Endo

Question 1

A 45-year-old female had myalgias, a sore throat, and a fever 2 weeks ago. She now has anterior neck tenderness and swelling, with pain radiating up to her ears. Your examination reveals a tender goiter.

Which one of the following would support a diagnosis of subacute granulomatous thyroiditis? (check one)
Pretibial myxedema
Exophthalmos
Multiple nodules on ultrasonography
Low radioactive iodine uptake (<5%)

Answer 1

Low radioactive iodine uptake (<5%)

Subacute granulomatous thyroiditis is the most common cause of thyroid pain. Free T4 is elevated early in the disease, as it is in Graves disease; however, later in the disease T4 becomes depressed and then returns to normal as the disease resolves. Pretibial myxedema, exophthalmos, and a thyroid thrill or bruit can all be found in Graves disease, but are not associated with subacute granulomatous thyroiditis. Multiple nodules on ultrasonography suggests multinodular goiter rather than subacute granulomatous thyroiditis. Patients with subacute granulomatous thyroiditis will have a low radioactive iodine uptake (RAIU) at 24 hours, but patients with Graves disease will have an elevated RAIU (SOR C).

Question 2

A 45-year-old female is being treated for hypothyroidism with levothyroxine (Synthroid), 112 :g daily. She is still having persistent fatigue and weight gain despite her TSH value of 1.5 :U/mL (N 0.5–5.5).

In addition to evaluating this patient for other causes of her symptoms, which one of the following would be appropriate management of her thyroid medication at this time? (check one)
Continuing the current therapy
Increasing the dosage
Adding liothyronine (Cytomel)
Switching to desiccated thyroid hormone (Armour Thyroid)

Answer 2

Continuing the current therapy

Some hypothyroid patients who are treated with appropriate dosages of levothyroxine and whose TSH levels are in the appropriate range continue to have persistent symptoms such as fatigue, depressed mood, and weight gain. If the TSH is in the appropriate range then no adjustment is necessary and annual serum TSH testing is recommended. Patients who remain symptomatic on an appropriate dosage of levothyroxine, as determined by a TSH <2.5 mIU/L, are not likely to benefit from combination triiodothyronine/thyroxine therapy (SOR A). Desiccated thyroid hormone preparations are not recommended by the American Association of Clinical Endocrinologists for the treatment of hypothyroidism. A meta-analysis of 11 randomized, controlled trials of combination T3/T4 therapy versus T4 monotherapy showed no improvements in pain, depression, or quality of life (SOR A).

Question 3

A previously healthy 58-year-old female sees you for evaluation of increased hair growth on her face and a weight gain of 18 kg (40 lb) over the past year. An examination is significant for a blood pressure of 155/98 mm Hg, a BMI of 34 kg/m2 with a truncal obesity pattern, striae on the sides of the torso and lower abdomen, marked hirsutism, and a rounded, swollen facial appearance. A urine pregnancy test is negative. Liver and renal function tests are normal, as are TSH, electrolyte, testosterone, and DHEA levels. A hemoglobin A1c is 6.2%.

Which one of the following would be most useful to diagnose the condition suggested by this patient’s presentation? (check one)
A 24-hour urinary free cortisol level
24-hour urinary metanephrines
ACTH stimulation testing
FSH and LH levels
Plasma renin activity testing and an aldosterone level

Answer 3

A 24-hour urinary free cortisol level

This patient presents with clinical findings strongly suggestive of Cushing disease, which is defined as the excessive production of adrenal cortical hormones. Options for confirmatory testing include 24-hour urinary free cortisol and overnight salivary cortisol levels. Metanephrines are used to diagnose pheochromocytoma. ACTH stimulation testing is used to diagnose adrenal insufficiency. FSH and LH levels test the hypothalamic-pituitary-gonadal axis. Plasma renin activity testing and an aldosterone level are useful in the workup of secondary hypertension to help diagnose hyperaldosteronism.

Question 4

Pretibial myxedema is a cutaneous manifestation of?

(check one)
Subclinical diabetes mellitus
Collagen vascular disease
Hyperlipidemia, type III
Ischemia
Graves disease

Answer 4

Graves disease

Pretibial myxedema is a complication of Graves disease, whether it presents as hypo-or hyperthyroidism. It is a dermopathy that most often occurs in the lower legs and results from increased deposition of mucin due to the endocrine abnormality. Diabetes mellitus can cause necrobiosis lipoidica, a lesion on the lower extremities; hyperlipidemia can cause waxy papules; and collagen vascular and ischemic disease can cause urticaria and/or ulceration.

Question 5

A 47-year-old postmenopausal female falls while carrying groceries into her house and sustains a right distal radial fracture. A chemistry panel reveals a calcium level of 11.2 mg/dL (N 8.6–10.6) and further evaluation leads to a diagnosis of primary hyperparathyroidism.

Which one of the following is the best course of treatment for this patient?
(check one)
Estrogen replacement therapy
Long-term bisphosphonate therapy
Daily furosemide treatment with increased oral fluids
Elimination of calcium and vitamin D from the diet
Referral to a surgeon for consideration of parathyroidectomy

Answer 5

Referral to a surgeon for consideration of parathyroidectomy

Hyperparathyroidism is usually caused by a single adenoma of one of the four parathyroid glands. A minority of cases (10%–15%) are associated with four-gland hyperplasia. Studies that localize the glands, such as a technetium scan or ultrasonography, help surgeons who are familiar with this condition achieve a cure rate of 95%–98%, with an estimated complication rate of 1%–3%. For patients <50 years old or symptomatic patients, such as those with a fragility fracture, parathyroidectomy is the treatment of choice. If a patient is older, is a poor surgical candidate, or has asymptomatic disease, long-term monitoring with treatment focused on reducing bony complications can be considered (SOR C).

