Question 1

A severe systemic illness that causes decreased peripheral conversion of T4 to T3, an increased conversion of T3 to the inactive rT3, and decreased binding of thyroid hormones is known as&#10;A) Hashimoto thyroiditis.&#10;B) Graves disease.&#10;C) euthyroid sick syndrome.&#10;D) Addison disease.

Accepted Answer

Euthyroid sick syndrome is hypothyroidism associated with protein-calorie malnutrition, surgical trauma, myocardial infarction, chronic renal failure, diabetic ketoacidosis, anorexia nervosa, cirrhosis, thermal injury, or sepsis. After the underlying cause is treated, the condition is usually resolved.

Question 2

Graves disease is an autoimmune disease in which the thyroid is diffusely enlarged (goiter) and overactive, producing an excessive amount of thyroid hormones. It is the most common cause of hyperthyroidism (overactive thyroid) in the United States. What is the primary target of circulating autoantibodies in this disease?

A) Insulin receptors
B) Thyroid-stimulating hormone (TSH) receptors
C) Thyrotropin-releasing hormone (TRH) receptors
D) Cortisol receptors

Accepted Answer

In Graves disease, the TRH receptor itself is the primary autoantigen and is responsible for the manifestation of hyperthyroidism. The thyroid gland is under continuous stimulation by circulating autoantibodies against the TRH receptor, and pituitary TSH secretion is suppressed because of the increased production of thyroid hormones. These thyroid-stimulating antibodies cause release of thyroid hormone and Tg and stimulate iodine uptake, protein synthesis, and thyroid gland growth.

Question 3

Botanical preparations have been found in animal studies to influence thyroid activity. Commiphora mukul (guggulsterones from guggul extract) has strong thyroid stimulatory action, demonstrated by&#10;A) increasing cortisol production.&#10;B) decreasing iodine uptake by the thyroid.&#10;C) increasing TPO activity.&#10;D) decreasing serum T4 concentrations.

Accepted Answer

Administration of 1 mg of Commiphora mukul/100 g body weight increases iodine uptake by the thyroid, increases TPO activity, and decreases lipid peroxidation, suggesting that increased peripheral generation of T3 might be mediated by this plant's antioxidant effects.

Question 4

Although some T3 is produced in the thyroid, approximately 80% to 85% is generated outside the thyroid in which organs?&#10;A) Nervous system and adrenal glands&#10;B) Liver and kidneys&#10;C) Pancreas and gastrointestinal tract&#10;D) Hypothalamus and pituitary gland

Accepted Answer

T3 is primarily produced by conversion of T4 in the liver and kidneys. The pituitary and nervous system are capable of converting T4 to T3, so they are not reliant on T3 produced in the liver or kidney.

Question 5

Maintaining thyroid hormone function throughout the aging process appears to be an important hallmark of healthy aging. What characteristic is an indicator of thyroid health in centenarians?&#10;A) Decreased free T4 and rT3 levels&#10;B) An increased libido&#10;C) Constant cortisol production&#10;D) The absence of circulating thyroid autoantibodies

Accepted Answer

Because unhealthy aging is associated with a progressively increasing prevalence of organ-specific and nonorgan-specific autoantibodies, the absence of these antibodies may represent a significantly reduced risk for cardiovascular disease and other chronic age-related disorders.

Question 6

Dietary intervention is a key therapeutic tool in managing patients with thyroid disease. In the absence of nutritional deficiencies, what is the main goal of nutritional support?&#10;A) Maintaining vitamin sufficiency&#10;B) Decreasing oxidative stress&#10;C) Increasing iodine concentrations&#10;D) Reducing antithyroidal antibodies

Accepted Answer

A variety of food antigens could induce antibodies that cross-react with the thyroid gland. A food elimination diet using gluten-free grains and possible elimination of casein, the predominant milk protein, might be considered for patients with hypothyroidism of unexplained origin.

Question 7

Which of these is NOT a product of the thyroid?&#10;A) Thyroxine (T4)&#10;B) Calcitonin&#10;C) Reverse T3 (rT3)&#10;D) Triiodothyronine (T3)

Accepted Answer

Reverse T3 (rT3) is derived from T4 through the action of deiodinase. It is an isomer of T3 but is not itself produced by the thyroid.

Question 8

Iodine deficiency is often a culprit in thyroid disorders. However, in which of these thyroid conditions may supplementing with iodine exacerbate the condition?&#10;A) Adrenal fatigue&#10;B) Hashimoto thyroiditis&#10;C) Polycystic ovary syndrome (PCOS)&#10;D) Graves disease

Accepted Answer

In autoimmune Hashimoto thyroiditis, supplementing with iodine may exacerbate the condition. Because iodine stimulates production of TPO, this in turn increases the levels of TPO antibodies (TPO Abs) dramatically, indicating an autoimmune flare-up. Some people develop symptoms of an overactive thyroid, but others have no symptoms despite tests showing an elevated level of TPO Abs. Therefore, one must be cautious regarding the use of iodine. Furthermore, although iodine deficiency is the most common cause of hypothyroidism for most of the world's population, in the United States and other westernized countries, Hashimoto thyroiditis accounts for the majority of cases.

