Lec 01: Pathology of Thyroid and Parathyroid Flashcards
True of the thyroid gland EXCEPT
A. weighs 15-25 g in the adult
B. found between the cricoid cartilage and suprasternal notch
C. normally moves with deglutition and palpable
D. made up of follicles surrounding colloid
E. NOTA
C.
The thyroid gland is normally not palpable.
Enumerate three arteries that supply the thyroid gland.
superior thyroid artery
inferior thyroid artery
thyroid ima artery
The thyroid ima artery branches from what main vessel?
A. external carotid artery B. thyrocervical trunk C. brachiocephalic trunk D. inferior laryngeal artery E. NOTA
C.
The following arises from
STA - external carotid artery
ITA - thyrocervical trunk
TIA - brachiocephalic trunk
ID: Extra thyroid tissue located near the isthmus found in some people.
pyramidal lobe
ID: Other name for follicular epithelial cells.
thyrocytes
T/F: The morphology of the thyrocytes can differentiate between metabolically active and inactive cells.
T
Metabolically active thyrocytes are taller and more columnar.
T/F: Parafollicular cells are not visible in typical staining.
T
C cells are pale-staining in routine H&E preparation. Immunohistochemical staining using antibody against calcitonin should be used to visualize C cells.
Differentiate thyrotoxicosis from hyperthyroidism.
thyrotoxicosis - state of increased thyroid hormones (T3 and T4) from any etiology
hyperthyroidism - state of thyroid gland hyperfunction leading to thyrotoxicosis
Causes of hyperthyroidism EXCEPT
A. nodular toxic goiter B. exogenous hormone intake C. TSH-secreting pituitary adenoma D. Graves' disease E. NOTA
B.
Technically, exogenous hormone intake is not a form of hyperthyroidism since the thyroid gland is not hyperfunctioning.
However, it is still classified as hyperthyroidism in the transcription, since thyrotoxicosis and hyperthyroidism are used synonymously.
T/F: Thyrotoxicosis due to thyroiditis is a form of hyperthyroidism.
F
Technically, again, in thyroiditis, there is only a spillage of preformed thyroid hormone due to thyrocyte desctruction and not due to thyroid gland hyperfunction.
However, again, it was also classified as hyperthyroidism due to synonymous usage with thyrotoxicosis.
T/F: Thyroid carcinomas are rarely functioning.
T
Most carcinoma are non-functional and appear as cold nodules.
Signs of thyrotoxicosis EXCEPT
A. tachycardia B. fine resting tremors C. lid lag D. dry skin E. NOTA
D.
Thyrotoxicosis presents with warm, sweaty, and flushed skin due to vasodilation and increased sweating due to sympathetic stimulation.
These group of symptoms are the earliest and most consistent to appear in a thyrotoxic state.
A. cardiac B. sympathetic C. ocular D. dermatologic E. gastrointestinal
A.
Cardiac signs include
- tachycardia
- palpitations
- arrhythmia
- high-output heart failure
ID: Pathophysiology of the wide, staring gaze, and lid lag in thyrotoxicosis.
overstimulation of the superior tarsal muscle (Muller’s muscle) which retracts the upper eyelid
T/F: True thyroid ophthalmopathy associated with proptosis occurs only in Graves’ disease.
T
Proptosis in GD is caused by accumulation of water-retaining glycosaminoglycans in the retro-orbital space leading to proptosis and exophthalmos.
The following are signs and symptoms of thyrotoxicosis EXCEPT
A. heat intolerance B. weight loss C. insomnia D. constipation E. NOTA
D.
SNS overactivity results in GI hypermotility leading to diarrhea, not constipation.
ID: This type of thyrotoxicosis commonly occurs in older adults, in whom advanced age and various co-morbidities may blunt / mask the features of thyroid hormone excess.
apathetic thyrotoxicosis
ID: The most useful single screening test for hypothyroidism.
TSH
The most consistent laboratory finding in thyrotoxicosis.
A. increased T4 / T3 B. decreased TSH C. increased RAIU D. increased TRH E. AOTA
A.
Increased TSH can be found in TSH-secreting pituitary adenoma.
Decreased RAIU can be found in most types of thyroiditis.
Decreased TRH is the expected response in thyrotoxicosis.
True of radioactive iodine uptake EXCEPT
A. surrogate marker of thyroid hormone synthesis
B. 10-25% of iodine is taken by the gland in normal states
C. up to 40% can be taken in hyperthyroidism
D. reflects the metabolic activity of the gland
E. NOTA
E. NOTA
The following are primary causes of hypothyroidism EXCEPT
A. Hashimoto thyroiditis B. thyroid agenesis C. radiation-induced ablation D. postpartum pituitary necrosis E. NOTA
D.
Postpartum pituitary necrosis (Sheehan syndrome) is a type of secondary hypothyroidism. It is due to deficient secretion of TSH due to hypopituitarism.
Enumerate three causes of tertiary hypothyroidism.
Tertiary hypothyroidism refers to deficient TRH secretion. It may be due to
- brain tumors
- brain trauma
- radiation to the brain
Signs and symptoms of cretinism EXCEPT
A. protuberant tongue B. coarse facial features C. tall stature D. mental retardation E. NOTA
C.
short stature
True of myxedema EXCEPT
A. accumulation of mucopolysaccharide ground substance in dermis
B. acquired in early childhood
C. slowing of physical and mental activity
D. cold intolerance
E. NOTA
B.
Myxedema is acquired during LATE childhood or adulthood.