Question 6

A 35-year-old nulligravida sees you for preconception counseling. She has hypothyroidism treated with levothyroxine (Synthroid), and her most recent TSH level was in the therapeutic range. She has no symptoms of hypothyroidism.

Which one of the following is the patient most likely to require if she becomes pregnant? (check one)
A decreased dosage of levothyroxine
An increased dosage of levothyroxine
The addition of liothyronine (Cytomel)
Substitution of desiccated thyroid hormone preparation (Armour Thyroid) for the levothyroxine

Answer 6

An increased dosage of levothyroxine

Thyroid hormone requirements increase during pregnancy. Most women with hypothyroidism who become pregnant require an increased levothyroxine dosage (SOR A). A common recommendation is to have women on fixed daily doses of levothyroxine begin taking nine doses weekly (one extra dose on 2 days of the week) as soon as the pregnancy is confirmed (SOR B). Thyroid function tests should be repeated regularly throughout the pregnancy to guide additional dosage adjustments.

Question 7

A patient with ascites is suspected to have secondary hyperaldosteronism. Which one of the following would be typical levels of electrolytes in an aliquot specimen of urine? (check one)
Sodium 2 mEq/L, potassium 40 mEq/L
Sodium 5 mEq/L, potassium 0 mEq/L
Sodium 40 mEq/L, potassium 40 mEq/L
Sodium 80 mEq/L, potassium 2 mEq/L
Sodium 100 mEq/L, potassium 20 mEq/L

Answer 7

Sodium 2 mEq/L, potassium 40 mEq/L

Secondary hyperaldosteronism is characterized by sodium retention, and thus decreased urinary sodium excretion, while potassium secretion is normal to increased.

Question 8

A 21-year-old gravida 1 para 0 is diagnosed with overt hyperthyroidism early in the first trimester. The most appropriate management at this time is (check one)
observation only
methimazole (Tapazole)
propylthiouracil
radioactive iodine
thyroidectomy

Answer 8

propylthiouracil

Overt hyperthyroidism during pregnancy is associated with adverse effects to the mother and fetus, so treatment is required. Since methimazole is associated with birth defects when used in the first trimester, propylthiouracil is preferred. Methimazole should be considered after the first trimester because the risk of congenital anomalies is less than the risk of liver failure associated with propylthiouracil. Surgery and radioactive iodine should only be used if there is a clear indication, and radioactive iodine would not be appropriate during pregnancy.

Question 9

In a 27-year-old white female with irregular menstrual cycles and infertility, which one of the following would be more indicative of Cushing’s syndrome rather than the more common polycystic ovarian syndrome? (check one)
Easy bruising
Acne
Hirsutism
Androgenic alopecia
Acanthosis nigricans

Answer 9

Easy bruising

Easy bruising, moon facies, buffalo hump, abdominal striae, hypertension, and proximal myopathy suggest Cushing’s syndrome. Because this syndrome is very rare compared to polycystic ovarian syndrome, routine screening is not indicated in women with hypoandrogenic anovulation. Acne, hirsutism, androgenic alopecia, and acanthosis nigricans are all consistent with polycystic ovarian syndrome.

Question 10

A 60-year-old female comes to your office several weeks after an emergency department (ED) visit for ureteral colic. At that time, a comprehensive metabolic panel was normal except for a calcium level of 10.6 mg/dL (N 8.6–10.5). An ionized calcium level was also elevated. A urinalysis showed 20 RBCs/hpf but a urine culture was negative. CT of the abdomen and pelvis demonstrated a 4-mm radiopaque calculus in the distal ureter but no other abnormality. She was treated with analgesics and tamsulosin (Flomax) and passed the stone several days later.

She currently has no urinary or gastrointestinal symptoms. This is her third episode of ureterolithiasis in the past 5 years.

Which one of the following would be the most appropriate test to order next? (check one)
An intact parathyroid hormone level
A 24-hour urine sample for calcium
A TSH level
Repeat urinalysis and urine culture
Renal ultrasonography

Answer 10

An intact parathyroid hormone level

Hyperparathyroidism is an under-recognized cause of recurrent nephrolithiasis. Mild elevations of serum calcium levels are often overlooked or ignored. Surgical treatment of hyperparathyroidism can reduce serum calcium levels, hypercalciuria, and the formation of kidney stones.

A 24-hour urine sample for calcium would not be the most appropriate next step. Thyroid disorders are not directly linked to nephrolithiasis so a TSH level is not indicated. Repeat urine studies will not affect management. A CT scan in the emergency department was sufficient to rule out anatomic abnormality, so renal ultrasonography is not necessary.

Question 11

A 45-year-old female presents with a 1-week history of pain at the base of her anterior neck radiating to her right jaw. Prior to the onset of pain she had a sore throat, fever, and body aches. These symptoms resolved and the neck pain started. She now reports palpitations and excessive sweating.

Her vital signs include a pulse rate of 110 beats/min, a blood pressure of 140/83 mm Hg, and a normal temperature. On examination she appears uncomfortable and diaphoretic. An HEENT examination is unremarkable and you note no cervical lymphadenopathy. Her thyroid is tender and mildly enlarged. A cardiac examination shows tachycardia with no murmurs.

