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Endocrinology Flashcards

1
Q

Anterior midline neck mass that moves with swallowing or tongue protrusion

A

THYROGLOSSAL DUCT CYST

Compare to branchial cleft cyst (lateral neck) from persistent cervical sinus which is not mobile

Note - Most common ectopic thyroid tissue site is the tongue (lingual thyroid - at base of tongue)

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2
Q

Thyroid embryologic origin

A

Endoderm - Thyroid tissue

Neural crest - Parafollicular (C) cells

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3
Q

Adrenal gland embryologic origin

A

Mesoderm - Cortex

Neural crest - Medulla

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4
Q

Layers and function of the adrenal cortex and medulla

“GFR”

A

Zona Glomerulosa - Aldosterone
Zona Fasciculata - Cortisol
Zona Reticularis - Sex hormones

Medulla/Chromaffin cells - Catecholamines

Note - Aldosterone, Cortisol, and Sex hormones all derived from cholesterol (e.g. SER)

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5
Q

Embryologic origin of Anterior pituitary (Adenohypophysis) and Posterior pituitary (Neurohypophysis)

A

Anterior - Oral ectoderm (Rathke’s pouch)
Posterior - Neuroectoderm (Hypothalamus)

Note - Craniopharyngiomas (solid, cystic, calcification) are tumors arising from remnants of Rathke’s pouch

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6
Q

Acidophil anterior pituitary hormones

A

GH
PRL

Note - All the rest (FSH, LH, ACTH, TSH) are basophils

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7
Q

Pituitary hormones sharing an a-subunit

A

TSH, LH, FSH share with hCG

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8
Q

Mechanism of posterior pituitary release of Vasopressin/ADH and Oxytocin

A

Produced in supraoptic and paraventricular nuclei of the hypothalamus, respectively

Transported to posterior pituitary via neurophysins

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9
Q

Orientation and function of pancreatic alpha, beta, and delta islets of Langerhans

A

alpha - Glucagon peripherally
beta - Insulin centrally (near capillaries)
delta - Somatostatin interspersed

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10
Q

Mechanism of insulin production

A

Cleavage of presignal from Preproinsulin (RER)
Proinsulin stored in secretory granules
Cleavage of proinsulin
Exocytosis of insulin (disulfide bonds) and C-peptide

Note - Both Insulin and C-peptide are increased in insulinomas and Sulfonylurea abuse

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11
Q

Insulin effect on kidneys

A

Increased Na retention

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12
Q

Insulin-independent tissues and their transporters

A

GLUT1 - Brain, Placenta, RBCs, Cornea
GLUT3 - Brain, Placenta
GLUT2 - Liver, Pancreas, Kidney, Basolateral intestines

Note - GLUT2 is bidirectional and has a high Km (sensing), while GLUT1/3 have a low km (basal)

Note - GLUT5 also insulin independent, but only used by Spermatocytes and Intestines (apical) for Fructose

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13
Q

Insulin-dependent tissues and their transporter

A

GLUT4 - Adipose, Striated muscle

Insulin binds Tyrosine Kinase Receptor (TKR)
Induces RAS/MAP pathway (cellular growth)
Also induces Phosphoinositide-3 kinase (PI3K) pathway
Increased GLUT4 and glycogen/lipid/protein synthesis

Note - GLUT4 increased during exercise

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14
Q

Mechanism of insulin secretion by beta cells

A 
Glucose enters beta cells with GLUT2
Glycolysis increases ATP
Closes ATP-sensitive K channels
Cell membrane depolarization
Voltage-gated Ca channels open
Ca-mediated stimulation of insulin exocytosis
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15
Q 
Function of hypothalamic hormones...
CRH
Dopamine
TRH
GHRH
Somatostatin
GnRH (pulsatile)
A 
CRH - Increased ACTH, MSH, b-endorphin
Dopamine - Decreased PRL, TSH
TRH - Increased TSH, PRL
GHRH - Increased GH
Somatostatin - Decreased GH, TSH
GnRH - Increased FSH, LH
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16
Q

