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Endocrine Flashcards

1
Q

Derivations of the anterior pituitary and posterior pituitary:

A

Anterior = oral ectoderm (Rathke pouch)

Posterior = neuroectoderm

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2
Q

Where is the most common site of ectopic thyroid?

A

Lingual thyroid- due to failed migration

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3
Q

Child presents with a midline anterior neck mass that moves when he swallows or sticks out his tongue

A

thyroglossal duct cyst

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4
Q

Origin of parafollicular cells (C cells) of the thyroid

A

neural crest (remainder of thyroid tissue is derived from endoderm)

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5
Q

How to distinguish between central diabetes insipidus and nephrogenic diabetes insipidus

A

water deprivation test

o Central DI- urine osmolality will inc after administration of ADH
o Nephrogenic DI- urine osmolality doesn’t change after administration of ADH

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6
Q

Adrenal gland derivations

A

Cortex = mesoderm

Medulla = neural crest cells

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7
Q

Adrenal cortex layers and functions

A

GFR corresponds with Salt (Na), Sugar (glucocorticoids), and Sex (Androgens) – the deeper you go the sweeter it gets

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8
Q

Zona Gomerulosa

A

Regulated by: renin angiotensin system

Secretes: aldosterone

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9
Q

Zona Fasciculata

A

Regulated by: ACTH, CRH

Secretes: Cortisol

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10
Q

Zona Reticularis

A

Regulated by: ACTH, CRH

Secretes: sex hormones (androgens)

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11
Q

Medulla (Chromaffin Cells)

A

Regulated by: Preganglionic sympathetics (ACh)

Secretes: catecholamines (epinephrine, norepinephrine)

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12
Q

What amino acid are the thyroid hormones derived from?

A

Tyrosine

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13
Q

Wolff Chaikoff effect

A

excess iodine temporarily inhibits thyroid peroxidase and causes dec iodine organification → dec T3/T4 production

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14
Q

How does a dietary deficiency of iodine cause goiter?

A

The gland enlarges in an attempt to access more blood to inc iodine uptake

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15
Q

Functions of T3

A

Brain maturation
Bone growth
B adrenergic effects (Inc CO, HR, SV, and contractility)
Basal metabolic rate increases (Via inc Na/K ATPase activity)
Inc glycogenolysis, gluconeogenesis, and lipolysis

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16
Q

Graves Disease

A

Hyperthyroidism – autoantibody that stimulates TSH receptor – Thyroid Stimulating Immunoglobulin (TSI) – and causes increased synthesis and release of thyroid hormone

(Type 2 hypersensitivity)

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17
Q

Goiter, exopthalmos, and pretibial myxedema

A

Graves Disease

o Goiter: constant TSH stimulation causes thyroid hyperplasia and hypertrophy
o Exopthalmos and pretibial myxedema fibroblasts behind the orbit and overlying the shin express the TSH receptor → inflammation due to infiltration of T cells that release cytokines and inc fibroblast secretion of glycosaminoglycan

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18
Q

Baby presents with developmental delay, a umbilical hernia, and a protruding tongue. What do you suspect?

A

Congenital hypothyroidism (cretinism)

pot bellied, pale, puffy faced, protruding umbilicus (hernia), protuberant tongue, and poor brain development

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19
Q

What drugs cause hypothyroidism?

A

Lithium and Amiodarone

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20
Q

Hashimoto Thyroiditis

A

autoimmune destruction of the thyroid gland – due to T cell sensitization to thyroid antigen and antibodies against thyroglobulin and thyroid peroxidase

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21
Q

What HLA subtype is Hashimoto thyroiditis associated with? What are patients with Hashimoto thyroiditis at inc risk of?

What other disease is associated with this HLA type?

A

HLA DR5 (Pernicious anemia)

Inc risk of non Hodgkin lymphoma

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22
Q

Patient presents with jaw pain, tender thyroid, and inc ESR after a recent viral infection

A

Subacute Granulomatous (De Quervain) Thyroiditis

Granulomatous thyroiditis- may be hyperthyroid early on and then progresses to hypothyroid

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23
Q

Patient presents with signs of hypothyroidism and a rock hard thyroid

A

Riedel Fibrosing Thyroiditis (hypothyroidism)

