11 Thyroid Disorders Nazemzadeh Flashcards
What are the thyroid levels like for HYPOthyroidism?
High TSH, Low T4, Low T3
What is the TSH normal range?
0.5-5
What is the Free T4 normal range?
0.8-2.7
What are the thyroid levels like for HYPERthyroidism?
Low TSH, High T4, High T3
What are the primary causes of HYPOthyroidism?
Thyroid gland failure. Hashimoto’s Thyroiditis
What medications can cause HYPOthyroidism?
Interferon, Ribavirin, Amiodarone, Lithium, etc.
What are the tests for autoimmunity and the normal values?
Thyroid peroxidase antibodies (TPOAb): < 100. Anti-thyroglobulin antibodies (TgAb) < 8%. Thyrotropin receptor antibodies (TRAb): negative
What are the most common signs and symptoms of HYPOthyroidism?
Fatigue. Weight gain. Cold intolerance. Constipation. Dry skin. Heavy menstrual periods. Depression. Infertility. Bradycardia. Enlarged thyroid
What are the common treatment options for HYPOthyroidism?
Levothyroxine. Liothyronine. Liotrix. Desiccated thyroid
What are the contents of Levothyroxine?
Synthetic T4, DOC. Patients own physiologic mechanisms control the production of active hormone
What are the contents of Liothyronine
Synthetic T3. Wide fluctuations (rapid absorption, short t1/2)
What are the contents of Liotrix?
Synthetic T4:T3 in 4:1 ratio. No therapeutic advantage
How should Levothyroxine (Synthroid) be dosed?
Healthy adult < 50 yo: 1.6-1.7 mcg/kg/day (adjust for patients < 50 or w/ cardiac disease)
How should Levothyroxine be titrated?
By 12.5-25mcg increments at 6-8 week intervals as needed. IV:PO = 1:2
What can cause reduced absorption (chelation) of Levothyroxine?
Antacids. Ferrous sulfate. Bile acid sequestrants. Sucralfate
What is monitoring like when starting Levothyroxine?
TSH measurements 4-8 weeks after initiation of tx or dose change. Once therapeutic dose determined: TSH after 6 months, then 12 month intervals
How do you counsel for Levothyroxine?
Take on empty stomach 30 minutes to 1 hour before breakfast. Separate administration of iron and levothyroxine by at least 4 hours. Will take several weeks to see effect. Usually lifelong w/ periodic lab testing. Do NOT d/c w/o discussing w/ provider
How does pregnancy affect treatment of HYPOthyroidism?
Increased thyroid hormone requirement. As early as 4-6 weeks of pregnancy. Increase through 16-20 weeks. Plateau until delivery
What are complications of pregnancy in untreated HYPOthyroidism?
Preterm delivery. Low birth weight. Miscarriage. Gestational HTN. Fetal neurocognitive deficits
What is the TSH reference range during pregnancy?
First: 0.1-2.5, Second: 0.2-3, Third: 0.3-3
What is the DOC for HYPOthyroidism in pregnancy?
Levothyroxine (Category A). Increase dose by 25-30% at onset of pregnancy. Postpartum: reduce dose back to pre-pregnancy range following delivery
What are the most common causes of HYPERthyroidism?
Graves disease (most common)
What are the signs/symptoms of HYPERthyroidism?
Nervousness. Tachycardia. Weight loss. Heat intolerance. Irritability. Tremor. Decreased menstrual flow. Insomnia. Diarrhea. Thyroid enlargement. Bulging eyes (exopthalmos)
What are the non pharmacologic treatment options for HYPERthyroidism?
Radioactive Iodine Therapy (RAI): treatment of choice for Graves disease, can result in chronic hypothyroidism. Thyroidectomy
What are the two drug therapy options for HYPERthyroidism?
Methimazole (Tapazole). Propylthiouracil (PTU)
What is the DOC in thyroid storm?
Propylthiouracil (PTU), otherwise Methimazole is preferred d/t its daily dosing
How are the drugs for HYPERthyroidism used during pregnancy?
PTU preferred in 1st trimester of pregnancy; Methimazole 2nd/3rd
Why are BBs used for symptomatic management in HYPERthyroidism?
Decrease HR and SBP. Decrease tremors. Decrease muscle weakness. Improve irritability