Amenorrhea
Osteoporosis
Hypogonadism
Galactorrhea

A

PITUITARY PROLACTINOMA

Prolactin suppresses GnRH (FSH, LH)

Treat with Bromocriptine (dopamine agonist)

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17
Q

Function and feedback mechanism of Prolactin release from anterior pituitary

A

Inhibits GnRH (FSH/LH) and stimulates milk production

Negative - Tonically by Dopamine, also Prolactin inhibits itself by promoting Dopamine release

Positive - Elevated TRH in hypothyroidism, and Estrogen (OCP, pregnancy)

Note - Renal failure causes hyperprolactinemia by decreasing elimination

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18
Q

Function and feedback mechanism of GH (somatotropin) release from anterior pituitary

A

Stimulates linear growth and muscle mass via IGF-1 secretion by the liver, also increases insulin resistance (diabetogenic)

Negative - Glucose, Somatostatin, feedback by IGF-1

Positive - Exercise, Sleep, Puberty, Hypoglycemia

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19
Q

Hormonal regulation of hunger and satiety

A

Hunger - Ghrelin from stomach
Satiety - Leptin from adipose tissue

Note - Also increased hunger via endocannabinoid stimulation of Hypothalamic/Nucleus accumbens

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20
Q

ADH levels in central and nephrogenic DI

A

Central - Decreased
Nephrogenic - Increased due to V2 resistance

Note - Posterior pituitary damage causes transient central DI, while hypothalamic damage causes permanent central DI

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21
Q

Mechanism of…
Bilateral adrenal hyperplasia
Hypertension
Hypokalemia
Lack of secondary sexual characteristics (XX)
Ambiguous genitalia and undescended testes (XY)

Increased Mineralocorticoids (Corticosterone), Pregnenolone
Decreased Cortisol, Androstenedione

Note - Decreased RAAS

A

17A-HYDROXYLASE DEFICIENCY (CAH)

Decreased conversion of…
Pregnenolone to 17-Hydroxypregnenolone

Low cortisol sensed by the hypothalamus - Treat with Corticosteroids to decrease ACTH and thus shunting to mineralocorticoids

Note - Androstenedione is converted to Testosterone mainly in the periphery not the adrenals

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22
Q 
Mechanism of...
Bilateral adrenal hyperplasia
Hypotension
Hyperkalemia
Virilization (XX)
Salt wasting in infancy, or precocious puberty (XY)

Increased Sex hormones, 17-Hydroxyprogesterone
Decreased Cortisol, Aldosterone

Note - Increased RAAS

A

21-HYDROXYLASE DEFICIENCY (CAH)

Decreased conversion of…
Progesterone to 11-Deoxycorticosterone

Low cortisol sensed by the hypothalamus - Treat with Corticosteroids to decrease ACTH and thus sex hormone production

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23
Q 
Mechanism of...
Bilateral adrenal hyperplasia
Hypertension
Hypokalemia
Virilization (XX)

Increased Sex hormones, 11-Deoxycorticosterone
Decreased Cortisol, Corticosterone, Aldosterone

Note - Decreased RAAS

A

11B-HYDROXYLASE DEFICIENCY (CAH)

Decreased conversion of…
11-Deoxycorticosterone to Corticosterone - Combination of increased sex hormones and increased mineralocorticoids

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24
Q

Mechanism of cortisol action on blood pressure

A

Upregulates a1 receptors on arterioles
Binds Aldosterone receptors

Note - May cause steroid-psychosis

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25
Q

Metabolic cortisol action (hyperglycemia)

A

Increases insulin resistance (diabetogenic)
Increases peripheral catabolism
Hypogonadism

Note - Paradoxically causes glycogenesis in the liver

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26
Q

MSK cortisol action

A

Decreases fibroblast activity (thinning, striae)
Decreases bone formation (osteoblast inhibition)

