|Print Date:||May 23, 2013, 1:16 pm|
|Text||Subacute thyroiditis (deQuervain's disease) is a nonsuppurative granulomatous inflammatory process that may affect all or part of the thyroid. The etiology is unproven but speculated to be viral. During the active phase the thyroid scintigram demonstrates decreased or absent uptake in the affected part of the gland.
The clinical picture can be confusing if there are minimal local symptoms. Often there is a history of recent upper respiratory tract infection and neck tenderness. Plasma levels of thyroid hormone are increased in the initial phase due to an outpouring of stored hormone caused by the inflammatory process in the gland. Patients may appear thyrotoxic clinically and may be mistaken for having Graves' disease. However, the percent uptake of I-131 is typically decreased in subacute thyroiditis. The possibility of subacute thyroiditis should always be borne in mind before a patient is treated with radioiodine for thyrotoxicosis.
Chronic thyroiditis or Hashimoto's thyroiditis is characterized by a lymphocytic infiltration of the gland. It occurs most frequently in women and may manifest with goiter or hypothyroidism. Rarely, a patient presents with hyperthyroidism and the slang term "Hashitoxicosis" is used. Scintigraphic findings are highly variable and depend on the stage in the natural history during which imaging is performed. The scintigram may be normal early in the course of the process. Later, diffuse enlargement may be demonstrated. Many patients with Hashimoto's thyroiditis eventually become hypothyroid. The scintigram often appears inhomogeneous with hot and cold areas.
Acute Thyroiditis due to suppurative bacterial infection is rare. The thyroid is typically enlarged and tender. Associated focal abscess may appear as a cold nodule scintigraphically. Reidel's thyroiditis or struma is also uncommon. The gland is replaced by fibrous tissue.
|References:||Thrall, James H. Nuclear Medicine: The Requisites. p 334. Mosby, St. Louis, 1995.
Putnam,C. et al., ed. Textbook of Diagnostic Imaging, 2nd ed. Pp 1465-1466. WB Saunders, Philadelphia, 1994.
|Contributor||David Brennan Cline (Walter Reed Army Medical Center)|
|Peer Reviewer||James G. Smirniotopoulos, M.D. (Uniformed Services University)|
|Record Number||: 3328|
|MedPix® Medical Image Database |
Content Text and Images may be Copyright © 1999 - 2006 by the Original Contributors