Endocrinology Flashcards

1
Q

Treatment for subacute thyroiditis (de Quervain thyroiditis)

A
  • Beta-blockers: control of thyrotoxic symptoms
  • NSAIDs: pain relief

*Glucocorticoids for severe thyroid pain not responding to NSAIDs

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2
Q

Most accurate markers indicating resolution of diabetic ketoacidosis

A
  • Serum anion gap

- Serum beta-hydroxybutyrate levels (not acetoacetate)

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3
Q

Best initial test to Dx acromegaly

A

Insulin-like growth factor-1 (IGF-1)→significantly ↑↑ level compared to the average for age-matched equivalents►positive screen

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4
Q

Confirmatory test for acromegaly

A

Measure GH after 100 g of glucose is given orally

  • Positive if GH remains high (>5 ng/mL)
  • Normally a glucose load completely suppresses levels of GH
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5
Q

Why don’t you have hyperkalemia and salt loss in secondary adrenal insufficiency caused by pituitary disease?

A

Aldosterone production is mainly dependent on the renin-angiotensin system not from ACTH

*Salt wasting, hyperkalemia, and death are associated with aldosterone deficiency

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6
Q

Use of Metyrapone test. How does it work?

A
  • Assess ACTH production
  • Block cortisol production→↑ACTH levels

*A failure of ACTH levels to rise→suggests pituitary insufficiency

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7
Q

Most common cause of panhypopituitarism

A

Pituitary adenomas

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8
Q

Most common presentation of glucagonoma

A
  • Glucose intolerance
  • Necrolytic migratory erythema→annular erythematous dermatitis, blistering and erosions
  • Weight loss
  • Normocytic normochromic anemia
  • Diarrhea, thromboembolism
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9
Q

What is the differential diagnosis in a patient with polydipsia and polyuria? Initial steps in management.

A
  • Diabetes insipidus, psychogenic polydipsia, Diabetes mellitus
  • 1st step to evaluate→measure urine osmolarity
  • 2nd step→Water deprivation test
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10
Q

Most sensitive test to diagnose pheochromocytoma

A

Plasma free fractionated metanephrines

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11
Q

Specific findings at the physical exam of Graves disease

A
  • Ophthalmopathy-exophthalmos (proptosis)
  • Periorbital edema
  • Pretibial myxedema
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12
Q

How are the potassium deposits in DKA and why?

A

Excess of glucagon→hyperglycemia, ketonemia, osmotic diuresis►net renal loss of K+→depletion of total body K+ stores

*Despite reduction in K+ stores→serum [K+] may be ↑ due to acidemia and ↓insulin activity►redistribution of K+ to the extracellular fluid compartment

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13
Q

Which androgen can be used as a diagnostic marker of androgen-producing adrenal tumors?

A

Dehydroepiandrosterone sulfate (DHEAS)

*produced predominantly in the adrenal glands that

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14
Q

How do you differentiate hyperthyroidism due to thyroiditis and exogenous thyroid hormone use (factitious thyrotoxicosis)? What do they have in common?

A
  • Common→Radioactive iodine uptake (RAIU) decreased
  • Differentiate:
  • ↑Thyroglobulin→thyroiditis (subacute or silent), iodide exposure
  • ↓Thyroglobulin→Factitious thyrotoxicosis
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15
Q

Why are the thyroid antibodies (antithyroid peroxidase/antithyroglobulin) important to evaluate hypothyroidism?

A

If TSH is less than double the normal and antibodies are positive→replace thyroid hormone

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16
Q

How can you suspect Hypoparathyroidism induced by low magnesium?

A
  • Low Calcium

- Low Phosphorus (different from other causes of hypoparathyroidism➡High Phosphorus)

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17
Q

Mechanism by which hypomagnesemia induce hypocalcemia

A

↓Mg→⬆resistance to PTH and ⬇PTH secretion

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18
Q

What potassium level do you expect in a hyperglycemic crisis (DKA or HHS)? Why?

A
  • Normal or slightly elevated serum potassium
  • Insulin deficiency→put K+ out of cells
  • Osmotic diuresis→excessive urinary K+ loss

*Total body potassium deficit (3-5 mg/kg)

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19
Q

Which is the implication of a total body potassium loss in a Hyperglycemic Hyperosmolar State?