Laboratory studies reveal a normal CBC, an erythrocyte sedimentation rate of 55 mm/hr (N 0–29), and a TSH level of 0.21 μU/mL (N 0.5–5.0). Total T3 and free T4 levels are within the normal range. You order a radioactive iodine uptake scan, which shows diffusely low iodine uptake in her thyroid.

In addition to a β-blocker, which one of the following would be most appropriate at this point? (check one)
Ibuprofen, 800 mg three times daily
Levothyroxine (Synthroid), 50 μg daily
Methimazole, 5 mg three times daily
Prednisone, 40 mg daily
Vancomycin, 20 mg/kg intravenously every 12 hours

Answer 11

Ibuprofen, 800 mg three times daily

This patient has signs and symptoms consistent with subacute thyroiditis, which is confirmed by laboratory testing (an elevated erythrocyte sedimentation rate, a low TSH level, and normal T3 and T4 levels) and a radioactive iodine uptake scan with diffusely low iodine uptake. Subacute thyroiditis often follows a viral infection and is most common in women in their fifties, with peak occurrence in the late summer and fall months. The goal of treatment is to reduce thyroid pain and treat symptoms of thyrotoxicosis. High-dose NSAIDs or acetylsalicylic acid are first-line recommendations (SOR C). This patient would also benefit from the use of a β-blocker to ameliorate her tachycardia and diaphoresis.

During the acute thyroiditis phase, thyroid hormone supplementation is not indicated and will likely worsen symptoms. Levothyroxine would be indicated once the acute thyrotoxic phase resolves and there is evidence of hypothyroidism. Since subacute thyroiditis is a self-limited condition, levothyroxine is recommended for 12 months. Antithyroid medications such as methimazole are not indicated in subacute thyroiditis, which is a destructive process itself. While glucocorticoids such as prednisone provide faster pain relief than first-line NSAIDs or aspirin, they should not be used unless first-line treatments have failed to resolve symptoms in 4 days. Antibiotics are prescribed in suppurative thyroiditis, which is characterized by fever, leukocytosis, and cervical lymphadenopathy in addition to thyroid pain. They should be started empirically after negative blood cultures have been obtained.

Question 12

A 12-year-old transgender female accompanied by her mother comes to your office to discuss persistent gender dysphoria. The patient has been in counseling for 2 years along with her family, who is supportive of her gender identity. The patient’s mother asks about puberty blockers.

In discussing GnRH analogs with her, you note that the current recommendation for beginning this medication is when she is at which Tanner stage of development? (check one)
1
2
3
4
5

Answer 12

2

The 2022 World Professional Association for Transgender Healthcare (WPATH) standards of care recommends that in eligible adolescents, pubertal suppression may begin at Tanner stage 2. Treatment prior to the onset of puberty is not recommended. Tanner stage 1 is prepubescent and Tanner stage 2 is the initial pubescent stage. It is not necessary and may be harmful to wait for further pubertal stages before initiating puberty blockers in an eligible transgender adolescent.

Question 13

A 45-year-old female sees you for follow-up 3 days after a visit to the emergency department (ED) for acute abdominal pain due to an initial episode of a kidney stone. Her past medical history and family history are unremarkable. A CT scan in the ED demonstrated a nonobstructing, 4-mm mid-ureteral stone and several smaller stones in both kidneys, measuring up to 2 mm. Laboratory studies in the ED showed a calcium level of 11.4 mg/dL (N 8.0–10.0) and microscopic hematuria on urinalysis but were otherwise normal. She was treated with intravenous hydration and pain control and was discharged home. She passed the stone the next day.

A physical examination today is normal. Follow-up laboratory studies confirm an elevated serum calcium level, along with elevated serum parathyroid hormone and 24-hour urine calcium levels. A DEXA scan and repeat microscopic urinalysis are normal.

At this point, you should (check one)
prescribe a bisphosphonate
prescribe a thiazide diuretic
refer her for genetic evaluation
refer her for cystoscopy
refer her for parathyroidectomy

Answer 13

refer her for parathyroidectomy

This patient has laboratory evidence of primary hyperparathyroidism, with hypercalcemia and an inappropriately elevated (as opposed to suppressed) parathyroid hormone (PTH) level. An elevated 24-hour urine calcium level further distinguishes primary hyperparathyroidism from familial hypocalciuric hypercalcemia. Treatment of primary hyperparathyroidism with parathyroidectomy has been shown to normalize PTH and calcium levels, decrease kidney stone production, and prevent declines in renal function and bone mineral density. Untreated primary hyperparathyroidism increases overall mortality as well as cardiovascular and cerebrovascular disease risk, in addition to increasing the risk of kidney stone production, renal function decline, and loss of bone mineral density. Parathyroidectomy is indicated in this patient based on her symptomatic hypercalcemia, age <50, and serum calcium level >1 mg/dL above the upper limit of normal. Other potential indications include the presence of osteoporosis, reduced kidney function, or other asymptomatic renal involvement, including silent nephrolithiasis on imaging, nephrocalcinosis, or hypercalciuria.