Note - Normal PTH

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27
Q

Inflammatory and immune cortisol action

A 
Blocks IL-2 (T cells)
Blocks NF-kB induced IL-1, TNF-a (Neutrophilia)
Blocks Phospholipase A2 (GI bleeding)
Blocks Histamine release from Mast cells
Reduces Eosinophils/Basophils
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28
Q 
Mechanism of acidosis induced...
Cramps
Pain
Paresthesia
Carpopedal spasm
A

Increased pH
Increased affinity of Albumin for Ca
Decreased ionized Ca - hypocalcemia

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29
Q

Function and feedback mechanism of Vit D activation (skin/intestine to liver to kidney)

A

As Calcitriol…
Increases Ca and PO4 absorption in the gut
Increases bone mineralization

Negative - Calcitriol, Hypercalcemia

Positive - PTH, Hypocalcemia, Hypophosphatemia

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30
Q

Function of PTH from chief cells of parathyroid

A

Increased bone resorption of Ca and PO4
Increased kidney (DCT) resorption of Ca
Decreased kidney (PCT) reabsorption of PO4
Increased 1a-hydroxylase (PCT) for Calcitriol production

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31
Q

Mechanism of bone resorption by PTH

A

Increased RANK-L and M-CSF by osteoblasts
Binds RANK on osteoclasts
Activates NF-kB and JTK

Note - Estrogen increases OPG expression by osteoblasts which acts as a decoy receptor for RANK

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32
Q

Feedback mechanism of PTH

A

Negative - Extreme hypomagnesemia, Hypercalcemia

Positive - Hypocalcemia (ionized), Hypomagnesemia, decreased 1,25-Vit D, Hyperphosphatemia

Note - Causes of hypomagnesemia include diarrhea, diuretics, alcohol abuse, and Aminoglycosides

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33
Q

Function and feedback mechanism of Calcitonin release from Parafollicular (C) cells

A

Decrease bone resorption of Ca

Positive - Hypercalcemia

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34
Q

Effects of T3 on bone, brain, heart, and metabolism

A

Bone growth with GH
Brain maturation
Increased b1 receptors in heart
Potentiates sympathetic activity (e.g. b3)
Increased metabolism via increased N/K-ATPase
Increased catabolism

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35
Q

Mechanism of T3 production

A

Tyrosine is turned into Thyroglobulin
Thyroglobulin released into follicular lumen
Combined with I2 (organification) and renters cell
Coupling makes T3 (DIT/MIT) or T4 (DIT/DIT)
T3 and T4 (Thyroxine) released into circulation
T4 converted to T3/rT3 in tissue by Deiodinase

Note - All enzymatic reactions by Thyroid peroxidase

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36
Q

Wolff-Chaikoff effect

A

Excess iodine temporarily inhibits thyroid peroxidase decreasing T3/T4 production

Note - Iodine enters follicle from blood via Na/I symporter and is oxidized to Iodine by Thyroid peroxidase

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37
Q

TBG binds most T3/T4 in blood and only free hormone is active - TBG is increased/decreased by…

Hepatic failure
Estrogen (Pregnancy, OCP)
Steroids

A

Increased - Estrogen

Decreased - Hepatic failure, Steroids

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38
Q

Signaling pathway for vasodilators…

BNP
ANP
NO
EDRF

A

Guanylyl cyclase - cGMP/PKG

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39
Q

Signaling pathway for growth factors…

Insulin
IGF-1
FGF
PDGF
EGF
A

TKR - RAS/MAP and PI3K/Akt/mTOR

Note - PI3K activity inhibited by PTEN

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40
Q

Signaling pathway for acidophiles and cytokines…

PRL
GH
G-CSF
Erythropoietin
Thrombopoietin
Immunomodulators (e.g. IL, IFN)
A

Non-receptor tyrosine kinase (JAK-STAT)

