Hyperthyroidism

Question 1

Clinical Features

Answer 1

General: Heat intolerance, Weight loss
HEENT: lid lag, proptosis, periorbital edema, hair loss, goiter, thyroid tenderness, nodularity, bruit
CVS: Palpitations/ tachycardia/ atrial fibrillation, Widened pulse pressure, HTN
MSK: Muscular weakness
Neuro: tremor
GU: amenorrhea

Question 2

Risk Factors

Answer 2

F>M
PMHx: Diffuse / Nodular goiter, Type 1 DM, Autoimmune Disorder
FMHx: Thyroid Disorder
Meds: Amiodarone, Lithium, Iodide
Post partum
Radiation

Question 3

Differential Diagnosis (low TSH)

Answer 3

Treatment Induced (Amiodarone, Iodine)
Graves (60-80%)
Thyroiditis
Toxic Multinodular Goiter / Toxic Adenoma
Tumor (metastatic thyroid CA, ovaria tumor, pituitary adenoma, trophoblastic)
Exogenous

Question 4

Screening Indications

Answer 4

NO evidence for screening unless high risk OR symptomatic patients

Question 5

Initial Investigations

Answer 5

TSH
TSH low (<0.2mU/L) - Possible Primary Hyperthyroidism
Free T4 to determine degree of hyperthyroidism
Baseline CBC, LFTs

Question 6

Indications for a Thyrotropin receptor antibodies (TRAb)

Answer 6

If no obvious cause (eg. Graves - new ophthalmopathy, goiter)

Question 7

Indication for Radioactive iodine uptake, contraindications

Answer 7

Radioactive iodine uptake if ↓TSH + ↑T4
(contraindicated in pregnant/breastfeeding)

Question 8

Indication of MRI

Answer 8

↑TSH + ↑free T4

Question 9

First Line TREATMENT FOR PRIMARY HYPERTHYROIDISM . Considerations for each medication

Answer 9

Beta-blockers (for symptom control)
Propanolol, Atenolol
Caution in elderly, COPD, asthma

Thionamides: Methimazole - MMI
Mild hyperthyroidism, can start MMI at 5-120 mg PO daily
WBC (ANC) and LFT prior to starting MMI

Question 10

Second line treatment

Answer 10

Propylthiouracil – PTU

Question 11

Treatment for Thyroiditis

Answer 11

NSAIDs, steroids
Beta-blockers for symptomatic treatment

Question 12

Treatment for Toxic adenoma/multinodular goiter

Answer 12

Radioiodine
Subtotal thyroidectomy
May consider thionamide initially for short-term
Beta-blockers for symptomatic treatment

Question 13

Clinical features of a thyroid storm

Answer 13

Hyperthermia, tachycardia, CNS Agitation / Delirium, CHF, N/V/D, dehydration, coma

Question 14

Labs on thyroid storm

Answer 14

↓TSH↓Hgb↑fT4↑WBC↑Glucose↑Calcium↑LFTs

Question 15

Treatment of Thyroid Storm

Answer 15

B-Blockers (Propranolol 60-80mg q4-6h)
Methimazole 60-120 mg
Potassium Iodide 5 drops
High-dose IV hydrocortisone 100mg IV q8h
Fluids, 02, cooling
Consider Cholesyramine (bile acid sequestrant)

Question 16

What kind of medication is Methimazole and how does it work

Answer 16

Thionamide works by blocking synthesis

Question 17

How does Propranolol work for hyperthyoidism

Answer 17

Treats symptoms but also blocks converstion of T3-T4

Question 18

How does Iodine work for hyperthyroid

Answer 18

Blocks release

Question 19

Why don’t we screen everyone with a TSH since it’s so often abnormal?

Answer 19

Because treating subclinic thyroid has no benefits on QOL, symptoms, CV events, or mortality

Question 20

When should you do a RAIU scan for a Thyroid Nodule

Answer 20

Hyperthyroid on labs

Question 21

When do you biopsy a thyroid nodule and how

Answer 21

Ultrasound guided FNA if;
Irregular border
>1cm
Calcifications
Taller compared to wide

Question 22

So you find someone to be hyperthyroid on labs. What do you do

Answer 22

1. Treat them symptomatically
2. Get Thyrotropin Receptor antibodies
3. Get and RAIU (unless preggo or breast feeding)

Question 23

What to do if you have a thyroid nodule

Answer 23

1. Ultrasound
2. Order TSH-if Hyper get RAIU