Endocrine: Thyroid Flashcards
What can we measure to assess Thyroid function?
- GOLD STANDARD: Thyroid Stimulating Hormone (TSH)
- T4
- T3
Normal range of Thyroid Stimulating Hormone (TSH)?
0.3 to 5 milliunits/L per ATI
What are some drugs used to treat Hypothyroidism?
- Levothyroxine
- Liothyronine (desiccated thyroid)
What are some causes of Hypothyroidism?
- Autoimmune Diseases (most common)
- Hashimoto’s
- Surgically removed thyroid (thyroid cancer)
- Certain Drugs: Lithium, Amiodarone
What are some common symptoms of Hypothyroidism?
- Thickened skin
- Hair loss
- Constipation
- Lethargy
- Weight gain
- Bradycardia
- Sleepy all the time
- Anorexia (no appetite)
Describe how thyroid drugs work to treat Hypothyroidism.
- Thyroid drugs are given to replace what the thyroid gland cannot produce to achieve normal thyroid levels (euthyroid).
- These drugs are used for the rest of the patient’s life
- Goal is to normalize TSH AND improve patient’s symptoms
Hypothyroidism treatment?
- Levothyroxine (GOLD STANDARD)= Synthetic T4 (Levo= 4 letters)
- Liothyronine= Synthetic T3 (Lio= 3 letters)
- Dessicated Animal Thyroid (Guidelines recommend AVOIDING)
What is Levothyroxine (T4) used to treat?
- Treat all forms of hypothyroidism
- Myxedema Coma
Levothyroxine special note?
- REMEMBER: Some people classify this as a catecholamine (increased alertness)
Levothyroxine adverse effects?
Overdose- “Hyperthyroidism”
- Heat intolerance
- Excitement (insomnia)
- Angina / Afib
- Restless
- Tachycardia/Tremor
Boxed Warning for Levothyroxine?
Boxed Warning: FDA recommends not to use as treatment for obesity/weight loss
Describe Levothyroxine Administration.
- Start with a low dose and increase based on TSH + symptoms
- Check a pulse before giving (hold if >100)
- This drug requires an empty stomach (acidic pH)
- Give first thing in the morning
Levothyroxine drug interactions?
- Concern with mixing with other drugs that can change pH of stomach (Antacids- Tums®)
- Do not administer with bile acid sequestrants (cholestyramine) separate by 4 hours
Levothyroxine drug profile?
Keep in mind this is a NARROW THERAPEUTIC INDEX drug
When is Liothyronine (T3) used?
- Used when someone has an issue converting to T4 to T3 (extremely rare)
- Used when someone is not sufficiently controlled with T4
Liothyronine (T3) and Desiccated Animal Thyroid (T4:T3 ratio) adverse effects?
- Heat intolerance
- Excitement (insomnia)
- Angina
- Restless
- Tachycardia/Tremor
What is Hyperthyroidism caused by?
- Graves’ disease
- Thyroid storm
Hyperthyroidism S/S?
Affects multiple body systems, resulting in an overall increase in metabolism
- Diarrhea
- Increased appetite
- Weight loss
- Muscle weakness
- Altered menstrual flow
- Flushing
- Fatigue
- Palpitations
- Nervousness
- Irritability
Heat intolerance
Excitement (insomnia)
Angina
Restless
Tachycardia/Tremor
How is Hyperthyroidism managed?
- Surgery- remove part/all of thyroid
- Pharmacological Drug therapy for rest of life
- Radioactive Iodine to destroy Thyroid
What drugs are used to treat Hyperthyroidism?
Main Drugs:
- Methimazole
- Propylthiouracil (PTU)
Extra Drugs:
- Radioactive Iodine (I-131)
- Potassium Iodide
What is Methimazole + Propylthiouracil (PTU) used to treat?
- Hyperthyroidism
- Graves Disease
- Thyroid Storm
Describe PTU.
PTU= Puts Thyroid Under
- They suppress creation of thyroid hormone
Methimazole + PTU adverse effects?
- Liver and Bone Marrow Suppression
- PTU- BOXED WARNING- hepatotoxicity
Methimazole + PTU patient education?
Avoid eating foods high in iodine (seafood, soy sauce, tofu, and iodized salt)
How should Methimazole + PTU be administered?
- Better tolerated when given with food
- Give at the same time each day to maintain consistent blood levels.
- Never stop these medications abruptly.
Describe Thyroid Storm.
Extreme surge of thyroid hormone (T3 +T4).
- Induced by Stress or Infection
- EXTREMELY DANGEROUS
- HEART
- Patients will present with tachycardia/atrial fibrillation, fever, confusion, maybe even organ damage
Thyroid Storm treatment?
- Give Propranolol
- Give PTU (or maybe Methimazole)
What does Radioactive Iodine do (I-131)?
- Surgery to remove all or part of the thyroid gland
- Lifelong thyroid hormone replacement will be needed.
What is Radioactive Iodine (I-131) used to treat?
- Graves Disease
- Thyroid Tumor
- Goiter
What is Potassium Iodide (SSKI) used to treat?
- Following radioactive iodine exposure, potassium iodide blocks the uptake of radioactive iodine by the thyroid, reducing the risk of thyroid cancer and thyroid destruction
- Thyroid Storm/Thyrotoxicosis