Note - No autophosphorylation

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41
Q

Signaling pathway for steroid hormones…

Progesterone
Estrogen
Testosterone
Cortisol
Aldosterone
T3/T4
Vit D
A

Intracellular receptors - DNA binding Zinc-finger domains

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42
Q

Signaling pathway for the following hormones…

ADH (V1)
Oxytocin
GnRH
TRH
Angiotensin II
Gastrin
A

Gq/PLC - IP3/Ca and DAG/PKC

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43
Q

Signaling pathway for the following hormones…

ADH (V2)
Glucagon
FSH/LH
GHRH
CRH/ACTH
TSH
PTH/Calcitonin
hCG
MSH
A

Gs/Adenylate cyclase - cAMP/PKA

Note - Like all G-proteins requires replacement of GDP with GTP to dissociate a subunit

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44
Q

Screening algorithm for Cushing syndrome

A

Increased 24-hr urine free cortisol
No suppression with overnight low-dose dexamethasone
Measure ACTH

Decreased ACTH (ACTH-independent):

1) Discontinue exogenous glucocorticoids - bilateral adrenal atrophy
2) MRI for adrenal adenoma - hyperplasia of involved gland with atrophy of uninvolved gland

Normal or Elevated ACTH (ACTH-dependent) - bilateral adrenal hyperplasia:

High-dose dexamethasone suppression test and CRH stimulation test

1) MRI for Cushing Disease/Pituitary Adenoma - suppression and stimulation
2) Chest CT for Ectopic ACTH (e.g. SCLC) - no suppression and no stimulation

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45
Q 
Diagnosis algorithm for...
Weakness
Fatigue
GI disturbance
Weight loss
Sugar and salt cravings
Orthostatic hypotension
Hyponatremia
A

ADRENAL INSUFFICIENCY

Random serum ACTH and cortisol:

Primary - Low cortisol, High ACTH
Secondary (pituitary) - Low cortisol, Low ACTH
Tertiary (hypothalamic) - Low cortisol, Low ACTH

Note - Follow with response to ACTH test to confirm

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46
Q

Metyrapone stimulation test algorithm

A

Metyrapone blocks 11-deoxycortisol to Cortisol:

Normal - Low Cortisol, High ACTH/11-deoxycortisol

Primary - Low Cortisol/11-deoxycortisol, High ACTH

Secondary/Tertiary - Low Cortisol, 11-deoxycortisol, ACTH

47
Q

Difference in presentation between primary and secondary/tertiary adrenal insufficiency

Note - Tertiary (hypothalamic) most often due to withdrawal from exogenous steroid use

A

Primary presents with mucosal hyperpigmentation, hyperkalemia, and hyperchloremic (non-anion gap) metabolic acidosis

Secondary/tertiary present with only hyponatremia secondary to hypotension induced ADH release - Aldosterone release is via RAAS

48
Q

Two most common causes of chronic adrenal insufficiency (Addison’s)

A

Autoimmune
TB

Note - Acute (shock, adrenal crisis) often due to Waterhouse-Friderichsen syndrome (N. meningitidis)

49
Q

Hypertension
Hypokalemia
Metabolic alkalosis

A

HYPERALDOSTERONISM

Primary due to adrenal adenoma (Conn syndrome) with low Renin

Secondary due to renovascular HTN or a JGA tumor with high Renin

No edema or hypernatremia due to aldosterone escape mechanism (ANP)

50
Q

Embryologic origin of neuroendocrine tumors

A

ENTEROCHROMAFFIN-LIKE CELLS

Contain amine precursor uptake decarboxylase

51
Q 
Toddler with...
Abdominal distention
Firm, irregular mass crossing midline
Opsoclonus-myoclonus
Elevated HVA and VMA (catecholamine metabolites)
A

NEUROBLASTOMA

Adrenal medulla tumor - Originates from neural crest cells and may occur anywhere along the sympathetic chain

Note - Compare to unilateral, smooth Wilms tumor (nephroblastoma)

52
Q 
Gene associated with...
Small blue round cells
Homer-Wright rosettes
Bombesin+
NSE+
A

NEUROBLASTOMA

N-myc oncogene

53
Q

Treatment of elevated urine catecholamines and metanephrines

Associated with…
VHL
MEN2 (RET)
NF1

Note - Often presents with orthostatic hypertension

A

PHEOCHROMOCYTOMA

Originates from Chromaffin cells (neuroendocrine - neural crest) or extra-adrenal sympathetic chain

