Thyroid Disorders Flashcards
What labs are monitored in patients being treated for thyroid disorders?
- TSH
- Free T4 (FT4)
FT4 = unbound, active form of T4
What are the s/sx of hypothyroidism?
- Cold intolerance/sensitivity
- Dry skin
- Fatigue
- Muscle cramps
- Voice changes
- Constipation
- Weight gain
- Goiter (possible; can be due to low iodine intake)
- Myalgias
- Weakness
- Depression
- Bradycardia
- Coarse hair or loss of hair
- Menorrhagia
- Memory and mental impairement
What is the most common cause of hyperthyroidism?
Graves’ disease
An autoimmune condition in which a patient’s own antibodies stimulate the thyroid to produce too much T4.
How often should TSH be monitored in patients with thyroid disease?
Every 4-6 weeks until levels are normal, then 4-6 months later, then yearly.
What complications can be seen in elderly patients if a too high dose of a thyroid hormone replacement therapy is used?
- Atrial fibrillation
- Fractures
What is the most common cause of hypothyroidism?
Hashimoto’s disease
An autoimmune condition in which a patient’s own antibodies attack the throid gland.
List the drugs that can cause hypothyroidism
- Interferons*
- Tyrosine kinase inhibitors (e.g., sunitinib)
- Amiodarone*
- Lithium
- Carbamazepine
*can also cause hyperthyroidism
I TALC
What is the uncommon but potentially fatal complication of hypothyroidism?
Myxedema coma
What are the s/sx of myxedema coma?
- Poor circulation
- Hypothermia
- Hypometabolism
What is the initial treatment for myxedema coma?
IV levothyroxine
What is the full replacement dose of levothyroxine?
1.6 mcg/kg/day
Use IBW
Start with full replacement dose in otherview healthy, young (< 50 years) pts with markedly elevated TSH.
If known CAD, start with 12.5-25 mcg daily.
What are the side effects of thyroid hormone replacement therapy?
Hyperthyroid symptoms can occur when the dose is too high:
* ↑HR
* Palpitations
* Sweating
* Weight loss
* Arrhythmias
* Irritability
How to take PO levothyroxine?
- Take with water at the same time every day
- Take at least 60 minutes before breakfast or at bedtime (at least 3 hours after the last meal)
What is the IV:PO conversion for levothyroxine?
0.75:1
Levothyroxine tablet colors
Orange - 25 mg
White - 50 mcg
Violet - 75 mcg
Olive - 88 mcg
Yellow - 100 mcg
Rose - 112 mcg
Brown - 125 mcg
Turquoise - 137 mcg
Blue - 150 mcg
Lilac - 175 mcg
Pink - 200 mcg
Green - 300 mcg
Orangutans Will Vomit On You Right Before They Become Large, Proud Giants.
Thyroid hormone replacement therapy can increase the effect
Warfarin
Thyroid hormone replacement therapy can decrease the level of
Theophylline
Thyroid hormone replacement dose may need to increase/decrease in pregnany?
30-50% increase
Hyperthyroidism is also known as
Overactive thyroid or thyrotoxicosis
What are some complications can be seen in patients with untreated hyperthyroidism?
- Tachycardia
- Arrhythmias
- Heart failure
- Osteoporosis
What are the s/sx of hyperthyroidism?
- Heat intolerance or increased sweating
- Weight loss
- Agitation, nervousness, irritability, anxiety
- Palpitations and tachycardia
- Fatigue and muscle weakness
- Frequent bowel movements or diarrhea
- Insomnia
- Tremor
- Thinning hair
- Goiter (possible)
- Exophthalmos (protrusion of the eyeballs), diplopia
- Light or absent menstrual periods
List the drugs that can cause hyperthyroidism
- Iodine
- Amiodarone
- Interferons
Treatment options for hyperthyroidism
- Antithyroid medications
- Radioactive iodine (RAI-131)
- Surgery
Surgery: thyroidectomy (partial or complete)
Which drug class is used for symptom control in patients w/ hyperthyroidism?
Beta-blcokers
To reduce palpitations, tremors and tachycardia
Role of antithyroid medications in hyperthyroidism treatment
- Antithyroid medications: Prophylthiouracil (PTU) and Methimazole.
- Takes 1-3 months of treatement at high doses to control symptoms. Once symptoms are controlled, the dose should be reduced to prevent hypothyroidism.
- Can be used as a temporary measure until surgery is complete.
MOA of antithyroid medications
- Inhibit synthesis of thyroid hormones by blocking the oxidation of iodine in the thyroid gland.
- PTU also inhibits peripheral conversion of T4 to T3.
Why is methimazole the drug of choice for hyperthyroidism?
Lower risk of liver damage compared to PTU
PTU is the preferred treatment for hyperthyroidism when
- Patient is having a thyroid storm
- Patient is in the 1st trimester of pregnancy
Role of potassium iodide
- Use after exposure to radiation.
- Blocks the accumulation of radiocative iodine in the thyroid gland, thus preventing thyroid cancer.
MOA of potassium iodide
Temporarily inhibit secretion of thyroid hormones
What are the s/sx of a thyroid storm?
- Fever (> 103 F)
- Tachycardia
- Tachypnea
- Dehydration
- Profuse sweating
- Agitation
- Delirium
- Psychosis
- Coma
How to treat a thyroid storm?
Antithyroid medication
+
Inorganic iodide therapy
+
Beta-blcoker
+
Systemic steroid
+
Aggresive cooling