Chronic inflammation with extensive fibrosis of the thyroid gland

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24
Q

Thyroid histo: branching papillary structures with interspersed calcified bodies

A

Papillary thyroid cancer

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25
Thyroid histo: tall/crowded follicular cells with scalloped colloid
Graves disease
26
Thyroid histo: Extensive stromal fibrosis that extends beyond the capsule
Riedel thyroiditis
27
Thyroid histo: Mixed cellular infiltration with occasional multinucleated giant cells
Subacute granulomatous thyroiditis (de Quervain)
28
Thyroid histo: Mononuclear parenchymal infiltration with well-developed germinal centers
Hashimoto thyroiditis
29
Thyroid histo: Empty appearing nuclei with central clearing (Orphan Annie eyes), psammoma bodies and nuclear grooves (coffee beans):
Papillary carcinoma
30
Thyroid histo: sheets of cells in an amyloid stroma
medullary carcinoma (from parafollicular “C cells” – produces calcitonin
31
Hypothyroid myopathy
Dec tendon refelxes and myoedema
32
Patient presents with decreased lateral vision. If you suspect a brain lesion, where would it be?
The patient appears to have bitemporal hemianopia, which is characteristic of a pituitary adenoma Patient will likely have inc prolactin levels, as prolactinomas are most common
33
Which MEN is associated with Pheochromocytomas, Medullary thyroid carcinoma, and parathryoid hyperplasia?
MEN2A (Mutation in RET gene) 2 P’s: parathyroid and pheochromocytoma
34
Which MEN is associated with pheochromocytomas, medullary thyroid carcinoma, mucosal neuromas, and marfanoid habitus?
MEN2B (Mutation in RET gene) 1 P: pheochromocytoma
35
Which MEN is associated with pituitary tumors, pancreatic endocrine tumors, and parathyroid adenomas?
MEN1 (Mutation in MEN1 tumor suppressor gene) 3 P’s: parathyroid, pancreas, and pituitary
36
Zollinger Ellison syndrome is associated with which MEN?
MEN1 | as are insulinomas and VIPomas
37
Pheochromocytoma is associated with which other disorders?
MEN2A/MEN2B, Von Hippel Lindau, and Neurofibromatosis type 1
38
What cells do pheochromocytomas arise from? What do they secrete?
Arise from chromaffin cells of the adrenal medulla -- secrete catecholamines (epinephrine, norepinephrine, and dopamine)
39
Cortisol functions
``` Catabolic BIG FIB Blood pressure inc Insulin resistance Gluconeogenesis, lipolysis, and proteolysis inc Fibroblast activity dec Inflammatory/immunosuppression Bone formation decrease ```
40
What is the most common cause of Cushings syndrome?
Exogenous corticosteroid use | causes dec ACTH and bilateral adrenal atrophy
41
Patient presents with HTN, weight gain, moon facies, abdominal striae, truncal obesity, osteoporosis, hyperglycmeia
Cushing Syndrome 1. HTN: cortisol increases BP 2. Striae: fibroblast inhbition 3. Osteoporosis: dec in bone formation
42
Cushing Disease vs Cushing Syndrome
Disease -- pituitary hypersecretion of ACTH usually from a pituitary adenoma high ACTH --> high cortisol Syndrome (many causes): low ACTH --> high cortisol
43
Cushing Disease
Pituitary hypersecretion of ACTH usually from a pituitary adenoma Excess ACTH leads to adrenal cortical hyperplasia and excess cortisol secretion
44
How can you distinguish between Cushing syndrome caused by pituitary secretion of ACTH vs ectopic ACTH secretion
Both will have inc ACTH Use dexamethasone suppression test Pituitary secretion: ACTH will dec Ectopic: ACTH will not dec
45
17a hydroxylase deficiency
Inc mineralocorticoid (aldosterone) production, dec cortisol, and dec sex hormones Inc BP and dec serum K+ Ambiguous genitalia, undescended testes, lack of secondary sex characterisitcs
46
21 hydroxylase deficiency
Inc sex hormones, dec aldosterone and cortisol Dec BP, inc serum K+ Salt wasting in infants Precocious puberty in children
47
11B hydroxylase deficiency
Dec aldosterone, inc 11-deoxycortisone (causes inc BP), dec cortisol, inc sex hormones Inc BP, dec serum K, dec renin, virilization
48
Dec renin | Inc Aldosterone
Primary hyperaldosteronism: the adrenal is making a lot of aldosterone and renin system shuts off
49
Inc renin | Inc aldosterone
Secondary hyperaldosteronism: abnormal activation of the renin-angiotensin system ex. juxtaglomerular cell tumor
50
Waterhouse-Friedrichsen syndrome
Acute adrenal insufficiency due to bilateral adrenal hemorrhage associated with septicemia (N meningitidis)
51
Addison disease
Chronic destruction of the adrenal cortex due to autoimmune destruction or TB infection
52
How does diabetes lead to ketoacidosis?
Usually only in T1DM Dec insulin in the blood causes lipolysis to proceed unregulated. Inc FFA are converted to acetyl-CoA and are used for ketogenesis --> ketone body formation!!