Irreversible a-antagonist (Phenoxybenzamine) followed by b-blocker prior to tumor resection to prevent hypertensive crisis. Phenoxybenzamine is an irreversible long acting alpha adrenergic blocker that prevents peripheral vasoconstriction. DO NOT give beta blockers alone because unopposed vasoconstriction

Note - Rule of ’10s”

54
Q

Difference between hypothyroid and hyperthyroid myopathy

A

Hypothyroid - Proximal weakness with high CK
Hyperthyroid - Proximal weakness with normal CK

Note - Hypothyroidism myopathy also presents with myoedema

55
Q

Cholesterol levels in hypothyroid and hyperthyroid

A

Hypothyroid - Hypercholesterolemia (low LDLR)

Hyperthyroid - Hypocholesterolemia (high LDLR)

56
Q

Smooth and diffuse goiter

A

Graves disease
Hashimoto thyroiditis
Iodine deficiency
TSH-secreting pituitary adenoma

57
Q

Nodular goiter

A

Toxic multinodular goiter
Thyroid adenoma
Thyroid cancer
Thyroid cyst

58
Q

Hurthle cell (pink cytoplasm)
Lymphoid aggregates with germinal centers
Moderately enlarged, nontender thyroid

Elevated TSH
Decreased T4
Normal/Decreased T3

Note - T3 has a short half life and may be normal due to increased conversion of T4 to T3

A

HASHIMOTO THYROIDITIS

Antithyroid peroxidase (antimicrosomal) and antithyroglobulin antibodies - associated with HLA-DR5

May initially present as hyperthyroid due to thyrotoxicosis from follicular rupture

Note - Associated with non-Hodgkin’s lymphoma (enlarging goiter)

59
Q 
Infant with...
Intellectual disability
Pot-bellied
Pale
Puffy-faced
Protruding umbilicus
Protuberant tongue
A

CONGENITAL HYPOTHYROIDISM (CRETINISM)

Due to maternal hypothyroidism, thyroid agenesis/dysgenesis, or iodine deficiency

60
Q

Viral infection followed by hyperthyroidism and then hypothyroidism

Elevated ESR
Jaw pain
Very tender thyroid
Decreased radioiodine uptake

A

SUBACUTE GRANULOMATOUS THYROIDITIS (DE QUERVAIN)

Mixed cellular infiltrate with granulomatous inflammation

61
Q

Fixed, hard painless goiter
Autoimmune pancreatitis
Retroperitoneal fibrosis
Noninfectious aortitis

A

RIEDEL THYROIDITIS (HYPOTHYROIDISM)

Thyroid replaced by fibrous tissue with inflammatory infiltrate - fibrosis may extend to surrounding structures like anaplastic carcinoma

Note - Systemic manifestations due to IgG4

62
Q

Tall crowded follicular epithelial cells
Scalloped colloid
Diffuse goiter

A

GRAVES DISEASE

TSI IgG leads to Type II hypersensitivity that stimulates TSH receptors (goiter)

63
Q

Mechanism of pretibial myxedema and exophthalmos

Note - Especially common during radioactive iodine therapy, and specific for Graves disease

A

Autoimmune reaction against TSHRs
Infiltrating Th1 cells release cytokines
Stimulated pretibial and retroorbital fibroblasts
Increased fibroblast secretion of hydrophilic GAGs
Increased osmotic swelling, inflammation, and adipocytes

Note - Treat with glucocorticoids

64
Q

Focal patches of hyperfunctioning follicular cells

A

TOXIC MULTINODULAR GOITER

TSH receptor mutation makes hot nodules work independently of TSH

Note - Rarely malignant

65
Q

Jod-Basedow phenomenon

A

Thyrotoxicosis if a patient with iron deficiency or hot nodule is repleted with iodine

66
Q

Treatment of thyroid storm

‘Four Ps”

A

Propranolol
Propylthiouracil
Prednisolone
Potassium Iodide (Lugol iodine)

