Tuesday, April 29, 2008

31 - thyroid mcqs 1 to 100


1. what is the colour of the normal thyroid gland ?

answer : brownish-red colour .

2. the thyroid gland is highly vascular. TRUE OR FALSE ?

answer : true .

3. which of the following statements about thyroid is true ?

a- thyroid is located anteriorly in the upper neck
b- thyroid is located posteriorly in the upper neck
c- thyroid is located anteriorly in the lower neck
d- thyroid is located posteriorly in the lower neck

answer : c . the thyroid is located anteriorly in the lower neck .

4. what is the vertical extension of the thyroid in relation to the vertebrae ?

a- C4 to T1
b- C5 to T1
c- C6 to T1
d- C3 to T1

answer : b . fifth cervical vertebra to the first thoracic vertebra . C5 to T1.

5. thyroid is ensheathed by a fascia . what is it ?

answer : pretracheal layer of the deep cervical fascia .

6. what are the number of lobes in thyroid ?

answer : 2 lobes . right and left lobes connected by a narrow, median isthmus .

7. what is the weight of the thyroid ?

answer : 25 g ( usually but can vary ) .

8. among men and women, who have heavier thyroids ?

answer : women have slightly heavier thyroids when compared to males.

9. a woman came to the doctor with complaints of increase in the size of thyroid during menstruation . if u were the doctor there, what would u do ?

answer : I would tell her that it is perfectly normal for the size of a woman’s thyroid to increase during menstruation .

10. a pregnant woman came to ur clinic with complaints of enlarged thyroid . what would you suggest ?

answer : I would tell her that there is nothing to worry , because it is absolutely normal for a woman’s thyroid to enlarge during pregnancy and menstruation .

11. how will you normally estimate the size of the thyroid gland ?

answer : by doing diagnostic ultrasound .

12. As I already told u women have heavier thyroids than men, hence the volume of thyroid in women is slightly more than in men. But there is a phase of life in both males and females where no significant difference between the volumes of the male and female thyroid was observed. When is that phase ?

answer : from 8 months to 15 years . between these ages the volumes of both male and female thyroid show no significant difference .

13. what is the shape of the lobes of the thyroid gland ?

answer : approximately conical .

14. the bases of the thyroid lobes are level with which tracheal cartilage ?

answer : 4th or 5th tracheal cartilages .

15. what is the length of each thyroid lobe ?

answer : 5cms long .

16. the posteromedial aspects of the thyroid lobes are attached to which structure ?

answer : cricoid cartilage .

17. what is the name of the ligament which attaches the lobes of thyroid to the cricoid cartilage posteromedially ?

answer : lateral thyroid ligament .

18. what is the part of the thyroid that connects the lower parts of the two lobes called ?

answer : isthmus .

19. what would you suggest to a healthy patient who has no isthmus ?

answer : I would suggest that it is physiologically normal for a person to be born without an isthmus and this happens occasionally . I would assure him that there is nothing to worry .

20. what is the length of the isthmus ?

answer : 1.25 cms transversely and vertically .

21. the isthmus normally lies anterior to which tracheal cartilages ?

answer : it usually lies anterior to second and third tracheal cartilages. ( it can lie slightly higher or slightly lower sometimes because of the variations in size and site of the thyroid gland )

22. what is the tumor marker of the medullary carcinoma of the thyroid?

answer : calcitonin .

23. what is the most common position of the thyroglossal cyst ?

answer : below the hyoid bone . ( check again ).

24. what is the name of the surgery done to treat the thyroglossal cyst/fistula ?

answer : sistrunk’s operation .

25. what is the hormone secreted by the thyroid that controls the calcium metabolism ?

answer : calcitonin .

26. superior thyroid artery is a branch of which artery ?

answer : external carotid artery .
( the branches of the external carotid artery are 1. superior thyroid artery 2.lingual artery 3.posterior auricular artery 4.facial artery 5.occipital artery 6.ascending pharyngeal artery 7.maxillary artery 8.superficial temporal artery ------ SLPFOAMS ------ SISTER LUCY’S POWDERED FACE OFTEN ATTRACTS MEDICAL STUDENTS . )

27. which is the only medial branch of the external carotid artery ?

answer : ascending pharyngeal artery . ( out of context but important .)

28. the thyroid develops from ?

a- ectoderm
b- mesoderm
c- dorsal pharyngeal gut endoderm
d- ventral pharyngeal gut endoderm

answer : d . ventral pharyngeal gut endoderm .

29. the development of thyroid occurs in which week of the intrauterine life ?

answer : 4th week .

30. what are the cells in the thyroid which produce the calcitonin ?

answer : C cells ( also called as the parafollicular cells .)

31. what is the function of calcitonin ?

answer : lowers blood calcium by inhibiting the bone resorption and inhibiting the calcium recovery from renal tubule ultrafiltrate .

