The thyroid is an endocrine organ that secretes hormones that regulate
metabolism and protein synthesis.
The gland is about 10 – 20 g and butterfly shaped with 2 lobes and isthmus, 30 % of the population also have a pyramidal lobe the extends superior to the isthmus.
reference range of T3: 75 -200 ng/dL
reference range for T4: 4.5 -11.5 ug/dL
TSH Thyroid stimulating hormone
reference range for TSH: 75 -200 ng/dL
Thyroid-binding globulin TBG
reference range for TBG: 1.1-2.1mg/dL
Under ultrasound the thyroid is smooth, homogenous with mid level echoes. Colloid follicles are normally seen in the parenchyma and are considered normal, these are
small cysts with punctuate echoes within.
The thyroid is bordered posteriorly by the trachea, laterally by the carotid and juglular, and anteriorly by the strap and sternocelidomastoid muscles.
Goiter or palpable mass
Abnormal thyroid function tests
Family history of thyroid cancer
Hashimoto’s thyroiditis (Chronic lymphocytic thyroiditis)
Frequent in adolescent girls and women over 40
Gland is typically enlarged, grossly heterogenous and hyperemic (thyroid inferno). The thyroid can have numerous nodules.
Antibodies attack thyroglobulin and tsh receptors causing lymphocytic infiltration and follicular atrophy.
Grave’s disease (Thyrotoxicosis)
thyroid stimulating immunoblobulin binds to TSH receptors
findings are similar to hashimoto’s.
Clinical features and symptoms are exophthalmos (protruding eyes) insomnia, hand tremor, hyperactivity, hair loss, excessive sweating, shaking hands, itching, heat intolerance, weight loss despite increased appetite, diarrhea, frequent defecation, palpitations, muscle weakness, and skin warmth and moistness.
Thyroid Nodules and Cancer
1% of new cancer diagnoses in the US per year.
papillary carcinomas (80%)
follicular carcinomas (10%)
medullary thyroid carcinomas (5-10%)
anaplastic carcinomas (1-2%)
primary thyroid lymphomas and primary thyroid sarcomas (rare)
An estimated 5-10% of solitary thyroid nodules are malignant
Source: 2015 American Thyroid Association Guidelines
Hyperparathyroidism and parathyroid masses
Hyperparathyroidism causes elevated parathyroid hormone (PTH) which increases serum calcium and may lead to calicifications and kidney stones
Caused by parathyroid adenoma in 80% of cases.