thyroid intro Flashcards
What are the main thyroid hormones?
T3 (Tri-iodothyronine) and T4 (Thyroxine).
What do thyroid hormones contain?
Iodine.
How do thyroid hormones affect metabolism?
They stimulate the basal metabolic rate, increase O2 consumption, and heat production.
How do thyroid hormones affect the heart?
Increase heart rate, contractile force, and cardiac output.
How do thyroid hormones affect growth?
Promote growth and development of the brain, nervous system, and skeletal muscles.
What regulates thyroid hormones?
Hypothalamus and anterior pituitary gland through a negative feedback loop.
What triggers thyroid hormone release?
Low blood levels of T3 & T4 → Hypothalamus releases TRH → Anterior pituitary releases TSH → Thyroid releases T3 and T4.
What test is used for hypothyroidism diagnosis?
Serum thyroid-stimulating hormone (TSH).
What does an elevated TSH level indicate?
Hypothyroidism.
What does the Serum T4 test measure?
Total T4 or free T4 to monitor thyroid replacement therapy and screen for dysfunction.
What does the Serum T3 test measure?
Total T3 or free T3 to diagnose hyperthyroidism and monitor therapy.
What are the symptoms of thyrotoxicosis?
Strong rapid HR, dysrhythmias, angina, nervousness, insomnia, muscle weakness, increased metabolism, increased body temperature, heat intolerance, warm/moist skin, increased appetite, weight loss.
What is severe hypothyroidism called in adults?
Myxedema.
What is the most common cause of hypothyroidism?
Hashimoto’s thyroiditis.
Other causes of hypothyroidism?
Iodine deficiency, surgical removal, or destruction by radioactive iodine.
What is hypothyroidism treatment?
Thyroid hormone replacement therapy (increased doses in pregnancy).
What is congenital hypothyroidism called?
Cretinism.
What is the most common cause of hyperthyroidism?
Grave’s disease (thyroid-stimulating immunoglobulins - TSIs).
Who is most affected by Grave’s disease?
Women ages 20-40.
Key symptom of Grave’s disease?
Exophthalmos (bulging eyes).
What is Toxic Nodular Goiter (Plummer’s Disease)?
A form of hyperthyroidism caused by an overactive thyroid nodule.
Treatments for hyperthyroidism?
Surgery, radioactive iodine, thyroid hormone synthesis suppression, beta-blockers, nonradioactive iodine.
What is Thyrotoxic Crisis (Thyroid Storm)?
Severe thyrotoxicosis triggered by major surgery or severe illness.
Symptoms of Thyroid Storm?
Hyperthermia (≥105°F), severe tachycardia, restlessness, agitation, tremor, unconsciousness, coma, hypotension, heart failure.
Treatment for Thyroid Storm?
Methimazole, beta-blockers, sedation, cooling, glucocorticoids, IV fluids.
