Imaging the thyroid

A Rare and Challenging Case of Neck Infection - Thyroid Abscess

Acute suppurative thyroiditis (AST) is serious and rare infection of the thyroid gland, often it can progress to thyroid abscess. Both anatomical defects and underlying thyroid disorders are attributed to etiopathogenesis of the disease. Bacteria usually reach the gland either by lymphatic spread or via hematogenous routes. If untreated it has fatal outcome and had serious complications. The mainstay of treatment is usually a combination of intravenous antibiotics and drainage, and sometimes surgery.

[Idiopathic thyroid abscess: a case study conducted at Marc Sankale Center Dakar]

L'abcès de la thyroïde est une maladie très rare en raison de sa situation anatomique et de la physiologie de la glande. Il survient la plus part du temps sur un terrain d'immunodépression. Le diagnostic est facile mais on y pense pas souvent et repose sur l'échographie. L'examen bactériologique permet de retrouver le germe responsable. Nous rapportons le cas d'un patient mauritanien vivant dans ledit pays et qui avait consulté pour une tuméfaction cervicale antérieur douloureuse associée à une fièvre. Le diagnostic était posé à l'échographie et confirmé par l'examen anatomopathologique du liquide de ponction, sans étiologie retrouvée à la bactériologie. L'évolution était marqué par une régression des symptômes sous antibiothérapie, avec une normalisation de la structure de la glande après 2 mois.

Thyroid Abscess: Challenges in Diagnosis and Management

Thyroid abscess is an uncommon infectious pathology. The thyroid is highly resistant to infection due to high iodine content, capsular encasement, and rich vascularity. Acute suppurative thyroiditis represents <1% of thyroid diseases that could potentially become a life-threatening endocrine emergency. A 48-year-old woman with AIDS presented with 3 days of fever, tender neck swelling, and methicillin-resistant Staphylococcus aureus bacteremia. Apart from leukocytosis, initial laboratory values including thyroid function tests were normal. The initial plain computed tomography scan of the neck and ultrasound scan of the neck were inconclusive as well. By day 4, she worsened, and on repeat computed tomography scan of the neck with contrast, multiloculated abscesses in the thyroid and retro pharynx were seen, which needed emergent drainage. Acute suppurative thyroiditis, a rare disease, occurs in patients with either preexisting disorders of the thyroid or in the immunocompromised. The most common pathogen is Staphylococcus aureus. In our case, we highlight the fact that initial imaging may be negative in the early stages of acute suppurative thyroiditis and lead to an erroneous diagnosis of subacute thyroiditis. There are less than 5 cases of methicillin-resistant Staphylococcus aureus suppurative thyroiditis reported.

Thyroid nodules: Evaluation with power Doppler and duplex Doppler ultrasound

This study purposes a new classification of thyroid nodules blood flow by power duplex Doppler ultrasound. A total of 177 nodules were studied with B-mode scanning, power Doppler, and spectral analysis. These data were compared with cytological results from ultrasound-guided fine-needle aspiration biopsy. Univariate and multivariate logistic regression analysis were performed. The power Doppler analysis of the nodules produced 5 vascular patterns: I, absence of signal blood flow; II, exclusively perinodular blood flow; III, perinodular > central blood flow; IV, central blood flow > perinodular blood flow; V, exclusively central blood flow. Statistical analysis revealed a significant relationship between these vascular patterns and cytological results. The spectral analysis demonstrated that the resistance index were higher in nodules with malignant versus other cytology ( P >0.001). The results indicate that power duplex Doppler facilitates screening of thyroid nodules at high risk for malignancy with elevated sensitivity (92.3%) and specificity (88%).

Thyroid disease in children: part 2 : State-of-the-art imaging in pediatric hyperthyroidism

Hyperthyroidism occurs secondary to overproduction of thyroid hormone by the thyroid gland. This condition can have rather serious effects on children, and thus timely diagnosis and treatment are of utmost importance. Imaging is quite useful in the management of children with hyperthyroidism. In addition to determining the underlying pathology, radiologic exams are crucial for therapy. This article describes the underlying etiologies of pediatric hyperthyroidism and provides general information on treatment.

