Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
Name 2 drugs which can inhibit thyroid hormone synthesis or release
|
Lithium & iodine (W-C block)
|
|
|
What impact does amiodarone have on thyroid function (3)?
|
1. Inhibits the enzymatic conversion of T4 -> T3
2. blocks T3 binding at nuclear receptor --> hypothyroidism 3. Direct toxic effects on thyroid follicular cells (may cause transient hyperthyroidism) |
|
|
If a person with an underlying thyroid disease experiences Wolff Chakoff block, what can happen?
|
Failure to escape from block --> HYPOthyroidism or HYPERthyroidism
|
|
|
Natural hypothyroid treatment
Complications |
Dessicated thyroid = T3 + T4 hog/cow/sheep
Antigenic potential, unstable and unpredictable |
|
|
Synthetic hypothyroid treatment
|
Levothyroxine (T4) preferred over T3 or T3/T4 mixtures
|
|
|
Benefits of levothyroxine
What patient will start on a high dose or levothyroxine? A small dose? How is the dose adjusted? |
Long T1/2, stable, not antigenic, inexpensive
High dose (50 mcg/dl) for young people or people >45 with no cardiac probs Low dose (12.5 mcg/dl) for elderly or pts with hx of cardiac probs Titrate based on cardiac sx and TFTs Steady after 6-8 weeks may be able to discontinue therapy |
|
|
Levothyroxine DDIs
|
Resin binders- cholestyramine, colestipol
Aluminum preparations- aluminum hydroxide, sucralfate Enzyme inducers- phenytoin, rifampin, phenobarbital, carbamazepine Increases TBG- estrogen, raloxifene (decrease free binding) |
|
|
When should patient take levo? What should they avoid when they take levo?
|
Take it in the morning on EMPTY STOMACH.
Avoid iron containing products, calcium containing products (2 hrs before or 4-6 hours after) |
|
|
True or false: there are slight dose variations from 1 brand of thyroxine compared to another.
|
True. For this reason, keep patient on same product if possible (monitor closely if change is necessary)
|
|
|
What is subclinical hypothyroidism? How is it treated?
|
Normal T4 with high TSH usually asymptomatic, may progress to hypothyroidism. No definitive evidence about treating these patients, may treat if TSH > 10 mIU/L
|
|
|
What is myxedema coma? Treatment?
|
End stage of untreated hypothyroidism.
Treat with IV bolus thyroxine (high dose) 300-500 micrograms + IV hydrocortisone + supportive therapy |
|
|
Hyperthyroidism, DOC? Other options?
|
Thionamides/thioureas are DOC for kids, adolescents, graves, pregnancy
Also radioactive iodine, surgery, adjunct therapy |
|
|
Thiourea drugs- examples, moa
|
Propylthiouracil, methimazole
MOA- inhibit TPO, inhibit coupling of iodotyrosines, inhibit peripheral conversion of T4-->T3 |
|
|
metabolism of thionamides? duration of treatment? Adverse effects
|
Hepatic
1-2 years Benign Transient leukopenia (MOST COMMON), Agranulocytosis, Maculopapular rash, GI intolerance, arthralgias |
|
|
In a patient with thionamide induced BTL what should be done?
|
continue therapy and monitor
|
|
|
Radioiodide- DOC for?? Contraindications?
|
Toxic autonomous nodules, multinodular goiters, elderly, cardiac disease
Breastfeeding/pregnant (goes to fetal thyroid --> thyroid destruction), children |
|
|
I-131- MOA? Adverse effects?
|
Disrupts hormone synthesis --> necrosis and follicular breakdown --> transient increase in thyroid hormone levels
Hyper-->hypothyroid, tenderness, dysphagia |
|
|
Pretreatment & Post treatment for RAI?
|
Pre- beta blockers (inhibit thyroid effects on HR), thionamides (in pts with long standing hyperthyroidism- quiet the gland before destruction)
Post- thionamide, BB?, iodide? Post |
|
|
When is surgery indicated for hyperthyroidism?
|
Malignancy, large thyroid gland, severe opthalmopathy, pressure sx/obstruction, not responding to thionamides
|
|
|
Pre surgical treatment
|
Thionamides (till pt is euthyroid), iodide, propranolol
|
|
|
Post surgery treatment
|
Propranolol (maybe iodide as well)
|
|
|
Potassium iodide- MOA, Use?
|
MOA- blocks thyroid hormone and inhibits thyroid hormone synthesis and decreases size & vascularity of the gland
Used as an adjunct (prep for surg), also used for people with exposure to a nuclear event with RADIOACTIVE IODINE CONTAMINATION |
|
|
Adrenergic antagonists- use?
|
for thyroiditis, prep for surgery or thyroid storm (beta blockers)
If beta blockers can't be used, centrally acting sympatholytic (clonidine) or calcium channel (verapamil) can be used |
|
|
Number one cause of subclinical hyperthyroidism?
|
Levothyroxine therapy
Low TSH, normal FT4 |
|
|
Thyroid storm- sx, mortality, treatment
|
Fever, tachycardia, tachypnea, NVD, dehydration, coma
Precipitated by infection, trauma, drug withdrawl Mortality = 100% if not treated Treat- Thionamides, iodides, propranolol, dialysis/plasmapheresis to remove circulating hormones |
