Evaluation and Treatment of Thyroid Problems in Young People

Ali A. Rizvi, MD

Department of Medicine

University of South Carolina

School of Medicine

A 23-year-old female presents with fatigue, mild weight gain, and cold intolerance of 6 months’ duration. She has a mildly enlarged and palpable thyroid gland. Lab tests: TSH 36, free T4 0.56, T3 185.

The most likely diagnosis is…A. Hashimoto’s thyroiditisB. Transient hypothyroidismC. Endemic goiterD. Subacute thyroiditis

What is the next step in management?A. Thyroid Peroxidase antibodies B. Thyroid Ultrasound (with Color Flow Doppler)C. Thyroid Technetium-99 scanD. Thyroid I-123 uptakeE. Treat with levothyroxine 100 mcg daily

Laboratory testing for thyroid disease

• Titrate using the sensitive TSH level to maintain a euthyroid state

• Retest and adjust dose 4-6 weeks after any change in brand or dose

• A small adjustment of LT4 causes much greater changes in TSH levels

Levothyroxine Therapy:Narrow Therapeutic Index!

Dosing Chart

Levothyroxine Therapy

Levothyroxine Tablets•Pick a brand and stick to it!

•Generics can have variable bioavailability…

•IF switching from brand to brand, brand to generic, etc., retest in 4-6

weeks

•Take at least an hour before or 2 hours after eating

• Food may decrease absorption of LT4 in the GI tract

• Drugs that can impair LT4 absorption:

- Iron preparations

- Antacids

- Lipid-lowering medications

- Calcium carbonate

- Soy products may bind to LT4

- Estrogens and estrogen-containing compounds may inhibit levothyroxine function

Levothyroxine Therapy

A 19-year-old student presents with difficulty sleeping, and palpitations, and anxiety. Her mother had thyroidectomy for “a big thyroid that was overactive”. Several other family members have thyroid disease. She has a mildly enlarged and palpable thyroid gland, bilateral exophthalmos, tachycardia, and hyperreflexia. Lab tests: TSH < 0.001, free T4 >6, T3 928.

The most likely diagnosis is…A. Early Hashimoto’s thyroiditis (“Hashitoxicosis”)B. Graves diseaseC. Toxic multinodular goiterD. Subacute thyroiditis

What is the next step in management?A. Thyroid Peroxidase antibodies B. Thyroid Ultrasound (with Color Flow Doppler)C. Thyroid Technetium-99 scanD. Thyroid I-123 uptakeE. Treat with methimazole or PTU

Graves Disease

• An autoimmune, multisystem disorder

• More common in women, family history present

• TSH is usually undetectable, T4 and T3 elevated, TRAB or TSI high

• Elevated uptake (>40%) and diffuse homogeneous increased activity on scan

• Symptomatic Rx: beta blockers

• Definitive Rx: antithyroid drugs, radioactive iodine ablation

A 25-year-old man presents with difficulty sleeping. He has a mildly enlarged and palpable thyroid gland. Lab tests: TSH 0.001, Free T4 2.8, T3 475.

The most likely diagnosis is…A. Early Hashimoto’s thyroiditis (“Hashitoxicosis”)B. Graves diseaseC. Toxic multinodular goiterD. Painless sporadic thyroiditisE. Subacute thyroiditis

What is the next step in management?A. Thyroid Peroxidase antibodies B. Thyroid Ultrasound (with Color Flow Doppler)C. Thyroid Technetium-99 scanD. Thyroid I-123 uptakeE. Treat with methimazole or PTUF. Treat with propranolol 20 mg q 6 hrs

Thyroid Scan and Uptake

• Scan is a picture (using I-123 or Tc-99), uptake is a percent number

• Can be ordered separately!

• Both evaluate thyroid function, not structure or anatomy

A 48-year-old female presents with difficulty sleeping, tremor, anxiety, and history of a recent upper respiratory tract infection. She has a palpable, mildly tender thyroid gland. Lab tests: TSH 0.001, Free T4 2.8, T3 475.

The most likely diagnosis is…A. Early Hashimoto’s thyroiditis (“Hashitoxicosis”)B. Graves diseaseC. Toxic multinodular goiterD. Subacute thyroiditisE. Painless sporadic thyroiditis

What is the next step in management?A. Thyroid Peroxidase antibodies B. Thyroid Ultrasound C. Thyroid Technetium-99 scanD. Thyroid I-123 uptakeE. Treat with methimazole or PTUF. Treat with propranolol 20 mg q 6 hrs

A 39-year-old female, 10 weeks postpartum, presents with tiredness, difficulty sleeping, irritability, and crying spells. She has a mildly enlarged and palpable thyroid gland. Lab tests: TSH 0.001 (0.5-4.5), Free T4 2.8 (0.9-1.8), T3 475 (150-205).

The most likely diagnosis is…A. Hashimoto’s thyroiditisB. Transient hypothyroidismC. Endemic goiterD. Subacute thyroiditisE. Painless postpartum thyroiditis

What is the next step in management?A. Thyroid Ultrasound (with Color Flow Doppler)B. Thyroid Technetium-99 scanC. Thyroid I-123 uptakeD. Treat with methimazole or PTU E. Treat with propranolol 20 mg q 6 hrs

A 39-year-old female, 10 weeks postpartum, presents with tiredness, difficulty sleeping, irritability, and crying spells. She has a mildly enlarged and palpable thyroid gland. Lab tests: TSH 23 (0.5-4.5), free T4 0.71 (0.9-1.8).

