Thyroid Flashcards
What is the most common hyperthyroid disorder?
Toxic diffuse goiter (Graves disease)
It is an autoimmune disorder characterized by thyroid-stimulating antibodies that stimulate hormone production.
What causes painful subacute thyroiditis?
Viral invasion of the parenchyma leading to inflammation and release of stored hormone
This condition is self-limiting.
What is the mechanism of action of toxic adenoma?
Autonomous production of thyroid hormones independent of pituitary and TSH
It involves a nodule in the thyroid gland.
Define toxic multinodular goiter.
Several autonomous follicles causing excessive thyroid hormone secretion
Also referred to as Plummer disease.
What are common clinical presentations of hyperthyroid disorders?
[“Weight loss or increased appetite”, “Lid lag”, “Heat intolerance”, “Goiter”, “Fine hair”, “Heart palpitations or tachycardia”, “Nervousness, anxiety, insomnia”, “Menstrual disturbances”, “Sweating or warm, moist skin”, “Exophthalmos”]
What laboratory findings are indicative of hyperthyroid disorders?
[“Elevated free T4 serum concentrations”, “Suppressed TSH concentrations”, “Radioactive iodine uptake elevated in active disorders”, “Radioactive iodine uptake suppressed in thyroiditis or hormone ingestion”]
What is the primary goal of therapy for hyperthyroid disorders?
Minimize or eliminate symptoms and improve quality of life
Also aims to normalize free T4 and TSH concentrations.
What are the indications for antithyroid pharmacotherapy?
[“Those awaiting ablative therapy or surgical resection”, “Those with a high probability of remission with oral therapy”, “Those who are not surgical candidates”, “Those with limited life expectancy”, “Those with moderate to severe active Graves ophthalmopathy”]
What is the initial dosing for propylthiouracil?
50–150 mg by mouth three times daily
Can be reduced to 50 mg two or three times daily once euthyroid.
What is the preferred agent for Graves disease according to AACE?
Methimazole
Initial dose is 10–30 mg by mouth once daily.
What are common adverse effects of antithyroid drugs?
[“Hepatotoxicity”, “Rash”, “Arthralgia, lupus-like symptoms”, “Fever”, “Agranulocytosis”, “Acute pancreatitis with methimazole”]
What is the mechanism of action of nonselective β-blockers in hyperthyroid disorders?
Blocks many hyperthyroidism manifestations mediated by β-adrenergic receptors
May also affect T4 conversion to T3.
What is the primary use of iodines and iodides in hyperthyroid treatment?
Inhibits the release of stored thyroid hormone
Used temporarily before surgery or after ablative therapy.
What defines subclinical hyperthyroidism?
Low or undetectable TSH with normal T4
Associated with elevated risk of atrial fibrillation in older patients.
What is thyroid storm?
Severe and life-threatening decompensated thyrotoxicosis
Mortality rate may be as high as 20%.
What are the common clinical presentations of hypothyroid disorders?
[“Cold intolerance”, “Dry skin”, “Fatigue, lethargy, weakness”, “Weight gain”, “Bradycardia”, “Slow reflexes”, “Coarse skin and hair”, “Periorbital swelling”, “Menstrual disturbances”, “Goiter”]
What is the drug of choice for treating hypothyroidism?
Levothyroxine
It is a synthetic form of T4.
What is the initial dosing recommendation for levothyroxine in otherwise healthy adults?
1.6 mcg/kg per day based on ideal body weight
Adjustments may be made based on response.
What is the definition of subclinical hypothyroidism?
Elevated TSH with normal T4
Often results from early Hashimoto disease.
What is the definition of subclinical hypothyroidism?
Elevated TSH (above upper limit of reference range) with normal T4.
Often the most result of early Hashimoto disease.
What is the risk associated with TSH greater than 7 mIU/L in older adults?
Elevated risk of heart failure.
TSH greater than 10 mIU/L associated with elevated risk of coronary heart disease.
What is the drug of choice for treating subclinical hypothyroidism?
Levothyroxine.
Considered due to its adverse effect profile, cost, lack of antigenicity, and uniform potency.
What is myxedema coma?
Severe and life-threatening decompensated hypothyroidism; mortality rate 30%–60%.
Coma is uncommon; altered mental state is very common.
What are the precipitating causes of myxedema coma?
Trauma, infections, heart failure, medications (e.g., sedatives, narcotics, anesthesia, lithium, amiodarone).
What are the symptoms indicating the need for treatment in hypothyroidism?
TSH 10 mIU/L or greater, symptoms of hypothyroidism, antithyroid peroxidase antibodies present, history of cardiovascular disease, heart failure, or risk factors for such.
What is the recommended initial daily dose of levothyroxine for myxedema coma?
25–75 mcg.
Adjust based on clinical response.
What is the role of antibiotic therapy in myxedema coma?
Empiric therapy with broad-spectrum antibiotics is advocated due to common infectious causes.
What is the recommended intravenous thyroid hormone replacement dose for T4?
200- to 400-mcg intravenous loading dose, followed by 1.6 mcg/kg daily.
What should be done if the random cortisol concentration is not depressed?
Corticosteroid therapy can be discontinued.
What is the significance of T3 in the treatment of myxedema coma?
Some advocate its use over T4 due to T3 being more biologically active and T4/T3 conversion may be suppressed in myxedema coma.
What is the typical intravenous dose comparison to oral administration for thyroid hormone?
Intravenous doses are around 75% of oral administration.
Fill in the blank: If levothyroxine is properly dosed, patients will maintain TSH and free T4 in the _______.
normal ranges.
True or False: Coma is a common presentation in myxedema coma.
False.
