Module 2 : Thyroid Flashcards
1
Q
what is the shape and location of the thyroid
A
- butterfly shape
- base of neck
2
Q
how are the two lobes of the thyroid connected
A
- with an isthmus
3
Q
is one lobe of the thyroid bigger than another
A
- yes it is common
- right often bigger
4
Q
does the thyroid have a capsule
A
- yes enclosed by a fibrous capsule
5
Q
where is the trachea in relation to the thyroid
A
- sits between the two lobes of the thyroid
6
Q
what is a pyramidal lobe
A
- fetal remnant
- third lobe
- extends superiorly from the isthmus
7
Q
what three things can change the size and shape of the thyroid
A
- gender
- age
- body habitus
8
Q
what gender has slightly larger thyroids
A
- females
9
Q
what is the normal length of the thyroid
A
4-6cm
10
Q
what is the normal AP of the thyroid
A
2cm
11
Q
what is the normal width of the thyroid
A
2cm
12
Q
what is the normal measurement of the isthmus
A
2-6mm
13
Q
where is the CCA and IJV located in relation to the thyroid
A
- lateral to lobes and posterior
- CCA medial to IJV
14
Q
where is the esophagus located in relation to the thyroid
A
- posterior and slightly left of the trachea
- anterior to the spine
15
Q
where is the longs Colli located in relation to the thyroid
A
- posterior to the lobes and cca
16
Q
where is the SCM located in relation to the thyroid
A
- anterolateral
17
Q
where are the strap muscles located in relation to the thyroid
A
- anterior
18
Q
what is contained in the neurovascular bundle and where is it location related to the thyroid
A
- inferiori thyroid artery and laryngeal nerve
- posterior to thyroid
19
Q
where are the parathyroid glands located in relation to he thyroid
A
- posterior
20
Q
is the thyroid vascular or avascular
A
- highly vascular
21
Q
what are the vessels that feed the thyroid and where do they originate from
A
- right na left superior thyroid artery (branches of ECA)
- right and left infer thyroid arteries (branches of subclavian arteries)
22
Q
what are the vessel that drain the thyroid. and what vessels do they drain into
A
- superior and middle thyroid veins (into IJV)
- inferior thyroid vein (into innominate vein)
23
Q
what is the lymphatic drainage fo the thyroid
A
- drained via the deep cervical lymph nodes around the carotids
24
Q
where is the most common site for thyroid cancer to metastasize
A
- deep cervical lymph nodes
25
what is the normal ultrasound appearance of the thyroid
- homogenous
- medium level echo
- hyperechoic thin capsule
26
what is the functional unit of the thyroid
- follicle
27
what hormones are produced by the thyroid follicle
- T3 and T4
28
what is contained within the lumen of the follicle and what is its purpose
- colloid
| - gelatinous substance that stores T3 and T4
29
what structure within the follicle produces the calcitonin
- parafollicular cells
30
what is the purpose of calcitonin
- helps regulate the bloods calcium levels and phosphate levels
31
what kind of gland is the thyroid
- endocrine
32
what are the three purposes of the thyroid when it comes to hormones
- synthesizes
- stores
- secretes
33
what is the main function of the thyroid
- regulates the metabolism
34
what are the there hormones the thyroid produces
- thyroxine T4
- triiodothyronine T3
- calcitonin
35
what due T3 and T4 effect in the body
- metabolic rate
36
what element from our diet synthesizes T3 and T4
- iodine
37
what is the function of the calcitonin
- maintains homeostasis of blood calcium
38
how does calcitonin maintain homeostasis of blood calcium
- decreases concentration of blood calcium
| - inhibits the breakdown of bone by osteoclasts
39
how is the maintenance of circulating concentrations of T3 and T4 achieved
- NEGATIVE FEEDBACK SYSTEM
- drop in circulating T3 and T4 decreases the basal metabolic rate BMR
- a falling BMR stimulates TRH (thyrotropin releasing hormone) from the HYPOTHALMUS
- this provokes release fo TSH (thyroid stimulating hormone) from the PITUITARY
- this causes the thyroid to release more T and T4
40
what is euthyroid
- normal function thyroid
41
what is hypothyroidism
- under secretion of thyroid hormones resulting in decreased body metabolism
42
what three things are cause and under secretion of thyroid hormone
- low intake of iodine
- dysfunction of gland
- pituitary gland abnormality
43
what are the 7 signs and symptoms of hypothyroidism
- weight gain
- hair loss
- lethargy
- cold intolerance
- deep husky voice
- constipation
- increased subcutaneous tissue around the eyes
