Sandbox:ddx graves

Suspected Graves' disease

Measure serum TSH and free T4

Normal TSH & free T4

↓ TSH & ↑ free T4

↓ TSH & Normal free T4

Normal or ↑ TSH & ↑ free T4

Hyperthyroidism ruled out

Hyperthyrodism

Measure free T3

TSH secreting pituitary tumor, Thyroid hormone resistance or Assay interference

Measure TSH receptor antibodies

↑ free T3

Normal free T3

Present

Absent

T3 Toxicosis

Sub-clinical Hyperthyrodism

Graves' Disease

Assess radioiodine uptake obtain radionuclide scan or both

Evolving Graves' disease Evolving toxic nodular goiter Excess thyroid hormone intake Non thyroidal illness

Homogeneous increased uptake

Patchy uptake or single nodule

Low or no uptake

Graves' disease

Toxic nodular goiter

Subacute thyroiditis Excess thyroid hormone intake HCG secreting tumor

Cause of thyrotoxicosis	TSH receptor Antibodies	Thyroid US	Color flow Doppler	Radioactive iodine uptake/Scan	Other features
Graves' disease	Present	Hypoechoic pattern	↑	↑	Ophthalmopathy, dermopathy, acropachy
Toxic nodular goiter	Absent	Multiple nodules	-	Hot nodules at thyroid scan	-
Toxic adenoma	Absent	Single nodule	-	Hot nodule	-
Subacute thyroiditis	Absent	Heterogeneous hypoechoic areas	Reduced/absent flow	↓	Neck pain-fever and elevated inflammatory index
Painless thyroiditis	Absent	Hypoechoic pattern	Reduced/absent flow	↓	-
Amiodarone induced thyroiditis-Type 1	Absent	Diffuse or nodular goiter	↓/Normal/↑	↓ but higher than in Type 2	High urinary iodine
Amiodarone induced thyroiditis-Type 2	Absent	Normal	Absent	↓/absent	High urinary iodine
Central hyperthyroidism	Absent	Diffuse or nodular goiter	Normal/↑	↑	Inappropriately normal or high TSH
Trophoblastic disease	Absent	Diffuse or nodular goiter	Normal/↑	↑	-
Factitious thyrotoxicosis	Absent	Variable	Reduced/absent flow	↓	↓ serum thyroglobulin
Struma ovarii	Absent	Variable	Reduced/absent flow	↓	Abdominal RAIU

Severity	Therapy	Mechanism	Advantages/disadvantages	Common Doses
Mild active disease	Topical solutions Artificial tears Glucocorticoids Avoidance of wind, light, dust, smoke Elevation of head during sleep Avoidance of eye cosmetics Selenium	Maintain tear film Reduce inflammation Reduces ocular surface desiccation, reduces irritation Reduces orbital congestion Reduces irritation Uncertain	Rapid action, minimal side effects Rapid action, minimal side effects Benefits not yet confirmed Benefits not yet confirmed
Moderate or severe active disease	Systemic glucocorticoids Oral Intravenous	Reduce inflammation and orbital congestion Reduce inflammation and orbital congestion	Hyperglycemia, hypertension, osteoporosis Rapid onset of anti-inflammatory effect, fewer side, liver damage	Up to 100 mg of oral prednisone daily, followed by tapering of the dose Methylprednisolone, 500 mg/wk for 6 wk followed by 250 mg/wk for 6 wk
	Orbital irradiation	Reduces inflammation	Can induce retinopathy	2 Gy daily for 2 wk (20 Gy total)
	B-cell depletion	Reduces autoreactive B cells	Very expensive; risks of infection, cancer, allergic reaction	Two 1000-mg doses of intravenous rituximab 2 wk apart
	Emergency orbital decompression	Reduces orbital volume
Stable disease (inactive)	Orbital decompression (fat removal)	Reduces orbital volume	Postoperative diplopia, pain
	Bony decompression of the lateral and medial walls	Reduces proptosis by enlarging orbital space	Postoperative diplopia, pain, sinus bleeding, cerebrospinal fluid leak
	Strabismus repair	Improves eye alignment, reduces diplopia
	Eyelid repair	Improves appearance, reduces lagophthalmos and improves function