CHAPTER 22 THYROID Flashcards
benign thyroid neoplasm characterized by complete fibrous encapsulation
adenoma
rare, undifferentiated carcinoma occurring in middle age
anaplastic carcinoma
remnant of embryonic development that appears as a cyst in the neck
branchial cleft cyst
a thyroid hormone that is important for maintaining a dense, strong bone matrix and regulating the blood calcium level
calcitonin
refers to a normal functioning thyroid gland
euthyroid
use of a fine-gauge needle to obtain cells from a mass
fine-needle aspiration
occurs as a solitary malignant mass within the thyroid gland
follicular carcinoma
enlargement of the thyroid gland that can be focal or diffuse; multiple nodules may be present
goiter
autoimmune disorder characterized by a diffuse toxic goiter, exophthalmos (bulging eyes), and cutaneous manifestations
Graves’ Disease
chronic inflammation of the thyroid gland caused by the formation of antibodies against normal thyroid tissue
Hashimoto’s thyroiditis
disorder associated with elevated serum calcium level, usually caused by a benign parathyroid adenoma
Hyperparathyroidism
oversecretion of thyroid hormones
Hyperthyroidism
low phosphatase level, which can be seen with hyperparathyroidism
hypophosphatasia –
undersecretion of thyroid hormones
hypothyroidism
small piece of thyroid tissue that connects the right and left lobes of the gland
isthmus
wedge-shaped muscle posterior to the thyroid lobes
longus colli muscle
disorder characterized by localized or generalized enlargement of the lymph nodes or lymph vessels
lymphadenopathy
neoplastic growth that accounts for 10% of thyroid malignancies
medullary carcinoma
tiny echogenic foci within a nodule that may or may not shadow
microcalcifications
nodular enlargement of the thyroid associated with hyperthyroidism
multinodular goiter
degenerative nodules within the thyroid
nodular hyperplasia
most common form of thyroid malignancy
papillary carcinoma
a hormone that is secreted by the parathyroid glands, which regulate serum calcium levels
parathyroid hormone (PTH)
enlargement of multiple parathyroid glands
parathyroid hyperplasia
oversecretion of parathyroid hormone, usually from a parathyroid adenoma
primary hyperparathyroidism
present in a small percentage of patients; extends superiorly from the isthmus
pyramidal lobe
enlargement of parathyroid glands in patients with renal failure or vitamin D deficiency
secondary hyperparathyroidism
lab value that is elevated with hyperparathyroidism
serum calcium
large muscles anterolateral to the thyroid
sternocleidomastoid muscles
group of three muscles (sternothyroid, sternohyoid, and omohyoid) that lie anterior to the thyroid
strap muscle
viral infection of the thyroid that causes inflammation
subacute (de Quervain’s) thyroiditis
congenital anomalies that present in midline of the neck anterior to the trachea
thyroglossal duct cysts
inflammation of the thyroid
thyroiditis
a hormone secreted by the pituitary gland that stimulates the thyroid gland to secrete thyroxine and triiodothyronine
thyroid-stimulating hormone (TSH)
What is the three hormones that the thyroid produces?
Triiodothyronine (T3)
Thyroxine (T4)
Calcitonin
What are the functions of the thyroid?
- It maintains metabolism, growth, and development
- Produces, stores, and secretes thyroid hormones
Is the thyroid part of the exocrine or endocrine system?
Endocrine
Where is the thyroid gland located?
Located in the anterorinferior neck at the level of the thyroid cartilage
Rt. and Lt. thyroid lobes located on each side of the _________. They are connected across midline by the _______ and bound laterally by the _____artery and _______ vein
Trachea
Isthmus
Carotid artery and jugular vein
Do females or males have larger thyroid glands?
Females
What are the adult measurements of the thyroid?
Adults
Length- 40-60mm (4-6cm)
AP- 20-30mm (2-3cm)
Width- 15-20mm (1.5-2cm)
Isthmus
AP- 4-6mm (0.4-0.6cm)
When in transverse, make sure you see the _______ in the measuring image.
Also where do you measure?
Isthmus
AP as well as length.
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* *
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If you are unable to get a clear measuring image of the thyroid gland is SAG what can you do?
Switch to a curvilinear transducer.
Where does the Thyroid get its blood supply?
Two superior thyroid arteries arise from external carotid artery (ECA) and descend to the upper poles
Two inferior thyroid arteries arise from the thyrocervical trunk of the subclavian artery and ascend to the lower thyroid poles
Corresponding veins drain into the internal jugular veins.
The pituitary gland produces ____ then controlled by ______, and the _____ secretion controls the release of thyroid hormones.
