Endocrine IV

Question 1

What is the likely explanation for the abnormal laboratory values in a pregnant woman that experiences fatigue, anxiety, and difficulty sleeping with normal TSH and elevated total T4? Thyroid examination is benign.

Answer 1

Increased thyroid-binding globulin (TBG) level

estrogen increases level of TBG, resulting in elevated total T4 but normal free T4 (euthyroid state); her symptoms are unrelated

Question 2

What is the likely source of an androgen-secreting tumor in a female with elevated testosterone and elevated dehydroepiandrosterone sulfate (DHEAS) levels?

Answer 2

Adrenal tumor

causes rapidly progressive hirsutism; androstenedione, DHEA, and testosterone are produced by both the ovaries and adrenals, while DHEAS is predominantly produced in the adrenals

Question 3

What is the likely source of an androgen-secreting tumor in a female with elevated testosterone and normal dehydroepiandrosterone sulfate (DHEAS) levels?

Answer 3

Ovaries (more common)

causes rapidly progressive hirsutism; androstenedione, DHEA, and testosterone are produced by both the ovaries and adrenals, while DHEAS is predominantly produced in the adrenals

Question 4

What is the major gluconeogenic amino acid in the liver?

Answer 4

Alanine

Question 5

What is the most beneficial therapy for reducing the progression of diabetic nephropathy?

Answer 5

Strict blood pressure control

some guidelines recommend a target BP of 130/80 mmHg, others recommend 140/90 mmHg

Question 6

What is the most common cause of primary adrenal insufficiency in developed countries?

Answer 6

Autoimmune adrenalitis

Question 7

What is the most common underlying cause of neuropathic ulcers?

Answer 7

diabetes mellitus

typically occur on the sole of the foot at weight-bearing areas (e.g. under head of first metatarsal)

Question 8

What is the most important contributing factor for diabetic foot ulcers?

Answer 8

Diabetic neuropathy

other important risk factors include previous foot ulceration, vascular disease, and foot deformity

Question 9

What is the most important initial step in management of a patient with hyperosmolar hyperglycemic state?

Answer 9

Fluid replacement with normal saline

may switch to 0.45% saline after a few hours if corrected Na+ levels are high; IV insulin +/- K+ are important as well, but not as important initially

Question 10

What is the most sensitive test for differentiating adrenal adenoma and bilateral adrenal hyperplasia in patients without a discrete unilateral adrenal mass on imaging?

Answer 10

Adrenal venous sampling

Question 11

What is the most serious adverse effect associated with anti-thyroid drugs (e.g. methimazole, PTU)?

Answer 11

Agranulocytosis

patient’s on these drugs that develop a sore throat and fever should have their WBC count checked

Question 12

What is the next step in a patient with suspected acromegaly that is found to have elevated IGF-1 levels?

Answer 12

Oral glucose suppression test

normally, glucose rapidly suppresses GH secretion; in acromegaly, glucose will not suppress (and may increase) GH secretion

Question 13

What is the next step in diagnosis for a patient with myalgias, proximal muscle weakness, elevated creatine kinase, and delayed reflexes?

Answer 13

Measure TSH and T4 (to evaluate for hypothyroid myopathy)

other manifestations include fatigue and other symptoms of hypothyroidism (e.g. hair loss, cold intolerance)

Question 14

What is the next step in management for a diabetic patient taking metformin and nightly insulin glargine that presents with an elevated hemoglobin A1c despite normal fasting glucose levels?

Answer 14

Add rapid-acting mealtime insulin

this patient likely has postprandial hyperglycemia

Question 15

What is the next step in management for a patient taking PTU or methimazole that develops fever and sore throat?

Answer 15

Discontinuation of the drug, measure WBC count

fever and sore throat in patients on PTU/methimazole suggests agranulocytosis

Question 16

What is the pathophysiology underlying hyperthyroid-induced bone loss?

Answer 16

Increased osteoclast activity

Question 17

What is the preferred first-line treatment for central diabetes insipidus?

Answer 17

Desmopressin (intranasal preferred over oral)

Question 18

What is the preferred imaging modality for evaluation of pituitary tumors?

Answer 18

MRI

recommended for patients with elevated prolactin, mass-effect symptoms, very low testosterone levels, or disruptions in other pituitary hormones

Question 19

What is the preferred initial test for evaluating patients with suspected acromegaly?

Answer 19

IGF-1 level

IGF-1 levels in acromegaly are elevated throughout the day vs. GH levels, which fluctuate widely

Question 20

What is the primary treatment for papillary thyroid carcinoma?

Answer 20

Surgical resection

Question 21

What is the recommended blood pressure goal for patients with diabetes without proteinuria?

