Endocrine Disorders

Question 1

1. L.S. is a 32-year-old, 50-kg woman recently given a
   diagnosis of secondary hypothyroid disease caused by
   idiopathic panhypopituitarism. She began treatment
   with levothyroxine 75 mcg orally once daily 2 weeks
   ago. The results of today’s thyroid function tests are
   as follows: total thyroxine (TT4) 4 mcg/dL (normal
   level 512), total triiodothyronine (TT3) 75 ng/dL (normal level 80–180), and thyroid-stimulating hormone (TSH) less than 0.1 mIU/mL (normal level 0.4–4.0).
   Given these laboratory tests, which one of the following is the best thyroxine (T4) dose adjustment for L.S.?

A. Increased because triiodothyronine (T3) and T4
levels are low.
B. Decreased because TSH levels are low.
C. Unchanged because free T4 levels are not
available.
D. Unchanged because she has not yet reached
steady state on this dose.

Answer 1

1. Answer: D
   The half-life of T4 in a euthyroid patient is about 1 week.
   This patient has been receiving therapy for 2 weeks, or
   about 2 half-lives. Steady state is reached in about 5 halflives (5 weeks) (Answer D is correct). Levels of FT4 and
   TT3 should be repeated after 3 to 4 additional weeks of
   therapy, with goal levels in the upper limits of the normal ranges (Answers A and C are incorrect). Because this
   patient has secondary HoTR, her TSH level will always be
   low (Answer B is incorrect); this does not represent

Question 2

2. T.R. is a 68-year-old white woman with a history of
   angina and hypertension (HTN) who recently received
   a diagnosis of hyperthyroidism (HTR) and is markedly
   symptomatic. She is to undergo radioactive iodine
   therapy in 6 weeks. Which one of the following is the
   best initial pharmacologic therapy for T.R. to relieve
   her symptoms?
   A. Propranolol 40 mg orally 4 times/day.
   B. Methimazole 10 mg orally 2 times/day.
   C. Potassium iodide and iodine solution 5 drops
   orally 3 times/day.
   D. Propylthiouracil 100 mg orally 3 times/day

Answer 2

2. Answer: A
   This patient with hyperthyroidism is markedly symptomatic
   and has a history of angina. Prompt symptom reduction that
   will not interfere with the planned RAI therapy is indicated.
   β-Blockers take effect within hours of administration and do
   not interfere with the efficacy of RAI (Answer A is correct).
   Lugol solution has a much quicker onset of action than thioamides, but it still takes days to work. In addition, iodides
   taken before RAI uptake therapy will prevent uptake of RAI
   by the thyroid gland, rendering its use ineffective (Answer
   C is incorrect). Thioamides inhibit organification and coupling, but they do nothing to stored thyroid hormone levels;
   thus, several weeks are required before a reduction is seen
   in hyperthyroid symptoms (Answers B and D are incorrect)

Question 3

3. L.R. is a 25-year-old obese woman given a diagnosis of polycystic ovary syndrome (PCOS) 4 years ago
   after presenting to her primary care physician with
   oily skin, acne, and excessive facial hair. She has managed these symptoms through weight loss and use of
   spironolactone 100 mg twice daily. She presents today
   with acanthosis nigricans and elevated blood pressure
   (BP) (142/90 mm Hg). Which one of the following
   choices is best for L.R.?
   A. Clomiphene.
   B. Metformin.
   C. Finasteride.
   D. Flutamide.

Answer 3

3. Answer: B
   The patient is showing signs of insulin resistance (acanthosis nigricans) and HTN. In addition to reducing blood
   glucose, metformin might allow her to lose weight, which
   will also decrease her insulin resistance and BP (Answer B
   is correct). Clomiphene is used to induce ovulation, thereby
   treating infertility (Answer A is incorrect). Finasteride is a
   5-α-reductase inhibitor used to treat acne and hirsutism by
   inhibiting the conversion of T to its active metabolite in the
   hair follicle (Answer C is incorrect). Like spironolactone,
   flutamide is an antiandrogen, but potential hepatotoxicity
   limits its use (Answer D is incorrect).

Question 4

4. Compared with women, how do men with prolactinomas most commonly present?
   A. With fewer symptoms.
   B. With a microprolactinoma.
   C. At an earlier age.
   D. With higher prolactin levels.