The BRAF(V600E) mutation is associated with malignant ultrasonographic features in thyroid nodules

CONTEXT

Several ultrasonographic (US) features of thyroid nodules have been reported to predict malignancy. The BRAF(V600E) mutation is a useful diagnostic marker for differentiating papillary thyroid carcinoma from benign thyroid nodules, especially in BRAF(V600E) -prevalent populations such as in Korea.

OBJECTIVE

To evaluate the association of BRAF(V600E) mutation with US features of thyroid nodules in predicting the malignancy of thyroid nodules in Korean patients.

DESIGN

A total of 991 thyroid nodules from 823 patients in fine-needle aspiration biopsy (FNAB) specimens were investigated. The relationship between US features and the presence of BRAF(V600E) mutation by pyrosequencing method was prospectively analysed.

RESULTS

The BRAF(V600E) mutation was associated with the following US features: solid composition [odds ratio (OR) 20·338; 95% confidence interval (CI): 4·952-83·532; P < 0·001], marked hypoechogenicity (OR 30·744; 95% CI: 15·951-59·255; P < 0·001), irregular margin (OR 9·889; 95% CI: 7·005-13·859; P < 0·001), taller-than-wide shape (OR 6·031; 95% CI: 4·343-8·376; P < 0·001) and the presence of microcalcifications (OR 6·664; 95% CI: 4·604-9·648; P < 0·001). The BRAF(V600E) mutation with malignant US features in FNAB enhanced the diagnostic accuracy compared with cytologic diagnosis alone (94·3%vs 69·7%).

CONCLUSION

The BRAF(V600E) mutation is significantly associated with malignant US features, such as solid composition, marked hypoechogenicity, irregular margin, taller-than-wide shape and the presence of microcalcifications. The application of BRAF(V600E) mutation analysis in US-guided FNAB can improve the diagnostic accuracy of thyroid nodules.

Pre- and posttreatment ultrasonography of the thyroid gland in hyperthyroid cats

Ultrasonography is useful for assessing the morphology of the thyroid gland in hyperthyroid cats. Our aim was to describe the ultrasonographic changes of the thyroid gland in hyperthyroid cats after 131I therapy. Ultrasonography was performed in 15 hyperthyroid cats at initial presentation and 6 months after 131I using a multifrequency linear transducer set at 12 MHz. The following criteria were evaluated: length, width, height, volume, shape, homogeneity, and vascularity, using Power Doppler. Pretreatment, 10 cats had bilaterally abnormal thyroid lobes, four cats one abnormal lobe with the contralateral lobe being normal or reduced in size, and one cat with one normal lobe and one lobe not visible. Six months after 131I therapy, there was a reduction in median volume from 819 to 210 mm3, reduced rounding, reduced heterogeneity, and decreased vascularity. In conclusion, ultrasonography may be used to monitor thyroid changes in order to assess 131I treatment response. Further studies are necessary to determine whether ultrasonography could contribute to the detection of a relapsing course of hyperthyroidism.

Vascular pattern and spectral parameters of power Doppler ultrasound as predictors of malignancy risk in thyroid nodules

INTRODUCTION

Determination whether spectral Doppler ultrasound parameters, including resistance index (RI) and pulsatility index (PI), or vascular pattern can be used to distinguish malignant from benign thyroid nodules.

MATERIALS AND METHODS

We prospectively examined 85 thyroid nodules in patients undergoing surgery. The flow pattern seen via power Doppler examination was ranked for each nodule on a scale of 0 to 4 as follows: absent, perinodular alone, mixed with perinodular prominency, mixed with intranodular prominency, and exclusively intranodular, respectively. For each nodule, the RI and PI values were recorded as the average of the recordings obtained. Pathological examination were used as a proof of final diagnosis to categorize all nodules as benign or malignant.

