AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

The broad category of thyroiditis includes the following inflammatory diseases of the thyroid gland: (1) acute suppurative thyroiditis, which is due to bacterial infection; (2) subacute thyroiditis, which results from a viral infection of the gland; and (3) chronic thyroiditis, which is usually autoimmune in nature. In childhood, chronic thyroiditis is the most common of these 3 types. The second form of thyroiditis, Riedel struma, is rare in children. Secondary thyroiditis may be due to the administration of amiodarone to treat cardiac arrhythmias or the administration of interferon-alpha to treat viral diseases.

Pathophysiology

Acute suppurative thyroiditis is rare in childhood because the thyroid is remarkably resistant to hematogenously spread infection. Most cases of acute thyroiditis involve the left lobe of the thyroid and are associated with a developmental abnormality of thyroid migration and the persistence of a pyriform sinus from the pharynx to the thyroid capsule. The usual organisms responsible include Staphylococcus aureus, Streptococcus hemolyticus, and pneumococcus. Other aerobic or anaerobic bacteria may also be involved.

Subacute thyroiditis is generally thought to be due to viral processes and usually follows a prodromal viral illness. Various viral illnesses may precede the disease, including mumps, measles, influenza, infectious mononucleosis, adenoviral or Coxsackievirus infections, myocarditis, or the common cold. Other illnesses or situations associated with subacute thyroiditis include cat-scratch fever, sarcoidosis, Q fever, malaria, emotional crisis, or dental work. The disease is more common in individuals with human leukocyte antigen (HLA)–Bw35.

Because chronic thyroiditis in children is usually due to an autoimmune process, it is HLA-associated, similar to other autoimmune endocrine diseases. The specific alleles in the atrophic and goitrous forms of the disease vary. The histologic disease picture varies, but lymphocytic thyroid infiltration is the hallmark of the disease and frequently obliterates much of the normal thyroid tissue. Follicular thyroid cells may be small or hyperplastic. The degree of fibrosis among patients also widely varies. Children usually have hyperplasia with minimal fibrosis. The blood contains autoantibodies to thyroid peroxidase and, frequently, autoantibodies to thyroglobulin. Autoimmune thyroiditis is also frequently part of the polyglandular autoimmune syndromes.

Frequency

United States

Studies in the United States and Western Europe report a prevalence of 1.2% in individuals aged 11-18 years. Approximately 25% of adults with type 1 diabetes have thyroiditis, about one half of whom have hypothyroidism. Approximately 10% of children with type 1 diabetes have antithyroid antibodies. Thirteen of 121 children with vitiligo were also found to have subsequent evidence of autoimmune thyroiditis¹. The disease is also more common in children with Down or Turner syndrome. Acute suppurative thyroiditis is rare in Western nations. Subacute thyroiditis is rare in childhood.

International

The prevalence of chronic autoimmune thyroiditis varies depending on screening procedures. A Greek study showed a prevalence of thyroid antibodies as high as 12.5% in some areas. Few data are available regarding the incidence of the various forms of thyroiditis in the non-Western world. Acute thyroiditis is more common in geographic areas where antibiotic use is less prevalent.

Mortality/Morbidity

Long-term morbidity or mortality from thyroiditis is uncommon.

• Patients with autoimmune thyroiditis frequently develop hypothyroidism and require lifelong treatment.


• Patients with subacute thyroiditis may briefly have hyperthyroidism but usually regain normal thyroid function.


• Patients with acute thyroiditis generally maintain normal thyroid function.

Age

The pediatric male-to-female ratio for autoimmune thyroiditis is 1:2. This is low when compared with the 90% female predominance in adults.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• Acute thyroiditis
  • A history of acute illness, including fever, chills, neck pain, sore throat, hoarseness, and dysphagia, is common.
  
  
  
  • Neck pain is frequently unilateral and radiates to the mandible, ears, or occiput. Neck flexion reduces the severity of the pain. The pain worsens with neck hyperextension.
     
• Subacute thyroiditis
  • Neck tenderness and swelling may occur.
  
  
  
  • Occasionally, the initial symptoms are those of hyperthyroidism.
  
  
  
  • Systemic symptoms such as weakness, fatigue, malaise, and fever are usually low grade.
     
• Chronic autoimmune thyroiditis is observed in the following 3 patterns:
  • Goiter that is usually diffuse and nontender: Systemic illness is not evident. The thyroid gland is frequently 2-3 times its normal size and may be larger. The patient, parent, or physician may discover the goiter.
  
