THE THYROID GLAND
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 ?
answer : AMINE PRECURSOR UPTAKE AND DECARBOXYLATION 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 .
