Thyroid

Question 1

Preferred routine lab pair to assess thyroid status?

Answer 1

TSH and free T4.

Question 2

Primary vs secondary vs tertiary thyroid dysfunction?

Answer 2

Primary: thyroid gland; Secondary: pituitary; Tertiary: hypothalamus.

Question 3

Name key metabolic effects of thyroid hormones.

Answer 3

↑ Basal metabolic rate, protein synthesis, mitochondria, ATP, Na/K+ pump activity.

Question 4

Systems affected by thyroid hormones?

Answer 4

Cardiac output, respiration, GI motility, sleep, mood/cognition, muscle tone, weight, sexual/menstrual function.

Question 5

Most common cause of hypothyroidism in iodine‑sufficient regions?

Answer 5

Hashimoto’s thyroiditis (autoimmune).

Question 6

Medications that can cause or affect hypothyroidism?

Answer 6

Lithium, amiodarone, thioamides; interferon; iodine excess.

Question 7

Pathology hallmark of Hashimoto’s?

Answer 7

Autoimmune lymphocytic infiltration; anti‑TPO and antithyroglobulin antibodies common.

Question 8

Compensatory change when T4 is low?

Answer 8

Goiter from ↑ TSH; increased peripheral conversion of T4→T3.

Question 9

Metabolic downstream effects of hypothyroidism?

Answer 9

↓ Metabolic rate; ↑ total & LDL cholesterol; ↑ triglycerides; slowed GI transit.

Question 10

Fluid change in long‑standing hypothyroidism?

Answer 10

Myxedema (hydrophilic proteoglycan accumulation).

Question 11

Classic hypothyroid symptoms (subjective)?

Answer 11

Fatigue, dry skin, weight gain, cold intolerance, constipation, heavy menses.

Question 12

Objective signs in hypothyroidism?

Answer 12

Bradycardia, periorbital edema, dry thick skin, brittle nails, slow/hoarse speech, diastolic HTN.

Question 13

Hypothyroidism in older adults—presentation?

Answer 13

Often atypical or muted; cold intolerance, fatigue, cognitive decline, and depression. may be asymptomatic; lab testing necessary.

Question 14

When should older adults be screened for thyroid disease?

Answer 14

With decline in clinical/cognitive/functional status; at nursing home admission.

Question 15

Lab pattern in primary hypothyroidism?

Answer 15

↑ TSH, ↓ free T4.

Question 16

Lab pattern in central (secondary/tertiary) hypothyroidism?

Answer 16

Low/normal/mildly ↑ TSH with ↓ free T4; low T3.

Question 17

Define subclinical hypothyroidism (labs).

Answer 17

Mildly ↑ TSH with normal free T4.

Question 18

Medications that affect TSH measurement?

Answer 18

Metoclopramide ↑TSH; dopamine, glucocorticoids, NSAIDs, somatostatin ↓TSH.

Question 19

Other agents altering thyroid tests?

Answer 19

Dilantin, amiodarone, lithium; nicotine can affect TFTs.

Question 20

Initial dosing strategy for levothyroxine?

Answer 20

Start low (e.g., 12.5–25–50 mcg/day) and titrate q6–8 weeks; mean full replacement ~1.6 mcg/kg/day.

Question 21

Special dosing caution in severe cardiac disease?

Answer 21

Begin even lower (e.g., 12.5 mcg/day).

Question 22

Time to steady state after dose change?

Answer 22

6–8 weeks; recheck TSH no sooner.

Question 23

Pregnancy and levothyroxine dosing?

Answer 23

Increase dose ~30% when pregnancy confirmed; follow free T4; revert postpartum and recheck TSH at ~8 weeks.

Question 24

Untreated hypothyroidism in pregnancy risks?

Answer 24

Maternal HTN, preeclampsia, anemia, PPH (post partum hemorrhage), cardiac issues; fetal loss, low birth weight.

Question 25

Subclinical hypothyroidism—when to treat?

Answer 25

Consider if +antibodies, CAD/HF, or symptoms; older adults often observe unless TSH persistently >10 mIU/L.

Question 26

Most common cause of hyperthyroidism?

Answer 26

Graves disease (autoimmune TSH‑receptor antibodies).

Question 27

Other causes of hyperthyroidism?

Answer 27

Toxic multinodular goiter, toxic adenoma, subacute thyroiditis, excess thyroid hormone ingestion, iodine excess, rare TSH‑secreting pituitary tumor.

Question 28

Younger vs older presentation differences in Hyperthyroid?

Answer 28

Younger: tremor/anxiety; Older: more CV symptoms (AF, dyspnea), weight loss; 'apathetic' hyperthyroidism possible.

Question 29

Graves ophthalmopathy features?

Answer 29

Periorbital edema, conjunctival injection, proptosis, lid lag, diplopia.

Question 30

Subacute (de Quervain) thyroiditis hallmark?

Answer 30

Acute painful, firm thyroid after viral illness. Pain may radiate to the jaw, upper chest, neck and throat. Presents with systemic flu-like systems, markedly elevated ESR and CRP; release of preformed hormone; low radioiodine uptake. Acute hyperthyroid

Question 31

Medications that alter thyroid binding/tests?

Answer 31

Anabolic steroids, estrogens, heparin, iodine compounds, phenytoin, rifampin, salicylates.

Question 32

Symptom control for tremor/palpitations associated with hyperthyroid?

Answer 32

Beta‑blockers (avoid in COPD/bronchospasm/HF; consider CCB).

Question 33

First‑line treatment for Hyperthyroid in many US adults?

Answer 33

I‑131 ablation → hypothyroid → lifelong levothyroxine. CAN be first line, but antithyroid drugs (methimazole or propylthiouracil), or thyroidectomy are also common.

Question 34

Which antithyroid drug preferred in pregnancy?

Answer 34

PTU- Propylthiouracil (crosses placenta; dose can often be reduced/ceased before delivery) BUT associated with less birth defects than MMI- Methimazole

Question 35

Subacute thyroiditis treatment?

Answer 35

Beta‑blockers and NSAIDs; corticosteroids if moderate‑severe or refractory.

Question 36

Thyroid storm—what to do?

Answer 36

Medical emergency; inpatient management per protocols (slides refer to text).

Question 37

Thyroid storm—symptoms?

Answer 37

High fever (>103), confusion/delirium/psychosis, extreme agitation/restlessness, profuse diaphoresis, severe weakness

Question 38

Why does amiodarone affect thyroid?

Answer 38

37% iodine by weight; alters synthesis/metabolism.

Question 39

Is RAI (radioactive iodine) useful in amiodarone hyperthyroidism?

Answer 39

Not typically (low uptake).

Question 40

When to order thyroid ultrasonography?

Answer 40

Hx radiation, MEN2, FH of thyroid cancer; unexplained lymphadenopathy; select nodules for biopsy; guide FNA; incidental nodules on CT/MRI/PET.

Question 41

How are functioning nodules usually classified?

Answer 41

Hot (functioning) and rarely malignant.

Question 42

What does a nonfunctioning ('cold') nodule imply?

Answer 42

Needs FNA to exclude malignancy.

Question 43

General size threshold for nodule evaluation?

Answer 43

>1 cm typically requires evaluation for malignancy.

Question 44

Most common thyroid cancer type?

Answer 44

Papillary (~60%).

Question 45

Major risk factor for thyroid cancer?

Answer 45

Ionizing radiation (head/neck).

Question 46

Key complication post‑thyroidectomy?

Answer 46

Hypocalcemia from parathyroid removal/damage.