Patients with primary hyperparathyroidism who are not candidates for surgery may be managed medically. Bisphosphonates may be used to increase bone mineral density. For this patient with a normal DEXA scan, surgical treatment would obviate the possible future need to treat her for bone density loss related to hyperparathyroidism. Thiazides may be used for treating certain hyperparathyroid states due to their impact on reducing calcium excretion and improving bone mineral density, although they are typically avoided in primary hyperparathyroidism because they can worsen hypercalcemia. Genetic evaluation would be warranted for a patient suspected of having multiple endocrine neoplasia type 1 or 2A, although this patient does not have any family history or presenting features to suggest involvement of either of these rare familial syndromes. Cystoscopy may be indicated in the setting of ureteral obstruction but is not necessary in this case.

Question 14

The most common electrolyte abnormality in a patient with primary hyperaldosteronism is (check one)
hypocalcemia
hypokalemia
hyponatremia
hyperkalemia
hypernatremia

Answer 14

hypokalemia

Primary hyperaldosteronism was previously thought to be rare, but it is now considered one of the more common causes of secondary hypertension. Hypokalemia is the most common electrolyte abnormality in patients with hyperaldosteronism. Excess aldosterone secretion independent of the renin-angiotensin system causes renal potassium wasting, although about half of patients with hyperaldosteronism have normal potassium levels. Hypocalcemia is commonly associated with inadequate levels of parathyroid hormone. Hyponatremia and hyperkalemia are associated with primary hypoaldosteronism. Hypernatremia is not a common finding in primary hyperaldosteronism.

Question 15

Which one of the following is known to cause hyperthyroidism? (check one)
Propranolol (Inderal)
Amiodarone (Cordarone)
Methimazole (Tapazole)
Propylthiouracil
Methotrexate (Rheumatrex, Trexall)

Answer 15

Amiodarone (Cordarone)

Amiodarone is 37% iodine and is the most common source of iodine excess in the United States.
Excessive iodine intake from dietary sources, radiographic contrast media, or amiodarone increases the
production and release of thyroid hormone in iodine-deficient individuals and in older persons with
multinodular goiter. Additionally, like other medications such as interferon and interleukin-2, amiodarone
can trigger thyroiditis in patients with normal thyroid glands. These characteristics combine to induce
hyperthyroidism in slightly over 10% of patients treated with amiodarone. -Blockers such as propranolol may be useful in controlling the symptoms of hyperthyroidism. Methimazole and propylthiouracil interfere with organification of iodine, thereby suppressing thyroid hormone production; they are commonly used as antithyroid agents when treating hyperthyroidism. Research is ongoing to determine if methotrexate plus prednisone is an effective treatment for the ophthalmopathy associated with Graves’ hyperthyroidism.

Question 16

A 20-year-old college wrestler is seen for an examination prior to the wrestling season. He tells you that some friends have told him he should start taking dehydroepiandrosterone (DHEA), and he asks for your advice.

Which one of the following is true about the effects of this drug?
(check one)
It enhances performance but not muscle strength
It enhances muscle strength but not performance
It enhances both performance and muscle strength
It does not enhance either performance or muscle strength

Answer 16

It does not enhance either performance or muscle strength

Dehydroepiandrosterone (DHEA) is illegal under the Anabolic Steroid Control Act of 2004, and is prohibited by the NCAA and the International Olympic Committee. Like androstenedione, DHEA is a precursor to testosterone, but neither of these substances has been shown to enhance either performance or strength. In fact, they increase serum estrogen and luteinizing hormone levels.

Question 17

A 40-year-old female sees you to discuss a thyroid nodule that was noted on a report from carotid ultrasonography performed by an independent organization. The patient is asymptomatic. Her family history is negative for malignancy.

On physical examination you confirm the presence of a thyroid nodule. The remainder of the examination, including the lymphatic system, is negative. A TSH level is normal.

Which one of the following would be the most appropriate next step? (check one)
Observation only
Thyroid ultrasonography
A radionucleotide thyroid uptake scan
Fine-needle aspiration only
Fine-needle aspiration with molecular testing

Answer 17

Thyroid ultrasonography

The first step in the evaluation of a palpable thyroid nodule is to obtain a TSH level and perform thyroid ultrasonography (SOR C). If the TSH level is low, a radionucleotide thyroid uptake scan is the appropriate next step to assess for a hyperfunctioning nodule. If the TSH level is normal or high, next steps are determined by the size and characteristics of the thyroid nodule on ultrasonography. Fine-needle aspiration (FNA) may be indicated depending on the size and nodule characteristics. Molecular testing of FNA specimens is useful in order to guide management of thyroid nodules with indeterminate cytology. Before molecular testing is performed, patients should be counseled about the potential benefits and limitations of the test (SOR C). Observation only would not be appropriate in this scenario.

Question 18

A 50-year-old gravida 2 para 2 who is 3 years post menopausal presents with fatigue, headache, galactorrhea, and loss of libido. Your evaluation reveals elevated serum prolactin and a pituitary adenoma of 5–6 mm.

You recommend (check one)
bromocriptine (Parlodel)
estrogens
haloperidol
testosterone
neurosurgical consultation

Answer 18

bromocriptine (Parlodel)

This patient has a pituitary microadenoma. Microadenomas <10 mm in size that are secreting prolactin may be treated with a dopaminergic agent such as bromocriptine. This will lower the prolactin level and shrink the adenoma. Nonprolactin-secreting adenomas, especially those >10 mm in size (macroadenomas), require neurosurgical evaluation.

Question 19

You evaluate a patient with fatigue, anorexia, and nausea for adrenal insufficiency. A morning cortisol level is low.

