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What is the size of the thyroid?
4-6 cm in length
1-2 cm wide
What week does thyroid grows rapidly & divides into two lobes & reaches final state
week 7
What is the size of the isthmus?
4-6mm
The structure connecting the right and left lobes of the thyroid is?
The isthmus
What are the anatomical variants (4)
pyramidal lobe - extension superiorly from isthmus
asymmetry in size of lobes
failure to descend
Failure to develop isthmus
Echogenicity of thyroid?
hypoechoic to anterior strap muscle, sternocleidomastoid muscle
& posterior longus colli
Euthyroid function means the thyroid function is?
Normal
Which muscle is located posterior to the thyroid?
Longus colli muscle
What is the function of the thyroid?
Produces, Stores and Secretes hormones
Regulates body growth
Body development
Controls metabolism
Increased levels of TSH indicate what?
Hypothyroidism
Decreased levels of TSH indicate what?
Hyperthyroidism
Increased T3 and T4 indicate
Decreased T3 and T4 indicate
Hyperthyroidism
Hypothyroidism
What are some symptoms of hypothyroidism
Weight gain
Hair loss
Lethargy
Enlarged goiter
Cold
T/F Hashimoto's is a form of Hyperthyroidism
False, Hypothyroidism
Symptoms of Hyperthyroidism/ Grave's disease
Weight loss
Finger Tremors
increase heart rate
Palpitations
Nervousness
Hot & flushed
Enlarged goitre
T/F Hot nodules on NM exam are worrisome for thyroid cancer
False Cold nodules 20% malignant don't take up iodine
Hot nodules are non-malignant
Roles of ultrasound for thyroid gland (7)
Detect size and location
Determine characteristics of nodule
guide biopsy/ aspiration
Determine extent of known malignancy
determine extent of local/regional recurrance
determine sonographic appearance of gland
NB: no functional info.
Describe the proper patient position for performing a thyroid ultrasound
Supine
Pillow under shoulders
Hyperextend neck
What are some questions you would ask your patient before performing an ultrasound?
Palpable mass
Thyroid medications
Abnormal labs
Previous imaging
Family hx of thyroid CA
Hx of radiation or prior thyroid surgeries
Why would you scan lateral to the jugular veins when performing a thyroid ultrasound?
To look for enlarged or abnormal lymph nodes
Normal thyroid sonographic appearance
Homogenous texture
Medium level echogenicity
Echogenic Capsule
Normal lymph node appearance
Hypoechoic
Oval
Echogenic Hilum
Vascular hilum
< 0.5
Overall worldwide, the most common cause of thyroid disorders is?
iodine deficiency
Most common cause of thyroid disorders in developed countries is?
autoimmune processes
What is the definition of a thyroid goiter?
Enlargement of the thyroid gland (focal or diffuse)
Causes of a goiter? (3)
Hyperplasia, neoplasia
inflammation
colloid distension of follicles
What is multinodular goitre?
diffuse diease
individual lesions appearance of adenoma - poorly circumscribed/ encapsulated
diffuse parenchyma heterogeneity & mixed echotexture
Nontoxic goiter
thyroid enlargement with no disturbance in thyroid function
Toxic goiter
Results from hyperactivity of thyroid gland
Graves disease
most common cause of hyperthyroidism - thyroid inferno - increase vascularity
Women
>30 years old
Autoimmune disorder
Thyrotoxicosis
Sonographic appearance of hyperthyoidism
generalised increase gland size
generalised lymphadenophy
Sonographic appearance of grave's disease
thyroid inferno
coarse echotexture
diffuse hyperplasia
Role of ultrasound in hypothyroidism
top low-value practice and intervention
do not routinely order thyroid ultrasound
Thyroiditis can be caused by?
bacterial/ viral (de Quervian's)
Can be autoimmune (Hashimoto)
Causes swelling and tenderness
Destroys thyroid gland
Sonographic appearance of thyroiditis
depends on stage of disease
acute
- swelling, homogenous, increase vasc.
chronic
- heterogenous, decrease in size
What is De Quervain's
Viral
Diffuse enlargement and inflammation
Eventually gland returns to normal
What are the two types of thyroiditis
De Quervain's Thyroiditis
Hashimotos
Hashimoto's Disease
Autoimmune disorder
Causes chronic inflammation
Usually occurs in young-mid aged women
Thyroid is diffusely enlarged
Hypothyroidism
Increased rate of malignancy
Sonographic appearance of Hashimotos
acute - increase vasc.
diffuse hypoechoic heterogenous echotexture
Describe the typical sonographic appearance of Hashimoto's disease
Heterogenous
Hypervascular
Coarse texture
Fibrotic septations
Enlarged
How can you tell the difference between a thyroid affected by graves disease vs. hashimoto's disease?
