This document discusses thyroid health and various thyroid conditions. It begins by describing the anatomy and function of the thyroid gland. It then discusses hypothyroidism (underactive thyroid), including causes, symptoms, diagnosis and treatment with levothyroxine replacement. Hyperthyroidism (overactive thyroid) is also covered, including causes, symptoms, diagnosis using labs and imaging, and treatment options. Goiter and thyroid nodules are briefly described.

1. Thyroid Health
Jeffrey Bauman, MD FACE ECNU
Chair, Department of Endocrinology
January 24, 2018

2. Outline
• What is the thyroid and what does it do?
• Hypothyroidism (underactive): diagnosis
and treatment
• Hyperthyroidism (overactive): diagnosis
and treatment
• Thyroid nodules
• Questions

3. • Butterfly-shaped gland
• Right and Left lobes with connecting Isthmus in center
• Parathyroids - nothing to do with thyroid
Anatomy

4. Thyroid Function
• Essential for life
• Produces hormones
• thyroxine (T4) - majority
• triiodothyronine (T3) - minority
• calcitonin - unclear clinical significance in
humans
• Thyroid hormone release controlled by pituitary

6. Iodine
• Iodine is necessary ingredient to make
thyroid hormone
• Not made by the body so we rely on our diet
• Iodine deficiency most common cause of
underactive thyroid and “goiter” worldwide
• Salt iodization program starting in 1920’s has
mostly eliminated iodine deficiency in US
(and other 1st world countries)

7. Common Sources of Dietary Iodine
• Dairy (milk, cheese, yogurt, ice cream)
• Soy milk
• Eggs
• Fruits including strawberries, cranberries,
bananas, pineapple
• Vegetables including potatoes, green beans
• Seawater fish
• Some breads

8. Lab Evaluation of Thyroid Function
• TSH
• most reliable indicator of thyroid function
• Main screening test
• Free & Total T4
• Free & Total T3
• Thyroid antibodies (TPO most common)
• Common in healthy population

9. Hypothyroidism

10. Hypothyroidism: Causes
• Hashimotos (autoimmune) - most common in
US
• Surgery
• Radiation treatment
• Thyroiditis
• Medications (lithium, amiodarone)
• Iodine deficiency (most common worldwide)
• Pituitary disease (uncommon)
• Other (rare)

11. Symptoms of Hypothyroidism
• Fatigue
• Increased sensitivity to cold
• Constipation
• Dry skin
• Weight gain
• Puffy face
• Hoarseness
• Muscle weakness
• Elevated blood cholesterol
• Muscle aches
• Pain, stiffness or swelling
in your joints
• Heavier than normal or
irregular menstrual periods
• Thinning hair
• Slowed heart rate
• Depression
• Impaired memory

12. Hypothyroidism: Labs
TSH:
T4/T3: (can be normal)
TPO Antibodies:
– often positive in Hashimotos

13. Treatment of Hypothyroidism
• Levothyroxine/T4 (Synthroid, Levoxyl,
Tirosint)
• Liothyronine/T3 (Cytomel)
• T4/T3 combination (Armour,
NatureThyroid)

14. Thyroid Hormone Replacement
• Long half-life, level is stable
• Best absorbed on empty
stomach
• Allow time before
eating/drinking/vitamins/other
medications
• Be consistent

15. • Adherence to taking medication
• Interference with absorption
• Change in weight
• Pregnancy
• Estrogen treatment (birth
control)
• Changing thyroid function
Factors That Affect Level

16. Hyperthyroidism

17. Hyperthyroidism: Causes
• Graves (autoimmune) – most common
• Hyperfunctioning nodules (toxic nodules)
• Temporary thyroiditis
• Medications (amiodarone)

18. Hyperthyroidism: Labs
TSH:
T4/T3: (can be normal)
Antibodies: often positive in Graves
Sed Rate (ESR): often elevated in temporary
thyroiditis

19. Hyperthyroidism: Imaging
Thyroid Ultrasound
• noninvasive, no radiation
• general appearance of gland
• identifies thyroid nodules
Thyroid Uptake/Scan
• assesses how much iodine taken up
by thyroid and in the pattern

20. Thyroid Uptake/Scan

21. Hyperthyroidism: Treatment
1. Reduce thyroid hormone production
(methimazole, PTU)
2. Radioactive iodine (RAI)
3. Surgery

22. Goiter

23. Goiter
• Enlargement of thyroid
• Independent of function:
• can be hypo, hyper, or normal
• If very large, can cause obstructive
symptoms

24. Causes of Goiter
• Iodine deficiency
• Hashimoto’s
• Graves’
• Nodules
• Medications

25. Thyroid Nodules
• Very common
• Often incidental on non-thyroid imaging
• Thyroid Ultrasound - best test
• Growth of thyroid cells forming a lump
within the thyroid gland
• Majority are benign
• Thyroid cancers are usually curable

26. Fine Needle Aspiration/Biopsy
• Safe and simple procedure
• Often done in office
• Ultrasound guidance to ensure correct
placement of needle when sampling
• Small needle - thinner than lab draw
• Minimal discomfort