Which one of the following would be the most appropriate confirmatory test? (check one)
A 21-hydroxylase antibody level
An ACTH stimulation test
A low-dose dexamethasone suppression test
A high-dose dexamethasone suppression test
CT of the adrenal glands

Answer 19

An ACTH stimulation test

An ACTH stimulation test is the most appropriate confirmatory test for suspected adrenal insufficiency. If a cortisol level drawn 1 or 2 hours after administration of ACTH is inappropriately low, adrenal insufficiency is confirmed, and further evaluation is indicated to determine the etiology. A 21-hydroxylase antibody level may indicate that adrenal insufficiency has an autoimmune cause but does not confirm the presence of adrenal insufficiency. Dexamethasone suppression tests, in which morning cortisol is tested after administration of dexamethasone the previous evening, are used in the evaluation of suspected Cushing syndrome. Inappropriately elevated cortisol levels are indicative of Cushing syndrome. Imaging might be useful in determining the cause of adrenal gland dysfunction once adrenal insufficiency is confirmed.

Question 20

In a patient presenting with truncal obesity, hypertension, type 2 diabetes mellitus, hirsutism, osteopenia, and skin fragility, which one of the following tests is needed to confirm the diagnosis of Cushing syndrome? (check one)
A dexamethasone suppression test
Inferior petrosal sinus sampling
Plasma corticotropin
Plasma free cortisol
Urinary free cortisol

Answer 20

Urinary free cortisol

In a patient presenting with obesity, hypertension, type 2 diabetes mellitus, and hirsutism, who also has thin skin and osteopenia, an elevated 24-hour collection showing high urinary free cortisol confirms the presence of Cushing syndrome. The dexamethasone suppression test, though still commonly used, no longer has a place in the diagnosis and treatment of patients with Cushing syndrome. Corticotropin-dependent and corticotropin-independent causes of Cushing syndrome can be separated by measuring plasma corticotropin. Plasma free cortisol measurements should be obtained only to determine the success or failure of transsphenoidal microadenomectomy or adrenalectomy. Inferior petrosal sinus sampling is used to confirm the source of corticotropin secretion before surgical intervention.

Question 21

A 62-year-old female who is a new patient requests a thyroid evaluation because she has a history of abnormal thyroid test results. You obtain a copy of her records, which include a TSH level of 0.2 μU/mL (N 0.4–4.2) and a free T4 level of 2.0 ng/dL (N 0.8–2.7) from 3 years ago. She reports feeling well and has no other health conditions. She does not take any medications.

A physical examination reveals normal vital signs, a BMI of 23 kg/m2, no neck masses, a normal thyroid size, and normal heart sounds. Laboratory studies reveal a TSH level of 0.1 μU/mL, a free T4 level of 2.5 ng/dL, and a free T3 level of 3.1 pg/mL (N 2.3–4.2).

Treatment for this condition would be indicated if the patient has an abnormal (check one)
calcium level
DXA scan
glucose level
lipid level
thyroid ultrasonography study

Answer 21

DXA scan

This patient has subclinical hyperthyroidism as evidenced by her low TSH level with normal free T4 and free T3 levels. Common causes of subclinical hyperthyroidism include Graves disease, autonomous functioning thyroid adenoma, and multinodular toxic goiter. Subclinical hyperthyroidism may progress to overt hyperthyroidism; this is more likely in patients with TSH levels <0.1 μU/mL. Even in the absence of overt hyperthyroidism these patients are at higher risk for several health conditions, including atrial fibrillation, heart failure, and osteoporosis. For this reason it is important to assess for these conditions and consider treating the underlying thyroid condition, as well as the complication. The American Thyroid Association recommends treating patients with complications who are either over age 65 or have a TSH level <0.1 μU/mL.

Lipid and glucose abnormalities are not known to be related to subclinical hyperthyroidism. Calcium levels may be abnormal in hyperparathyroidism but not hyperthyroidism. Thyroid ultrasonography may be helpful to determine the cause of hyperthyroidism but is not used to help decide when to treat subclinical hyperthyroidism.

Question 22

A 28-year-old female presents with a 3-month history of fatigue and postural lightheadedness. On examination she is diffusely hyperpigmented, especially her skin creases and areolae. A CBC and basic metabolic panel are normal except for an elevated potassium level. You order a corticotropin stimulation test.

Prior to the corticotropin injection, you should order which one of the following tests to confirm that this patient has a primary insufficiency and not a secondary (pituitary) disorder? (check one)
ACTH
Aldosterone
Melanocyte-stimulating hormone
Renin
TSH

Answer 22

ACTH

A plasma ACTH level is recommended to establish primary adrenal insufficiency. The sample can be obtained at the same time as the baseline sample in the corticotropin test. A plasma ACTH greater than twice the upper limit of the reference range is consistent with primary adrenal insufficiency. Aldosterone and renin levels should be obtained to establish the presence of adrenocortical insufficiency, but these do not differentiate primary from secondary adrenal insufficiency. The hyperpigmentation of Addison’s disease is caused by the melanocyte-stimulating hormone (MSH)–like effect of the elevated plasma levels of ACTH. ACTH shares some amino acids with MSH and also produces an increase in MSH in the blood. TSH is not part of the feedback loop of adrenal insufficiency.

Question 23

A 40-year-old female presents with a 4-week history of a persistent sore throat despite supportive treatment for a viral upper respiratory infection provided by an urgent care facility. She reports palpitations, weight loss, frequent bowel movements, and anxiety with insomnia for the past month.