RESULTS

The malignant nodules had a mean RI of 0.72 +/- 0.13. These values were significantly higher than those associated with benign nodules (0.60 +/- 0.08) (P = .000). Malignant nodules had a mean PI of 1.15 +/- 0.33 that were also significantly different from those associated with benign nodules (0.91 +/- 0.19) (P = .000). Shifting to intranodular vascularization had a significant correlation with malignancy (P = .001).

CONCLUSION

Spectral parameter and vascular pattern are useful to distinguish malignant from benign thyroid nodules, especially for those with suspicious or undetermined fine-needle aspiration biopsy.

Prevalence of thyroid cancer at a medical screening center: pathological features of screen-detected thyroid carcinomas

PURPOSE

To assess the incidence of thyroid malignancy in an adult population screened by high-resolution ultrasonography at a medical screening center and to compare the clinical and pathological features of screen-detected thyroid carcinomas to symptomatic overt thyroid carcinomas.

MATERIALS AND METHODS

We calculated the prevalence of screen-detected thyroid cancer at a medical screening center using high- resolution ultrasonography and fine needle aspiration. We then compared the clinical and pathological features of screen-detected thyroid cancers (n = 46) to clinical symptomatic thyroid cancers (n = 157). We evaluated age, gender, size, perithyroidal extension, lymphovascular extension, stage, histological lymph node metastasis, and the type of cancer. We also compared the above findings of micropapillary carcinomas to papillary thyroid carcinomas that were larger than 1cm in diameter.

RESULTS

Screen-detected thyroid nodule patients were 2,747 (37%) of 7,491 patients. Nodules selected for fine needle aspiration were 658 and cytology confirmed malignancy were 79 (12%) nodules. When screen-detected thyroid cancers (n = 46) were compared to symptomatic overt thyroid cancers (n = 157), only statistically significant factor was size (p = 0.002). Papillary thyroid carcinomas that were larger than 1 cm had more frequent capsular invasion (p = 0.000) and a higher stage (p = 0.027), and a higher prevalence of lymph node metastases (p = 0.002).

CONCLUSION

Screen-detected thyroid cancers should be managed as same as symptomatic thyroid cancers in respect to size, and an assessment should strictly be based on the ultrasound features and fine needle aspiration biopsy findings.

High prevalence of carcinoma in ultrasonography-guided fine needle aspiration cytology of thyroid nodules

OBJECTIVE

The purpose of this study was to assess the rate of malignancy in thyroid nodules incidentally detected at sonography and to determine the diagnostic value of ultrasonography-guided fine needle aspiration cytology (USgFNAC) in thyroid nodules.

METHODS

Five hundred patients (84 men and 416 women) who had thyroid incidentalomas underwent USgFNAC at Konkuk University Hospital between August 2005 and July 2006. Thyroid sonography and guided aspiration was performed on all single nodules and on dominant nodules with suspected malignancy in cases of multinodular goiter.

RESULTS

Five hundred fifty-eight nodules from 500 patients were aspirated using ultrasonography guidance. The USgFNAC results for all patients were as follows: 307 (61.4%) benign, 108 (21.6%) suggestive of malignancy, 56 (11.2%) indeterminate, and 29 (5.8%) inadequate for cytologic diagnosis. The rate of malignancy was significantly higher in women than in men (23.6% in women vs 11.9% in men, p<0.01). Ultrasonographic characteristics that had a significant association with thyroid malignancy included solid echocomponent, hypoechogenecity, ill defined margin, and presence of microcalcifications (p<0.05). Eighty-eight patients underwent surgical resection. The positive predictive value of USgFNAC was 90.2% (74/82), and the accuracy index was 84.1% (74/88). In 80 patients with well-differentiated thyroid carcinoma after surgery, 49% (39/80) had lesions smaller than 1 cm.

CONCLUSION

The rate of malignancy in incidental thyroid nodules on USgFNAC was 21.6%. Ultrasonographic features could be useful in differentiating between benign and malignant nodules.