67
Q

Diagnosis algorithm of thyroid adenoma/carcinoma

A

Decreased radioactive iodine uptake

Proceed to FNA

68
Q

Fibrous capsule

Colloid containing microfollices

A

THYROID (FOLLICULAR) ADENOMA

Invasion of capsule means follicular carcinoma - spreads hematogenously

Note - Surgical resection needed for diagnosis

69
Q

Hoarseness from thyroid surgery occurs during ligation of which arteries near which nerves

A

Inferior thyroid artery damages recurrent laryngeal nerve - all intrinsic laryngeal muscles (arytenoids) except cricothyroid

Superior thyroid artery damages external superior laryngeal nerve - cricothyroid. Internal branch supplies sensation to the supraglottic area

Note - L recurrent loops under aortic arch and R recurrent loops under bifurcation of brachiocephalic trunk

70
Q

Empty appearing nuclei with central clearing - “orphan annie eyes”
Branching papillary structures with Psammoma bodies
Nuclear grooves

Note - Tall cell variant also has elongated epithelial cells

A

PAPILLARY CARCINOMA

Childhood irradiation - spreads to cervical nodes

71
Q 
Mutations associated with...
Papillary carcinoma
Follicular carcinoma
Medullary carcinoma
Anaplastic carcinoma
A

RET/BRAF
RAS
RET
p53

72
Q

Sheet of spindle cells in amyloid stroma - stains with Congo red

A

MEDULLARY CARCINOMA

Tumor arising from parafollicular “C” cells

73
Q 
Shortened 4th/5th digits
Short stature
Hypocalcemia
Hyperphosphatemia
Elevated PTH
A

ALBRIGHT OSTEODYSTROPHY

Pseudohypoparathyroidism 1A - Autosomal dominant mutation in Gs causing end-organ resistance to PTH

Note - Maternal inheritance only due to imprinting

74
Q

Shortened 4th/5th digits
Short stature
Normal Ca, PO4, PTH

A

PSEUDOPSEUDOHYPOPARATHYROIDISM

Occurs when mutation in Gs is inherited from father

75
Q

Mechanism of familial hypocalciuric hypercalcemia

A

Mutation in G-protein coupled receptor (CaSR) in parathyroid and kidneys means higher than normal Ca levels required to suppress PTH

Note - PTH levels may be normal or elevated

76
Q

Hypercalcemia with low PTH

A

PTH-INDEPENDENT HYPERCALCEMIA

Excess Ca intake
Thiazide diuretics
Malignancy

77
Q 
Hypercalcemia
Hypercalciuria
Hypophosphatemia
Elevated PTH
Elevated ALP
Elevated cAMP (urine)
A

PRIMARY HYPERPARATHYROIDISM

Parathyroid adenoma or hyperplasia

78
Q

Skeletal manifestations (3) of hyperparathyroidism

A

OSTEITIS FIBROSA CYSTICA

Subperiosteal thinning

Cystic spaces filled with brown fibrous tissue - osteoclasts and deposited hemosiderin

Salt-and-pepper skull

79
Q

Hypocalcemia
Hyper or hypophosphatemia
Elevated PTH
Elevated ALP

A

SECONDARY HYPERPARATHYROIDISM

Hyperplasia due to decreased Ca absorption

Hyperphosphatemia in CKD, hypophosphatemia in other causes

Note - Causes renal osteodystrophy (osteoid matrix accumulation in bone lesions)

80
Q

Hypercalcemia

Markedly elevated PTH

A

TERTIARY HYPERPARATHYROIDISM

Refractory hyperparathyroidism resulting from CKD

81
Q

Hyperpigmentation
Headaches
Bitemporal hemianopia

A

NELSON SYNDROME

Enlargement of exciting ACTH-secreting pituitary adenoma after bilateral adrenalectomy for refractory Cushing disease - removal of cortisol feedback mechanism

Treat with pituitary irradiation or removal

82
Q

Increased serum IGF-1 (somatomedin C) with failure to suppress serum GH following oral glucose tolerance test