A

Insulin therapy→abruptly decrease K+ - severe hypokalemia

*K+ reposition during initial insulin therapy

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20
Q

Most likely secondary cause of bone loss when presented with ⬆creatinine, anemia and hypercalcemia?

A

Multiple myeloma

*⬆Total protein might be found

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21
Q

Cause of Osteitis fibrosa cystica and clinical presentation

A
  • Primary Hyperparathyroidism➡⬆Resorption in cortical bone with subperiosteal thinning and cystic degeneration▶hypercalcemia (constipation, fatigue, etc)
  • Secondary hyperparathyroidism➡chronic renal failure

*X-ray: lytic lesions with multifocal involvement

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22
Q

Clinical presentation of myopathy in Cushing syndrome

A
  • Painless progressive proximal muscle weakness, atrophy, no tenderness (may interfere with daily activities)
  • Lower extremity more involved
  • ESR and CK normal
23
Q

Cause of myopathy in Cushing syndrome

A

Glucocorticoid-induced myopathy: Direct catabolic effects of cortisol on skeletal muscle➡muscle atrophy

24
Q

Common findings of chronic primary adrenal insufficiency

A
  • Hyponatremia: hypovolemia-induced antidiuretic hormone secretion
  • Hypoglycemia: cortisol deficiency
  • Peripheral eosinophilia: normally inhibited by corticosteroids

*History of weakness, fatigue, anorexia, weight loss

25
Q

Markers of Nonclassic congenital adrenal hyperplasia

A
  • Hyperandrogenism
  • ⬆ 17-hydroxyprogesterone

*Cause by partial ⬇ 21-hydroxylase activity

26
Q

How do you differentiate central vs nephrogenic diabetes insipidus?

A

Vasopressin stimulation test

  • Central➡⬇urine volume, ⬆urine osmolality
  • Nephrogenic➡no effect on urine volume or osmolality
27
Q

Treatment for hyperprolactinemia

A
  • Dopamine agonists: Cabergoline>Bromocriptine
  • Transsphenoidal surgery when not responding to medications
  • Radiation (rarely needed)
  • Asymptomatic does not need treatment
28
Q

What is the Kallman syndrome and which is the etiology?

A

Defective migration of neurons and failure of olfactory bulbs to develop➡⬇GnRH➡⬇FSH, LH, testosterone▶hyposmia/anosmia, Infertility, 50% Renal agenesis

*Failure to complete puberty; a form of hypogonadotropic hypogonadism

29
Q

Best initial test for GH deficiency

A

Injecting GHRH➡normal response is ⬆GH

30
Q

Treatment options for acromegaly

A
  • Surgery: transsphenoidal resection (responds in 70% of cases)
  • Medications:
  • Cabergoline: Dopamine agonist➡❌GH release
  • Octreotide or lanreotide: Somatostatin agonist➡❌GH release
  • Pegvisomant: GH receptor antagonist➡❌IGF release from the liver
  • Radiotherapy: for no response to surgery or medications
31
Q

What is Euthyroid sick syndrome?

A

⬇T3,⬆reverse T3 (rT3), ⬇T4, TSH does not rise

*Clinically euthyroid patients with nonthyroidal systemic illness have low serum levels of thyroid hormones

32
Q

Most common cause of hypercalcemia

A

Primary hyperparathyroidism and cancer 90% of cases

33
Q

First-line treatment for acute hypercalcemia

A
  • Saline hydration at high volume

- Bisphosphonate: Pamidronate, zoledronic acid (take several days to work)

34
Q

Treatment for acute hypercalcemia when the first option does not work

A

Calcitonin➡❌Osteoclasts, onset of action is very rapid

35
Q

Causes of primary hyperparathyroidism

A
  • Solitary adenoma (80%-85%)
  • Hyperplasia of all 4 glands (15%-20%)
  • Parathyroid malignancy (1%)
36
Q

Possible clinical presentation of primary hyperparathyroidism

A
  • Asymptomatic
  • Acute severe hypercalcemia
  • Slower o chronic presentation➡Osteoporosis; Nephrolithiasis and renal insufficiency; muscle weakness, anorexia, nausea, vomiting, abdominal pain; Peptic ulcer disease (calcium ⬆gastrin)
37
Q

Standard of care for primary hyperparathyroidism and which are the indications?

