Flashcards in Thyroid Disorders Deck (51):
What are the two types of goiter?
Endemic : Caused by lack of iodine in the diet
Sporadic: drugs – Propylthiouracil, lithium, iodides, Foods – rutabagas, cabbage, soybeans, peanuts, peaches, peas, strawberries, spinach and radishes
What is a goiter?
Occurs when the thyroid gland is unable to secrete enough thyroid hormone to meet metabolic needs. Hyperplasia is caused by chronic stimulation via elevation TSH
What are the symptoms of a goiter?
Monotone voice, Dysphagia (difficulty swallowing), Tracheal compression
How are goiters diagnosed and treated?
T3, T4 and TSH are usually normal. Thyroid Ultrasound for asymmetry or palpable nodules.
needle aspiration for fast growing goiters. Partial thyroidectomy for large goiters
What are the causes of primary hypothyroidism?
iodine deficiency, autoimmune (Hashimotos), iatrogenic (iodine therapy, thyroidectomy), post partum thyroiditis, drug induced (lithium, amiodarone, antithyroid), congenital
What are the causes of teritary hypothyroidism?
hypothalamus dysfunction, hemochromatosis, sarcoidosis
What are symptoms of hypothyroidism?
fatigue, cold intolerance, weakness, lethargy, weight gain, constipation, myalgias, arthalgias, menstrual irregularities, hair loss
What are signs of hypothyroidism?
dry, course skin., hoarse voice, brittle nails, periorbital/peripheral edema, delayed reflexes, bradycardia
How is hypothyroidism diagnosed?
TSH level is elevated, indicating thyroid hormone production is insufficient to meet metabolic demands, and free thyroid hormone levels are depressed.
How is hypothyroidism treated?
100-200mg Levothyroxine (T4) daily. Start at 25-50mcg daily for elderly and slowly increase. Take on empty stomach. monitor clinical features, TSH (for patients w/intact hypothalamic-pituitary axis), Free T4 (for patients with pituitary insufficiency)
How does age effect medication dosage for hypothyroidism?
stable dosing until 7th decade: With age, thyroid binding may decrease, and the serum albumin level may decline. Levothyroxine dosage may need to be reduced by up to 20 percent
What is hashimoto's thyroiditis?
"Chronic lymphocytic thyroiditis." Can be associated with non-Hodgkins lymphoma. automimmune hypothyroidism. more common in women btw 30-60.
What are clinical findings associated with Hashimoto's?
Goiter, low hormone levels. Increased number of antibodies to the enzyme, thyroid peroxidase. Anti-thyroid peroxidase (anti-TPO) antibodies
What are symptoms of Hashimotos?
painless goiter, fatigue, muscle weakness, weight gain, feeling of fullness in the throat, neck pain, low-grade fever
What is the treatment of Hashimoto's?
Levothyroxine (T4) (Levothyroid, Synthroid): 50-100mcg daily – under 60 w/o CAD. 100-150mcg daily – pregnant women. 12.5-50mcg daily – over 60 or pts with CAD. Monitor TSH
What is subclinical hypothyroidism?
no symptoms or minimal symptoms suggestive of hypothyroidism with normal serum free T4 and T3 and elevated serum TSH concentrations
What are strong predictors of subclinical hypothyroidism progressing to overt hypothyroidism?
anti-TPO antibodies, TSH>20, radioiodine ablation Hx (Graves Dz), or other radiation therapies.
What is myxedema?
develops in older adults. droopy eyelids, lethargy, fatigue, mental sluggishness, decreased reflexes. mucopolysaccharide infiltration of the dermal space causes facial puffiness, periorbital edema, non-pitting pretibial edema
How is myxedema treated?
Levothyroxine (T4) (Levothroid, Synthroid)
50-100mcg daily – under 60 w/o CAD
100-150mcg daily – pregnant women
12.5-50mcg daily – over 60 or pts with CAD. Monitor TSH
What is a myxedema coma?
life-threatening end-stage expression of hypothyroidism. Occurs most frequently in elderly women w/hypothyroidism and may be caused by stress, cold, narcotics, or discontinuation of therapy
What are symptoms of a myxedema emergency?
Coma, hypothermia, cardiovascular collapse, hypoventilation, severe metabolic disorders (hyponatremia, hypoglycemia, and lactic acidosis)
What is Cretinism?
stunted physical and mental growth due to untreated congenital deficiency - usually due to maternal hypothyroidism. puberty is delayed, ovulation is impeded, infertility common, cognitive impairment
What are etiologies of hyperthyroidism?
Common: Graves’ Disease, Toxic Adenoma (solitary), Toxic Multinodular Goiter. Less common: Subacute thyroiditis, Hashimoto’s thyroiditis with transient hyperthyroid state, postpartum thyroiditis.
What are symptoms of hyperthyroidism?
nervousness, diaphoresis, heat intolerance, palpitations, fatigue, weight loss, frequent bowel movements
What are signs of hyperthyroidism?
tachycardia, goiter, pretibial myxedema, tremor, exopthalmos, conjunctival inflammation, extraocular muscle dysfxn, lid lag, osteoporosis
What are the anti-thyroid drugs for patients with sustained forms of hyperthyroidism?