Magnetic resonance imaging of thyroid cancer

Thyroid cancer is a unique malignancy arising from the endocrine system, and its nature is different from more common squamous cell carcinoma in the head and neck region. Multiple imaging modalities are used for imaging work up for thyroid cancer, including nuclear medicine imaging, ultrasound, computed tomography, and magnetic resonance imaging (MRI). Imaging findings of benign and malignant thyroid lesions overlap substantially, and differentiation may be difficult. The role of MRI is to evaluate the extent of disease and to assess the spread of nodal disease. In this chapter, we will discuss the role of MRI in thyroid cancer staging and key imaging appearance that affect staging of thyroid cancer.

CT Screening for Lung Cancer:Prevalence and Incidence of Mediastinal Masses

PURPOSE

To determine the frequency and natural course of mediastinal masses in asymptomatic people at high risk for lung cancer who were undergoing computed tomographic (CT) screening.

MATERIALS AND METHODS

Informed consent and institutional review board approval for this HIPAA-compliant study were obtained at each participating institution. All documented mediastinal masses among the 9263 baseline and 11 126 annual repeat screenings performed in the Early Lung Cancer Action Project (ELCAP) and its successor project, the New York ELCAP, were identified. Two radiologists confirmed all cases, identified the location and measured the diameter (average of length and width) of each mass, and reviewed all subsequent CT and clinical and surgical results. The prevalence and incidence of mediastinal masses were then determined.

RESULTS

Of the 9263 individuals, 71 had a mediastinal mass seen at baseline screening (prevalence of 0.77%). Of the 71 masses, 41 were thymic, 16 were thyroidal, two were esophageal cancers, six were tracheal-esophageal diverticula, and six were other masses. Among the 11 126 annual repeat screenings, only one new mediastinal mass was identified (incidence of 0.01%). This suggests a long average duration for mediastinal masses in asymptomatic people. Among the 41 thymic masses, five were larger than 3.0 cm in diameter, and all five were resected; of these five, one was a thymic carcinoma and four were noninvasive thymomas. Of the remaining 36 thymic masses, 25 were evaluated at follow-up CT 1 year later: Five had increased in diameter, two had decreased, and 18 remained unchanged. All 16 thyroid masses were due to goiter; none of these were changed at follow-up CT 1 year later.

CONCLUSION

Mediastinal masses found in the context of CT screening for lung cancer in asymptomatic people should be approached in a "conservative" manner; this includes thymic masses smaller than 3 cm in diameter, as most of these remain unchanged or even decrease in size.

Prevalence, clinical and ultrasonographic characteristics of thyroid incidentalomas

High-resolution ultrasonography (US) has made possible the detection of asymptomatic small thyroid nodules. Thyroid incidentalomas have created a clinical dilemma as to how to properly manage such incidental findings. We investigated the prevalence, the clinical and US characteristics, and optimal diagnostic approach to incidentally detected benign and malignant thyroid nodules < 1.5 cm. Retrospective review was done on 1475 patients who had visited Samsung Medical Center, Soul Korea from January 1999 to December 2000. The prevalence of thyroid incidentalomas was 13.4%. The malignancy rate within thyroid incidentalomas was 28.8%. There were no significant differences in age, nodule size and number, thyroid function test, and Tc99m thyroid scan between benign and malignant incidentalomas. US characteristics of solid echostructure, irregular margin, and calcification showed meaningful diagnostic value in detecting malignancy in thyroid incidentalomas (p < 0.05). Most malignant incidentalomas were low stage. In conclusion, occult thyroid cancers are a fairly common finding. There were no significant differences in clinical and laboratory parameters between benign and malignant thyroid nodules <1.5 cm; however, US findings can be used in the decision of optimal management strategies.

