Soal tiroid

1 . In a patient with iodine-deficiency goiter who moves from an iodine deficient

area to an iodine-replete area, the occurrence of hyperthyroidism

most likely represents

a. Graves' disease

b. Jod-Basedow phenomenon

c. Choriocarcinoma

d. Struma ovarii

e. Toxic multinodular goiter

(ans: Thyrotoxicosis can have several etiologies. Iodine-induced hyperthyroidism is called the Jod-

Basedow phenomenon and can occur in patients with endemic goiter who

move to areas where iodine is plentiful.)

2. Thyrotoxicosis and uniformly increased radioactive iodine uptake in

the thyroid can occur without any thyrotropin receptor antibodies or any

thyroid autoimmunity in

a. Graves' disease

b. Jod-Basedow phenomenon

c. Choriocarcinoma

d. Struma ovarii

e. Toxic multinodular goiter

(ans: Diffusely increased radioiodine uptake in the thyroid accompanying thyrotoxicosis usually

indicates Graves' disease, in which the thyrotropin receptors are stimulated

by antibodies. However, in patients with choriocarcinoma high levels of

human chorionic gonadotropin can also stimulate the thyrotropin receptor

and produce the same finding.)

3. Pretibial myxedema is associated with

a. Graves' disease

b. Jod-Basedow phenomenon

c. Choriocarcinoma

d. Struma ovarii

e. Toxic multinodular goiter

(ans: Graves' disease is associated with related autoimmune phenomena in other

tissues such as Graves' ophthalmopathy in the orbit and pretibial myxedema

in the skin.)

4. Infiltration of orbital soft tissue and extraocular muscles with lymphocytes,

mucopolysaccharides, and fluid is seen with

a. Graves' disease

b. Jod-Basedow phenomenon

c. Choriocarcinoma

d. Struma ovarii

e. Toxic multinodular goiter

5. Thyrotoxicosis with a low uptake of iodine in the thyroid bed but

uptake in the pelvis can be seen with

a. Graves' disease

b. Jod-Basedow phenomenon

c. Choriocarcinoma

d. Struma ovarii

e. Toxic multinodular goiter

(ans: Ovarian teratomas can

contain thyroid tissue (struma ovarii) and rarely cause thyrotoxicosis with

excess thyroid hormone produced by the teratoma rather than the thyroid)

6. The most common cause of spontaneous hypothyroidism in the

U.S. is

a. Iodine deficiency

b. Lithium

c. Hashimoto's thyroiditis

d. Propylthiouracil

e. Toxic multinodular goiter

(ans: Hypothyroidism can result from several causes including congenital

defects, chronic autoimmune thyroiditis (Hashimoto's thyroiditis), medications

(thionamides, lithium, iodine), other iatrogenic causes, iodine deficiency,

and hypothalamic or pituitary insufficiency. Chronic autoimmune

thyroiditis is the most common cause of hypothyroidism in the U.S.)

7. The most common cause of goiter in developing nations is

a. Iodine deficiency

b. Lithium

c. Hashimoto's thyroiditis

d. Propylthiouracil

e. Toxic multinodular goiter

(ans: World-wide, iodine deficiency (endemic) goiter is very common. It

is not common in the United States or other countries where salt is fortified

with iodine.)

8. Endemic goiter results from

a. Iodine deficiency

b. Lithium

c. Hashimoto's thyroiditis

d. Propylthiouracil

e. Toxic multinodular goiter

9. The conversion of T4 to T3 is inhibited by

a. Iodine deficiency

b. Lithium

c. Hashimoto's thyroiditis

d. Propylthiouracil

e. Toxic multinodular goiter

(ans: Propylthiouracil, propranolol, glucocorticoids, and iodine inhibit

conversion of T4 to T3.)

10. High levels of thyroidal peroxidase antibody are found with

a. Iodine deficiency

b. Lithium

c. Hashimoto's thyroiditis

d. Propylthiouracil

e. Toxic multinodular goiter

(ans: Chronic autoimmune thyroiditis (Hashimoto's thyroiditis) is the

most common cause of hypothyroidism in the U.S. and it is associated with

high levels of thyroid autoantibodies)

11. A patient without symptoms and without a recent illness is found to

have a normal free T4 and elevated TSH which are confirmed on repeated

measurements. The most likely explanation is

a. Hyperthyroidism

b. Nonthyroidal illness (sick euthyroidism)

c. Estrogen therapy

d. Subclinical hypothyroidism

e. Familial (euthyroid) dysalbuminenic hyperthyroxinemia

(ans: Laboratory measurements of thyroid hormones and thyroidstimulating

hormone have proven invaluable in determining the true functional

status of the thyroid gland. However, various medications and

nonthyroidal illnesses can alter certain values, so usually a combination of

values is used to make a diagnosis. TSH values tend to be the most reliable

in the absence of hypothalamic or pituitary disease, and mild elevation is

seen in hypothyroidism before free T4 declines)

12. The pattern of normal TSH, normal T4, and low T3 is most consistent

with

a. Hyperthyroidism

b. Nonthyroidal illness (sick euthyroidism)

c. Estrogen therapy

d. Subclinical hypothyroidism

e. Familial (euthyroid) dysalbuminenic hyperthyroxinemia

(ans: In severe nonthyroidal illness, T3 declines first, followed by T4

if the disease is severe enough, but TSH is usually normal)

