1. Subacute Thyroiditis And Related Disorders
Richard M. Jordan, MD, Regional Dean,
School of Medicine
Texas Tech Health Sciences Center at Amarillo

2. Dr. Smith’s Backyard

3. Subacute Thyroiditis And Related Disorders Definitions
Subacute Thyroiditis – (DeQuervain’s Thyroiditis, Granulomatous Thyroiditis, Giant Cell Thyroiditis) A Post Viral Syndrome with Thyroid Pain
Painless Thyroiditis – (Subacute Lymphocytic Thyroiditis, Silent Thyroiditis) Probable Variant of Autoimmune (Hashimoto’s) Thyroiditis. Excludes Women with Painless Thyroiditis Occurring within 1 Year of Delivery.
Postpartum Thyroiditis – Probable Variant of Autoimmune Thyroiditis, Similar to Painless Thyroiditis But Occurring Postpartum.
Drug Induced Thyroiditis – Amiodarone, Lithium, Interleukin- 2, Denileukin Diffitoxin,
Radiation Induced – Occurs Post Radioactive Iodine Treatment

4. Subacute Thyroiditis
Preceding Viral Infection with Sore Throat, Fever, Myalgias
May occur in Clusters
Damage to the Thyroid Follicles with Release of Thyroid Hormone
Goiter with Neck Pain – Can Radiate to Jaw or Ear
Elevated Sedimentation Rate, Elevated Thyroglubulin
Triphasic Course – Hyperthyroidism to Hypothyroidism to Euthyroidism
Permanent Hypothyroidism may develop in 10-15%

5. Normal Histology of the Thyroid

6. Subacute Thyroiditis (DeQuervain’s, Granulomatuous
Acute viral infection
Presents with viral prodrome, thyroid tenderness, and hyperthyroid symptoms
Pathology
Disruption and Collapse of the Thyroid Follicles
Infiltration with Inflammatory Cells
Neutrophils
Lymphocytes
Histiocytes
Multinucleated “Giant” Cells

8. Subacute Thyroiditis
Suppressed Radioactive Iodine Update in Hyperthyroid Phase
Sedimentation Rate approximately > 50 mm/h
Treatment – NSAIDS or Steroids, Beta Blocker
in Hyperthyroid Phase

9. Painless Thyroiditis
Probable Variant of Autoimmune (Hashimoto’s) Thyroiditis
Sedimentation Rate is Normal or Slightly Elevated
May have Elevated Antithyroid Peroxidase (TPO) Levels
Thyroglobulin Levels Are Elevated
Pathology-Lymphocytic Infiltration which Persists in Recovery
Clinical Course-Similar to Subacute Thyroiditis; Hyperthyroidism (Usually Mild) Followed by Recovery or Hypothyroidism
Permanent Hypothyroidism Develops in 20-50%

12. Treatment of Painless Thyroiditis
Hyperthyroidism-Mild may require no therapy. If Symptomatic give beta-bockers
Hypothyroidism-If Symptomatic or TSH>10mU/L give thyroid hormone replacement
Monitor for the development of hypothyroidism

13. Painless Thyroiditis vs Factitious Thyrotoxicosis
Painless Thyroiditis Factitious Thyrotoxicosis
Goiter Small Usually Absent
Thyroglobulin Elevated Undetectable
Occupation Not Specific Access to Thyroid Hormone

14. Post Partum Thyroiditis
Variant of Autoimmune (Hashimoto’s) Thyroiditis
Follows Delivery
Autoimmune Damage to the Follicles with Release of Thyroid Hormone
Painless with Small Goiter
Variable Triphasic Course
Suppressed Radio Iodine Uptake
Sedimentation Rate-<30 mm/h

15. Postpartum Thyroiditis
Prevalence
7 to 10 Percent of All Pregnancies
Most Common Variety of Hyperthyroidism Associated with
Pregnancy
Risk Factors
Elevated TPO Antibodies – 50% Will Develop Postpartum Thyroiditis
Type I Diabetes Mellitus – 25% Will Develop Postpartum Thyroiditis
Postpartum Thyroiditis with Prior Pregnancy
Pathology
Lymphocytic Infiltration, Disruption of Follicles, Germinal Centers
Variant of Hashimoto’s Thyroiditis

18. Postpartum Thyroiditis
Course
25% - Classic Triphasic Response
35% - Only Hyperthyroidism
40% - Only Hypothyroidism
Persistent Hypothyroidism
After 4 years 25 to 50% have hypothyroidism or Goiter or Both
56% with a Hypothyroid Phase Develop Permanent Hypothyroidism
Patients with Postpartum Hypothyroidism
Require Yearly Screening

19. Postpartum Thyroiditis Versus Graves’ Disease
Postpartum Graves’ Disease
Goiter Small, No Bruit Small to Large, Bruit Present
Course Mild, Short Duration Mild to Severe, Long Duration
Opthalmopathy Absent May Be Present
Iodine Uptake Low Normal to Elevated
TSI Absent Present
* TSI-Thyroid Stimulating Immunoglobulin

20. Postpartum Thyroiditis Treatment
Hyperthyroid Phase – Beta Blocker
Hypothyroid Phase – Thyroid Hormone
Selenium During Pregnancy in TPO Positive Patients

21. Amiodarone and Thyroid Function
Hypothyroidism-Iodine Induced Overt Hypothyroidism – 5% Subclinical Hypothyroidism – 25% Hyperthyroidism – 3-5% Type 1- (Jod-Basedow, Iodine-Induced), Underlying MNG, Graves’ Disease Type 2 – Chemical Destructive Thyroiditis

22. Distinguishing Type 1 from Type 2 Hyperthyroidism
I123 Uptake is Usually Suppressed in Both Types
Of the I123 Detectable Type 1 is Likely
Presence of the Diffuse Goiter, MNG or TSI suggests Type 1
Color Flow Doppler
Increased Flow (increased vascularity) – Type 1
Decreased Flow (absent vascularity) – Type 2
Interpretation Difficult

23. Treatment of Amiodarone-Induced Hyperthyroidism
Type 1
Thionamides (Methimazole or PTU)
Radioactive Iodine (If I123 Uptake is Detectable)
Thyroidectomy (Failure of Other Options)
Type 2
Prednisone 40 mg daily for 6 to 12 weeks
Uncertain If Type 1 or Type 2 (Usually the Case)
Start Prednisone 40 mg and Methimazole 40 Mg daily
Measure Thyroid Function in 6 weeks
If Improved Taper Methimazole
If Unimproved Taper Prednisone

24. Treatment of Amiodarone-Induced Hyperthyroidism
Type 1
Thionamides (Methimazole or PTU)
Radioactive Iodine (If I123 Uptake is Detectable)
Thyroidectomy (Failure of other options)
Type 2
Prednisone 40 mg daily for 6 to 12 weeks
Uncertain if Type 1 or Type 2 (Usually the Case)
Start Prenisone 40 mg and Methimazole 40 Mg daily
Measure Thyroid Function in 6 weeks
If Improved Taper Methimazole
If Unimproved Taper Prednisone

25. Etiology of Chemical or Destructive Thyroiditis
Interferon Alfa-10% Hypothyroidism, Painless Thyroiditis, or Graves Disease
Interleukin 2% Painless Thyroiditis
Lithium-Painless Thyroiditis But Hypothyroidism more common
Denileukin Difitox