44
what are the 4 causes of hypothyroidism
- hashimotos
- iodine deficiency
- partial thyroidectomy
- pituitary gland problems affecting TSH production
45
what is the most common cause of hypothyroidism in North America
- hashimotos
46
what is the most common cause of hypothyroidism worldwide
- iodine deficiency
47
what is hyperthyroidism
- over secretion of hormones resulting in increased body metabolism
48
what are 2 things that cause over secretion of thyroid hormones
- entire thyroid gland over functioning
| - neoplasm producing excess hormones
49
what are the 8 signs and symptoms of hyperthyroidism
- weight loss
- increased appetite
- nervousness
- excessive sweating
- heat intolerance
- palpitations
- fatigue at the end of day
- exophthalmos
50
what are the 5 causes of hyperthyroidism
- graves diseases (with goiter)
- toxic adenoma
- inflammation of the thyroid
- excessive thyroid medication
- pituitary tumors
51
what are the 4 lab tests that can be done to test thyroid function
- serum T3
- serum T4
- serum TSH
- thyroid antibodies
52
what is the other imaging method of the thyroid
- thyroid scan
+ nuke med test determines function
+ hot and cold nodules
53
what does a hot nodule mean in a nuke med scan
- hot >> hyper-functioning>> benign
54
what does a cold nodule mean in a nuke med scan
- cold >> nonfunctioning >> possible malignancy
55
what are the 4 for a thyroid scan
- increased in gland size (symmetric or asymmetric)
- change in metabolism
- cold nodule on NM scan
- palpable lump
56
what are the two categories of benign thyroid pathology
- benign focal
| - bengin diffuse
57
what are the 3 benign focal thyroid pathologies
- cysts
- thyroglossal duct cyst
- adenomas
58
are true thyroid cysts rare or common
- rare
59
what are thyroid cysts more commonly a representation of
- cystic degeneration of a follicular adenoma
60
when can hemorrhagic cysts be identified in the thyroid
- blunt trauma to neck
| - acute hemorrhage of adenoma
61
what is the sonographic appearance of thyroid cysts
- simple = anechoic
- complex = internal echoes irregular walls
- colloid cyst = echogenic with COMET TAIL ARTIFACT
62
what type of anomaly is a thyroglossal duct cyst
- congenital
63
where is a thyroglossal duct cyst located
- midline of neck
| - anterior to trachea
64
what is a thyroglossal duct cyst
- remnant of tract that fails to atrophy
65
sonographic appearance of thyroglossal duct cyst
- fusiform cystic structure less than 3cm in size
66
what is an adenoma
- a benign neoplasm with a capsule
67
which gender is more commonly affected by adenomas
- women
68
what is the most common type of adenoma
- follicular adenoma
69
are adenomas more symptomatic or asymptomatic
- asymptomatic
70
are adenomas hot or cold on nuke med
cold
71
what is the sonographic appearance of a thyroid adenoma
- anechoic>isoechoic>hyperechoic
- solitary defined round or oval
- hypoechoic halo
- eggshell calcifications
72
what are the two categories of diffuse benign thyroid disease
- inflammatory
| - hyperplasia
73
what is the inflammatory benign diffuse diseases
- thyoirditis
| - swelling tenderness of gland with fever
74
is thyroiditis more commonly found in men or women
- women
75
what are the 5 types of thyroiditis
- haschimotos
- acute supperative
- subacute granulomatous
- silent
- invasive fibrous
76
what is hashimotos thyroiditis
- chronic lymphocytic inflammatory disease
| - autoimmune
77
what is the most common cause of adult hypothyroidism
- hashimotos
78
what gender is more effected by diseases of the thyroid
- women
79
is hashimotos painful or painless
- painless
80
what lab value would be effected with hashimotos
- antithyroid antibodies
81
what is associated with hashimotos
increased risk of developing lymphoma
82
what is the ultrasound appearance of hashimotos
- diffuse heterogenous enlargement of gland
- hypoechoic
- discreet nodules of calcifications
- indistinguishable from multi nodular goiter
- hyper vascular in acute phase
- cervical lymphadenopathy
83
in what patients is acute suppurative thyroiditis most common
children
84
what are the signs and symptoms of acute suppurative thyroiditis
- firm painful thyroid
| - low grade fever and sore throat
85
what type of infection causes acute suppurative thyroiditis
bacterial
86
ultrasound appearance of acute suppurative thyroiditis
- diffuse enlargement
- hypoechoci
- possible abscess
87
what is another name for subacute granulomatous thyroiditis
- de quervain thyroiditis