Note - Increased risk of CRC

A

ACROMEGALY

GH-secreting pituitary adenoma in adults - Increased IGF-1 leads to increased proliferation of chondrocytes in growth plate

Treat with resection or Octreotide (Somatostatin)

Note - Same adenoma in children causes increased linear bone growth instead (gigantism), and eventually HF

83
Q 
Short height
Small head circumference
Saddle nose
Prominent forehead
Small genitalia
Decreased IGF-1
Increased GH
A

LARON SYNDROME (DWARFISM)

Defective GH receptor leads to decreased linear growth

84
Q

Lab findings in DI…
ADH
Urine specific gravity
Serum osmolality

A

Decreased (central) or normal (nephrogenic)
< 1.006
> 290 mOsm/kg

Note - In central urine osmolality increases by 50% with exogenous ADH, in nephrogenic there is minimal response

85
Q

Treatment of nephrogenic DI

A

Hydrochlorothiazide - increases Na excretion

Stop offending agents (e.g. Lithium)

86
Q

Mechanism of euvolemic hyponatremia

A

SIADH

Water retention leads to decreased aldosterone and increased ANP/BNP

Urinary Na secretion with normalization of ECF

87
Q

Treatment of SIADH

A

Fluid restriction
Salt tablets
Demeclocycline (ADH antagonist)

Note - Correcting hyponatremia too quickly may result in osmotic demyelination syndrome (central pontine myelinolysis)

88
Q

Failure to lactate
Absent menstruation
COld intolerance

A

SHEEHAN SYNDROME

89
Q

Sudden onset severe headache
Bitemporal hemianopsia
Diplopia (CN III palsy)

A

PITUITARY APOPLEXY

Sudden hemorrhage - often of an already existing adenoma

Treat with glucocorticoids to prevent hypotension

90
Q

Embryologic origin and location of branchial cleft cyst

A

Second branchial cleft (pharyngeal groove) - Anterior to sternocleidomastoid

Note - First branchial cleft forms external auditory meatus

91
Q

Interaction between insulin resistance and FFA

A

Chronically elevated FFAs contribute to insulin resistance by impairing insulin-dependent glucose uptake and increasing hepatic gluconeogenesis

92
Q

Most common cause of hereditary hypothalamic DI

A

Mutation in neurophysin carrier molecule

93
Q 
Hyperglycemia
Weight loss
Necrolytic migratory erythema
DVT
Depression
A

GLUCAGONOMA

Treat with Octreotide

94
Q

Mechanism of cataract formation and peripheral neuropathy in hyperglycemia

A

POLYOL PATHWAY

Aldose reductase converts Glucose to Sorbitol
Sorbitol dehydrogenase converts Sorbitol to Fructose
Hyperglycemia saturates Sorbitol dehydrogenase
Sorbitol builds up inside the lens and Schwann cells
Increased osmotic pressure pulls water into the lens

Note - Seminal vesicles use this pathway the most as sperm relies on fructose for energy

95
Q

Mechanism of insulin resistance by TNF-a, Catecholamines, Glucocorticoids/Cortisol, and Glucagon

A

Activation of Serine proteases leads to phosphorylation of Serine and Threonine residues on Insulin Receptor and Insulin Receptor Substrate

96
Q

Weight gain
Hypertension
Hyperglycemia
Proximal muscle weakness (normal CK)

A

CUSHING SYNDROME

Will also see...
Skin hyperpigmentation (ACTH excess)
Skin atrophy
Purple striae
Central obesity
97
Q

Mechanism of microangiopathy (nephropathy, retinopathy, neuropathy) in hyperglycemia

A

Excess non-enzymatic glycosylation
Crosslinking with collagen in vessel walls and interstitium

Note - Also facilitates inflammatory cell infiltration and LDL deposition leading to atherosclerosis

98
Q

Most effective all-cause mortality preventative measure in diabetics

A

Smoking cessation

Note - Tight glycemic control reduces microvascular complications but has no effect on macrovascular complications (e.g. MI, stroke)

