GH
GH deficiency and Turner syndrome
109
Uses of octreotide
Acromegaly, carcinoid, gastrinoma, glucagonoma, hepatorenal syndrome
110
Uses of oxytocin
Stimulate labor, uterine contractions, milk let down, and controlling uterine hemorrhage
111
Demeclocycline
ADH anatgonist, use in SIADH. May cause nephrogenic DI, photosensitivity, abnormalities of bone and teeth
112
What effect do glucocorticoids have on liver sugar metabolism?
Stimulate gluconeogenesis (have an anti-insulin effect)
113
Uses of glucocorticoids
Addisons, inflammation, immune suppression, asthma, Graves
114
What is the bone finding in Cushings?
Osteoporosis
115
3 tumors secreting stuff you cannot suppress
Parathyroid adenoma making PTH, adrenal adenoma making cortisol, adrenal tumor secreting aldosterone
116
Most common cause of hypopituitarism in adults
Nonfunctioning pituitary adenoma
117
What type of necrosis occurs in Sheehans syndrome?
Coagulative (pituitary is not part of the brain)
118
Second most common cause of hypopituitarism in adults
Sheehans syndrome
119
Most common cause of hypopituitarism in kids
Craniopharyngioma
120
First signs of hypopituitarism
Amenorrhea or impotence (due to loss of gonadotropins)
121
Test of choice for pituitary dwarfism
Sleep GH and IGF-1 levels
122
What amino acids stimulate growth hormone release?
Histidine and arginine
123
Order in which hormone production disappears in hypopituitarism
(first to go) Gonadotropins, GH, TSH, ACTH, prolactin (last to go)
124
Stimulators of prolactin synthesis
OCPs, hydralazine, Ca channel blockers, psychotropic drugs, primary hypothyroidism
125
What non-thyroid related symptom is seen in women with primary hypothyroidism and why?
Galactorrhea. Low thyroid hormones levels increase synthesis of TSH and TRH. TRH stimulates prolactin synthesis
126
Prolactin level above what value always means prolactinoma?
200
127
Increased T4 with a normal TSH
Estrogens such as OCPs or pregnancy (due to increase in TBG)
128
Use of I-131 test
Distinguishes Graves from exogenous thyroid supplementation
129
Cardiac abnormality associated with Graves
A-fib
130
Most common symptom of hypothyroidism
Proximal muscle weakness (cannot get out of chairs, serum CK will be high)
131
Give the rule for cold thyroid nodules
Any cold nodule in a man or child is cancer until proven otherwise. Cold nodules in (esp older) women are often benign
132
Thyroid cancer prognosis
(Best) Papillary then follicular then medullary (worst)
133
Most common cause of hypocalcemia
Hypoalbuminemia (albumin carries about 40 percent of total Ca)
134
Why is alkalosis associated with tetany?
Because albumin is made of acidic AAs, and thus will bind more free calcium (lowering ionized calcium levels) in alkalotic state. Will not have hypocalcemia on labs but will have tetany and functional hypocalcemia
135
Purple striae, obesity, thin extremities
Cushings
136
What type of Cushings can you suppress with high dose dexamethasone?
Pituitary
137
What will the low dose dexamethasone suppression test result be in all types of Cushings?
Failure to suppress. You will, however, see suppression at low doses in normal patients
138
Why do Cushings patients have thin exremities and central obesity?
Cortisol encourages protein (muscle) breakdown, but leads to hyperglycemia, which leads to insulin release, which causes fat and sugar storage centrally. Essentially we are moving tissue from our muscles centrally
139
Why are the striae in Cushings purple?
Cortisol decreases collagen synthesis
140
Why will patients with Conns syndrome have tetany?
Metabolic alkalosis causes functional hypocalcemia
141
Patient with neurofibromatosis and HTN
Suspect pheochromocytoma. Check VMA and metanephrines
142
Only meningitis with petechial lesions
N meningitidis