On examination she has a mildly enlarged thyroid gland. Laboratory evaluation is notable for a suppressed TSH level along with elevated free T4 and total T3 levels. A radioactive iodine uptake scan shows low uptake.

Which one of the following is the most likely diagnosis? (check one)
Factitious thyrotoxicosis
Graves disease
Multinodular goiter
Subacute thyroiditis
TSH-secreting pituitary adenoma

Answer 23

Subacute thyroiditis

The initial “destructive” phase of subacute thyroiditis presents with signs, symptoms, and laboratory findings of overt hyperthyroidism; however, a radioactive iodine uptake scan is negative in this phase. Graves disease and toxic multinodular goiter also present with overt hyperthyroidism, but radioactive iodine uptake is high. Factitious thyrotoxicosis is associated with low TSH and elevated or normal free T4 and total T3, but a goiter is not present. A TSH-secreting pituitary adenoma results in elevated TSH, free T4, and total T3.

Question 24

A 66-year-old asymptomatic male presents with a 6-month history of ongoing pruritus. A physical examination is normal. Laboratory studies are also normal except for an LDL-cholesterol level of 150 mg/dL, a free T4 level of 1.4 ng/dL (N 0.9–2.3), and a TSH level of 6.22 μU/mL (N 0.4–4.5).

Which one of the following would be most appropriate at this point? (check one)
No treatment at this time and a repeat TSH level in 3 months
Testing for thyroid antibodies and treatment with levothyroxine if the test is negative
A 131I uptake and scan with no treatment pending results
Liothyronine (Cytomel)
Levothyroxine (Synthroid)

Answer 24

No treatment at this time and a repeat TSH level in 3 months

This patient has subclinical hypothyroidism and should have a TSH level repeated in 1–3 months, as TSH may fluctuate in patients without thyroid disease and return to normal on subsequent testing. In a patient with a normal free T4 the TSH level must be >10 μU/mL for a diagnosis of hypothyroidism. Mild TSH elevations may be a normal manifestation of aging.

Question 25

A 26-year-old female presents with a 3-month history of abdominal pain, lightheadedness with standing, and some hyperpigmentation. Her CBC is normal, but a basic metabolic panel reveals a slightly low sodium level and a slightly high potassium level.

Which one of the following would be the most appropriate next step in your evaluation of this patient? (check one)
A serum aldosterone level
A corticotropin (ACTH) stimulation test
Paired morning cortisol and melanocyte stimulating hormone levels
21-hydroxylase antibodies and 17-hydroxyprogesterone levels

Answer 25

A corticotropin (ACTH) stimulation test

This patient has signs and symptoms consistent with primary adrenal insufficiency (PAI). In Western countries autoimmunity is responsible for 90% of these cases. Because the corticotropin (ACTH) stimulation test has a higher degree of sensitivity and specificity than morning cortisol and ACTH concentrations, it is the preferred test in all patients with possible primary adrenal insufficiency. Serum aldosterone paired with plasma renin activity is used to screen for adrenal hyperplasia in hypertensive patients and also for establishing the existence of mineralocorticoid insufficiency in patients with PAI. Once the diagnosis is established, 21-hydroxylase antibodies and 17-hydroxylase progesterone levels are used to determine the etiology of PAI.

Question 26

A 45-year-old female comes to your office for follow-up of palpitations and anxiety. Her pulse rate is 112 beats/min and her heart rate is regular with no audible murmurs. Her thyroid is nontender with no palpable nodules. You note bilateral exophthalmos as well as pretibial myxedema. Her TSH level is 0.05 μU/mL (N 0.5–5.0); free T4 and total T3 levels are elevated. A pregnancy test is negative.

Which one of the following would be the best option for limiting the progression of this patient’s ophthalmopathy? (check one)
Atenolol (Tenormin)
Cholestyramine (Questran)
Methimazole (Tapazole)
Prednisone
Radioactive iodine

Answer 26

Methimazole (Tapazole)

Based on her clinical presentation and classic ophthalmopathy, this patient has Graves disease. Unlike radioactive iodine, methimazole has been shown to decrease the risk of development or progression of ophthalmopathy in Graves disease (SOR B). Atenolol is used for symptomatic control in hyperthyroidism. Cholestyramine can help lower thyroid hormone acutely but is not a long-term treatment. Prednisone is used for severe hyperthyroidism and not long-term treatment. Atenolol, cholestyramine, and prednisone do not have any effect on the long-term complications of Graves disease.

Question 27

A 36-year-old female has had elevated blood pressure readings since establishing care with you 6 months ago. You have increased her antihypertensive therapy monthly in an attempt to treat her hypertension, and she is currently taking the maximum dosage of three antihypertensive medications from different classes. She confirms that her blood pressure is also elevated at home, typically ranging from 155/92 mm Hg to 165/98 mm Hg. She is otherwise well. She does not have chest pain, shortness of breath, headaches, daytime sleepiness, or lower extremity edema. Her family history is significant for hypertension diagnosed in her father in his 50s.
On examination the patient has a blood pressure of 168/95 mm Hg. Her pulse rate is 78 beats/min and her BMI is 28.1 kg/m2. She has a normal cardiac examination and no peripheral edema.
You order laboratory testing, with the following significant findings:
Sodium…………………………………………144 mEq/L (N 136–142)
Potassium…………………………………….3.0 mEq/L (N 3.5–5.0)
Creatinine……………………………………..0.72 mg/dL (N 0.6–1.2)
Fasting glucose………………………….. 98 mg/dL
TSH…………………………………………….. 1.46 μU/mL (N 0.4–4.2)
EKG…………………………………………….. normal