Microbiology and management of acute suppurative thyroiditis in children

This review describes the microbiology, diagnosis and management of suppurative thyroiditis (ST). Staphylococcus aureus, Streptococcus pyogenes, Streptococcus epidermidis, and Streptococcus pneumoniae, are the predominant aerobic isolates. The most common anaerobic bacteria are Gram-negative bacilli and Peptostreptococcus spp. Agents that are rarely recovered include Klebsiella spp., Haemophilus influenzae, Streptococcus viridans, Salmonella spp., Enterobacteriaceae, Mycobacterium tuberculosis, atypical mycobacteria, Aspergillus spp., Coccidioides immitis, Candida spp., Treponema pallidum, and Echinococcus spp. Viruses have been associated with subacute thyroiditis, and include measles, mumps, influenza, enterovirus Epstein-barr, adenovirus, echovirus, and St Louis encephalitis. Therapy includes administration of antibiotics effective against the causative pathogen(s). Proper selection of therapy can be guided by culture of the lesion. Surgical drainage may be necessary in case of suppuration.

Comparison of methods for thyroid volume estimation in patients with Graves' disease

Individualised dosage models are frequently applied for radioiodine therapy in patients with Graves' hyperthyroidism, especially in Europe. In these dosage schemes the thyroid volume is an important parameter. Thyroid volume determinations are usually made with ultrasonography or with thyroid scintigraphy, although the accuracy of planar scintigraphy for this purpose is not well established. The aim of this study was to compare the accuracy of three modalities for the determination of the thyroid volume in patients with Graves' disease: planar scintigraphy (PS), single-photon emission tomography (SPET) and ultrasonography (US). These three modalities were compared with magnetic resonance imaging (MRI) as the gold standard. Thyroid volume estimations were performed in 25 patients with Graves' disease. The PS images were subjected to filtering and thresholding, and a standard surface formula was used to calculate the thyroid volume. With SPET the iteratively reconstructed thyroid images were filtered, and after applying a threshold method an automatic segmentation algorithm was used for the volume determinations. Thyroid volumes were estimated from the US images using the ellipsoid volume model for multiple two-dimensional measurements. For MRI, thyroid segmentation was performed manually in gadolinium-enhanced T1-weighted images and a summation-of-areas technique was used for the volume measurements. The thyroid volumes calculated with MRI were 25.0+/-13.8 ml (mean+/-SD, range 7.0-56.3 ml). PS correlated poorly with MRI ( R(2)=0.61) and suffered from a considerable bias (-4.0+/-17.6 ml). The differences between PS and MRI volume estimations had a very large spread (33+/-58%). For SPET both the correlation with MRI ( R(2)=0.84) and the bias (1.8+/-11.9 ml) were better than for PS. US had by far the best correlation with MRI ( R(2)=0.97) and the best precision, but the bias (6.8+/-7.5 ml) was not negligible. In conclusion, SPET is preferred over PS for accurate measurements of thyroid volume. US is the most accurate of the three modalities, if a correction is made for bias.

US-guided core-needle biopsy of the thyroid gland

PURPOSE

To evaluate safety, yield, and accuracy of ultrasonography (US)-guided core-needle biopsy of the thyroid gland.

MATERIALS AND METHODS

Findings at 209 consecutive core-needle biopsies of lesions of the thyroid gland in 198 patients (median age, 48 years; age range, 14-80 years) were retrospectively reviewed. In 138 (66%), findings at previous fine-needle aspiration cytologic (FNAC) analysis were nondiagnostic on one to five occasions. Biopsy was performed as an outpatient procedure with direct US guidance by using nonadvancing 16-18-gauge core needles. Hospital records were reviewed 6 months to 5 years following biopsy to determine final diagnosis, delayed complications, and influence of biopsy findings on subsequent patient treatment. Final diagnoses were determined on the basis of findings at excisional histologic analysis, clinical course, or other laboratory values. The sensitivity, specificity, and accuracy of US-guided core-needle biopsy were calculated.