88
what type of infection causes subacute granulomatous
- viral
89
what are the signs and symptoms of subacute granulomatous
- gland swells rapidly, very painful and tender
| - hyperthyroidism
90
ultrasound appearance of subacute granulomatous
- enlarged gland
- hypoechoic
- normal or decreased vascularity
91
characteristics of silent thyroiditis
- enlarged gland with no pain
- sonographically resembles hashimotos
- clinically resembles subacute granulomatous
92
characteristics of invasive fibrous (riedels struma)
- rarest form
- results in complete destruction of thyroid
- enlarged heterogenous thyroid
- inflammatory process can extend extra thyroid
93
what does thyroid hyperplasia mean
- goiter
94
what are the causes of hyperplasia
- iodine deficiency
| - defect in normal hormone synthesis
95
what is graves disease
- diffuse toxic goiter (thyrotoxicosis)
- hyperthyroidism
- autoimmune disease
96
is graves disease rare or common
- common
97
what are 3 clinical features of graves disease
- exophthalmos
- skin thickening at low extremities
- clubbed toes and fingers
98
ultrasound appearance of graves disease
- diffuse symmetrical enlargement
- lobulated
- homogenous or heterogeneous
- hypoechoic
- thyroid inferno (hyper vascular)
99
what is a non toxic goiter
- endemic or sporadic
- related to lack iodine in the diet
- no functional disturbances
100
ultrasound appearance of non toxic goiter
- diffusely and uniformly enlarged
- smooth or nodular echotexture
- not as large as multi nodular goiter
101
what's a multi nodular goiter
- adenomatous
- iodine deficiency
- iodine deficiency results in inadequate thyroid hormone production>> pituitary gland releases more TSH>> causes thyroid gland to enlarge
102
ultrasound appearance of multi nodular goiter
- enlarged often asymmetrical
- diffusely heterogenous with multiple nodules
- calcifications with cystic areas
103
are solitary nodules or multiple nodules more suspicious of malignancy
- solitary
104
what is needed for diagnosis of thyroid malignancy
FNA
105
signs and symptoms of malignant thyroid disease
- pressure symptoms = difficulty breathing or swallowing
- painless palpable neck mass
- change in voice
106
ultrasound appearance of malignant diseases
- variable
- hypoehcoic
- poorly defined borders
- jagged borders
- absence of halo or incomplete halo
- micro calc
- taller than wide
- enlarged nodes.
107
what are the 6 types of thyroid malignancy
- papillary
- follicular
- medullary
- anaplastic
- lymphoma
- metastases
108
what is the most common thyroid malignancy
- papillary carcinoma
109
what is the least aggressive thyroid malignancy
- papillary carcinoma
110
is papillary carcinoma slow or fast growing
- slow growing but can spread
111
is papillary carcinoma symptomatic or asymptomatic
- asymptomatic
112
ultrasound appearance of papillary carcinoma
- solid
- hypoechoic
- microcalcs
- tiny
- hyper vascular
113
is follicular adenoma more aggressive than papillary and how does it grow
- slow growing
| - more aggressive >> mets to lung and bone
114
what increases risk of follicular adenoma
- history of radiation
115
ultrasound appearance of follicular adenoma
- enlarge encapsulated nodule with irregular borders thick halo and possible microcalcifications
116
characteristics of medullary carcinoma
- hard bulky mass
- men = women
- pheochromocytomas
- metastasize readily
- secrete calcitonin
117
ultrasound appearance of medullary carcinoma
- solid
- hypoechoic
- well circumscribed
- encapsulated
- coarse calc
118
characteristics of anaplastic carcinoma
- rarest
- most aggressive
- older patients
- invades adjacent structures
- death by compression asphyxiation
119
ultrasound appearance of anaplastic carcinoma
- hypoechoci
- solid
- irregular
- encasing/invading blood vessels
- neck muscles
120
characteristics of lymphoma
- primarily non Hodgkins
- older females
- rapidly growing mass
- history of hashimotos
121
ultrasound appearance of lymphoma
- hypoechoic
- lobulated
- non vascular
122
characteristics of metastases to the thyroid
- infrequent
- spread through hematogenous route
- breast lung colon melanoma
123
what are 5 common associated features of benign thyroid lesions
- regular well defined borders
- thin hypoechoic halo
- solitary or multiple minute cysts within mass
- hyperechoic
- large calc around periphery
124
what are 3 common associated features of malignant thyroid lesions
- irregular borders
- absence of halo
- micro calc