Answer 21

< 140/90 mmHg

patients with diabetic nephropathy may benefit from lower BP goals (e.g. < 130/80 mmHg) but evidence is conflicting

Question 22

What is the recommended insulin regimen in patients with diabetic ketoacidosis?

Answer 22

IV insulin initially followed by subcutaneous insulin (see below); overlap SQ & IV insulin by 1-2 hours

insulin should be held if serum K+ < 3.3 mEq/L

Question 23

What is the recommended IV fluid regimen for hydration in patients with diabetic ketoacidosis?

Answer 23

0.9% NS initially, add dextrose 5% when serum glucose is <200.

Question 24

What is the recommended treatment for patients with primary hyperaldosteronism that are poor surgical canidates?

Answer 24

Aldosterone antagonists (e.g. spironolactone, eplerenone)

surgery is preferred for primary hyperaldosteronism due to unilateral adrenal adenoma

Question 25

What is the treatment for a patient with symptomatic primary hyperparathyroidism?

Answer 25

Parathyroidectomy other indications for parathyroidectomy include age \< 50 and those at increased risk for complications (e.g. Ca2+ \> 1 mg/dL above normal, evidence of osteoporosis)

Question 26

What is the typical underlying etiology of acromegaly?

Answer 26

Pituitary somatotroph adenoma (excessive secretion of GH)

Question 27

What is the underlying etiology of altered mental status in patients with hyperosmolar hyperglycemic state?

Answer 27

Hyperosmolality common precipitating factors include infection, medications

Question 28

What medications (4) should be administered to a patient with suspected thyroid storm? ## Footnote 1. [...] 2. [...] 3. [...] 4. [...]

Answer 28

What medications (4) should be administered to a patient with suspected thyroid storm? 1. **Propanolol (beta blocker)** 2. **Propylthiouracil (PTU)** 3. **Potassium iodide (unless pregnant)** 4. **Prednisone (or other glucocorticoid)** "the four P's" of thyroid storm management

Question 29

What musculoskeletal pathology is associated with pseudofractures (Looser zones)?

Answer 29

Osteomalacia

Question 30

What musculoskeletal pathology is caused by impaired osteoid matrix mineralization?

Answer 30

Osteomalacia i.e. defective mineralization

Question 31

What pregnancy complication is associated with Hashimoto thyroiditis?

Answer 31

Miscarriage due to high titers of anti-thyroid peroxidase antibodies; increased risk in both euthyroid and hypothyroid women

Question 32

What should be suspected in a patient taking PTU or methimazole that presents with fever and sore throat?

Answer 32

Agranulocytosis warrants discontinuation of the drug and WBC count measurement

Question 33

What test should be used to screen for diabetes mellitus in patients with polycystic ovarian syndrome?

Answer 33

Oral glucose tolerance test more sensitive than fasting glucose and HbA1c in patients with PCOS

Question 34

What thyroid abnormality (hyper- or hypothyroidism) is associated with hyperlipidemia (e.g. hypercholesterolemia, hypertriglyceridemia)?

Answer 34

Hypothyroidism most patients have high cholesterol (due to decreased LDL receptors) with or without high trigylcerides (decreased LPL activity); patients may also develop hyponatremia and asymptomatic elevations in CK and AST/ALT

Question 35

What treatment option for Graves disease may be associated with worsening of ophthalmopathy?

Answer 35

Radioactive iodine contraindicated in patients with severe ophthalmopathy (due to increased thyroid-stimulating immunoglobulin titers); glucocorticoids and antithyroid drugs may be given initially to minimize side effects of RAI in patients with mild ophthalmopathy

Question 36

What type of thyroid nodule, hyperfunctioning ("hot") or hypofunctioning ("cold"), is more likely to be cancerous?

Answer 36

Hypofunctioning ("cold") thyroid function is evaluated using thyroid scintigraphy, usually with I123; cold nodules should be evaluated with FNA

Question 37

What vitamin/mineral deficiency is associated with carcinoid syndrome?

Answer 37

Niacin (B3) deficiency serotonin and niacin are synthesized from tryptophan; increased conversion of tryptophan to serotonin may result in niacin deficiency

Question 38

Which anti-thyroid drug, methimazole or PTU, is preferred in most patients?

Answer 38

Methimazole (exception: women during the first trimester of pregnancy) methimazole is a 1st-trimester teratogen; PTU has a black box warning for severe liver injury

Question 39

Which subtype of thyroid cancer is associated with elevated calcitonin?

Answer 39

Medullary thyroid carcinoma

Question 40

Which subtype of thyroid cancer is associated with psammoma bodies and "orphan annie-eye nuclei"?

Answer 40

Papillary thyroid carcinoma

Question 41

Which subtype of thyroid cancer typically invades blood vessels and metastasizes hematogenously?

Answer 41

Follicular thyroid carcinoma