Question 9

Selenium deficiency, inadequate protein, excess carbohydrates, chronic illness, and stress (high cortisol levels) can all impact what thyroid metabolic process?&#10;A) Thyroid-stimulating hormone (TSH) production&#10;B) Organification of iodide&#10;C) Thyroid-binding globulin (TBG) T4 transport&#10;D) 5'-Deiodinase conversion of T4 to T3

Accepted Answer

Changes in 5'-deiodination occur in a number of situations, such as stress, poor nutrition, illness, selenium deficiency, and drug therapy. Toxic metals such as cadmium, mercury, and lead have been associated with impaired hepatic 5'-deiodination in animal models. Free radicals are also involved in inhibition of 5'-deiodinase activity.

Question 10

Polycystic ovary syndrome (PCOS) is characterized by which of the following biochemical and endocrine abnormalities?&#10;A) Elevated testosterone, insulin resistance, and impaired glucose tolerance&#10;B) Thyrotoxicosis, iodine deficiency, and elevated estrogen&#10;C) Impaired glucose tolerance, increased T4 conversion, and hypertension&#10;D) Low blood calcium, thyroid receptor hypersensitivity, and elevated cortisol

Accepted Answer

Biochemical and endocrine abnormalities in women with PCOS include elevated levels of androgens (dehydroepiandrosterone, testosterone, and androstenedione), hyperinsulinemia (which results from insulin resistance), impaired glucose tolerance, and hyperlipidemia. Hyperandrogenism is responsible for many of the symptoms of PCOS, such as reproductive and menstrual abnormalities, hirsutism, and acne.

Question 11

Some plant foods (cauliflower, broccoli, cabbage) exert antithyroid activity through what mechanism?&#10;A) Binding iodine species&#10;B) Inhibiting thyroid peroxidase&#10;C) Increasing thyroglobulin antibodies&#10;D) Stimulating cortisol

Accepted Answer

The answer of Some plant foods (cauliflower, broccoli, cabbage) exert...

Question 12

A rare primary adrenal insufficiency in which insufficient levels of steroid hormones are produced despite adequate levels of the hormone ACTH is known as&#10;A) adrenal fatigue.&#10;B) Addison disease.&#10;C) Cushing syndrome.&#10;D) euthyroid sick syndrome.

Accepted Answer

The answer of A rare primary adrenal insufficiency in which...

Question 13

Before 1960, reports surfaced that soy formula-fed infants were developing hypothyroidism. The addition of what supplement to these formulas ameliorated this problem?&#10;A) Iodine&#10;B) Selenium&#10;C) Iron&#10;D) Tyrosine

Accepted Answer

The answer of Before 1960, reports surfaced that soy formula-fed...

Question 14

Thyroid health has been shown to be impacted by the elimination of which foods?&#10;A) Seafood&#10;B) Gluten&#10;C) Mushrooms&#10;D) Barley

Accepted Answer

The answer of Thyroid health has been shown to be...

Question 15

Which of these is NOT required for the production of thyroxine (T4) and triiodothyronine (T3)?&#10;A) Thyroid peroxidase (TPO)&#10;B) Tyrosine&#10;C) Thyroid-binding globulin (TBG)&#10;D) Iodide

Accepted Answer

The answer of Which of these is NOT required for...

Question 16

Thyroid health in some adults can be improved by increasing the conversion of T4 to T3. This can be accomplished by&#10;A) supplementing with tyrosine.&#10;B) correcting zinc deficiencies with zinc glycinate or zinc citrate.&#10;C) increasing naturally occurring flavonoids in the diet.&#10;D) cautiously supplementing with lipoic acid.

Accepted Answer

The answer of Thyroid health in some adults can be...

Question 17

Low energy, cold hands and feet, fatigue, hypercholesterolemia, muscle pain, depression, and a positive test result for thyroid peroxidase antibodies could all be indicative of what condition?&#10;A) Diabetes mellitus&#10;B) Graves disease&#10;C) Hashimoto thyroiditis&#10;D) Polycystic ovary syndrome (PCOS)

Accepted Answer

The answer of Low energy, cold hands and feet, fatigue,...

Question 18

Characteristics of chronic adrenal stress do NOT include&#10;A) increased thyroid-binding protein activity.&#10;B) decreased conversion of T4 to active forms of T3.&#10;C) weakened immune barriers of the digestive tract, lungs, and brain.&#10;D) increased sensitivity to thyroid hormones.

Accepted Answer

The answer of Characteristics of chronic adrenal stress do NOT...

Question 19

More than 90% of people with autoimmune thyroid disease have a genetic defect affecting their ability to metabolize what?&#10;A) Vitamin D&#10;B) Flavonoids&#10;C) Selenium&#10;D) Tyrosine

Accepted Answer

The answer of More than 90% of people with autoimmune...

Question 20

Cushing syndrome is characterized by weight gain, easy bruising, depression, muscle loss, and weakness. It is caused by&#10;A) an increased concentration of endocrine autoantibodies.&#10;B) thiocyanate ions, which can compete with iodine for uptake by the thyroid gland.&#10;C) too much cortisol remaining in the bloodstream over a long period.&#10;D) thyroid hormone deficiency during pregnancy.

Accepted Answer

The answer of Cushing syndrome is characterized by weight gain,...

Deck 31: Medical Nutrition Therapy for Thyroid, Adrenal, and Other Endocrine Disorders