Thyroid Flashcards
Size of thyroid and isthmus?
Length: 4-6cm
Width: 2cm
AP: 2-3cm
Isthmus: 4-6mm
What is a normal variant extending superior to the isthmus?
Pyramidal lobe
May be seen in pediatric but usually atrophies in the adult
Arterial supply of the thyroid?
right and left superior arteries, first branch off the ECA, and the inferior thryoid arteries.
Venous drainage of the thyroid?
superior and middle thyroid veins drain into the jugular vein and the inferior thyroid veins into the inominate vein.
“Strap” muscles that anteriorly surrond the thyroid?
Sternohyoid, Omohyoideus, and Sternothyoid
Where are the muscles of the neck in relation to the thyroid?
Sternocleidomastoid: anterolateral
Longus colli muscles: posterior
What are the three hormones?
Endocrine gland
T3 (serum triiodothyronine)
T4 (thyroxine)
calcitonin- important for calcium metabolism
hormones occur via iodine metabolism
The production and release of the thyroid hormones are under the control of what?
Thyroid stimulating hormone (TSH)
produced by the anterior pituitary gland
Function of the thyroid?
Metobolic rate
growth and development
heart and blood vessel function
brain function
behavior
What does Euthyroid mean?
State in which the thyroid is producing the right amount of thyroid hormone.
Hyperthyroidism
occurs when there is an increased production of T-3 and T-4
most frequent cause of graves disease
results in: thyroid enlargement, increased metabolic rate, weight loss, and nervousness
De Quervains
Usuallu viral
diffuse enlargement
tenderness/mild to severe
transient hyperthyroidism
Hashimoto’s thyroiditis
Chronic, autoimmune thyroiditis
most common form
diffuse enlargement
painless
eventual hypothroidism
more prevalent in women
possibly hypoechoic, thick fibrous strands, variable vascularity
Graves disease
occurs more frequently in women over 30
related to autoimmune disorder
hypermetabolism, diffuse toxic goiter, exopthalamos
heterogenous with “thyroid inferno”
Hypothyroidism
decreased production of T-3 and T-4
may be caused by thyroid failure or abnormalities of the pituitary gland or hypothalamus
Adults: thick skin, puffy face, course hair, husky voice
Infants: decreased physical and mental growth
With a normal functioning pituitary and hypothalmus what are the lab values for hypo and hyperthyroidism?
hypo: isncreased TSH, decreased T4/T3
hyper: decreased TSH, increased T4/T3
Multinodular goiter
most common abnormality
common in females age 50-70
enlarged and heterogeneous
Follicular adenoma
benign, singular
well defined, hypoechoic
50% will have a halo or ring surronding
endemic goiter
due to large iodine intake
low T3 and T4 levels
more frequent in female during puberty
Parathyroid
4 glands, posterior
2 superior
2 inferior
secrete PTH (parathormone), maintains proper calcium levels in blood
Enlarged lymphnodes?
termed lymphadenopathy
greater than 1 cm
result for infections and maligancies
may lose their normal hilar features and contain calcifications