99
Q

XY with feminized genitalia
Normal blood pressure
Normal testosterone
Enzyme deficiency resulting

A

5A-REDUCTASE TYPE 2 DEFICIENCY

Decreased conversion of Testosterone to DHT results in male pseudohermaphroditism

Note - During puberty type 1 in the skin becomes activated and external genitalia masculinize

100
Q

Diabetes
Gallstones
Hypochlorhydria
Steatorrhea

A

SOMATOSTATINOMA (D CELL TUMOR)

Hyperglycemia from insulin inhibition
Gallstones from CCK inhibition
Hypochlorhydria from Gastrin inhibition
Steatorrhea from Secretin inhibition and decreased motility

101
Q

Mechanism of functional hypothalamic amenorrhea in low BMI patients

A

Decreased Leptin as a result of low adipose stores decreases pulsatile GnRH release, inhibiting pituitary LH/FSH release and thus estrogen

Note - Increases risk of osteoporosis

102
Q

Pituitary and hypothalamic causes of hypopituitarism

A 
Pituitary:
Infiltration (lymphocytic hypophysitis)
Hemorrhage
Ischemia
Mass lesion

Hypothalamic:
Sarcoidosis
Radiation
Infection

Note - Hypothalamic causes will paradoxically elevate Prolactin due to reduced Dopamine production

103
Q

Competitive agonist for I/Na symporter - pretreatment reduces radioiodine effectiveness

A

Perchlorate

104
Q

Large pleomorphic giant cells in a thyroid nodule

A

ANAPLASTIC CARCINOMA

105
Q

Glutamic acid decarboxylase antibodies - HLA-DR3/4

A

T1DM

Note - Genetic predisposition of T2DM is actually higher

Note - Insulin sensitivity is actually high in T1DM rather the disease is due to direct beta cell destruction

106
Q

Histology of T2DM

A

Islet amyloid polypeptide (IAPP) deposits

107
Q 
Recurrent...
Diarrhea
Flushing
Wheezing
Right-sided endocardial fibrous plaques
Tricuspid regurgitation
Elevated urinary 5-HIAA

Prominent rosettes on histology

A

CARCINOID SYNDROME

Small intestine neuroendocrine tumor - Become symptomatic only after metastasis due to high first pass metabolism of Serotonin

108
Q

Common mutations and tumors in…
MEN1
MEN2A
MEN2B

Note - All are autosomal dominant

A

MEN1 (Menin) - Pituitary adenoma, Pancreatic endocrine (e.g. Gastrinoma, Insulinoma), Parathyroid hyperplasia

MEN2A (RET) - Medullary thyroid cancer, Pheochromocytoma, Parathyroid hyperplasia

MEN2B (RET) - Medullary thyroid cancer, Pheochromocytoma, Mucosal neuroma and Marfanoid habitus

Note - MEN2A all derived from neural crest

109
Q

Criteria for diagnosis of diabetes

A

Fasting > 126
Random > 200
A1C > 6.5

Note - OGT mostly used for gestational diabetes

110
Q

Fetal effects of diabetes

A

Increased placental glucose transfer…
Macrosomia
b-cell hyperplasia
Hypoglycemia after delivery

Note - Also associated with hypertrophic cardiomyopathy, placental vasculopathy, and malformations

111
Q

Drugs causing osteoporosis by…

Increasing Vit D catabolism
Decreasing Estrogen
Decreasing Testosterone and Estrogen
Decreasing Ca absorption
Decreasing bone formation
A

Phenobarbital, Phenytoin, Carbamazepine (CYP-450)
Aromatase inhibitors, Medroxyprogesterone
GnRH agonists
PPIs
Steroids, Unfractionated Heparin, Thiazolidinediones

112
Q

absence of GnRH secretory neurons in hypothalamus

defective migration fromt he olfactory placode

A

kallman syndrome

central hypogonadism
anosmia
delayed puberty
impaired sense of smell

113
Q

DKA labs

A

hyperkalemia
hyponatremia and hypovolemia
hyperglycemia

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