thyroiditis
TRANSCRIPT
Thyroiditis
Uaepong Limpapanasit 23/5/54
Introduction
l Thyroid inflammation l acute illness with severe thyroid pain l conditions in which there is no clinically evident
inflammation and the illness is manifested primarily by thyroid dysfunction or goiter
THYROIDITIS WITH THYROID PAIN AND TENDERNESS
l Subacute granulomatous thyroiditis l Infectious thyroiditis l Radiation thyroiditis l Palpation- or trauma-induced thyroiditis
Subacute granulomatous thyroiditis
l Subacute nonsuppurative thyroiditis, de Quervain's thyroiditis, or subacute thyroiditis
l Most common cause of painful thyroiditis l Caused by a viral infection or postviral
inflammatory process l Many pt. have a Hx of URI preceding the
onset l Etiologic agents : mumps, echovirus,
coxsackievirus, Epstein-Barr virus, influenza and adenovirus
l Acute neck pain, a tender diffuse goiter, elevated T4 and/or T3, and low TSH
l In summary, the PE, an elevated ESR, an elevated thyroglobulin level and a low RAIU confirm the Dx
l 4 phases, generally unfold over 4-6 months l The acute phase of thyroid pain and
thyrotoxicosis may last three to six weeks or longer.
l Transient asymptomatic euthyroidism follows l Hypothyroidism often ensues and may last weeks
to months or may be permanent (in up to 5 percent of patients).
l The final phase is a recovery period, during which thyroid function tests normalize
l Therapy l antithyroid drugs is not indicated because this
disorder is caused by the release of preformed hormone rather than synthesis of new T3 and T4
l beta blockers may be indicated for the symptomatic treatment of thyrotoxicosis
l NSAIDs effective in reducing thyroid pain in patients with mild cases.
l Patients with more severe disease require a tapering dosage of prednisone (20-40 mg/d) over 2-4 weeks
Infectious thyroiditis
l Acute infections (acute suppurative thyroiditis), with abscess formation, may be caused by gram-positive or gram-negative l most commonly Staphylococcus & Streptococcus l Most patients have a preexisting thyroid disorder,
usually nodular goiter
l Anterior neck pain and tenderness are common l Other clinical features include fever, pharyngitis
and dermal erythema.
l Most patients have a unilateral neck mass, which may be fluctuant
l DDx : hemorrhage into a thyroid nodule, subacute thyroiditis
l Lab l leukocytosis and an elevated ESR level l TSH, T4 and T3 levels are typically normal l RAIU may be normal or show cold nodules in areas of
abscess formation l Therapy
l should be evaluated immediately with needle aspiration of the mass, followed by drainage and antibiotic therapy
l Surgical drainage if failed med
l Chronic infections : Mycobacterial, fungal, Pneumocystis infections l nearly all occur in immunocompromised host l often have bilateral disease l Thyroid pain and tenderness are less prominent,
and some patients have hypothyroidism l The essential steps in evaluation are aspiration
biopsy of the thyroid to identify the causative organism and radiologic studies to identify fistulae or tracts contributing to the disease process.
Radiation thyroiditis
l Occasional Graves‘ disease pt. treated with radioiodine develops thyroid pain and tenderness 5-10 days later due to radiation-induced injury and necrosis
l The neck pain and tenderness are usually mild and may be transient exacerbation of the hyperthyroidism
l subside spontaneously in a few days to one week.
l Rx : Beta blocker, NSAIDs, Steroid
Palpation- or trauma-induced thyroiditis
l Vigorous palpation of the thyroid gland during l physical examination l manipulation of the gland during thyroid biopsy or
neck surgery, especially parathyroid surgery l trauma from an automobile seat belt
l manifested by transient neck pain and tenderness and transient hyperthyroidism
l Rx : Beta blocker, NSAIDs, Steroid
THYROIDITIS WITHOUT PAIN AND TENDERNESS
l Painless thyroiditis (subacute lymphocytic thyroiditis)
l Chronic autoimmune thyroiditis (Hashimoto's thyroiditis)
l Postpartum thyroiditis l Drug-induced thyroiditis l Fibrous (Riedel's thyroiditis)
Painless thyroiditis
l silent thyroiditis, subacute lymphocytic thyroiditis
l a variant form of Hashimoto's thyroiditis, suggesting that it is part of the spectrum of thyroid autoimmune disease.
l It can also be caused by administration of interferon-alfa, interleukin-2, amiodarone, or lithium administration
l 1-10 % of cases of hyperthyroidism
l Characterized primarily by transient hyperthyroidism, followed sometimes by hypothyroidism, and then spontaneously recovery
l The key findings are mild hyperthyroidism of short duration(< 2 months), little or no thyroid enlargement, and no Graves' ophthalmopathy or pretibial myxedema
l Lab : l T4 Free and TSH l Antithyroid Peroxidase Antibody(positive in 50%) l Thyroid Stimulating Immunoglobulins absent
l Contrast with Grave's Disease
l Rx : - need no treatment - symptomatic : betablocker, levothyroxine
Chronic autoimmune (Hashimoto's) thyroiditis l The most common cause of hypothyroidism
in iodine-sufficient areas l 2 forms : goitrous and atrophic l caused by cell- and antibody-mediated
destruction of thyroid tissue l Cytotoxic T cells may directly destroy thyroid cells. l > 90 % of pt. have high serum concentrations of
autoantibodies to thyroglobulin, thyroid peroxidase (thyroid microsomal antigen)
l more common in women l Gradual loss of thyroid function: Hyperthyroid
state is followed by a period of euthyroid, followed by persistent hypothyroidism.