Answer 4

4. Answer: D
   Men usually present at an older age, with more symptoms,
   with macroprolactinomas versus microprolactinomas
   (Answers A, B, and C are incorrect) and with higher prolactin levels than in women (Answer D is correct), because
   women are typically identified much earlier during the disease because of changes in menstruati

Question 5

5. D.V. is a 64-year-old man who has been receiving
   octreotide therapy for almost a year for the treatment
   of acromegaly after transsphenoidal pituitary surgery.
   Because of continued elevated growth hormone (GH)
   and insulin-like growth factor (IGF)-1 levels, pegvisomant was initiated 2 months ago. His current IGF-1
   level is normal, but his GH level is twice as high as
   it was before starting pegvisomant. Which one of the
   following explanations is most likely?
   A. Recurrence of the GH-producing pituitary tumor.
   B. Too low a dose of pegvisomant.
   C. Too low a dose of octreotide.
   D. Normal response to pegvisomant treatment.
6. In the above case, if D.V. subsequently develops weakness, fatigue, anorexia, dizziness, and hypotension
   (BP 88/50 mm Hg), with which one of the following
   would be best to treat empirically?
   A. Octreotide LAR.
   B. Levothyroxine.
   C. Hydrocortisone.
   D. Testosterone.

Answer 5

5. Answer: D
   Unlike somatostatin analogs that directly inhibit GH secretion, pegvisomant is a GH receptor antagonist. It blocks
   the binding of endogenous GH to its receptor sites, leading to decreased IGF-1 levels. However, because it is a
   modified GH molecule, it is detected by commercial GH
   assays, thereby interfering with GH level measurements
   and causing falsely elevated GH levels (Answer D is correct). Because IGF-1 levels have decreased, Answers A, B
   and C are incorrect
6. Answer: C
   Patients after pituitary surgery are at an increased risk of
   pituitary failure, with subsequent decreases in GH, LH/ FSH,
   TSH, ACTH, and antidiuretic hormone secretion caused by
   pituitary injury because of the surgery. If this patient exhibits symptoms of adrenal deficiency, he should empirically
   be initiated on adrenal hormone replacement therapy even
   before a definitive diagnosis is made (Answer C is correct).
   Levothyroxine (Answer B is incorrect) is used to treat HoTR
   and testosterone (Answer D is incorrect) is used to treat
   hypogonadism, not adrenal insufficiency. Octreotide LAR is
   a long-acting somatostatin preparation (Answer A is incorrect) used to treat acromegaly, not adrenal insufficienc

Question 6

7. A 20-year-old woman presents to your clinic for an
   initial visit. She has always been heavy, but she has
   gained almost 18.2 kg since starting college 3 years
   ago. She has a diet rich in convenience and snack
   foods. She has several alcoholic beverages on most
   weekends and does not smoke. She played soccer competitively before college, but she now finds little time
   for regular physical activity. Her father is overweight
   and has type 2 diabetes mellitus (DM) and HTN. The
   patient denies polyuria, polydipsia, blurred vision,
   changes in her skin or hair, changes in her menses, or
   cold intolerance. On physical examination, she is 66
   inches tall and weighs 99.5 kg; her body mass index
   (BMI) is 35 kg/m2
   . Her BP is 148/92 mm Hg. Which
   one of the following would be the most appropriate
   management of obesity in this patient?

A. Phentermine 8 mg three times per day with meals,
plus a low-carbohydrate diet.
B. Phentermine topiramate 15/92 mg every morning
plus a calorie-restricted diet with a calorie deficit
of 500 kcal/day, less than 10% calories from saturated fat, and limited refined sugars.
C. A diet with a calorie deficit of 500 kcal/day, less
than 30% calories from fat, and limited refined
sugars, combined with a progressive exercise
program.
D. An exercise prescription for 60 minutes of soccer five times per week with a plan to increase to
every day

Answer 6

7. Answer: C
   In general, lifestyle changes need to be attempted before
   initiating drug therapy for weight loss (Answers A and B
   are incorrect) In addition, the poorly controlled BP makes
   these poor choices. A multifaceted approach is the most
   effective means to treat obesity; therefore, Answer C is
   correct. Answer D is somewhat reasonable, but relying
   totally on exercise for weight reduction in a patient who
   “finds little time for regular physical activity” is unrealistic
   (Answer D is incorrect).

Question 7

8. N.M. is a 67-year-old man with significant heart disease who recently received a diagnosis of Cushing
   syndrome caused by an adrenal tumor. He also
   receives twice-daily high-dose lansoprazole for severe
   gastroesophageal reflux disease. Given that he is not
   a surgical candidate because of his heart disease,
   which one of the following treatments would be best
   to initiate?
   A. Ketoconazole.
   B. Metyrapone.
   C. Eplerenone.
   D. Spironolactone

Answer 7

8. Answer: B
   Eplerenone and spironolactone are aldosterone antagonists
   used to treat hyperaldosteronism, not Cushing syndrome
   (Answers C and D are incorrect). Ketoconazole and metyrapone are used to treat Cushing syndrome, but ketoconazole
   requires an acidic stomach pH for absorption. Because
   this patient is receiving high-dose proton pump inhibitor
   therapy (Answer A is incorrect), metyrapone would be the
   better choice (Answer B is correct)