CC2 LAB EXAM (THYROID GLAND AND ITS DISORDERS)

Thyroid Gland

known as “butterfly-shaped gland”

Isthmus

Thyroid has lobes that are connected by a narrow band called ____

Follicles

fundamental structural unit of thyroid gland

follicular cells (T3 and T4) and Parafollicular cells (Calcitonin)

2 types of cells of Thyroid Gland

Tissue growth, mental development, development of CNS

Function of Thyroid Hormones

Triiodothyronine (T3) and Tetraiodothyronine (T4)

Major Thyroid Hormones

Triiodothyronine (T3)

Thyroid hormone that is most active thyroid hormonal activity

T3 thyrotoxicosis

principal application of T3 is diagnosing ______

T3

better indicator of Hyperthyroidism.

T3

helpful in confirming diagnosis of Hyperthyroidism

60-150 ug/dl

reference value of Triiodothyronine (T3) for Adult

105-245 ng/dL

Reference value of Triiodothyronine (T3) for Children ages 1-14 yrs old

tetraiodothyronine (T4)

principal secretory product of Thyroid hormone

tetraiodothyronine (T4)

Thyroid hormone that has major fraction of organic iodine in circulation; a prohormone for T3 production

Elevated Thyroxine

causes inhibition of TSH secretion

5.5-12.5 ug/dL

reference value of Tetraiodothyronine (T4) for Adult

11.8-22.6 ug/dL

reference value of Tetraiodothyronine (T4) for Neonates

Thyroxine Binding Globulin (TBG)

Thyroid Hormone Binding Proteins that transport majority of T3 (affinity for T3 is lower than T4)

Thyroxine Binding Globulin (TBG)

Thyroid Hormone Binding Proteins that transports 70-75% of total T4

70-75%

Thyroxine-Binding Globulin (TBG) transport how many percent of total T4

Thyroxine-Binding Prealbumin (transthyretin)

Thyroid Hormone Binding Proteins that transport 15-20% of total T4

Thyroxine-Binding Prealbumin (transthyretin)

Thyroid Hormone Binding Proteins that T3 has no affinity

15-20%

Thyroxine-Binding Prealbumin (transthyretin) transport how many percent of total T4?

Thyroxine-Binding Albumin

Thyroid hormone binding proteins that transports T3 and 10% of T4

10%

Thyroxine-Binding Albumin transport T3 and how many percent of T4?

thyroperoxidase (TPO)

Thyroid autoantibodies that is involved in tissue destructive process (Hashimoto’s disease)

TSH receptor (TR)

Thyroid autoantibodies that is involved in Grave’s Disease

Grave’s Disease

TSH receptor is involved in what disease?

Hyperthyroidism

excess of circulating thyroid hormones

Primary Hyperthyroidism

elavated T3 & T4 decreased TSH

Secondary Hyperthyroidism

increased T4 and TSH (due to primary lesion in pituitary gland)

Thyrotoxicosis

applied to a group of syndromes caused by high levels of free thyroid hormones in circulation

Plummer’s disease

other name for T3 thyrotoxicosis

T3 Thyrotoxicosis

FT3 increased but FT4 normal w/ low TSH

T4 thyrotoxicosis

T3 normal or low but T4 increased w/ low TSH

Grave’s Disease

most common cause of thyrotoxicosis

Grave’s Disease

an autoimmune disease in which antibodies are produced that activate TSH receptor

exophthalmus and Pretibial myxedema

features of Grave’s Disease

TSH receptor antibody test

Diagnostic test for Grave’s disease

Riedel’s Thyroiditis

thyroid turns into a woody or stony-hard mass

Subclinical Hyperthyroidism

shows no clinical symptoms but TSH level is low, and FT3 and FT4 normal

Subacute Granulomatous

Associated w/ neck pain, low-grade fever, and swings in thyroid function tests

Hypothyroidism

develops whenever insufficient amouns ot thyroid hormone are available to tissues

thyroid hormone replacement therapy (levothyroxine)

What treatment used in Hypothyroidism

Primary Hypothyroidism

primarily due to deficiency of elemental iodine; caused by destruction or ablation of thyroid gland

Hashimoto’s Disease

most common cause of primary hypothyroidism; characterized by thyroid replaced by a nest of lymphoid tissue

Hashimoto’s Disease

associated w/ enlargement of thyroid gland (goiter)

Hashimoto’s Disease

disease that has a Lab result of high TSH & positive TPO antibody

Myxedema

describes perculiar nonpitting swelling of skin; skin becomes infiltered by mucopolysaccharides

myxedema coma

severe form of primary hypothyroidism

Secondary Hypothyroidism

due to pituitary destruction/pituitary adenoma

Tertiary Hypothyroidism

due to hypothalamic disease; T3 and T4 low levels, TSH decreased

Congenital Hypothyroidism/Cretinism

defect in development or function of the gland

T4 decreased

Screening test result for Congenital Hyporthyroidism/Cretinism

TSH increased

Confirmatory result for Congenital Hypothyroidism/Cretinism

TSH < 10 mIU/L

Congenital Hypothyroidism interpretation if there is no further test needed

TSH 10-20 mIU/L

Congenital Hypothyroidism interpretation if it needs to repeat test in 2-6 weeks

TSH > 20 mIU/L

Congenital Hypothyroidism interpretation if its for endocrinologic evaluation to diagnose hypothyroidism

Subclinical Hypothyroidism

disease with a lab result of T3 and T4 normal but TSH is slightly increased