12. A low TSH, high T4, and high T3 suggests

a. Hyperthyroidism

b. Nonthyroidal illness (sick euthyroidism)

c. Estrogen therapy

d. Subclinical hypothyroidism

e. Familial (euthyroid) dysalbuminenic hyperthyroxinemia

13. The pattern of normal TSH, high T4, and high T3 is seen often with

a. Hyperthyroidism

b. Nonthyroidal illness (sick euthyroidism)

c. Estrogen therapy

d. Subclinical hypothyroidism

e. Familial (euthyroid) dysalbuminenic hyperthyroxinemia

(ans: Estrogens increase thyroxine-binding globulin, elevating

total T4 and T3, whereas free T4, free T3, and TSH remain normal)

14. A patient with a low TSH and high T3 most likely has

a. Hyperthyroidism

b. Nonthyroidal illness (sick euthyroidism)

c. Estrogen therapy

d. Subclinical hypothyroidism

e. Familial (euthyroid) dysalbuminenic hyperthyroxinemia

(ans: Low TSH with high T4 and T3 or T3 alone (T3 toxicosis) reflects

hyperthyroidism.)

15. The most common variety of thyroid cancer is

a. Thyroid lymphoma

b. Medullary thyroid carcinoma

c. Papillary thyroid carcinoma

d. Anaplastic thyroid carcinoma

e. Follicular thyroid carcinoma

(ans: Thyroid cancers may arise from the thyroid follicular epithelium, the parafollicular C cells, or

lymphoid cells in the thyroid. Papillary carcinomas, including tumors with

mixed papillary and follicular elements, are most common and account for

70% of thyroid cancers. Fifteen percent of thyroid cancers have purely follicular

histology.)

16. A patient with thyroid cancer is told that he has a life expectancy of

less than 6 months from diagnosis. The variety of thyroid cancer with this

prognosis is

a. Thyroid lymphoma

b. Medullary thyroid carcinoma

c. Papillary thyroid carcinoma

d. Anaplastic thyroid carcinoma

e. Follicular thyroid carcinoma

(ans: The prognosis of anaplastic cancers, which likely represent dedifferentiation of better differentiated

papillary or follicular carcinomas, is very poor with average survival

less than 6 months.)

17. A patient with chronic autoimmune (Hashimoto's) thyroiditis develops

a rapidly enlarging thyroid mass. Most likely this is

a. Thyroid lymphoma

b. Medullary thyroid carcinoma

c. Papillary thyroid carcinoma

d. Anaplastic thyroid carcinoma

e. Follicular thyroid carcinoma

(ans: Thyroid lymphomas constitute about 5% of thyroid cancers and occur most often in patients

with Hashimoto's thyroiditis. Lymphomas and anaplastic carcinomas tend to grow rapidly.)

18. Elevated plasma calcitonin is seen with

a. Thyroid lymphoma

b. Medullary thyroid carcinoma

c. Papillary thyroid carcinoma

d. Anaplastic thyroid carcinoma

e. Follicular thyroid carcinoma

(ans: Medullary thyroid carcinomas secrete calcitonin, arise in the calcitonin-producing parafollicular

cells, and account for about 5% of thyroid cancers.)

19. A 40-year-old patient with a recent viral infection presents with a significantly

tender gland, low radioiodine uptake, and signs and symptoms

of thyrotoxicosis. This presentation is most likely

a. Graves' disease

b. Subacute thyroiditis

c. Toxic multinodular goiter

d. Hashimoto's thyroiditis

e. Toxic adenoma

(ans: The pattern and amount of radioiodine uptake on 123I scan is fundamental to

the correct diagnosis of thyrotoxicosis. Low-uptake thyrotoxicosis can

occur when there is destruction of the thyroid follicles with release of thyroid

hormone, such as in subacute thyroiditis, which usually presents as

an exquisitely painful gland. Iodine-induced hyperthyroidism, factitious

hyperthyroidism, and painless (silent) thyroiditis also cause low-uptake

thyrotoxicosis.)

20. A 65-year-old man presents with signs and symptoms of thyrotoxicosis.

His radioiodine scan and 24-h uptake show a patchy pattern but normal

amount of radioiodine uptake. This presentation is most consistent

with

a. Graves' disease

b. Subacute thyroiditis

c. Toxic multinodular goiter

d. Hashimoto's thyroiditis

e. Toxic adenoma

(ans: Patchy radioiodine uptake is common in multinodular goiter and

Hashimoto's thyroiditis, but hyperthyroidism with normal or increased

uptake typifies toxic multinodular goiter)

389. A 30-year-old woman with thyrotoxicosis has a diffusely enlarged

gland on palpation of the neck. Her thyroid scan and 24-h uptake show

uniformity of uptake and an increased percentage uptake. This patient has

a. Graves' disease

b. Subacute thyroiditis

c. Toxic multinodular goiter

d. Hashimoto's thyroiditis

e. Toxic adenoma

(ans: In Graves' disease, the uptake tends to be increased and more uniform.

Uptake may be increased without thyrotoxicosis in conditions characterized

by defects in organification of iodine, such as is found in some patients

with Hashimoto's thyroiditis, but the uptake tends to be patchy.)

sumber : PreTest® Self-Assessment and Review

Second Edition

Maurice A. Mufson, M.D., M.A.C.P.