Which one of the following additional tests is most likely to reveal the cause of her hypertension? (check one)
A dexamethasone suppression test
Plasma aldosterone/renin activity
Plasma free metanephrines
A sleep study
Renal ultrasonography

Answer 27

Plasma aldosterone/renin activity

In young patients with hypertension it is important to consider secondary causes in addition to the more common essential hypertension. This patient’s relatively young age and elevated home blood pressure readings despite drug therapy warrant further evaluation. The initial evaluation showed hypokalemia, which suggests an endocrine cause of hypertension, specifically hyperaldosteronism. Other potential causes of secondary hypertension include coarctation of the aorta, renal artery stenosis, thyroid disorders, obstructive sleep apnea, pheochromocytoma, and Cushing syndrome. Each of these presents with clinical findings that help to distinguish them from other potential causes, and the laboratory evaluation would depend on the suspected cause.

Question 28

Which one of the following coexisting conditions could require the use of a much higher than expected dose of levothyroxine (Synthroid) to adequately treat hypothyroidism? (check one)
Chronic kidney disease
Diabetes mellitus
Helicobacter pylori gastritis
Hepatitis C infection
Hyperparathyroidism

Answer 28

Helicobacter pylori gastritis

Absorption of levothyroxine is impaired by several gastrointestinal conditions, including atrophic gastritis, chronic proton pump inhibitor use, and Helicobacter pylori infection. Treatment of H. pylori infection reverses this effect, and following eradication of the infection a reduction of the levothyroxine dosage by 30% or more will often be required.

Question 29

A 32-year-old female presents with heat intolerance, excessive weight loss, and anxiety. She gave birth 6 months ago and recently stopped breastfeeding. On examination her thyroid gland is slightly diffusely enlarged and nontender. Laboratory studies reveal a decreased TSH level and elevated free T3 and T4 levels. You suspect that she has postpartum thyroiditis.

Which one of the following tests would be most useful to confirm the diagnosis? (check one)
Radioactive iodine uptake
Thyroid peroxidase antibody levels
Thyroid ultrasonography
Thyrotropin receptor antibody levels

Answer 29

Radioactive iodine uptake

Postpartum thyroiditis is defined as a transient or persistent thyroid dysfunction that occurs within 1 year
of childbirth, miscarriage, or medical abortion. Release of preformed thyroid hormone in the bloodstream
initially results in hyperthyroidism. During the hyperthyroid phase, radioactive iodine uptake will be low,
which can help to confirm the diagnosis. Pregnancy and breastfeeding are contraindications to radionuclide
imaging. Thyroid peroxidase antibody levels are elevated with chronic autoimmune thyroiditis
(Hashimoto’s thyroiditis), and patients present with symptoms of hypothyroidism. The Endocrine Society
and American Association of Clinical Endocrinologists do not recommend routine thyroid ultrasonography
in patients with abnormal thyroid function tests if there is no palpable abnormality of the thyroid gland.
Thyrotropin receptor antibody levels are positive in Graves disease.

Question 30

A 30-year-old gravida 2 para 1 in her second trimester is evaluated for hypothyroidism. The normal TSH range in pregnancy is (check one)

lower than in the nonpregnant state
higher than in the nonpregnant state
the same as in the nonpregnant state
not useful for evaluating hypothyroidism after the first trimester

Answer 30

lower than in the nonpregnant state

The TSH reference range is lower during pregnancy because of the cross-reactivity of the -subunit of
hCG. Levels of hCG peak during weeks 7–13 of pregnancy, and hCG has mild TSH-like activity, leading
to slightly high free T4 levels in early pregnancy. This leads to a feedback decrease in TSH.

Question 31

A 46-year-old female with a history of hyperthyroidism controlled with methimazole (Tapazole), 10 mg daily, returns to your office after an absence of several years. She has new symptoms of palpitations, heat intolerance, and hoarseness. A physical examination reveals an enlarged thyroid and a radioactive iodine uptake scan shows accumulation of tracer in multiple areas.

Which one of the following is the appropriate definitive treatment for this patient? (check one)
Methimazole alone, 20 mg daily
Methimazole, 20 mg daily, plus propranolol, 80 mg twice daily
Propylthiouracil alone, 50 mg 3 times daily
Radioactive iodine
Thyroidectomy

Answer 31

Thyroidectomy

This patient has a medical history, physical examination, and radioactive iodine uptake scan consistent with
toxic multinodular goiter, which is the second most common cause of hyperthyroidism in the United States.
Although the addition of propranolol and an increase in methimazole may control her palpitations and other
symptoms of hyperthyroidism, these measures will not permanently eliminate the problem. Radioactive
iodine ablation and thyroidectomy with subsequent thyroid hormone replacement are both appropriate
treatments for toxic multinodular goiter, but thyroidectomy is indicated for this patient because she has
compressive symptoms from the goiter itself.

Question 32

A 33-year-old female presents to your office concerned about feeling fatigued for the past few months. She says that she feels cold often, has intermittent joint discomfort, and has gained 5 lb. She has not experienced any pain or problems swallowing. She gave birth to her youngest child almost 3 years ago, and she recently started an oral contraceptive. She has not had any recent illnesses. Her family history is significant for rheumatoid arthritis.