A

Surgical removal of involved parathyroid glands

  • Bone disease (Ex, Osteoporosis)
  • Renal involvement, including stones
  • Age <50 yrs
  • Calcium consistently 1 point above normal
38
Q

Most common cause of hypocalcemia. Other causes.

A
  • Primary hypoparathyroidism prior neck surgery (Ex, thyroidectomy)
  • Other causes:
  • Hypomagnesemia➡Mg is needed to release PTH
  • Renal failure➡kidney 25 OH-D▶1,25 OH-D
  • Vitamin D deficiency➡inadequate sunlight exposure or insufficient intake; Rickets and Osteomalacia
  • Genetic disorders
  • Fat malabsorption
  • Hypoalbuminemia (no symptoms because free Ca is normal)
39
Q

Treatment for primary hyperparathyroidism when the first line of management is not possible

A

Cinacalcet➡❌release of PTH

40
Q

Most accurate test for Paget disease of bone. Best initial test.

A
  • Radionuclide (technetium) bone scan
  • Best initial: Plain film x-rays (lytic and sclerotic lesions, depending on disease stage)

*⬆Alkaline phosphatase; normal GGTP and Bilirrubin aid in diagnosis

41
Q

Best initial test for hypercortisolism. What other options to rule out it?

A
  • 24-hour urine cortisol (also more specific)

- 1 mg dexamethasone suppression test (sensitive, might be false positive)➡normally suppress morning cortisol level

42
Q

Best initial test to determine the cause (source) or location of hypercortisolism

A

ACTH level

43
Q

Treatment options for endogenous hypercortisolism when surgically removing the source (pituitary, adrenal or cancer) is not possible

A
  • Pasireotide: somatostatin analog➡❌levels and activity of ACTH (for ACTH dependent Cushing sx)
  • Mifepristone: ❌cortisol receptors throughout the body
  • Mitotane: ❌steroidogenesis, also cytotoxic to adrenal tissue (for adrenal cancer cannot be fully resected or metastatic disease can’t be identified)
44
Q

Most specific test of adrenal function (mainly for hypoadrenalism)

A

Cosyntropin (synthetic ACTH) test: measure cortisol before and after administration➡normally ⬆cortisol after giving it

45
Q

Most common classic presentation of primary hyperaldosteronism

A

High blood pressure + Hypokalemia

46
Q

Best initial test for primary hyperaldosteronism

A

Ratio of plasma aldosterone to plasma renin >20:1

47
Q

Most accurate test to confirm unilateral adrenal adenoma

A

Sample of venous blood draining the adrenal➡⬆Aldosterone

48
Q

Most common cause of primary hyperaldosteronism

A
  1. Solitary adenoma

2. Bilateral hyperplasia

49
Q

Treatment for bilateral adrenal hyperplasia in primary hyperaldosteronism

A

Eplerenone or Spironolactone

50
Q

Which treatment for Graves disease may worsen the ophthalmopathy?

A

Radioactive Iodine➡⬆thyrotropin receptor antibody

*Corticosteroids and antithyroid drugs➡minimize RAI effects

51
Q

Most common cause of isolated, asymptomatic elevation of alkaline phosphatase in an elderly

A

Paget disease of bone

52
Q

Greatest risk of complication if left untreated hyperthyroidism

A
  • ⬆⬆T3, T4➡⬆Osteoclastic bone activity▶⬆bone resorption, ⬇bone density▶osteoporosis
  • Also cardiac tachyarrhythmias (AFib)

*⬆Bone turnover➡Hypercalcemia, Hypercalciuria

53
Q

Best initial and most accurate test for pheochromocytoma

A
  • Best initial: Level of free metanephrines in plasma

- Most accurate: 24-hour urine collection for metanephrines

54
Q

How do you look for a pheochromocytoma outside the adrenal gland?

A

Metaiodobenzylguanidine (MIBG) scanning