-IBIS-1.5.0-
tx
endocrine system
goiter
diagnoses

definition and etiology

definition: Enlargement of the thyroid gland, causing a swelling in the front part of the neck.

etiology: A goiter is a nonspecific indication of thyroid pathology. There are many causes for thyroid enlargement:

• Grave's Disease (hyperthyroidism): see "Grave's disease".
• Plummer's Disease (toxic multinodular goiter)
• Toxic adenoma
Silent thyroiditis
Hypothyroidism goiter
Congenital goiter: This can occur with or without hypothyroidism and is classified into types based upon the causative defect: Hashimoto's thyroiditis, subacute thyroiditis (aka DeQuervain's thyroiditis), euthyroid goiter (aka nontoxic nodular goiter; simple/endemic/ nontoxic diffuse goiter)

signs and symptoms

• Grave's Disease (hyperthyroidism): see "Grave's disease".

• Plummer's Disease: This occurs when one nodule of the thyroid hyperfunctions idiopathically. Hyperthyroidism does not always occur with the multinodular goiter. Lab results include increased T3 and T4; and increased RAI uptake only in the hyperfunctioning nodule.

• Toxic adenoma: Essentially the same as for Plummer's disease.

Silent thyroiditis: Recognized by mild to moderate thyroid gland enlargement; lack of tenderness upon palpation; increased ESR, normal WBC indices.

Hypothyroidism goiter: Typically occurs in areas where goiters are endemic from lack of ingested iodine (see euthyroid goiter below). See also: "hypothyroidism" card.

Congenital goiter:
» Hashimoto's thyroiditis: This disease is theorized to be the leading cause of primary hypothyroidism. It is characterized by a painless enlargement of the thyroid that is not tender to palpation. It is much more common in women, especially between the ages of 30-50. Other autoimmune diseases are frequently seen in these patients, such as RA, SLE, and Sjogren's syndrome. Lab results show high levels of antithyroid antibodies, and decreased T4 and RAI uptake.
» Subacute thyroiditis: This disease is thought to be caused by a virus, and not infrequently, there is a history of mumps or URI. The patient presents with a sore throat/neck pain, fever of 100-101°F, and tenderness on throat palpation. The thyroid is enlarged and firm; typically the patient develops hyperthyroidism that usually spontaneously resolves to euthyroidism. The lab shows increased T4, decreased RAI uptake, increased ESR, and leukocytosis.
» Euthyroid goiter: Enlargement of the thyroid gland from decreased thyroid hormone production, but without the clinical presentation of hypothyroidism. It can be due to lack of dietary iodine (endemic goiter); ingestion of goitrogens; and drugs. This type of thyroid enlargement is the most common, and is often seen at puberty, during pregnancy, and at menopause. Lab usually shows normal results for RAI uptake, T4, and T3-resin uptake.

course and prognosis

• Grave's Disease (hyperthyroidism): see "Grave's disease".

• Plummer's Disease: This disease is more common in the elderly and is treated with surgery or radioiodine.

• Toxic adenoma: Essentially the same as for Plummer's disease.

Silent thyroiditis: after a self-limited hyperthyroid episode lasting weeks to months, the patient returns to being euthyroid.

Hypothyroidism goiter: prognosis good with increased iodine intake.

Congenital goiter: This can occur with or without hypothyroidism and is classified into four types based upon the causative defect.
» Hashimoto's thyroiditis: Conventional treatment consists of lifelong replacement with thyroid hormone.
» Subacute thyroiditis: Conventional treatment is usually not needed.
» Euthyroid goiter: Treatment consists of identifying and removing the cause. Conventional treatment may consist of blocking TSH and then administering full thyroid hormone replacement therapy; or surgery if the goiter grows too large.

differential diagnosis

• Thyroid cancer.
• Cyst.
• Other neoplasm.


footnotes