32. the embryonic thyroid descends from a foramen located in the posterior part of the tongue . what is it ?

answer : it is called the foramen caecum .

33. the thyroid usually reaches the front of the trachea by the end of how many months of the intrauterine life ?

answer : by the end of 2nd month of intrauterine life .

34. the thyroglossal duct is originally a hollow tube running from foramen caecum to pharynx . TRUE OR FALSE ?

answer : true . ( check again )

35. thyroglossal duct tissue normally becomes solid and remains uncanalised after transit of the thyroid . TRUE OR FALSE ?

answer : FALSE ( check again )

36. the pyramidal lobe of the thyroid represents part of the thyroglossal duct . TRUE OR FALSE?

answer : TRUE ( check again ) .

37. most common histological type of thyroid cancer ?

answer : papillary carcinoma .

38. thyroid carcinoma with best prognosis ?

answer : papillary carcinoma .

39. screening method for medullary carcinoma of thyroid ?

a- serum calcitonin
b- serum calcium
c- serum ALP
d- serum acid phosphatase

answer : a . serum calcitonin .

40. the carcinoma of thyroid associated with hypocalcemia ?

answer : medullary carcinoma of thyroid . ( remember it secretes calcitonin ).

41. medullary carcinoma of thyroid arises from ?

a- parafollicular cells
b- cells lining the acini
c- capsule of thyroid
d- stroma of the gland

answer : a . parafollicular cells .

42. papillary carcinoma of thyroid usually presents as ?

answer : single nodule + local lymph node .

43. which of the following is/are used in the management of thyroid malignancy?

a- Iodine 131
b- Iodine 125
c- Technitium 99
d- Phosphorus 32
e- strontium

answer is a . Iodine 131 .

44. which of the following factors contribute to the development of duodenal ulcer ?

a- Iodine 131
b- Iodine 125
c- Technitium 99
d- Phosphorus 32

answer : a . iodine 131 .

45. characteristic eye sign in dysthyroid status ?

a- exopthalmos
b- ptosis
c- optic neuropathy
d- myopathy

answer : a . exopthalmos .

45. hurthle cells are seen in ?

a- hashimoto’s thyroiditis
b- follicular cell carcinoma
c- hurthle cell thyroid adenoma
d- all the above

answer is d . all the above .

46. the C cells of the thyroid parenchyma belongs to the APUD system of dispersed neuron-endocrine cells . what is APUD system ?


47. how did the C cells get their name ?

answer : C stands for Clear cells , because they have pale staining cytoplasm and hence appear clear .

48. what is arteria thyroidea ima ?

answer : an artery supplying thyroid which is seen occasionally and arises from the brachiocephalic trunk or aortic arch .

49. what are the two main arteries that supply the thyroid ?

answer : superior and inferior thyroid arteries . superior thyroid artery is a branch of the external carotid artery and the inferior thyroid artery is branch of the thyrocervical trunk .

50. C cells populate which part of the lateral lobe of the thyroid ?

a- upper one-third of the lateral lobe of thyroid
b- middle one-third of the lateral lobe of thyroid
c- lower one-third of the lateral lobe of the thyroid
d- distributed equally all over the lateral lobe of the thyroid

answer : b . C cells populate the middle one-third of the lateral lobe of the thyroid .
( typically found scattered within thyroid follicles , inside the basal lamina but not reaching the follicle lumen .)

51. pick out the correct statements .

a- the external laryngeal nerve runs close to the superior thyroid artery .
b- the recurrent laryngeal nerve runs close to the inferior thyroid artery .
c- the external laryngeal nerve runs close to the inferior thyroid artery .
d- the recurrent laryngeal nerve runs close to the superior thyroid artery .

answer : both a and b are correct . ( so the surgeon has to be very careful while ligating those arteries, while performing thyroidectomy ).

52. what are the branches of the thyrocervical trunk ?

answer : 1. inferior thyroid artery 2.suprascapular artery 3.transverse cervical artery ( also called transversalis artery colli ) .

53. thyrocervical trunk arises from which artery ?

answer : subclavian artery .

54. what are the active thyroid hormones secreted by the follicular epithelial
cells of the thyroid ?

answer: tri-iodothyronine T3 and tetra-iodothyronin T4 ( thyroxine ) .

55. treatment of medullary carcinoma of the thyroid with lymphnode metastasis?

a- subtotal thyroidectomy + radioiodine
b- subtotal thyroidectomy + radiotherapy
c- neartotal thyroidectomy + radioiodine
d- neartotal thyroidectomy + radiotherapy
e- total thyroidectomy + radiotherapy

answer : e . total thyroidectomy + radiotherapy .

56. what is near total thyroidectomy ?

a- right lobectomy + isthmusectomy
b- left lobectomy + isthmusectomy
c- bilateral lobectomy with isthmusectomy
d- right lobectomy + isthmusectomy + left half lobectomy
e- right and left lobectomy

answer : d .