The most likely diagnosis is…A. Hashimoto’s thyroiditisB. Transient hypothyroidismC. Endemic goiterD. Subacute thyroiditisE. Painless postpartum thyroiditis

What is the next step in management?A. Thyroid Peroxidase antibodies B. Thyroid Ultrasound (with Color Flow Doppler)C. Thyroid Technetium-99 scanD. Thyroid I-123 uptakeE. Treat with levothyroxine

Inflammation of the Thyroid Gland: Thyroiditis Terminology

Painless Postpartum Thyroiditis

• Thyrotoxicosis 1-6 months after delivery followed by hypothyroid phase lasting 4-6 months

• 20% may remain hypothyroid

• High antibodies, normal ESR

• Low 24-hour uptake (distinguishing it from postpartum Graves)

• May need treatment with beta-blockers or levothyroxine

• Continued f/u, increased risk of future hypothyroidism

Painless Sporadic Thyroiditis

• Similar to postpartum thyroiditis

• 1% of all cases of thyrotoxicosis

• Mild symptoms, small, firm, diffuse goiter

• 24-hour uptake should be performed when the cause of thyrotoxicosis is unclear

Painful Subacute Thyroiditis

• A self-limited inflammatory disorder, commonest cause of thyroid pain

• Probable viral cause, usually follows an URI

• Myalgias, fatigue, pharyngitis, fever, neck pain, swelling, palpitations

• Increased TFTs, elevated ESR, low uptake

• Treatment for symptomatic relief: NSAIDs, beta blockers, glucocorticoids

Clinical Course of Painful Subacute Thyroiditis, Painless Postpartum Thyroiditis, and Painless Sporadic Thyroiditis

TSH, T4 and iodine-123 uptake show thyrotoxicosis during the first three

months, followed by hypothyroidism for three months and then by euthyroidism

A 19-year-old freshman presents with mild fatigue, occasional palpitations, and insomnia. The thyroid gland is not enlarged or tender. Meds: steroid nasal spray once a day, Zyrtec 10 mg daily, and Alesse-28 (BCP).Lab tests: TSH 2.8 (0.5-4.5), total T4 17.3 (5-12), total T3 275 (150-205) .

The most likely thyroid problem is…A. Graves diseaseB. Toxic multinodular goiterC. Euthyroid hyperthyroxinemiaD. Subacute thyroiditisE. Painless sporadic thyroiditis

What is the next step in management?A. Reassurance B. Free T4 and free T3 levels C. Thyroid Technetium-99 scanD. Thyroid I-123 uptakeE. Treat with methimazole or PTUF. Treat with propranolol 20 mg q 6 hrs

Euthyroid Hyperthyroxinemia

• Pregnancy• Estrogens• Hereditary increase in thyroxine-binding globulin

(TBG) or pre-albumin (TBPA), or mutant albumin with high affinity

• Rare thyroid hormone resistance states• Total T4 and/or T3 may be elevated• TSH and free T4/T3 are normal• Patients are asymptomatic• Explanation and reassurance

Pregnancy and the Thyroid• In diagnosed hypothyroidism, adjust T4 dose to reach a TSH level not

higher than 2.5 µU/ml before pregnancy • In hypothyroidism diagnosed during pregnancy: TFTs should be normalized

as rapidly as possible. The T4 dosage should be titrated (may require a 30–50% increase) to rapidly reach and maintain serum TSH less than 2.5 in the first trimester or 3 µU/ml in the second and third trimesters)

• After delivery, most hypothyroid women need a decrease in the T4 dosage they received during pregnancy

• Start T4 replacement in subclinical hypothyroidism; target TSH 2.5• Overt hyperthyroidism: treat with PTU to keep T4 in upper normal range,

do not have to normalize TSH• No evidence that treatment of subclinical hyperthyroidism improves

pregnancy outcome • Thyroid function tests should be measured in all patients with

hyperemesis gravidarum; few will have concurrent thyroid disease requiring treatment

Subclinical Hypothyroidism

• Elevated TSH with normal T4 and T3

• Treat if planning pregnancy, pregnant, or TSH above 10, or symptomatic

• Routine treatment not recommended for TSH 4.5 – 10 (?if positive peroxidase antibodies)

• Follow at 6-12 monthly intervals

Subclinical Hyperthyroidism

• Suppressed or undetectable TSH, normal T4 and T3

• Increased long-term risk of tachyarrythmias, bone loss, and neuropsychiatric problems (esp. if TSH <0.1)

• 2 categories: mildly low but detectable TSH (0.1-0.45) can be followed and retested at 3-6 months if asymptomatic and no cardiac disease, Afib, or arrythmias

• Clearly low TSH (<0.1): thyroid uptake and scan (Graves or toxic goiter vs. thyroiditis), treat cause

You discover an approx. 1.5 cm nodule upon thyroid

palpation in a 37-year old patient. She feels fine.

What is the next step in management?

A. Reassurance and follow-up in 6 months

B. TSH level

C. Thyroid ultrasound

D. Thyroid scan and uptake

E. Fine-needle aspiration biopsy

• Record and follow the size, volume and physical characteristics of nodule or goiter accurately and objectively

• Real-time office imaging: quick, painless, safe

• Not a definitive test for benign vs. malignant

• Ultrasound-guided FNA Biopsy

• Doppler with color flow

Uses of Thyroid Ultrasound:Evaluation of thyroid structure

Think of it as an extension of your physical examination

When would you obtain the following tests?1. Thyroid Peroxidase antibodies

2. Thyroid Ultrasound

3. Thyroid Scan

4. Thyroid I-123 uptake

5. None of the above….

Think first…do not adopt a shotgun approach!

Increases patient anxiety, unnecessary wait time, cost,

findings that are superfluous and will not change management….

sometimes less is more