Hashimoto thyroiditis is part of the spectrum of autoimmune thyroid diseases (AITDs) and is characterized by the destruction of thyroid cells by various cell- and antibody-mediated immune processes. This condition is the most common cause of hypothyroidism in the United States in individuals older than 6 years. [1] The treatment of choice for Hashimoto thyroiditis (or hypothyroidism from any cause) is thyroid hormone replacement. The drug of choice is orally administered levothyroxine sodium, usually for life.

Signs and symptoms of Hashimoto thyroiditis

Hypothyroidism typically has an insidious onset with subtle signs and symptoms that may progress to more advanced or even florid signs and symptoms over months to years. The presentation of patients with hypothyroidism may also be subclinical, diagnosed based on routine screening of thyroid function. Such patients may have nonspecific symptoms that are difficult to attribute to thyroid dysfunction. They frequently do not improve with thyroid hormone supplementation..

Early nonspecific symptoms may include the following:

Fatigue

Constipation

Dry skin

Weight gain

More advanced/florid symptoms may include the following:

Cold intolerance

Voice hoarseness and pressure symptoms in the neck from thyroid enlargement

Slowed movement and loss of energy

Decreased sweating

Mild nerve deafness

Peripheral neuropathy

Galactorrhea

Depression, dementia, and other psychiatric disturbances

Memory loss

Joint pains and muscle cramps

Hair loss

Menstrual irregularities

Sleep apnea and daytime somnolence

See Autoimmune Disorders: Making Sense of Nonspecific Symptoms, a Critical Images slideshow, to help identify several diseases that can cause a variety of nonspecific symptoms.

See Clinical Presentation for more detail.

Diagnosis of Hashimoto thyroiditis

Physical findings are variable and depend on the extent of the hypothyroidism and other factors, such as age. Examination findings may include the following:

Puffy face and periorbital edema typical of hypothyroid facies

Cold, dry skin, which may be rough and scaly

Peripheral edema of hands and feet, typically nonpitting

Thickened and brittle nails (may appear ridged)

Bradycardia

Elevated blood pressure (typically diastolic hypertension)

Diminished deep tendon reflexes and the classic prolonged relaxation phase

Macroglossia

Slow speech

Ataxia

Testing

Laboratory studies and potential results for patients with suspected Hashimoto thyroiditis include the following:

Serum thyroid-stimulating hormone (TSH) levels: Sensitive test of thyroid function; levels are invariably raised in hypothyroidism due to Hashimoto thyroiditis and in primary hypothyroidism from any cause

Free T4 levels: Needed to correctly interpret the TSH in some clinical settings; low total T4 or free T4 level in the presence of an elevated TSH level further confirms diagnosis of primary hypothyroidism

T3 levels: Low T3 level and high reverse T3 level may aid in the diagnosis of nonthyroidal illness

Thyroid autoantibodies: Presence of typically anti-TPO (anti-thyroid peroxidase) and anti-Tg (anti-thyroglobulin) antibodies delineates the cause of hypothyroidism as Hashimoto thyroiditis or its variant; however, 10-15% of patients with Hashimoto thyroiditis may be antibody negative

The following tests are not necessary for the diagnosis of primary hypothyroidism but may be used to evaluate complications of hypothyroidism in some patients, as indicated:

Complete blood count: Anemia in 30-40% of patients with hypothyroidism

Total and fractionated lipid profile: Possibly elevated total cholesterol, LDL, and triglyceride levels in hypothyroidism

Basic metabolic panel: Decreased glomerular filtration rate, renal plasma flow, and renal free water clearance in hypothyroidism; may result in hyponatremia

Creatine kinase levels: Frequently elevated in severe hypothyroidism

Prolactin levels: May be elevated in primary hypothyroidism

Imaging tests

Features of Hashimoto thyroiditis are usually identifiable on an ultrasonogram; however, a thyroid ultrasonogram is usually not necessary for diagnosing the condition. This imaging modality is useful for assessing thyroid size, echotexture, and, most importantly, whether thyroid nodules are present.

Chest radiography and echocardiography are not usually performed and are not necessary in routine diagnosis or evaluation of hypothyroid patients.

Procedures

Hashimoto thyroiditis is a histologic diagnosis. Therefore, perform fine-needle aspiration of any dominant or suspicious thyroid nodules to exclude malignancy or the presence of a thyroid lymphoma in fast-growing goiters. [2]

See Workup for more detail.

Management

Pharmacotherapy

The treatment of choice for Hashimoto thyroiditis (or hypothyroidism from any cause) is thyroid hormone replacement. The drug of choice is individually tailored and titrated levothyroxine sodium administered orally, usually for life.

Surgery

Indications for surgery include the following:

A large goiter with obstructive symptoms, such as dysphagia, voice hoarseness, and stridor, caused by extrinsic obstruction of airflow

Presence of a malignant nodule, as demonstrated by cytologic examination

Presence of a lymphoma diagnosed on fine-needle aspiration

Cosmetic reasons (eg, large, unsightly goiters)

See Treatment and Medication for more detail.