57. papillary carcinoma of thyroid with bone metastasis is treated by?

a- subtotal thyroidectomy + radioiodine
b- subtotal thyroidectomy + radiotherapy
c- near total thyroidectomy + radioiodine
d- near total thyroidectomy + radiotherapy
e- total thyroidectomy + chemotherapy

answer : c and d . both . near total thyroidectomy with radioiodine and radiotherapy.

58. most common cause of thyroiditis is ?

a- hashimoto’s thyroiditis
b- reidl’s thyroiditis
c- subacute thyroiditis
d- viral thyroiditis

answer : a . hashimoto’s thyroiditis .

59. recurrent laryngeal nerve is in close association with ?

a- superior thyroid artery
b- inferior thyroid artery
c- middle thyroid vein
d- superior thyroid vein

answer : b . inferior thyroid artery .

60. thyroglossal cyst may occasionally give rise to which carcinoma ?

a- papillary
b- anaplastic
c- medullary
d- follicular

answer : a . papillary carcinoma of the thyroid .

61. a post-thyroidectomy patient develops signs and symptoms of tetany. The management is ?

a- I.V calcium gluconate
b- Bicarbonate
c- Calcitonin
d- Vitamin D

Answer : a . I.V calcium gluconate .

62. hypoparathyroidism following thyroid surgery occurs with in ?

a- 24 hours
b- 2-5 days
c- 7-14 days
d- 2-3 weeks

Answer : b . 2-5 days .

63. what are the normal levels of calcium in our body ?

answer : calcium,ionized - wholeblood – 1.1 to 1.4 mmol/litre – 4.5 to 5.6 mg/dl(meq/l) .

calcium - serum - 2.2 to 2.6 mmol/litre – 9 to 10.5 mg/dl(meq/l) .

64. a patient undergoes thyroid surgery following which he develops perioral tingling . his blood calcium is 8.9 meq/l. next step in the management is ?

a- vitamin D orally
b- oral calcium and vitamin D
c- intravenous calcium gluconate and serial monitoring
d- wait for calcium to decrease to less than 7 meq/l before taking further action

answer : b . oral calcium and vitamin D .

65. a patient after undergoing thyroid surgery presents with perioral paraesthesia . serum calcium level is 7 mg/dl . what will be the best management ?

a- oral vitamin D3
b- oral vitamin D3 and calcium
c- I.V calcium gluconate
d- Oral calcium

Answer : d . oral calcium .

66. which of the following is not a complication of total thyroidectomy ?

a- bleeding
b- airway obstruction
c- hoarseness
d- hypercalcemia

answer : d . hypercalcemia .

67. in post operative room after thyroid surgery , patient developed sudden respiratory distress , dressing was removed and it was found to be slightly blood stained and wound was bulging . what will be the first thing to be done ?

a- tracheostomy
b- cricothyroidectomy
c- laryngoscopy and intubation
d- remove the stitch and take the patient to O.T

answer : d . remove the stitch and take the patient to the O.T .

67. a patient presents with swelling in the neck following a thyroidectomy. What is the most likely resulting complication ?

a- respiratory obstruction
b- recurrent laryngeal nerve palsy
c- hypovolemia
d- hypocalcemia

answer : a . respiratory obstruction .

68. a patient presents with neck swelling and respiratory distress few hours after a thyroidectomy surgery. Next management would be ?

a- open immediately
b- tracheostomy
c- wait and watch
d- oxygen by mask

answer : a . open immediately .

69. after thyroidectomy patient developed stridor within 2 hours. All are likely causes of stridor except ?

a- hypocalcemia
b- recurrent laryngeal nerve palsy
c- laryngomalacia
d- wound hematoma

answer : a . hypocalcemia due to hypoparathyroidism after thyroid surgey normall results with in 2-5 days .

70. which of the following will not lead to respiratory distress after thyroid surgery?

a- laryngomalacia
b- bilateral recurrent laryngeal nerve palsy
c- hypocalcemia
d- none

answer : d . none . all the 3 can lead to respiratory distress .

71. how does hypocalcemia result in respiratory distress ?

answer : pending .

72. papillary carcinoma of the thyroid ( PCT ) patients are ?

a- euthyroid
b- hypothyroid
c- hyperthyroid
d- T3 thyrotoxicosis

Answer : a . euthyroid .

73. medullary carcinoma of thyroid is derived from which cells ?

a- follicular
b- para follicular
c- oxyphilic
d- lymphocytes

answer : para follicular cells ( also called C cells ) .

74. HURTHLE cell carcinomas are derived from which cells ?

a- follicular cells
b- para follicular cells
c- oxyphilic cells
d- lymphocytes

answer : c . oxyphilic cells .