  
  
  • Symptoms of hypothyroidism: In children, this frequently includes poor growth or short stature. Adolescent girls may have primary or secondary amenorrhea. Boys may have delayed puberty. Because the disease develops slowly, the patient or parent may not notice other signs of hypothyroidism, including constipation, lethargy, and cold intolerance. The child with diabetes may have decreasing insulin requirement.
  
  
  
  • Symptoms of hyperthyroidism: These may include poor attention span, hyperactivity, restlessness, heat intolerance, or loose stools.
     
• Asymptomatic thyroiditis with or without thyroid function abnormalities may also be discovered upon routine screening of children at high risk; these include children with Down or Turner syndrome and children with other autoimmune endocrine disorders (eg, type 1 diabetes, Addison disease, vitiligo).

Physical

• Acute thyroiditis
  
  
  • The patient may have a fever of 38-40°C.
  
  
  • Acute illness may be evident.
  
  
  • Neck tenderness is present, and the swollen thyroid gland is tender. The swelling and tenderness may be unilateral. Erythemas develop over the gland, and regional lymphadenopathy may develop as the disease progresses. Abscess formation may occur.


• Subacute thyroiditis
  
  
  • The patient may have signs of systemic illness, such as low-grade fever and weakness.
  
  
  • Signs of hyperthyroidism, including increased pulse rate, widened pulse pressure, fidgeting, tremor, nervousness, tongue fasciculations, brisk reflexes (possibly with clonus), weight loss, and warm moist skin, may be present.
  
  
  • The thyroid gland may be enlarged and tender, with tenderness exacerbated by neck extension.
  
  


• Chronic autoimmune thyroiditis
  
  
  • Initially, an enlarged, lumpy, bumpy, and nontender thyroid is often present. The gland may not be enlarged, particularly in children have profound hypothyroidism. Signs of hypothyroidism include slow growth rate, weight gain, slow pulse, cold dry skin, coarse hair and facial features, edema, and delayed relaxation of the deep tendon reflexes.
  
  
  • Signs of hyperthyroidism are occasionally present early in the disease.
  
  

Causes

• Acute suppurative thyroiditis is more common in poorer geographic areas where antibiotic use is less prevalent. It usually occurs in children with embryologic abnormalities such as a persistent thyroglossal duct or brachial cleft cysts.
• Chronic autoimmune thyroiditis is more common in developed countries with increased iodine intake.
• Children with Down or Turner syndrome and those who have type 1 diabetes or another autoimmune endocrine disease are at particular risk of chronic thyroiditis.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Acute thyroiditis
  
  
  • Laboratory abnormalities in acute thyroiditis reflect the acute systemic illness.
  
  
  • Findings include leukocytosis with a left shift and an increased sedimentation rate.
  
  
  • Thyroid function test results are within the reference range.


• Subacute thyroiditis
  
  
  • The primary laboratory abnormalities are consistent with abnormal thyroid function. Initially, the thyroid-stimulating hormone (TSH) level is suppressed, and the free thyroxine (T4) level is increased. As the disorder progresses, transient or sometimes permanent hypothyroidism may develop.
  
  
  • The WBC count is usually within the reference range but may be mildly elevated. High-sensitivity C-reactive protein levels are usually elevated in subacute thyroiditis.


• Chronic thyroiditis
  
  
  • Laboratory abnormalities reflect thyroid function abnormality and evidence of autoimmunity.
  
  
  • TSH levels are increased in children with subclinical and overt hypothyroidism. Free T4 levels are within the reference range in the former and low in the latter. In children with hyperthyroidism, TSH levels are suppressed. Many children have normal thyroid function and normal TSH levels.
  
  
  • Antithyroid peroxidase (antithyrocellular, antimicrosomal) antibody levels elevated above the reference range are the most sensitive indicator of thyroid autoimmunity. Many children also have antithyroglobulin antibodies, although this is less sensitive and less specific.

Imaging Studies

• Radioactive iodine thyroid scanning
  • Radioactive iodine thyroid scanning is not necessary for acute suppurative thyroiditis because the results are normal and do not aid in diagnosis. A scan may be helpful after diagnosis to identify a persistent thyroglossal duct as a route for infection.
  
  
  
  • This test is also unnecessary for chronic thyroiditis because the results can be misleading and may show increased uptake consistent with Graves disease, a multinodular goiter, or a hypofunctioning or hyperfunctioning nodule.
  
  
  
  • Radioactive iodine thyroid scanning is helpful in patients with hyperthyroidism who are thought to have subacute thyroiditis because the extremely low uptake is consistent with the thyrocellular destruction in progress.
     
• Thyroid ultrasonography is useful in revealing abscess formation in patients with acute thyroiditis.

