Thyroid Flashcards
The sternocleidomastoid muscle is ___ to the thyroid
Anterior lateral
The strap muscles of the neck are __ to the thyroid gland
Anterior
The common carotid arteries and internal jugular veins are ___ to the thyroid.
Lateral
The longus colli muscle is ___ to the thyroid
Posterior
The minor neurovascular bundle is ___ to the thyroid
Posterior
The normally located parathyroid glands are ___ to the thyroid
Posterior
Arterial supply to the thyroid
Rt and lt superior thyroid arteries (branch of external carotid)
Rt and lt inferior thyroid arteries (branches of the thyrocervical arteries which come from subclavian artery)
Venous drainage from thyroid
Drained into internal jugular vein by the superior and middle thyroid veins.
Drained into innominates by the inferior thyroid veins.
Thyroglossal duct cyst
Congenital anomaly that appears as a superficial cyst in the midline of the neck anterior to the trachea and superior to the thyroid
(Thyroglossal duct normally obliterates in fetal life)
The MC malignancy of the thyroid
Papillary carcinoma 75-90%, presents with enlg cervical nodes
Chronic lymphocytic (Hashimoto’s) thyroiditis
Autoimmune disease. Painless diffuse enlg of thyroid, young women, mc cause of hypothyroidism, course echo texture. Hypoechoic gland.
Enlg gland cold intolerance, weak, fatigue, facial droop, dry scaly skin, weight gain, intellectual impairment, gradual personality change, course hair, constipation, dec sweating, hair loss
Hypo, norm or inc size, hetero, small Ca+, goiter
Pyramidial lobe
Extends off isthmus 15-30%
Thyroid
4-6 cm L
1.5-2 cm W
2-3 cm AP
Isthmus 2-6 mm
Thyroid
Endocrine gland, controls growth, metabolism, development
Produces T3 triiodothyronine and T4 thyroxine
Produces calcitonin which aids parathyroid and dec Ca in blood.
Requires iodine
Regulated by: TSH & thyrotropin produced by pituitary & TRH from hypothalamus
Euthyroid
Normal thyroid hormone levels
Hypothyroidism
Under secretion of thyroid hormones
Myxedema, weigt gain, hair loss, subcutaneous tissue around eyes, lethargy, intellectual motor slowing, cold intolerance, constipation, deep husky voice, course hair, dec sweating,facial droops, dry skin
Hyperthyroidism
Over secretion of thyroid hormones
Weight loss, inc appetite, nervous, energy tremor, excess sweating, heat intolerance, palpitations, exothalmus
Thyroid US
Low mid level echoes, homogeneous, slightly hyperechoic to muscle
Variants
Lingual (tongue base)
Sublingual
Suprahyoid
Substernal
Multinodular goiter/ adenomatous hyperplasia / nodular hyperplasia
MC cause of thyroid enlargement
Females 50-70yrs
Normal labs, Asymptomatic, pain with hemorrhage
Subacute Thyroiditis / De Quervain’s / Granulomatous Thyroiditis
Viral
May cause hyperthyroidism that subsides in weeks-months
Painful thyroid, fever, malaise
Enlg hypo goiter hetero
Grave’s Disease / Diffuse Hyperthyroidism / Diffuse Toxic Goiter / Thyrotoxicosis
MC cause if hyperthyroidism
Females
Child bearing age
Enlg goiter, hyperthyroid, inc vascularity, multinodular
Heat intolerance, inc heart rate, tremors, wt loss, nervous, inc metabolism, exothalmus, acropachy, palp lymph nodes, myxedema
Thyroid inferno
Increase vascularity
Thyroid & pregnancy
Assoc with infertility and abnl menses
Silent thyroiditis
3-6 months after birth. Hyper then hypothyroidism.
Hypo enlg
Cyst
20% of solitary nodules
Cold on nuc med
Nodular cyst have Echogenic dot within
Adenoma
MC benign neoplasm
Young adults, females
Neck mass, pain with pressure and hemorrhage
Hot on Nuc med. or cold. Usually hot.
Well defined, oval/round, any echogenicity, cystic degeneration, hypo halo
Thyroid cancer
Rare
Females, young adults, hx of radiation
Slow growing
Hard/fixed
Asymptomatic, pressure if large, lump, vocal cord paralysis, solitary
Cold on nuc med
Most hypo, solid, solitary
Cystic, complex, calcification, inc vasc flow, no halo, enlg adj lymph nodes
Papillary Carcinoma
MC cancer Young adults Child bearing women Least aggressive Mets to nodes, lungs, bone, brain Best prognosis 6% mortality in 20 years
Follicular Carcinoma
2nd MC cancer 15% of thy ca Slow growing May look like a regular nodule Mets to nodes lung bones
Medullary carcinoma
5% of thy ca
Assoc with MEN’S syndrome
Mets to lung nodes bones
Ca+
Anaplastic Cancer
2% Most lethal Aggressive Males > 50yrs 90% with lymphadenopathy Mets common when dx
Lymphoma
Usually Non-Hodgkin’s
Older females
Assoc with Hashimoto’s thyroiditis
Poor prognosis
Mets to thyroid
MC from breast ca
Also from bronchogenic, renal, melanoma, gastric cancer
Parathyroid glands
4 glands
Sup and inf
Post / med
< 4 mm
Calcium metabolism and regulation
Hypocalcemia
Dec calcium in blood
Numb Tingling lips, tongue, fingers, feet Dementia Depression Psychosis Muscle aches/spasms EKG changes Fatigue Irritability Anxiety
Hypercalcemia
Inc calcium in blood
Polyuria, nocturia, polydipsia, nephro/urolithiasis, osteitis, bone cyst, EKG changes, anorexia, Abd pain, ileus, n/v, arthritis
Hypoparathyroidism
Usually due to underlying disease
Hyperparathyroidism
Usually due to adenomas, hyperplasia, carcinoma
Adenomas MC cause, usually solitary, homo, hypo, well defined
Parathyroid hyperplasia
Uncommon cause of Hyperparathyroidism
Usually more than 1 gland involved.
Parathyroid carcinoma
Rare cause of Hyperparathyroidism
Indistinguishable from Adenoma and hyperplasia
Shadowing
High serum calcium
Brachial Cleft Cyst / Lateral Cervical Cyst
Embryonic remnant
Cyst or complex mass below angle of mandible
Lymphadenopathy
Due to infection or malignancy
Single or multiple well circumscribed round/oval hypoechoic
Malignant degenerative lymph nodes lose reniform shape and fatty hilum
Reidel’s thyroiditis
Chronic fibrosing disease. Thyroid displaces & compresses trachea & esophagus. Diffuse bilateral enlargement & hetero
Women>men
