Thyroid Disorders Flashcards
Thryoid hormones have an important role in ____, ____, and _____
-Metabolism
-Cardiac function
-Growth (promotes maturation in infancy and childhood)
What is synthetic T4?
Levothyroxine
What test is most commonly done to test for thyroid function and to monitor dosing of medications?
thyroid-stimulating hormone (TSH)
When thyroid function is low, TSH is ____
high
Hypothyroidism
Causes
-Hashimoto’s (autoimmune)
-Insufficient iodine in diet
-Surgical removal of thyroid
What is the risk of hypothyroidism in the first trimester of pregnancy?
Permanent neuropsychologic deficits in the child
What is the risk of hypothyroidism in infants?
-Cognitive impairment
-Derangement of growth
What is the most common cause of hyperthyroidism?
-Grave disease (autoimmune)
-Thyroid-stimulating immunoglobulins (TSIs)
Non-pharmacological treatment of Graves Disease
-Surgical removal of thyroid tissue
-Destruction of thyroid tissue (with radioactive iodine)
Medications for Graves Disease
-Methimazole
-Propylthiouracil (PTU)
-Beta blockers (control heart rate)
-Methimazole
-Propylthiouracil (PTU)
Mechanism
Suppression of thyroid hormone synthesis and release
What is thryotoxic crisis?
Extreme hyperthyroidism caused by significant stress (e.g. surgery or illness) - NOT triggered by a rise in thyroid hormones
Thyrotoxic crisis
Symptoms
Hyperthermia (105 or higher)
Restlessness
Tremor
Coma
Hypotension
Heart failure
Thyrotoxic Crisis
Treatment
Methimazole
Beta blocker
How do you take levothyroxine?
-Take in the morning at least 30-60 minutes before breakfast
Levothyroxine
Adverse effects
Tachycardia
Angina
Tremors
Mainly occur because dose is too high
Methimazole vs. propylthiouracil (PTU)
-Methimazole does not cause liver damage associated with PTU
-Methimazole is more dangerous than PTU during lactation and 1st trimester of pregnancy
-PTU has shorter half-life - requires 2-3 doses per day
Methimazole
Adverse effect
-Agranulocytosis (very serious! fever and sore throat can be signs)
How long does it take for methimazole to work?
3-12 weeks
Methimazole
Therapeutic Uses (4)
-1st line for Graves’ disease
-Adjunct to radiation therapy
-Suppress thyroid hormone to prepare for thyroid gland surgery
-Thryotoxic crisis
When is PTU preferred over Methimazole?
1st trimester of pregnancy
PTU
Adverse effects
Agranulocytosis
Sever liver damage
Radioactive Iodine -131
How long to start working?
2-3 months for full effect