Procedures

• Fine-needle thyroid aspiration
  
  
  • This procedure is advocated by some to document the presence of thyroid lymphocytic infiltration in autoimmune thyroiditis. Histologic results are predictive of thyroid function; however, the results can be misinterpreted and can lead to unnecessary thyroid surgery.
  
  
  • Reserve this test for patients in whom underlying malignancy is suggested by a discrete thyroid nodule.
  
  
  • In patients with acute thyroiditis, needle aspiration can be used to obtain material for culture, enabling appropriate antibiotic therapy.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

• Acute thyroiditis
  
  
  • Acute thyroiditis requires immediate parenteral antibiotic therapy before abscess formation begins. For initial antibiotic therapy, administer penicillin or ampicillin to cover gram-positive cocci and the anaerobes that are the usual causes of the disease.
  
  
  • In patients who are allergic to penicillin, cephalosporins are appropriate.


• Subacute thyroiditis
  
  
  • Subacute thyroiditis is self-limiting; therefore, the goals of treatment are to relieve discomfort and to control the abnormal thyroid function. The discomfort can usually be relieved with low-dose aspirin (divided every 4-6 h). In the rare cases that aspirin does not relieve the discomfort, administer prednisone for 1 week and then taper.
  
  
  • Propranolol can be used to reduce signs and symptoms of hyperthyroidism.
  
  
  • Low-dose levothyroxine may be necessary in some patients who develop hypothyroidism.
  
  


• Chronic autoimmune thyroiditis
  
  
  • Treatment for chronic autoimmune thyroiditis depends on the results of the thyroid function tests. Patients with overt hypothyroidism who have high TSH and low free T4 levels require treatment with levothyroxine. The dose is age dependent. TSH levels should be monitored and the dose should be adjusted to maintain levels within the reference range.
  
  
  • The treatment of subclinical hypothyroidism in patients with elevated TSH and normal free T4 levels is controversial. These children may enter a remission phase and may not have permanent hypothyroidism. Most pediatric endocrinologists recommend treatment of subclinical hypothyroidism during childhood to ensure normal growth and development. If thyroxine administration may not be permanently required, treatment may be stopped once the patient has completed pubertal development, and thyroid function then can be reassessed.
  
  
  • The use of thyroxine treatment in patients with a goiter due to autoimmune thyroiditis who have normal TSH and free T4 levels is even more controversial. Some studies in adults have suggested that treatment may decrease gland size, but the only pediatric study published suggests that reduction in gland size is likely only in children with initially elevated TSH levels.

Surgical Care

• In acute thyroiditis, surgery may be necessary to drain the abscess and to correct the developmental abnormality responsible for the condition.


• The surgical service consulted depends on the institution and the physician who has the most experience with thyroid surgery. Options include the following:
  
  
  • Pediatric surgery
  
  
  • Otolaryngology
  
  
  • A specialized endocrine surgery service

Consultations

• Acute thyroiditis: Consulting with a pediatric infectious disease specialist may be useful for selecting appropriate antibiotic therapy.


• Subacute and chronic thyroiditis: Consulting with a pediatric endocrinologist should be considered in treating children with these disorders. This is particularly true if the child has experienced poor growth possibly due to hypothyroidism, has symptoms of overt hyperthyroidism, or has a discrete thyroid nodule.

Diet

• No dietary limitations are necessary.

Activity

• Children with overt hyperthyroidism or hypothyroidism have poor exercise tolerance. These children usually limit their own activity. As treatment progresses and thyroid function levels return to normal, their exercise tolerance should increase.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Drug Category: Antibiotics

These agents are used to treat acute suppurative thyroiditis. First-line antibiotic choices to treat acute thyroiditis include parenteral penicillin or ampicillin. These drugs cover most of the gram-positive cocci and anaerobes that cause the disease.

Drug Category: Anti-inflammatory drugs

These drugs are used to decrease discomfort in patients with subacute thyroiditis.

Drug Category: Beta-adrenergic blocking agents

Many signs and symptoms of hyperthyroidism are due to increased beta-adrenergic sensitivity. In particular, these include the hemodynamic abnormalities of tachycardia and hypertension. Beta-adrenergic blockade can reduce many of these symptoms. These agents are the DOC in treating cardiac arrhythmias that result from hyperthyroidism. These agents control cardiac and psychomotor manifestations within minutes.

Drug Category: Hormones

These agents are used to treat hypothyroidism due to autoimmune thyroiditis. Use TSH levels to monitor dose and keep them within the reference range.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Inpatient Care

• Patients with acute thyroiditis may require inpatient care to complete 10-14 days of antibiotics and to recover from any surgical procedures.