Through labs
Sonographically there is no differance
What are two benign thyroid lesions
Thyroid cysts
Adenoma
Adenoma
Benign
Females 7x more than Males
Euthyroid-normal
Hyperthyroid
Can be multiple
Sonographic findings of an adenoma
Variable
From anechoic to Hyperechoic
Fibrous capsule
Well circumscribed
May have a hypoechoic halo
May have a calcified rim
Can have hemorrhage
Necrosis
What are some risk factors for malignant thyroid lesions
Age 25-65
Female
Asian
Family history
History of radiation to head or neck
What are the types of malignant thyroid lesions
Papillary Carcinoma
Follicular Carcinoma
Medullary Carcinoma
Anaplastic Carcinoma
Lymphoma
Papillary Carcinoma 5
1.Most common
2.Least aggressive
3.Good prognosis
4.25% Mets to cervical lymph
5.Small punctate calcifications
Follicular Carcinoma 4
1. Single mass
2. 2nd most common
3. Spreads through blood
4. Mets to 4 thing
-Brain
-Lung
-Bone
-Liver
Medullary Carcinoma 3
1. 10%
2. Nodule or whole gland
3. Sipple Syndrome
Anaplastic Carcinoma
Rare
Rapid growth
Highly metastatic
Elderly patients
Invade through surrounding muscles
Lymphoma
Non-Hodgkin's type
Primarily affects older women
Rapidly Growing
Chronic Hashimoto's
Abnormal Cervical lymph nodes
Rounded
Hypoechoic
Absence of fatty hilum
Punctate Calcs
Cystic changes
>0.5
Cysts of the neck
Brachial cleft cysts
-Congenital
-Lat neck mass
-Beneath mandible
Cystic Hygroma
-inadequate drainage of lymph fluid
-Post neck mass
Thyroglossal Cyst
-Embryonic remnant
-Anterior
-between tongue and isthmus
What are some Pitfalls Of Thyroid Imaging
Edge refraction shadowing from muscles anterior
Clavicle
Swallowing/ Breathing/Talking
Taut neck muscles
Parathyroid glands
4 total
4-6 mm length
2-4 mm width
0.5-2 mm thick
What is the function of the parathyroid
Regulates blood calcium levels
-bone
-intestines
-kidneys
Decreased calcium levels causes Parathyroid gland to produce and secrete what?
more PTH
- Causes glands to enlarge
- Pregnancy can also cause glands to enlarge due to an increased need for Calcium
Increased calcium levels causes Parathyroid glands to?
stop producing PTH
Primary hyperparathyroidism
Increased function-PTH
Woman are affected 2-3x more than men
Common after menopause
Leads to Hypercalcemia and Hypercalciuria
low serum levels of phosophate
The most likely cause of hyperparathyroidism is?
Adenoma
most common cause
Parathyroid Adenoma
Benign
< 3cm
1 gland
low level echogenicity
Symptoms: "Stones, Bone, Groans and psychic overtones"
Secondary Hyperparathyroidism
Hypocalcemia
Caused by
-Renal failure
-vitamin D deficiency
-malabsoption
Causes stimulate parathyroid to excrete excessive PTH
Affects all 4 glands
Aplasia of a lobe occurs most frequently on what side?
left
What type of gland is the thyroid?
Endocrine
Hyperthyroidism is most associated with
Grave's disease and exoplathalmic goiter
Name the salivary glands
1. Parotid Gland
2. Parotid (Stensen's Duct)
3. Submandibular (Wharton's) Duct
4. Sublingual Glands
5. Sublingual Ducts