TSH
Hypothalamus
TSH secretion
The mechanism for producing thyroid hormones is ________
iodine metabolism
When the thyroid is producing the correct amount of thyroid hormone this is called ___________.
euthyroid
Causes-
1) Low intake of iodine (goiter) in the body
2) Inability of the thyroid to produce adequate amount of the thyroid hormone
3) A pituitary gland that does not control the thyroid production
What is the diagnosis and the treatment?
Hypothyroidism which is the undersecretion of thyroid hormones
Treatment would be hormone medication.
A patient comes in and complains that she has recently lost some hair, gained weight, been very cold, and her voice has deepened.
What could this indicate?
Hypothyroidism
Occurs when the entire gland is out of control or when a localized neoplasm (adenoma) that causes overproduction of the thyroid hormone
Hyperthyroidism
A patient comes in and complains of weight loss, excessive sweating and heat intolerance, and you notice her eyes seem to be protruding from her eye sockets.
What could this indicate?
Hyperthyroidism (the sudden increase of thyroid hormones
What are some questions you should ask the patient before starting the exam?
Has there been any changes in your health?
Any use of thyroid medication or history of use?
Previous imaging of thyroid?
Family history of hyperparathyroidism or thyroid cancer?
Sonographically the thyroid gland is enlarged heterogenous w/ isoechoic/hyperechoic nodules with a thin peripheral halo and calcifications.
What could this indicate?
goiter
most common malignancy of the thyroid that is more commonly found in females.
90% hypoechoic
Microcalcification with or without shadowing
90% hypervascular
What is this?
Papillary Carcinoma
Carcinoma that spreads through the blood stream versus the lymphatics. It is also more aggressive that papillary. Mets to bone, lung, brain and liver.
Sonographically-
Irregular margin with thick irregular halo
Nodular enlargement
Tortuous internal blood vessel
Follicular Carcinoma
5% of thyroid cancers—Often familial- 20% of the time
May be multicentered and/or bilateral in familial cases
High incidence in metastatic involvement of lymph nodes
Ultrasound findings
Similar to papillary ca.- hypoechoic
Calcium deposits are often noted
Careful evaluation of the entire neck are and liver to rule out metastases
Medullary Carcinoma
Rare- less than 2% that usually occurs after age 50
Hard fixed mass with rapid growth
Growth is locally invasive in surrounding neck structures
It usually causes death by compression and asphyxiation due to invasion of the trachea
Ultrasound Findings
Hypoechoic
Invasion of surrounding muscles and vessels
Anaplastic Carcinoma
Which of the carcinomas of the thyroid can cause death by compression and asphyxiation due to invasion of trachea?
Anaplastic Carcinoma
________ in the thyroid is usually non-Hodgkin type
Affects older females and 4% of all thyroid malignancies
Clinically-rapid growing neck mass
Many cases patient has preexisting chronic lymphocytic thyroiditis (Hashimoto’s disease) or hypothyroidism
Ultrasound findings Nonvascular Hypoechoic Lobulated Thyroid tissue may be heterogenous because of associated thyroiditis Can have areas of cystic necrosis
Lymphoma
Most common type of thyroiditis
Characterized by destructive autoimmune disorder, which leads to chronic inflammation of thyroid commonly found in young or middle age female
Painless and diffuse enlargement
Ultrasound Findings
Coarse and slightly more hypoechoic
Initially homogenous enlargement occurs with nodularity then progresses to inhomogenous enlargement.
Can develop into hypothyroidism
Hashimoto’s Thyroiditis
People who have ____________ thyroiditis are at risk to develop hypothyroidism
Hashimoto’s Thyroiditis
Characterized by thyrotoxicosis and is the most frequent cause of hyperthyroidism
Findings-
hypermetabolism, diffuse toxic goiter, exophthalmos, and cutaneous manifestations
Thyroid gland is diffusely homogeneous and enlarged
Graves’ Disease
What is the most common cause of thyroid disorders worldwide and what can it lead to?
iodine deficiency
goiter formation and hypothyroidism
What is the most common carcinoma of the thyroid?? Is it more common in females or males?
Papillary.
Females
Which cancer is more aggressive? Papillary or follicular?
Follicular
How does follicular carcinoma spread??
Through the bloodstream
What is the most common case of thyroiditis?
Hashimoto’s Thyroiditis
What can Hashimoto’s Thyroiditis lead to ?
Hypothyriodism
How many parathyroid glands do most people have?
4 but there can be 3-5
Most commonly there is two superior and two inferior
What is most common cause of primary hyperparathyroidism?
Adenoma (80% cases)
What is the most frequent cause of hyperthyroidism
Graves disease