l Serum antithyroid antibodies l need not be measured routinely in overt primary
hypothyroidism, because almost all have chronic autoimmune thyroiditis
l may be useful to predict the likelihood of progression to permanent overt hypothyroidism in patients with subclinical hypothyroidism or those with painless (silent) thyroiditis or postpartum thyroiditis
l Lab : TFT stepwise change l First: TSH rises l Next: T4 declines l Next: T3 decline l Last: Symptomatic Hypothyroidism
l Rx : levothyroxine
Postpartum thyroiditis
l similar clinically and pathogenetically to painless thyroiditis
l Occurs within 1 year postpartum (or after spontaneous or induced abortion)
l 8-10 % of pregnancies l It is likely to recur after subsequent
pregnancies l DDX : postpartum exacerbations of Graves'
disease
l usually mild hyperthyroidism and minimal thyroid enlargement l whereas women with Graves' hyperthyroidism are
usually more symptomatic, more thyroid enlargement, and have ophthalmopathy or pretibial myxedema.
l Thyroid U/S with Doppler flow helpful in differentiating these two conditions l Hypervascularity typically occurs with Graves' l Decreased vascularity in postpartum thyroiditis
l Improvement after 2–4 weeks
Drug-induced thyroiditis
l Interferon-alfa l The most common interferon-alfa-associated
thyroid abnormality is the development of de novo antithyroid antibodies without clinical disease (5-15 %)
l 5-10 % of pt. develop clinical thyroid disease, including painless thyroiditis, Hashimoto's thyroiditis, or Graves' disease
l after three months of therapy &can occur as long as interferon-alfa is given
l Interleukin-2 l a syndrome mimicking painless thyroiditis
occurred in about 2 % of the patients l Denileukin diftitox
l is a fusion protein of diphtheria toxin and the ligand-binding domain of IL-2 used to treat mycosis fungoides and other T-cell disorders.
l have been reported with thyrotoxicosis after treatment, radioiodine uptake is low, consistent with thyroiditis
l Amiodarone l contains 37 % iodine l occurs via an unknown mechanism and causes a
clinical syndrome that is similar to painless thyroiditis
l Hyperthyroidism seems to occur more frequently in iodine deficient areas and hypothyroidism occurs more frequently in iodine sufficient areas
l Amiodarone induced hyperthyroidism l Type 1, which is thought to be due to iodine release l Type 2, which is considered to be thyroiditis related to
a direct thyroid toxic effect of the drug
l usually occurs during the 1st months of therapy l Patients with thyroiditis have little thyroid enlargement
and a low thyroid radioiodine uptake l Rx :
§ antithyroid agent, (eg, PTU or methimazole) can be given with careful monitoring for adverse effects such as skin rash, arthralgia, hepatotoxicity and rarely bone marrow suppression.
§ If attributed to thyroiditis rather than iodine excess, either a nonsteroidal antiinflammatory drug or prednisone should be given, with the duration of therapy depending on the response
l In many patients, the two types of hyperthyroidism cannot be differentiated. In this setting, both an antithyroid drug(s) and an antiinflammatory drug may be indicated
l Amiodarone induced hypothyroidism l via the antithyroid action of iodine (especially in
patients with preexisting thyroid disease) l Amiodarone induced hyperthyroidism occurs, on
average, after three years of taking amiodarone, although thyroid dysfunction can occur at anytime
l Lithium l lithium therapy were increased 4.7-fold in patients
with subacute lymphocytic thyroiditis as compared with those with Graves' hyperthyroidism
l Tyrosine kinase inhibitors l associated with the development of
hypothyroidism and an elevated TSH in 50-70 % of patients, most frequently reported with sunitinib
l Hyperthyroidism, possibly from a destructive thyroiditis, has also been reported
Fibrous thyroiditis
l Riedel's thyroiditis or invasive thyroiditis l Extensive fibrosis and macrophage and
eosinophil infiltration of the thyroid gland that extends into adjacent tissues
l Probably a primary fibrosing disorder, also had mediastinal and retroperitoneal fibrosis
l S&S l neck discomfort or tightness, sometimes
dysphagia or hoarseness
l diffuse, although occasionally asymmetric, goiter that is very hard, fixed, and often not clearly separable from the adjacent tissues
l Most patients are euthyroid, but a few are hypothyroid
l The diagnosis is established by thyroid biopsy
l Rx : l Prednisone therapy may alleviate local symptoms l In a small case series, tamoxifen appeared to be
effective in delaying, or perhaps even helping resolve, the progression of disease
l surgery may be indicated to relieve tracheal or esophageal compression and occasionally to exclude carcinoma.
Thanks for your attention
References l Thyroiditis: differential diagnosis and management. Slatosky J, Shipton B, Wahba H. Am Fam Physician. 2000 Feb 15;61(4):1047-52, 1054. l UpToDate 18.3