53
C-peptide
Secreted from secretory granules with endogenous insulin | Do not see C peptide with exogenous peptide administration
54
Insulin: catabolism or anabolism?
Anabolism!! Promotes the storage of protein, glucose, and lipids Prevents glycogenolysis by activation of protein phosphatase Prevents gluconeogenesis by increasing F26BP
55
What type of fuel do RBCs utilize and why?
ONLY glucose. They lack mitochrondria so they can't metabolize FFA or ketones
56
What enzyme does insulin activate, which promotes the storage of glucose as glycogen?
Protein phosphatase
57
Autonomic nervous system effects on insulin
Sympathetics (epinephrine) prevents insulin release: because during fight or flight, the body wants to mobilize glucose Parasympathetics (ACh) causes insulin release: during rest or digest, the body wants to store glucose as glycogen for future use
58
What is the major regulator of insulin release?
Glucose - enters pancreatic B cells via GLUT2 and promotes insulin secretion
59
Insulin receptor
Tyrosine kinase (MAP Kinase)
60
Which transporters are insulin dependent and where are they located?
GLUT4, on adipose and skeletal muscle tissue
61
Steps of insulin release
1. glucose enters pancreatic B cells via GLUT2 2. Glucose undergoes glycolysis to produce ATP 3. ATP binds to K+ channels and shuts them 4. K+ cannot leave the cell, causing cell depolarization 5. Voltage gated Ca2+ channels open and Ca2+ enters the cells 6. Inc Ca2+ in the cell stimulates the exocytosis of insulin granules
62
Glucagon action: catabolism or anabolism?
Catabolism Promotes glycogenolysis, gluconeogenesis, lipolysis, ketogenesis
63
Histology of T1DM vs T2DM
Type 1: leukocytic infiltrate (autoimmune destruction) Type 2: amyloid polypeptide deposition
64
14 year old boy presents with delayed puberty and complaints of anosmia
Kallmann syndrome Defective migration of GnRH cells and formation of the olfactory bulb -- leads to dec GnRH synthesis (synthesis) Dec GnRH, LH, FSH, and testosterone
65
What cancer can cause SIADH
Small cell lung cancer
66
Findings on SIADH
Euvolemic hyponatremia: no edema or JVD, due to compensatory suppression of the renin-angiotensin system (water is absorbed, inc extracellular volume, dec renin ang system, salt wasting) Urine osmolality>Serum osmolality
67
Roles of prolactin
Stimulates milk production and decreases GnRH secretion
68
Effects of dopamine on prolactin
Dopamine inhibits secretion of prolactin -- dopamine antagonists cause prolactin levels to rise --> galactorrhea
69
What do you use to treat prolactinomas?
Dopamine agonists (Bromocriptine)
70
Corticosteroid effects on WBCs
Neutrophilia -- induces demargination of neutrophils previously attached to the vessel wall Neutrophil recruitment to fight infection in tissues is dcreased
71
What is the primary site of PTH action?
The kidney - 1. inc calcium reabsorption in the DCT 2. dec phosphate reabsorption in the PCT 3. inc activation of vitamin D
72
PTH effects on bone
Stimulates Osteoblasts to secrete RANKL -- which increases the number and function of osteoclasts Bone resorption and inc Ca release
73
PTHrP Actions? When do you see it?
PTH related peptide -- Functions like PTH | Commonly increased in malignancies (squamous cell carcinoma of the lung, renal cell carcinoma)
74
What lung cancer secretes PTHrP?
Squamous cell carcinoma of the lung
75
Vitamin D functions
Inc Ca and phosphate absorption in the intestines
76
What activates Vitamin D? Where does this occur?
Vitamin D is activated in the kidney by 1a hydroxylase to 1,25 OH2 D3 24,25 OH2 D3 is the inactive form Activated by inc PTH or by dec phosphate
77
What pathology can increase vitamin D and lead to hypercalcemia?
Granulomatous disease Macrophages cause inc activation of vitamin D
78
Signs of hypocalcemia vs hypercalcemia
Hypocalcemia: - neuromuscular excitability - muscle cramps, perioral paresthesias, hypotension, chvostek sign, trousseau sign (common cause = parathyroid damage in thyroid surgery) Hypercalcemia: - constipation, polyuria/polydipsia, muscle weakness (thiazides, bones mets, multivitamin overdose)
79
Hypercalcemia is seen in which MEN syndrome(s)?
MEN1 MEN2A Due to parathyroid pathology
80
POMC gives rise to what?
ACTH Beta endorphins (opioids) MSH
81
Patient presents complaining of recent weight gain, inc bruising, and hyperpigmentation of the skin. He has epigastric abdominal pain that is relieved by over the counter antacids. He has elevated BP and a CXR shows an irregular mass in the right lung field. What is the mass and what is likely responsible for his symptoms?
