Fayetteville VA Medical Center Grand Rounds
January 16, 2015
Fayetteville, NC
Thyroid Update
Stanley A. Tan
MD, MS, MPH, PhD, DTM&H, FACE, FACC, FCCP
Disclosure Statement
• Nothing to disclose
Objectives
• After this grand rounds presentation, you
should be able to:
– 1. Diagnose and manage hypothyroidism &
hyperthyroidism
– 2. Evaluate and manage thyroid nodule(s) and
goiters
– 3. Describe and manage thyroid cancers
Thyroid Anatomy
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Largest endocrine organ in body—20 g
Right and left lobes
Isthmus
Pyramidal lobe
Goiter = enlargement of thyroid
– Diffuse
– Nodular
Thyroid Physiology
• Iodide + tyrosine
– MIT & DIT
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MIT + DIT = T3
2 DIT = T4
Thyroglobulin – storage
Thyroid binding globulin – circulation
Deiodinase
– T4  T3
Thyroid Physiology
• Hypothalamic-Pituitary-Thyroid Axis
– TRH (stimulates TSH & Prolactin)
– TSH
– T4 & T3 – Negative feedback
• Thyroid C-cell
– Calcitonin
– Thyroid Medullary Carcinoma (MEN type II)
Thyroid Diagnostic Evaluation
• TSH
• Free T4
– Old tests: T4, T3 uptake, FTI
• T3—Total & Free T3
• Thyroid Peroxidase Antibody
– Old test: Anti (thyroid) microsomal antibody
• Thyroglobulin Antibody
• Thyroglobulin
Thyroid Imaging
• Thyroid Ultrasound Scan
– Anatomical
• RAI Thyroid Uptake & Scan
– Physiologic & Anatomical
– Uptake
• High: Graves’, Hashimoto Thyroiditis, Plummer’s
• Low: Hypothyroidism, exogenous thyroid or iodine, Subacute
Thyroiditis
– Scan
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Graves—Diffuse
Hashimoto—Diffuse or patchy
Plummer’s—Multi hot nodules
Cold nodule—1-5 % malignancy
FNA Thyroid Biopsy
• Solitary Nodule
• “Cold” nodule
– If negative, observe; repeat ultrasound scan 6
mo, rebiopsy if larger; continue observe if
stable
– If indeterminate, thyroid suppression;
ultrasound 6 mo later, rebiopsy if larger or not
shrinking
Hypothyroidism
• Symptoms
– Weight gain, tired, sleepy, cold intolerance,
constipation
• Signs
– Myxedema facie, dry skin, scalp hair loss,
brittle nail, periorbital edema, decreased DTR
– Goiter
• Hashimoto thyroiditis, adenomatous
• No goiter: Idiopathic Primary Hypothyroidism
Hypothyroidism
• Diagnostic Studies
– TSH, Free T4, Thyroid Peroxidase Antibody
– Thyroid Ultrasound Scan
• Therapy
– Levothyroxine
– Dessicated Thyroid
– Liothyronine
Hyperthyroidism
• Graves
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Graves opthalmopathy
Goiter
Hyperthyroidism
Thyroid Stimulating Immunoglobulin (TSI)
• Hashimoto Thyrotoxicosis
– Thyroid Peroxidase Antibody
• Plummer’s Disease
– Hyperthyroid Multinodular Goiter
Hyperthyroidism
• Subacute Thyroiditis
– Painful Goiter
– Elevated Sed Rate
– Decreased RAI Thyroid Uptake
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Acute Suppurative Thyroiditis
Struma Ovarii
Exogenous thyroid
Secondary—TSH producing pituitary tumor
Goiter
• Diffuse
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Hashimoto Thyroiditis
Graves’ Disease
Subacute Thyroiditis
Postpartum, Silent, Painless Thyroiditis
Adenomatous Goiter
• Multinodular
– Plummer’s Disease
– Adenomatous Multinodular Goiter
• Solitary Nodule
Evaluation of Thyroid Nodule
• FNA Thyroid Biopsy
– Solitary Nodule
– Dominant Nodule in a Multinodular Goiter
– “Cold” Nodule
• If benign, observe, repeat ultrasound scan in
6 mo
• If indeterminate, suppress, repeat scan,
rebiopsy if not shrinking or enlarging
Thyroiditis
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Hashimoto Thyroiditis
Subacute Thyroiditis
Postpartum, Silent, or Painless Thyroiditis
Acute Infectious Thyroiditis
Riedel’s thyroiditis
Hashimoto Thyroiditis
• Chronic lymphocytic thyroiditis
• Associated Polyglandular auto-immune
disease (Schmidt’s Syndrome)
• Thyroid Peroxidase Antibody
• Transient hyperthyroidism (Hashimoto
Thyrotoxicosis), euthyroidism, then
hypothyroidism
Thyroid Cancer
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Thyroid Papillary Carcinoma
Thyroid Follicular Carcinoma
Thyroid Medullary Carcinoma
Undifferentiated Thyroid Carcinoma
Lymphoma
Thyroid Carcinoma
• Thyroidectomy
• High dose I-131 radiation therapy
• Synthroid suppression
– Non-detectable TSH
• Yearly Thyroglobulin level
• RAI Total Body Scan
– Year anniversary
– Thyrogen stimulated
Thyroid Carcinoma
• Thyroid Papillary Carcinoma
– Local lymph node invasion
• Thyroid Follicular Carcinoma
– May be mixed with papillary
– May be T4 producing—can cause
hyperthyroidism with metastases
– Hematogenous metastases to bone
Thyroid Medullary Carcinoma
• Thyroid C-Cells
• Calcitonin
• MEN Type II
– Sipple Syndrome
– Pheochromocytoma, Thyroid Medullary
Carcinoma, Parathyroid Adenoma
– Autosomal Dominant
• Surgery