Further Outpatient Care

• Subacute thyroiditis
  
  
  • This is a self-limiting disease that may last 2-7 months.
  
  
  • During this time, monitor thyroid function and adjust medications as needed.


• Chronic autoimmune thyroiditis
  
  
  • Outpatient care involves monitoring thyroid function tests. Patients with normal thyroid function test results should be examined every 6 months to ensure that they do not develop hypothyroidism. After a year, these visits may be annual.
  
  
  • Children who require thyroxine therapy should undergo thyroid function tests every 3-12 months, depending on age. More frequent testing is required in younger children. TSH and free T4 levels should be checked 1 month after any change in dosage.
  
  

Prognosis

• Acute thyroiditis: Recovery is usually complete, and thyroid function returns to normal.


• Subacute thyroiditis: This self-limiting disease may last 2-7 months.


• Chronic autoimmune thyroiditis: Permanent hypothyroidism is the main complication. Some children enter remission and develop euthyroidism.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Medical legal pitfalls regarding thyroiditis mainly involve missed diagnosis.
  
  
  • In acute thyroiditis, searching for any predisposing congenital anomalies is important.
  
  
  
  • Because the signs of hypothyroidism can be subtle in chronic thyroiditis, the diagnosis may be missed. If this occurs during early puberty, it may lead to impairment of adult height.
  
  
  
  • The rare association of autoimmune adrenal insufficiency (ie, Addison disease) and chronic thyroiditis must be considered.
     
• Treatment of hypothyroidism could provoke an adrenal crisis, but this is  rare in children.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

1. Iacovelli P, Sinagra JL, Vidolin AP, et al. Relevance of thyroiditis and of other autoimmune diseases in children with vitiligo. Dermatology. 2005;210(1):26-30. [Medline].
2. Bauer DC, Brown AN. Sensitive thyrotropin and free thyroxine testing in outpatients. Are both necessary?. Arch Intern Med. Nov 11 1996;156(20):2333-7. [Medline].
3. Bogazzi F, Bartalena L, Tomisti L, et al. Glucocorticoid response in amiodarone-induced thyrotoxicosis resulting from destructive thyroiditis is predicted by thyroid volume and serum free thyroid hormone concentrations. J Clin Endocrinol Metab. Feb 2007;92(2):556-62. [Medline].
4. Dayan CM, Daniels GH. Chronic autoimmune thyroiditis. N Engl J Med. Jul 11 1996;335(2):99-107. [Medline].
5. de Kerdanet M, Lucas J, Lemee F, Lecornu M. Turner's syndrome with X-isochromosome and Hashimoto's thyroiditis. Clin Endocrinol (Oxf). Nov 1994;41(5):673-6. [Medline].
6. Foley TP Jr. Disorders of the Thyroid in Children. In: Sperling M, Saunders WB, eds. Pediatric Endocrinology. 1996:171-196.
7. Hay ID. Thyroiditis: a clinical update. Mayo Clin Proc. Dec 1985;60(12):836-43. [Medline].
8. Kennedy RL, Jones TH, Cuckle HS. Down's syndrome and the thyroid. Clin Endocrinol (Oxf). Dec 1992;37(6):471-6. [Medline].
9. Mandac JC, Chaudhry S, Sherman KE, Tomer Y. The clinical and physiological spectrum of interferon-alpha induced thyroiditis: toward a new classification. Hepatology. Apr 2006;43(4):661-72. [Medline].
10. McCanlies E, O'Leary LA, Foley TP, et al. Hashimoto's thyroiditis and insulin-dependent diabetes mellitus: differences among individuals with and without abnormal thyroid function. J Clin Endocrinol Metab. May 1998;83(5):1548-51. [Medline]. [Full Text].
11. Nordyke RA, Gilbert FI Jr, Miyamoto LA, Fleury KA. The superiority of antimicrosomal over antithyroglobulin antibodies for detecting Hashimoto's thyroiditis. Arch Intern Med. Apr 12 1993;153(7):862-5. [Medline].
12. Pearce EN, Bogazzi F, Martino E, et al. The prevalence of elevated serum C-reactive protein levels in inflammatory and noninflammatory thyroid disease. Thyroid. Jul 2003;13(7):643-8. [Medline].
13. Pearce EN, Farwell AP, Braverman LE. Thyroiditis. N Engl J Med. Jun 26 2003;348(26):2646-55. [Medline].
14. Rother KI, Zimmerman D, Schwenk WF. Effect of thyroid hormone treatment on thyromegaly in children and adolescents with Hashimoto disease. J Pediatr. Apr 1994;124(4):599-601. [Medline].

Article Last Updated: Jun 1, 2007