75. patients with MEN 2a also may have hirschsprung’s and lichen cutaneous amyloidosis ? TRUE OR FALSE ?

answer : true .

76. the malignancy which is common on long standing goiter ?

a- PCT
b- MCT
c- FCT
d- Anaplastic

Answer : c . Follicular carcinoma of the thyroid .

77. cancer common in iodine deficient areas ?

a- papillary
b- medullary
c- anaplastic
d- follicular

answer : c and d . follicular and anaplastic both are common .

78. least malignant thyroid cancer ?

e- papillary
f- medullary
g- anaplastic
h- follicular

answer : e . papillary .

79. commonest tumor of the thyroid ?

answer : papillary carcinoma of the thyroid .

80. which of the following gene defects is associated with development of the medullary carcinoma of the thyroid ?

a- RET proto oncogene
b- FAP gene
c- RB gene
d- BRCA 1 gene

Answer : a . RET proto oncogene .

81. what are the other diseases associated with the RET gene ?

answer : medullary thyroid carcinoma, hirschsprung’s disease and pheochromocytoma.

82. RET proto-oncogene encodes for ?

a- tyrosine kinase receptor on the cytoplasmic membrane
b- protein kinase
c- IP3
d- All the above

Answer : a . tyrosine kinase receptor on the cytoplasmic membrane .

83. RET gene is located on which chromosome ?

Answer : 10 th chromosome .

84. rearrangement of RET gene leads to ?

a- PTC
b- MTC
c- FCT
d- Lymphoma

Answer : a. papillary thyroid cancer .

85. gene implicated in papillary thyroid cancer is ?

a- RET
b- K ras
c- C myc
d- APC

Answer : a . RET gene .

86. point mutation of RET gene leads to ?

answer : familial medullary carcinoma ( MEN 2A AND MEN 2B ).

87. RET ligand is identified as ?

Answer: GDNF ( glial cell line-derived neurotropic factor ).

88. psammoma bodies are seen in all of the following conditions except ?

a- serous cystadenoma of ovary
b- papillary carcinoma of thyroid
c- meningioma
d- mucinous cystadenoma of ovary

answer : d .

89. all of the following are early life threatening complications of thyroid operation except ?

a- tracheomalacia and collapse of larynx
b- wound hematoma with compression of the trachea
c- hypocalcemia
d- thyroid storm

answer : c . hypocalcemia .

90. in pregnancy ?

a- thiouracil is contraindicated
b- surgery is contraindicated
c- radioiodine is contraindicated
d- none

answer: c . only radioiodine is contraindicated .

91. amyloid stroma is seen in which carcinoma of thyroid?

Answer : medullary carcinoma of thyroid .

92. lateral aberrant thyroid refers to ?

a- congenital thyroid abnormality
b- metastatic foci from primary in the thyroid
c- struma ovarii
d- lingual thyroid

answer : b . metastatic foci from primary carcinoma in the thyroid .

93. a patient with long standing multinodular goiter develops hoarseness of voice ; also the swelling undergoes sudden increase in size. Likely diagnosis is ?

answer : follicular carcinoma of thyroid .

94. a patient has pituitary tumor and pheochromocytoma and a thyroid nodule . which carcinoma is most likely to occur ?

answer : medullary carcinoma of the thyroid . the condition is MEN 2a or MEN 2b. MEN 1 comprises of parathyroid , pituitary and pancreatic tumors. MEN 2a comprises of parathyroid, medullary carcinoma of thyroid and pheochromocytoma tumors. MEN 2b comprises of medullary carcinoma of thyroid, pheochromocytoma and neuromas .

95. a patient presented with headache and flushing . he has a family history of his relative having died of a thyroid tumor. The investigation that would be required for this patient will be ?

a- chest x-ray
b- measurement of 5-HIAA
c- measurement of catecholamine
d- intravenous pyelography

answer : c . measurement of catecholamines . headache and flushing suggest symptoms of adrenal tumor and a history of thyroid tumor in the relative suggest the MEN syndrome type 2a or 2b . so the adrenal tumor is probably pheochromocytoma and so catecholamines have to be measured .

96. cancer that develops after irradiation ?

a- PCT
b- MCT
c- FCT
d- Anaplastic

Answer : papillary carcinoma of the thyroid .

97. what is an oncogene ?

answer : gene that contributes directly to tumor genesis .

98. mutated p53 gene is formed in most of ?

a- anaplastic carcinomas
b- PCT
c- MCT
d- FCT

Answer : a . anaplastic carcinomas .

99. deletion of which chromosome accompanies transformation of follicular adenoma to follicular adeno carcinoma ?

answer : 3p .

100. treatment of choice for medullary carcinoma of thyroid is ?

a- total thyroidectomy
b- partial thyroidectomy
c- iodine 131 ablation
d- hemithyroidectomy

answer : a . total thyroidectomy .

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