Thyroid

Question 1

Which test is performed to evaluate thyroid nodules for potential malignancy in a patient who has thyroid nodules and the primary care provider suspects thyroid cancer?

Radionuclide imaging

Serum TSH level

Serum calcitonin

Thyroid ultrasound

Answer 1

Thyroid ultrasound evaluation should be performed for all patients with known thyroid nodules; high-resolution sonography can clearly distinguish between solid and cystic components.

Question 2

Testing for Thyroid Disorders

Answer 2

TSH testing is the most sensitive indicator. If TSH is abnormal, then test T3/T4

Question 3

TSH Levels

Answer 3

TSH <0.3/0.5 = Hyerpthyroid
TSH 0.3 - 4.0 = Euthyroid
TSH > 4 = Hypothyroid

TSH levels increase in response to low T3/T4 and TSH level drops when T3/T4 is high.

Question 4

TSH and T3/T4

Answer 4

High TSH with normal or slight low T3/T4 = subclinical hypothyroid
Low TSH and Low T3/T4 = Secondary hypothyroidism

Question 5

Thyroid Antibody Test

Answer 5

Positive TBO = Hashimoto (autoimmune issues)

Question 6

Thyroid Nodules

Answer 6

nodules are classified as hot, warm, or cold according to the concentration of iodine isotope in the nodule in comparison with the rest of the thyroid gland.
Hot nodules are usually but not always benign.
Most cold nodules (solid or cystic) are benign; however, most malignant neoplasms also appear as cold nodules

Question 7

Thyroid Ultrasound / Scan

Answer 7

Always needed in hyperthyroid to rule out toxic nodules, does not assess thyroid function

Question 8

Thyroid Cancer Signs / Risks

Answer 8

Exposure to radiation
Family history of thyroid cancer
Male gender
Older than 60

Question 9

Thyroid Nodule Eval

Answer 9

Ultrasound
Fine Needle Aspiration
Nuclear scan if TSH is supressed

Question 10

Hyperthyroid

Answer 10

TSH low, T3/T4 usually elevated

Question 11

Graves Disease

Answer 11

Most common cause of hyperthyroid.

Autoimmune hyperhtyroid - autoantibodies actiavte thyroid hormone release

Question 12

Hyperthyroid v. Thyroxicosis

Answer 12

Hyperthyroid - thyroid is source of excess thyroid hormone

Thyrotoxicosis - syndrome of excess thyroid hormone regardless of source (such as excess iodine)

Question 13

Subacute thyroiditis

Answer 13

Postviral illness, tender thyroid

Question 14

Hyperthyroid Presentation

Answer 14

High metabolism
Tachycardia, palpitations, angina, hypertension
Resltess, anxious
Dry eyes, blurry vision
Itching, menses irregularity
Heat intolerance, high body temp
Prominent goiter (Graves Disease)

Question 15

Hyperthyroid Treatment

Answer 15

Beta blockers to relieve symptoms (prompranolol 10-40mg every 6 hours or atenolol 25mg daily)

Thioamide therapy - methimazole or PTU. PTU is not preferred for first line unless patient is first trimester pregnant or nursing

Thioamides have liver, arthlagia, and agranulocytosis risk

Radioiodine therapy is treatment of choice if thioamide therapy fails or severe cases

Question 16

Thioamide Dosing

Answer 16

Methimazole - 5-20mg every 8 hours

PTU - 50-100 mg every 6/8 hours

Question 17

Subclinical hyperthyroid

Answer 17

Low TSH, normal T3/T4

Treat if concerned for osteoporosis, Graves, risk for heart issues or heart comorbids, elderly

Question 18

Subacute Thyroiditis

Answer 18

May need beta blockers for hyperthyroid phase
NSAIDs for pain relief or aspirin; prednisone if pain relief does not occur with those

Recheck thyroid levels every 2-8 weeks as hypothyroidism may follow

Question 19

Thyroid Stom

Answer 19

rare, life-threatening form of hyperthyroidism that leads to systemic decompensation. The diagnosis is based on clinical findings: temperature of 102°F to 105°F, profuse sweating, pulse above 120 to 140 beats/min, atrial fibrillation, restlessness, confusion, agitation, and coma. Gastrointestinal symptoms may include severe vomiting, diarrhea, and hepatomegaly with jaundice

Refer to ED right away

Question 20

Hypothyroidism

Answer 20

High TSH, low T3/T4

Question 21

Hashimoto Thyroiditis

Answer 21

Autoimmune form of hypothyroid
Presence of antithyroid antibodies

Goiter may be present

Question 22

Hypothyroid Presentation

Answer 22

Low metabolism effects
Fatigue
Cold intolerance
Weight gain
Puffiness of skin, hands
Dry and brittle skin/hair
Muscle aches
Slow mentation

Question 23

Subclinical Hypothyroid

Answer 23

Elevated TSH

Normal T4

Question 24

Hypothyroid Treatment

Answer 24

Levothyroxine orally dosed to return TSH to normal
Usually 1.7 mcg/kg/day

Often start with 25-50 mcg per day (12.5 - 25 mcg for older adults)
Increase at 4-6 week intervals to get desired TSH level
MAX DOSE 100 MCG PER DAY

Question 25

Hypothyroid Treatment Monitoring

Answer 25

Once desired TSH level achieved, monitor levels at least annually (every 6 months best)

If estrogen therapy is started or stopped, re-check TSH in 12 weeks

Question 26

Subclinical Hypothyroid treatment

Answer 26

Usually treatment is not started unless TSH is above 10

Decision to treat depends on presence of secondary symptom severity
Type 1 diabetics may need treatment
Patients having depression / fatigue may need treatment

Question 27

Myxedema Coma

Answer 27

Severe hypothyroid state
Respiratory depression, mental status changes

May be triggered by extreme stress, severe infection, substance that depresses CNS

Medical emergency, ED referral right away

Question 28

Drugs that Affect Thyroid

Answer 28

Amiodarone - can cause hypothyroidism, even years after stopping the med
Lithium - can cause hypothyroid or thyroiditis
Biotin - May cause false low TSH levels or false elevates T3/T4 levels

Question 29

Thyroid and Pregnancy

Answer 29

For hyperthyroid - PTU during first trimester, switch to methimazole after. Beta blockers to control symptoms until thiomaides work. Monitor fetal growth.

For Hypothyroid - Increase levothyroxine dose by 30% right away (can exceed 100mcg laily limit). Monitor thyroid levels, fetal growth. After delivery, return to pre-pregnancy doses and check levels in 6 weeks.