Methimazole (Tapazole) 5-15mg/day or Propylthiouracil (PTU) 100-150mg/day- Both Prevent trapping of iodine
What is the most widely recommended permanent treatment of hyperthyroidism?
radioactive iodine treatment of injected I-131. absorbed by the hyperplastic, toxic thyroid gland within 1 day of injection. doses repeated until no hyperthyroid
What is the treatment option for patients with temporary forms of hyperthyroidism?
beta blocker Propanolol: Initial dose: 40 mg orally twice a day. Maintenance dose: 120 to 320 mg/day. Symptomatic treatment only. Prevents the peripheral conversion of T4 to T3
What is Grave's Disease?
body creates circulating autoimmune antibodies, antithyroperoxidase (anti-TPO), and antithyroglobulin (anti-TG) antibodies. An important autoantibody in Grave’s disease is thyroid-stimulating immunoglobulin (TSI).
What role does TSI play in Grave's disease?
TSI is directed toward follicles of the thyroid-stimulating hormone (TSH) receptor and acts as a TSH-receptor agonist. Similar to TSH, TSI binds to the TSH receptor on the thyroid follicular cells to activate thyroid hormone synthesis and release and thyroid growth (hypertrophy)
What are the tetrad of symptoms of Graves Disease?
nontender, smooth, symmetric thyroid enlargement. Thyrotoxicosis – hyperthyroid state. Exopthalamos. Pretibial myxedema
What is the most specific test for Graves disease?
ELISA for TSHR-ab levels. If elevated the TSI can also help establish the diagnosis.
What are treatment options for Graves disease?
Propylthiouracil (PTU) and Methimazole (Tapazole) for at least 12 to 18 months. Beta Blockers – Propanolol (Inderal). Radioactive Iodine. Surgery
What is multinodular goiter "plummer's disease?"
functionally autonomous nodules shown on thyroid scan caused by hyperplasia of the follicular cells whose activity becomes independent of TSH. suppressed TSH, markedly elevated T3, moderately elevated T4
What is factitious hyperthyroidism?
Ingestion of Levothyroxine by euthyroid pts. May be seen in health care workers, dieters, body builders as an attempt to lose weight.
What is thyrotoxicosis?
Elevated T3 and/or T4. Sometimes due to inflammation of the thyroid. Can occur after ingestion of levothyroxine as a weight loss. Usually no history of hyperthyroid condition
What is a thyroid storm?
life-threatening crisis precipitated by hyperthyroidism, stress, infection, diabetic ketoacidosis, trauma, manipulation during thyroidectomy
What are clinical features of a thyroid storm?
very high fever, cardiovascular effects, CNS effect, N/V
How is a thyroid storm treated?
Peripheral cooling. Replace fluids, glucose and electrolytes. Propranolol to block effects of T4 on CV function. Glucocorticoids to correct adrenal insufficiency and to inhibit peripheral conversion of T4 to T3. Propylthiouracil (PTU) and Methimazole (Tapazole)
What is acute thyroiditis?
complication of septicemia. fever, redness of the skin over the thyroid and thyroid tenderness. Blood cultures or aspiration of thyroid gland to diagnose organism. treated with IV antibiotics, occasionally I&D of the gland
What is subacute thyroiditis (de Quervain’s thyroiditis or Granulomatous thyroiditis)?
secondary to a viral infection. fever and anterior neck pain, tender thyroid gland. ESR is high and thyroid scan shows little or no uptake of radioiodine. Treatment of choice is symptomatic. Complete recovery w/in months
What is postpartum thyroiditis?
Onset is within 3-12 months of delivery. Nontender thyroid, low uptake of RAI. Presence of TPO anitibodies increases risk. Increased risk of reoccurrence with subsequent pregnancies and progression to hypothyroidism. Treat w/propanolol, levothyroxine
What is iodine induced (Jod-Basedow) thyroiditis?
Induced by contrast agents for angiography or CT scan. Low uptake of radioactive iodine. Absence of antithyroid antibodies
What is amiodarone induced thyroiditis?
Iodinated drug with antiarrhythmic and antianginal properties. Type 1 – occurs in pts. w/ underlying thyroid dz. Type 2 – occurs in normal thyroids
What is Riedel's struma (invasive fibrous thyroiditis)?
chronic thyroiditis seen in middle aged women. gland is stony hard and adherent to the surrounding structures and may cause dysphagia, dyspnea or hoarseness. Treat w/tamoxifen, steroids
Describe thyroid cancer
may present as painless swelling in the thyroid region. Thyroid fxn tests are normal. Radioactive iodine scanning shows malignancies to be hypofunctioning (cold)
What is papillary carcinoma?
most common thyroid cancer. Usually occurs in 30s and is associated w/exposure to ionizing radiation. well-differentiated, slow-growing.
How is papillary carcinoma diagnosed and treated?
Painless neck mass or metastatic disease to cervical lymph nodes. Thyroglobulin levels are elevated. Treatment includes thyroidectomy w/radioactive iodine. lifetime synthroid
What is follicular carcinoma?
slow growing thyroid cancer. Spreads to regional nodes, hematogenous spread to lung or bone. Treatment is same as papillary
What is medullary carcinoma?
thyroid cancer that occurs in the C-cells of the thyroid. Presents as a nodule in upper half of thyroid. Calcitonin is a unique tumor marker. Treatment is surgical removal