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Thyroiditis

Thyroiditis may be caused by a number of unrelated clinical conditions involving autoimmune, infectious, or unknown insults to the thyroid. Symptoms may include painless or painful enlargement of the thyroid, symptoms of hyper-or hypothyroidism, and signs of infection thyroiditis, Hashimoto's thyroiditis, hashimoto thyroiditis.

Hashimoto's Thyroiditis. The most common thyroiditis is Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis (Table 7). Hashimoto's thyroiditis is seen most often in middle-aged women and presents with painless enlargement of the

Subacute Lymphocytic Thyroiditis. Subacute lymphocytic thyroiditis, also known as painless or silent thyroiditis, is an autoimmune disease. The autoimmune insult is usually transient. Patients with subacute lymphocytic thyroiditis often have fairly acute enlargement of the thyroid without pain. Insult to the thyroid may result in release of preformed thyroid hormone, resulting

Subacute Granulomatous Thyroiditis. Subacute granulomatous thyroiditis, also known as giant cell thyroiditis or de Quervain's thyroiditis, is similar to subacute lymphocytic thyroiditis, but is not an autoimmune disease. In subacute granulomatous thyroiditis, a viral illness usually precedes symptom development and the thyroid enlargement is mildly painful. Acute inflammation of the

Suppurative Thyroiditis. Suppurative thyroiditis is an acute bacterial infection of the thyroid gland, usually caused by

Classification of Thyroiditis

Lifetime risk of

Type Frequency Cause Presentation hypothyroidism

Chronic lymphocytic Most common Autoimmune Goiter; High (5 percent

(Hashimoto's) hypothyroidism per year)

Subacute lymphocytic Common Autoimmune Nontender goiter; Low (less than l0

(silent/painless) hyperthyroidism percent total)

Subacute granulomtous Common Viral Tender neck mass; Low (10 percent

(de Quervain's) hyperthyroidism total)

Suppurative Rare Bacterial Tender, hot thyroid; Very low (less

fever; elevated white than I percent

blood count total)

Invasive fibrous (Reiders) Rare Unknown Woody, firm goiter Very low (less

than 1 percent

total)

Staphylococcus aureus, Streptococcus pyogenes (group A streptococci), or Streptococcus pneumoniae. Patients have a tender swollen thyroid, fever, elevated white blood cell count, and other manifestations of 

Fibrous Thyroiditis. Invasive fibrous thyroiditis, also known as Reidel's thyroiditis, presents with a gradually enlarging and firm, but painless thyroid. In this disease, thyroid tissue is infiltrated with dense fibrous tissue that causes a hard, wood-like goiter. Although patients are usually euthyroid, a small minority can 

Treatment. Treatment of thyroiditis is usually straightforward (Table 8). As noted above, patients with subacute granulomatous thyroiditis may benefit from administration of anti-inflammatory medications, such as aspirin. These medications provide symptomatic benefit; there is little evidence that they reduce the duration of symptoms or alter the long-term chance of

Symptoms in subacute lymphocytic thyroiditis and subacute granulomatous thyroiditis can be effectively reduced by beta blockers. Most patients can be started on a low dose of a beta blocker, and the dosage titrated to provide maximal symptom relief with the fewest side effects. Because thyroid production is not increased in thyroiditis, propylthiouracil (PTU) and methimazole (Tapazole) are ineffective in decreasing symptoms of

Thyroid hormone replacement is warranted for hypothyroidism associated with Hashimoto's thyroiditis and persistent hypothyroidism secondary to subacute lymphocytic or subacute granulomatous thyroiditis. Replacement should start with low doses (25 meg per day) in patients at high risk for ischemic heart disease and increase slowly to a target dose between 100 and

Table 8

Treatment of Thyroiditis

Condition Treatment

Chronic lymphocytic Monitor for hypothyroidism; begin (Hashimoto's) replacement therapy if hypothyroid

to target dose of thyroxine, 100 to 150 mcg per day, and/or normal thyroid stimulating hormone

Subacute lymphocytic Acute: may need beta blocker for (silent/painless) treatment of hyperthyroid symptoms

Maintenance: thyroxine replacement for less than 10 percent of patients with persistent hypothyroidism

Subacute granulomatous Acute: anti-inflammatory agents (aspirin, (de Quervain's) nonsteroidal anti-inflammatory drugs or prednisone) for control of symptoms and may need beta blocker for treatment of hyperthyroid symptoms 

Maintenance: thyroxine replacement for less than I 0 percent of patients with persistent hypothyroidism

Suppurative Parenteral antibiotics to cover Staphylococcus aureus, group A Streptococcus and Streptococcus pneumoniae (cefazolin, Kefzol, Zolicef] or other first-generation cephalosporin or nafcillin [Nallpen] or oxacillin [Bactocill])

Suppurative thyroiditis is treated in the same manner as any other serious acute bacterial infection. Parenteral administration of antibiotics is indicated to provide empiric treatment for the

Invasive fibrous thyroiditis generally requires no therapy. Occasionally, surgical removal of large firm thyroids may be required if they are uncomfortable or compress nearby structures. Otherwise, monitoring for symptoms of hypothyroidism is all that is