2. Pathology of Endocrine Systems (Thyroid).pdf

PART 2 : Disorders of Thyroid Gland Zariyantey Abdul Hamid (PhD) UKM  THYROID GLAND : OVERVIEW Produce T4, T3, (major hormones) and calcitonin (responsive to level > - of blood calcium) function : ↓ blood...

PART 2 : Disorders of Thyroid Gland Zariyantey Abdul Hamid (PhD) UKM  THYROID GLAND : OVERVIEW Produce T4, T3, (major hormones) and calcitonin (responsive to level > - of blood calcium) function : ↓ blood calcium T4 and T3 synthesis require iodine (dietary source) Major Functions: a) Body metabolism = b) Regulate body temperature => c) Growth development - Macam Taik Grajah & metabolism temperative "growth  THYROID FUNCTIONS Overall, Thyroid hormone involve in: a) Burn calories to energy b) Control how fast new cells replace dying cells : Increase cell metabolism, thus produce heat – increase body temperature c) Stimulate sympathetic nervous systems (alertness, responsiveness, reflexes) d) Increase GIT motility e) Increase O2 demand f) Increase HR g) Increase brain development h) Act on bone to stimulate osteoclast activity and bone resorption.  Regulation of Thyroid Hormone Secretion >99% of thyroid hormones are carried in plasma bound to protein = osteoclast activity leading to bone N H pain and fracture B  HYPERTHYRODISM CAUSES : (5) [GET IT] a) Grave’s disease : AUTOIMMUNE MEDIATED – Thyroid stimulating = immunoglobulin (TSI) which acts like TSH – cause stimulation of thyroid gland to produce thyroid hormone. Sign and Symptoms Bulging & similar to hyperthyroidism with additional unique features which is eyes Exophthalmos b) Toxic Nodular Goiter (TNG) – NOT AN AUTOIMMUNE MEDIATED. S Nodular growth like goiter which over secrete T 4 and T 3. No Exophthalmos c) Thyroiditis – inflammation of gland lead to Thyroid hormone release = into circulation. d) Excess dietary iodine - e) Can be induced by over-treatment with thyroid hormones. =>  HYPERTHYRODISM TREATMENTS AND INTERVENTIONS 1. Anti-thyroid medications 2. Monitor HR, BP, ECG, 3. Educate about medication 4. Monitor THYROID STORM 5. Sedatives / cooling blanket 6. Thyroidectomy  Endocrine system : Thyroid Gland vessel -blood colloid Normal thyroid seen microscopically consists of As in all endocrine glands, the interstitium has a follicles lined by a cuboidal epithelium and filled rich vascular supply into which hormone is with pink, homogenous colloid. The follicles vary secreted. somewhat in size. Dr ZAH Graves disease At low power microscopically, note the prominent infoldings of the hyperplastic follicular epithelium. Depleted, scalloped, watery colloid. Tall, columnar epithelial cells. Hyperplasia of the follicular cells with multiple layers. Dr ZAH  scallop ~ Shown at high power, the tall columnar thyroid epithelium & with Graves disease lines the hyperplastic infoldings into the colloid. Note the clear vacuoles in the colloid indicating scalloping out of the colloid in the follicle. Dr ZAH  HYPO = REDUCE Thyroid hormone secretion HYPOTHYROIDISM - Body working at SLOW and LOW rate PATHOPHYSIOLOGICAL CHANGES Decrease O2 demand leading to Reduce burning calories Reduce GIT motility reduce respiratory rate lead to weight gain leading to constipation bradycardia, reduce cardiac motility reduce cardiac output leading Reduce gluconeogenesis Affecting neurological function to reduce peripheral blood lead to hypoglycemia affecting personality – depression, circulation foggy brain. Reduce lipolysis Affecting kidney function reduce cellular metabolism – by the reduce of GFR due producing less heat and reduce to reduce renal blood flow, body temperature leading to cold Reduce stimulation of SNS reduce SODIUM TUBULAR intolerance which reduce heart rate REABSORPTION – HYPONATREMIA X changes in bone resoption (unlike hyperthyroidi  HYPOTHYRODISM CAUSES : [CHIP] a) Hashimoto’s thyroiditis: AUTOIMMUNE MEDIATED – attack thyroid S gland– cause reduce or no production of thyroid hormone b) Iodine deficiency - c) Pituitary tumor – NO TSH thus no thyroid gland stimulation. - d) Complication from long term anti-thyroid medications for z hyperthyroidism. TREATMENT: Thyroxine Replacement Therapy  Hashimoto thyroiditis Lymphoid follicles with germinal center This low power microscopic view of and lymphocyte infiltration and thyroid gland shows an early stage of proliferation Hashimoto thyroiditis with prominent lymphoid follicles containing large, active germinal centers. There is replacement of the thyroid tissue with lymphoid tissue. As the disease progresses, much of the thyroid may be replaced by scar tissue. Dr ZAH  Lymphoid follicles with germinal center and lymphocyte infiltration and thyroid follicles with reduced colloids proliferation Dr ZAH  The thyroid follicular cells undergo metaplastic changes as a result of continuing inflammatory cell damage resulting in so-called “Hurthle” cell or more appropriately “Oxyphil” cell change. These cells are larger with abundant finely granular eosinophilic cytoplasm and enlarged nuclei that may show some atypia (arrow). Note the presence of abundant lymphoplasmacytic infiltrate around follicles (curved arrow). Dr ZAH  Sick Euthyroid Syndrome During severe illness (non-thyroidal diseases), the metabolic drive on the human body by the thyroid is reduced. The term 'sick euthyroid' is used in this condition since it represents a state of thyroid function appropriate for a sick individual; and it returns to normal with the return of good health. In the typical sick euthyroid reduced peripheral conversion of T4 to T3, leading to reduced level of circulating T3 , but the total T4 may be normal or even raised since there is reduced conversion to T3. Conversely, fT4 may be low since the majority is carried on serum binding proteins and their synthesis may be suppressed by severe illness. The absence of a raised TSH excludes primary hypothyroidism.  Thyroid Function Tests TTG TT3 fT4 fi3 Blood level of TSH, total T4, total T3, free T4, free T3 & Thyroid autoantibodies for diagnostic workout : => Thyroid peroxides antibodies (TPOAb) , TSH - receptor antibodies (TSH-RAb) Measurement of carrier proteins for diagnostic => workout: Thyroid binding globulin (TBG), Thyroxine- binding prealbumin (TBPA) and Albumin. (Bawa Auto Car W carrier & bood sest 2 thyroid proteins autoantibodies THANK YOU!