A physical examination reveals a mild goiter but is otherwise unremarkable. Her vital signs are stable. A CBC and comprehensive metabolic panel are normal. A TSH level is 6.48 μU/mL (N 0.4–4.5) and a thyroid peroxidase antibody level is 378 IU/mL (N <34). A free T4 level is normal.

Which one of the following is the most likely diagnosis for this patient? (check one)
Drug-induced thyroiditis
Hashimoto thyroiditis
Postpartum thyroiditis
Subacute thyroiditis

Answer 32

Hashimoto thyroiditis

Thyroiditis, a general term for inflammation of the thyroid gland, is associated with thyroid gland dysfunction. It is classified based on clinical symptoms: painless or painful, acute or subacute, and underlying etiology (medication-induced, infection, radiation-induced, or autoimmune). The most common forms of thyroiditis include Hashimoto, subacute, and postpartum. Thyroiditis often results in a triphasic disease pattern of thyroid dysfunction: hyperthyroidism due to the release of preformed thyroid hormone from damaged thyroid cells followed by hypothyroidism when the thyroid stores are depleted. Eventually normal thyroid function is restored, or the patient develops permanent hypothyroidism. This patient presents with symptoms commonly seen in thyroid disease. Further testing reveals elevated TSH and thyroid peroxidase (TPO) levels. Elevated TPO levels are found in 95% of patients with Hashimoto thyroiditis. In addition, this patient’s family history includes rheumatoid arthritis, another autoimmune disease, making Hashimoto thyroiditis the most likely diagnosis. Treatment is lifelong thyroid hormone therapy.

Several medications are linked to thyroiditis, including lithium, amiodarone, interferon-alfa, interleukin-2, immune checkpoint inhibitors, and tyrosine kinase inhibitors. However, there is no proven link between oral contraceptives and Hashimoto thyroiditis. Postpartum thyroiditis occurs within 1 year of delivery, miscarriage, or medical abortion, not 2–3 years. Subacute thyroiditis is self-limited and often occurs after upper respiratory infections, causing thyroid pain and dysphagia due to inflammatory destruction of thyroid follicles.

Question 33

A nulliparous 34-year-old female comes to your office for evaluation of fatigue, hair loss, and anterior neck pain. These symptoms have been gradually worsening for the past few months. Her past medical history is unremarkable. She has gained 5 kg (11 lb) since her last office visit 18 months ago. Examination of the thyroid gland reveals tenderness but no discrete nodules. Her TSH level is 7.5 μU/mL (N 0.4–4.2), her T4 level is low, and her thyroid peroxidase antibodies are elevated.

Which one of the following would be the most appropriate next step? (check one)
Continue monitoring TSH every 6 months
Begin thyroid hormone replacement and repeat the TSH level in 6–8 weeks
Begin thyroid hormone replacement and repeat the TSH level along with a T3 level in 6–8 weeks
Order ultrasonography of the thyroid
Order fine-needle aspiration of the thyroid

Answer 33

Begin thyroid hormone replacement and repeat the TSH level in 6–8 weeks

This patient has thyroiditis with biochemical evidence for autoimmune (Hashimoto’s) thyroiditis. The most
appropriate plan of care is to begin thyroid hormone replacement and monitor with a repeat TSH level 6–8
weeks later. It is not necessary to include a T3 level when assessing the levothyroxine dose. There is no
need to routinely order thyroid ultrasonography when there are no palpable nodules on a thyroid
examination. Fine-needle aspiration may be necessary to rule out infectious thyroiditis when a patient
presents with severe thyroid pain and systemic symptoms.

Question 34

A 70-year-old female presents to your office to discuss osteoporosis that was noted on a recent bone density test. Initial laboratory studies reveal an abnormal TSH level of 0.27 μU/mL (N 0.36–3.74). Additional studies reveal the following:

Repeat TSH …………. 0.04 μU/mL
Free T3 ……………….. 3.4 pg/mL (N 1.7–5.2)
Free T4 ……………….. 1.4 ng/dL (N 0.7–1.6)

A radioactive iodine uptake scan is notable for multiple areas of increased and suppressed uptake.

Which one of the following is the most likely explanation for these findings? (check one)
Exogenous thyroid hormone use
Graves disease
Painless thyroiditis
Recent excess iodine intake
Toxic multinodular goiter

Answer 34

Toxic multinodular goiter

This patient has a low serum TSH level in the presence of normal free T4 and total or free T3 levels, which is consistent with subclinical hyperthyroidism. The etiology of overt and subclinical hyperthyroidism should be determined by clinical symptoms, biochemical markers, and, if indicated, diagnostic studies such as a radioactive iodine uptake (RAIU) scan. A scan that shows multiple areas of increased and suppressed uptake is consistent with toxic multinodular goiter. There is no RAIU with exogenous ingestion of thyroid hormone, painless thyroiditis, and recent excess iodine intake. Graves disease causes diffuse RAIU.

It is important to determine the etiology of subclinical hyperthyroidism in order to treat it appropriately. In patients who have TSH levels that are persistently <0.1 μU/mL, the American Thyroid Association has a strong recommendation with moderate-quality evidence for treating patients 65 years of age and older; persons with cardiac risk factors, heart disease, or osteoporosis; postmenopausal women not on estrogens or bisphosphonates; and those with hyperthyroid symptoms.