Silent thyroiditis differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Furqan M M. M.B.B.S[2]

Overview

Silent thyroiditis must be differentiated from other causes of thyroiditis, such as De Quervain's thyroiditis, Hashimoto's thyroiditis, Riedel's thyroiditis, and suppurative thyroiditis. Silent thyroiditis must also be differentiated from other diseases which cause hypothyroidism. As silent thyroiditis may cause transient thyrotoxic symptoms, the diseases causing thyrotoxicosis must also be considered in the differential diagnosis.

Differentiating Silent Thyroiditis from other Diseases

Differentiating silent thyroiditis from other causes of thyroiditis

• Silent thyroiditis must be differentiated from other causes of thyroiditis, such as De Quervain's thyroiditis, Hashimoto's thyroiditis, Riedel's thyroiditis, and suppurative thyroiditis.

Conditions	Causes	Age at onset	Pathological findings	Diagnostic approach
Silent thyroiditis	Autoimmune	All ages, peak at 30-40	Lymphocytic infiltration Lymphoid follicles	Increased TSH (hypothyroidism) and/or Decreased TSH (transient hypothyroidism) TPO antibodies present in high titer I-123 uptake usually decreased
Hashimoto's thyroiditis	Autoimmune	All ages, peak at 30-50	Lymphocytic infiltration Germinal centers Fibrosis (in some variants)	Increased TSH (hypothyroidism) TPO antibodies present in high titer I-123 uptake usually decreased
Painful subacute (De Quervain's) thyroiditis	Unknown	20-60	Giant cells Granulomas	Increased TSH (hypothyroidism) and/or Decreased TSH (Thyrotoxicosis) TPO antibodies absent or very low titer I-123 uptake decreased
Postpartum thyroiditis	Autoimmune	Childbearing age	Lymphocytic infiltration	Increased TSH (hypothyroidism) and/or Decreased TSH (transient hypothyroidism) TPO antibodies present in high titer I-123 uptake usually decreased
Riedel's thyroiditis	Unknown	30-60	Dense fibrosis	Normal TSH (euthyroidism) TPO antibodies usually present I-123 uptake decreased or normal
Suppurative thyroiditis	Infection	Children, 20-40	Abscess formation	Normal TSH (euthyroidism) TPO antibodies absent I-123 uptake normal

Differentiating silent thyroiditis from other causes of hypothyroidism

• Silent thyroiditis must be differentiated from other causes of hypothyroidism on the basis of history and symptoms and laboratory findings:

Disease		History and symptoms		Laboratory findings							Additional findings
		Fever	Pain	TSH	Free T4	T3	T3RU†	Thyroglobin	TRH	TPOAb^
Transient hypothyroidism	Silent thyroiditis	-	-	↑/↓	↓/↑	Normal	↓	↑	Normal	Present (high titer)	May present primarily with hyperthyroidism
	Postpartum thyroiditis	+/-	+/-	↑/↓	↓/↑	Normal	↓	↑	Normal/↑	Present (high titer)	May present primarily with hyperthyroidism
	Subacute (de Quervain's) thyroiditis	+/-	+/-	↑/↓	↓/↑	Normal	↓	↑	Normal	Low/absent	May present primarily with hyperthyroidism
Primary hypothyroidism	Autoimmune (Hashimoto's thyroiditis)	-	-	↑*	↓	Normal/↓	Normal/↓	Normal/↑	Normal	Present (high titer)	May be accompanied by other autoimmune diseases
	Riedel's thyroiditis	-	-	Normal/↑	Normal/↓	Normal/↓	Normal/↓	Normal	Normal	Usually present	Riedel's thyroiditis usually presents with hard and fixed thyroid mass.
	Infectious thyroiditis	+	+	Normal	Normal	Normal	Normal	Normal	Normal	Absent	Infectious thyroiditis associated with neck pain
Others	Drug-induced	-	-	↑/↓	↓/↑	Normal	↓	Normal/↑	Normal	Absent**	History of hyperthyroidism History of trauma History of drug use, surgery, or radiation
	Radiation-induced
	Trauma induced
	Radioiodine induced
	Thyroidectomy
	Subclinical hypothyroidism	-	-	↑	Normal	Normal	Normal	Normal	Normal	Normal/↑	Asymptomatic

Differentiating silent thyroiditis from other causes of thyrotoxicosis

• Silent thyroiditis can initially present with thyrotoxicosis which must be differentiated from other causes of thyrotoxicosis.

Disease		History and symptoms		Laboratory findings								Additional findings
		Fever	Pain	TSH	Free T4	T3	T3RU†	Thyroglobin	TRH	TSH Receptor Antibody	TPOAb^
Thyroiditis	Silent thyroiditis	-	-	↑/↓	↓/↑	Normal	↓	↑	Normal	Absent	Present (high titer)	May present with hypothyroidism
	Hashimoto's thyroiditis (Hashitoxicosis)	-	-	↑*	↓	Normal/↓	Normal/↓	Normal/↑	Normal	Absent	Present (high titer)	May be accompanied by other autoimmune diseases
	Subacute (de Quervain's) thyroiditis	+/-	+/-	↑/↓	↓/↑	Normal	↓	↑	Normal	Absent	Low/absent	May present with hypothyroidism
	Postpartum thyroiditis	+/-	+/-	↑/↓	↓/↑	Normal	↓	↑	Normal/↑	Absent	Present (high titer)	May present with hypothyroidism
Primary hyperthyroidism	Grave's disease	-	-	↓	↑	Normal/↑	↑	↑	Normal	Present	Absent	Patient may have opthalmopathy and dermopathy
	Toxic thyroid nodule	-	-	↓	↑	Normal/↑	↑(hot nodule)	Normal/↑	Normal	Absent	Absent	-
Secondary hyperthyroidism	Pituitary adenoma	-	-	↑	↑	Normal/↑	↑	Normal/↑	Normal	Absent	Absent	Inappropriately normal or increased TSH
Tertiary hyperthyroidism	Tertiary hyperthyroidism	-	-	↑	↑	↑	↑	Normal/↑	↑	Absent	Absent	Inappropriately normal or increased TSH
Drug induced	Amiodarone type 1	-	-	↓	↑	Normal/↑	↓	Normal/↑	Normal	Absent	Absent	High urinary iodine
	Amiodarone type 2	-	-	↓	↑	Normal/↑	Absent/↓	Normal/↑	Normal	Absent	Absent	High urinary iodine
Others	Factitious thyrotoxicosis	-	-	↓	↑	Normal/↑	↓	↓	Normal	Absent	Absent	Decreased thyroglobulin
	Trophoblastic disease	-	-	↓	↑	Normal/↑	↑	-	Normal	Absent	Absent	-
	Struma ovarii	-	-	↓	↑	Normal/↑	↓	-	Normal	Absent	Absent	-

(†)T3RU; Triiodothyronine Resin uptake. (^)TPOAb; Thyroid peroxidase antibodies.

References

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