Thyroid Conditions PDF 2024-2025

PATH 1017 Thyroid Conditions Professor Jennifer Lamarre PATH 2024-2025 1 Thyroid Hormone Regulation Review Pituitary- hypothalamus axis and negative feedback mechanism Do you remember the various thyroid hormones from anatomy class?...

PATH 1017 Thyroid Conditions Professor Jennifer Lamarre PATH 2024-2025 1 Thyroid Hormone Regulation Review Pituitary- hypothalamus axis and negative feedback mechanism Do you remember the various thyroid hormones from anatomy class? PATH 2024-2025 2 Thyroid Diagnostic Tests Blood tests: Why is TSH tested first? TSH T3 and T4 Serum-free T4 What is the purpose of T4 resin uptake the biopsy? Thyroid antibodies Radioactive iodine uptake Fine-needle biopsy Thyroid scan, radio scan, or scintiscan PATH 2024-2025 3 Thyroid Imbalances Hypothyroidism Hyperthyroidism (thyrotoxicosis) Congenital (present Graves disease at birth) Thyroid tumors Acquired Hashimoto thyroiditis Thyroidectomy PATH 2024-2025 4  Why do goiters Goiter occur? Associated with: 1) Over-secretion of thyroid hormone (hyperthyroidism) Why is it rare to see goiters in North 2)Iodide deficiency America? leading to inadequate thyroid hormone levels (hypothyroidism) PATH 2024-2025 5 Acquired Hypothyroidism Suboptimal thyroid function Develops later in life, women 5x>men Leads to slowing of metabolism due to decreased thyroid hormone Severity varies from mild to life-threatening PATH 2024-2025 6  Acquired Hypothyroidism Caused by: Disease or destruction of thyroid gland (primary hypothyroidism) Hashimoto thyroiditis (most common) –what happens? Hypothalamus or pituitary gland disorders (secondary hypothyroidism) Other- medications (lithium) ingestion of large amounts of iodide- what happens? hyperthyroidism treatments PATH 2024-2025 7 Hypothyroid Manifestations Vary from mild to severe Caused by: Hypometabolic state due to thyroid hormone deficiency Myxedematous involvement of body tissues Hard non-pitting edema caused by increased quantities of mucins in subcutaneous tissue that trap water in interstitial space Can affects organs and leads to severe s+s PATH 2024-2025 8 Hypothyroidism Manifestations Which manifestations are most common? Which manifestations occur early vs. later in the illness? PATH 2024-2025 9 Hypothyroidism - Diagnostics Lab values: PATH 2024-2025 10 Medical Management of Hypothyroidism Synthetic levothyroxine-replacement therapy Be aware of medication interactions Effects of hypnotic and sedative agents: reduce dosage Impact on diabetic patients Support of cardiac function and respiratory function Prevention of complications (i.e. CAD) PATH 2024-2025 11  Congenital Hypothyroidism The baby often appears Affects 1 in 5000 infants normal at birth – why? Inadequate thyroid hormone secretion during fetal development What manifestations might the baby have? Factors: Lack of thyroid gland Abnormal synthesis of thyroid hormone Too little TSH secretion PATH 2024-2025 12  Congenital Hypothyroidism If untreated- “cretinism” develops –effects? Screening Test: heel stick blood test for T4 or TSH Treatment- thyroid hormone replacement Prognosis- good if begun in first 6 weeks PATH 2024-2025 13 Hyperthyroidism “thyrotoxicosis” occurs due to excessive levels of thyroid hormones Caused by: Graves disease (most common) Other-multi-nodule goiter; thyroid adenoma (cancer); excess thyroid hormone ingestion (meds) PATH 2024-2025 14 Hyperthyroid Manifestations Caused by: Increased O2 consumption & use of metabolic fuels due to hypermetabolism Increased sympathetic nervous system activity What are the most common manifestations? PATH 2024-2025 15 Graves Disease Autoimmune disorder Excessive stimulation of the thyroid gland and thyroid hormone release by antibodies Leads to hyperthyroidism accompanied by classic signs: Goiter Exophthalmos Dermopathy (thickening of skin) Onset- 20-40 years Women 5x > men PATH 2024-2025 16 Hyperthyroidism - Diagnostics Lab results: PATH 2024-2025 17  Medical Management of Hyperthyroidism Radioactive 131I therapy What is the purpose of radioactive iodine? Medications: Propylthiouracil and Why beta-blockers? methimazole Sodium and potassium iodine solutions Dexamethasone Beta-blockers Surgery and subtotal thyroidectomy PATH 2024-2025 18  Thyroid Storm (Crisis) Rare, extreme, life-threatening form of thyrotoxicosis (++++ T4) Often related to undiagnosed or inadequately treated hyperthyroidism High mortality rate Precipitating factors: Manipulation of thyroid gland during surgery (most common) Stress, infection, DKA, trauma, emotional event. Manifestations: Very high fever, Extreme CV effects –examples? Severe CNS effects –examples? PATH 2024-2025 19 Thyroid Storm (Crisis) Requires rapid diagnosis and treatment Supportive measures: Cooling measures Fluids, glucose and electrolyte replacement Beta-blocker drug (propranolol) Glucocorticosteroids Proplythiouracil Iodide contrast PATH 2024-2025 20