Small cell carcinoma of the lung that is secreting ACTH excess ACTH leads to adrenal cortical hyperplasia and excess glucocorticoid secretion o Will see hyperpigmentation of the skin because ACTH directly stimulates melanotropin receptors due to significant sequence homology with a-MSH
82
Laryngeal nerves
o Superior laryngeal nerve (branch of CNX) – innervates the cricothyroid muscle – 4th branchial arch o Recurrent laryngeal nerve (branch of CNX) – innervates the rest of the laryngeal muscles – 6th branchial arch (can be damaged during thyroid surgery)
83
Why is there pigmentation in primary adrenal insufficiency?
Increased levels of ACTH (in an attempt to stimulate the adrenal gland) stimulates melanocytes **ACTH and MSH are both derived from POMC
84
Patient presents with progressive lethargy. She has had a loss of appetite, constipation, muscle weakness, and inc thirst and urination. She admits to taking large doses of vitamin and mineral substances to help boost her health. What do you suspect?
Hypercalcemia Likely due to inc vitamin D intake from multivitamins
85
A patient with a past medical history of pheochromocytoma presents with a thyroid mass and is diagnosed with thyroid cancer. What type of cancer is most likely in this patient and why?
Medullary carcinoma With a past hx of pheochromocytoma, the patient likely has MEN2A/2B.
86
What are neurophysins?
carrier proteins for oxytocin and vasopressin (ADH) – act as chaperone molecules and shuttle these hormones from the hypothalamus to the nerve terminals in the posterior pituitary
87
Familial Hypocalciuric Hypercalcemia
defective Ca2+ sensing receptor (G coupled proteins) causing higher than normal calcium levels to suppress PTH o Inc PTH → inc Calcium renal reuptake → mild hypercalcemia with normal to inc PTH levels
88
Pathophysiology of cataracts and peripheral neuropathy in diabetes:
during hyperglycemia, excess plasma glucose is converted to sorbitol by aldose reductase. Sorbitol accumulates in some cells (eye lens and schwann cells) and attracts water into these tissues leading to osmotic cellular injury.
89
Patient presents with several month history of diabetes and a month history of a rash that are coalescing erythematous lesions with crusting and scaling at the borders and central areas of bronze colored necrosis. Biopsy shows superficial necrolysis.
Glucagonoma ``` tumor of pancreatic a cells → overproduction of glucagon o Presents with the D’s o Dermatitis (necrolytic migratory erythema) o Diabetes (hyperglycemia) o DVT o Declining weight o Depression o Tx: octreotide, surgery ```
90
How does increased ethanol intake cause hypoglycemia?
Ethanol metabolism uses up NAD+ to form NADH, which causes an increase in the NAD+/NADH ratio. Lack of NAD+ causes inhibition of gluconeogenesis (lactate cannot be converted to pyruvate and the reaction is instead driven from pyruvate to lactate due to excess NADH).
91
Postpartum female presents with cold intolerance and failure to lactate. What should you be concerned about?
Sheehan syndrome: ischemic infarct of pituitary following postpartum bleeding o During pregnancy, the pituitary enlarges due to estrogen-induced hyperplasia of the lactotrophs → more susceptible to ischemia
92
Hormone changes in chronic glucocorticoid use in response to stress?
Tertiary adrenal insufficiency Dec CRH Dec ACTH Dec cortisol
93
What should you be concerned about in a patient with Grave's disease who comes in with fever and sore throat?
Agranulocytosis This is a rare complication of thionamides (propylthiouracil and methimazole)
94
Estrogen effects in TBG
o Inc estrogen → Inc TBG → inc total T4 and T3 (normal levels of free T3 and T4) o They remain Euthyroid!
95
If patient is exposed to radioactive iodide, what is the best medical management?
Potassium iodide
96
Child presents with abdominal distention and myoclonus. Parents report that they have noticed spontaneous bursts of non-rhythmic conjugate eye movements in various directions. What is the likely diagnosis?
Neuroblastoma - tumor of the adrenal medulla seen in children Originates from neural crest cells Child presents with abdominal distention, hypertension, and opsoclonus-myoclonus syndrome (dancing eyes and dancing feet) Associated with N-myc oncogene
97
Peripheral artery disease: Pathophys Risk factors Treatment
Atherosclerotic plaques causing luminal narrowing Common in diabetes, hyperlipidemia, HTN, smoking, age >70 Intermittent claudication: symptoms occur with exercise and resolve with rest Cilostazol: reduces platelet activation by inhibiting platelet phosphodiesterase and is a direct arterial vasodilator

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