Thyroid Powerpoint Flashcards
Thyroid gland length
4-6 cm
Thyroid gland AP
2-3 cm
Throid gland width
2 cm
Isthmus diameter
4-6 mm
Thyroid in relations with trachea
lateral
Thyroid in relations with esophagus and cervical spine
anterior
Thyroid in relations with IJV and carotid artery
medial
Pyramidal Lobe
a normal variant extending superior to the isthmus May be seen in pediatric but usually atrophies in the adult present in 15 to 30% of thyroids
Vascular Supply
right and left superior thyroid arteries and inferior thyroid arteries
First branch off the ECA
right and left superior thyroid arteries
Venous Drainage
superior and middle thyroid veins into the jugular vein and the inferior thyroid veins into the inominate vein
Strap Muscles
thin sonolucent bands along the anterior surface of thyroid Sternohyoid Omohyoid Sternothyroid
Sternocleidomastoid muscle location
anterolaterally to thyroid
Common Carotid artery and internal jugular vein location
lateral to thyroid glands
Longus collie muscle
Posterior to the thyroid wedge-shaped sonolucent structure adjacent to the cervical vertebrae
Esophagus is usually hidden because of what
Trachea
Minor neurovascular bundle location
posterior to thyroid
Parathyroid location
posterior to thyroid
Thyroid gland function
Endocrine gland T3 T4 CALCITONIN
The production and releae of the thyroid hormones are under the control of
TSH
What is TSH produced by
anterior pituitary gland which is located in the brain
Hormones affects
Metabolic rate Body’s growth and development Heart and blood vessel functions Brain function Behavior
Calcitonin is important for
calcium metabolism
Euthyroid
state in which the thyroid is producing the right amount of thyroid hormone
When does hyperthroidism occur
increased production of T-3 and T-4
Hyperthyroidism results in
Thyroid enlargement Increased metabolic rate Weight loss Nervousness
Thyroid Storm
acute situation with uncontrolled hyperthyroidism, usually precipitated by infection or surgery
Hyperthyroidism may be life threatening because
of resulting hyperthermia, tachycardia, heart failure and delirium
Sonographic Appearance of hyperthyroidism
Hypoechoic with diffuse enlargement without palpable nodules Doppler shows increased vascularity (thyroid inferno)
Diffuse thyroid disease (Thyroiditis)
inflammation of thyroid causing swelling and tenderness due to infection
Diffuse thyroid disease (Thyroiditis) is caused by
caused by infection or autoimmune disorder
Diffuse thyroid disease (Thyroiditis) sonographic appearance
enlarged and hypoechoic
De Quervain’s (sub acute granulamatous)
usually viral diffuse enlargement tenderness/mild to severe transient hyperthyroidism
Hashimoto’s Thyroiditis
goitrous from of autoimmune thyroiditis-(chronic) a. Most common form b. auto-immune- chronic inflammation c. diffuse enlargement possibly asymmetric d. painless/ may develop mild pain over time e. eventual hypothyroidism f. more prevalent in women
Hashimoto’s Thyroiditis Sonopgraphic appearance
a. possibly hypoechoic/normal echo texture b. thick fibrous strands c. Color flow variable can be increased or decreased vascularity with color doppler
Hypothroidism occurs when theres a
decreased production of T-3 and T-4
Hypothyroidism may be caused by
thyroid failure, or abnormalites of the pituitary gland or hypothalamus
Hypothyroidsm for adults
thick skin,puffy face,course hair, husky voice
Hypothyroidsm for infants and children
decreased physical and mental growth
Hypothyroidism with a normal functioning pituitary and hypothalmus
increased TSH decreased T4/T3
Hyperthyroidism with a normal functioning pituitary and hypothalmus
decreased TSH increased T4/T3
Nuclear medicine
Differentiates between hyperfunctioning “hot”nodules and hypofuntioning “cold” nodules. “Cold” nodules have a higher risk of malignancy
Indications for exam
Palpable enlargement Abnormal thyroid hormone level (s) Palpable mass in neck/thyroid Swelling of the neck Asymmetry of neck Redness and/or tenderness
Normal gland is
homogenous with fine echogenicity
Multinodular goiter
most common abnormality, most common in females age 50-70 Appears as an enlarged, heterogenous
Follicular adenomas
benign, usually single tumors Appears as a well defined hypoechoic mass 50% will have a halo or ring surrounding
Endemic goiter
due to low iodine intake Low T-3 and T-4 levels. More prevelant in females during puberty Uncommon in the US
Graves Disease
autoimmune disorder which produces hyperthyoidism Protruding eyeballs, thickening of the skin on the feet Appears as a diffusely enlarged thyroid Increased color doppler due to overactivity of the gland
Graves Disease: Sonographic appearance
heterogenous gland, increased color flow “thyroid inferno”
Graves Disease: Clinical Findings
hypermetabolism, diffuse toxic goiter, exopthalamos
Graves Disease: more common in what gender and age Hyperthyroidism
women over 30
Malignant
papillary, follicular, medullary
Tumor characteristics
may be isoechoic, hypoechoic, cystic or solid
Risk of malignancy decreases when
multiple nodules are present
FNA is necessary for
definitive diagnosis
Parathyroid
4 glands 2 superior 2 inferior
Parathyroid secretes
PTH (parathormone) which maintains the proper calcium levels in the blood
Thyroglossal duct cyst
congenital,benign cysts located within the midline of the neck superior to the thyroid gland near the hyoid bone Asymptomatic, although may become painful when inflammed
Branchial cleft cysts
benign congenital cysts found most often near the angle of the mandible
Cervical Lymph nodes
Enlargement termed lymphadenopathy Greater than 1cm (Beth says 2cm) Can result from infections and malignancies May lose their normal hilar features and contain calcifications
Thyroid FNA’s
Performed by Radiologist Guided by ultrasound Cells read by Pathologist Results to endocrinologist
Disorder associated with hyperthyroidism
diffuse toxic hyperplasia (Graves Disease) Toxic Multinodular Goiter Toxic Adenoma makes up 99% of cases
Nontoxic Simple Goiter Clinical Findings
Thyroid enlargement
Nontoxic Simple Goiter Sonographic Appearance
sometimes smooth, sometime nodular possible compressoin of surrounding tissue
Nontoxic Simple Goiter Differential Considerations
Thyroidism Hypothyroidism Neoplasm
Toxic Multinodular Goiter Clinical Findings
Thyroid Enlargment
Toxic Multinodular Goiter Sonographic Appearance
enlarged inhomogeneous gland can have focal scarring, focal ischemia, necrosis, and cyst formation
Toxic Multinodular Goiter Differential Consideration
Neoplasm Cyst
Graves Disease Clinical Findings
Diffuse toxic goiter
Graves Disease Sonographic Findings
Diffusely homogeneous and enlarge
Graves Disease Differential Consideration
Neoplasm Ophthalmopathy Cutaneous manifestation Hyperthyroidism
Thyroidism Clinical Findings
swelling and tenderness of thyroid later hypthyroidism
Thyroidism Sonographic Appearacne
homogeneous enlargement with nodularity later inhomogeneous
Thyroidism Differential Consideration
Neoplasm
Cyst Clinical Findings
solitary nodule or multiple nodule
Cyst Sonographic Appearance
Anechoic areas, echogenic fluid, or moving fluid levels1
Cyst Differential Consideration
Toxic multinodular goiter
Adenoma Clinical Findings
Usually euthyroid or hyperthyroid
Adenoma Sonographic Appearance
Compression of adjacent structure fibrous encapsulation ranges from anechoic to hyperechoic may have a halo
Adenoma Differential Consideration
Grave’s Disease