RESULTS

One hundred ninety-nine (95%) specimens were adequate for histologic diagnosis. The sensitivity, specificity, and accuracy of core biopsy in differentiating neoplastic (malignant and benign) from nonneoplastic lesions of the thyroid gland were 96% (74 of 77), 89% (109 of 122), and 92% (183 of 199), respectively. The sensitivity, specificity, and accuracy of core-needle biopsy in the detection of malignant neoplasms were 61% (11 of 18), 100% (181 of 181), and 96% (192 of 199), respectively. After US-guided core-needle biopsy, 115 (58%) of 198 patients were treated conservatively, and no evidence of missed tumor manifested during the follow-up period. In the 83 patients who underwent surgical resection, biopsy was performed for therapeutic reasons in 76 (92%) and for diagnostic reasons in seven (8%). There were three cases of small postbiopsy hematomas and one of minor hemoptysis, but none required hospital admission. There were no major complications.

CONCLUSION

US-guided core-needle biopsy of the thyroid gland is a safe outpatient procedure with a high diagnostic yield and accuracy, and frequently it obviates surgery in patients in whom findings at FNAC analysis are recurrently nondiagnostic.

Thyroid ultrasound

Evaluation of the thyroid gland can be performed by several imaging techniques. Although ultrasound (US) lacks specificity for tissue diagnosis and can rarely distinguish benign from malignant disease, it can distinguish solid nodules from simple and complex cysts. It allows accurate estimation of thyroid size, gives a rough estimate of tissue density (echogenicity), shows vascular flow and velocity (color-flow Doppler), can identify regional lymphadenopathy, and aids in the accurate placing of needles for diagnostic or therapeutic purposes. In addition, it is widely available, relatively rapid and cheap, visualizes the whole anterior neck, and does not involve ionizing irradiation. This article aims at clarifying the role of US in clinical thyroidology by pointing to areas where the technology can aid in clinical decision making. It is argued that more clinician endocrinologists should master and use this technology for diagnostic and therapeutic purposes.

The thyroid and parathyroid glands. CT and MR imaging and correlation with pathology and clinical findings

Thyroid imaging approach is based on the preliminary clinical evaluation. Lesions that are smaller than 2 cm should be assessed with US, which is capable of discriminating masses as small as 2 mm and distinguishing solid from cystic nodules. US-guided FNAB provides tissue for cytologic examination of thyroid nodules. CT and MR imaging are indicated for larger tumors (greater than 3 cm diameter) that extend outside the gland to adjoining structures, including the mediastinum, and retropharyngeal region. Metastatic lymph nodes in the neck and invasion of the aerodigestive tract are also in the realm of CT and MR imaging. Thyroid nodules are categorized on scintigraphy as hot or cold nodules. Hot nodules are rarely malignant, whereas cold nodules have an incidence of 10% to 20% of malignancy. Calcifications (amorphous, globular, nodular, and linear) occur in adenomas and carcinomas and have no differential diagnostic features except for psammomatous calcifications, which are a pathognomonic finding in papillary carcinomas and a small percentage of medullary carcinomas. Papillary carcinoma is the most common malignant tumor (80%) followed by follicular (20% to 25%); medullary (5%); undifferentiated; anaplastic carcinomas (< 5%); lymphoma (5%); and metastases. Lymph node metastases are common in papillary carcinoma, 50% at presentation, and less common in follicular carcinomas. The metastatic nodes in papillary carcinoma may enhance markedly (hypervascular); show increased signal intensity on T1-weighted images (increased thyroglobulin content or hemorrhage); and reveal punctate calcifications. Localized invasion of the larynx, trachea, and esophagus occurs predominantly in papillary and follicular carcinomas; the incidence is less than 5%. Ectopic thyroid tissue may be encountered in the tongue (foramen cecum); along the midline between posterior tongue and isthmus of thyroid gland; lateral neck; mediastinum; and oral cavity. Goiter and malignant tumors, notably papillary carcinoma, may develop in ectopic thyroid tissue. Carcinomas may also arise in thyroglossal duct cysts, which develop from duct remnants between the foramen cecum and thyroid isthmus. Infectious disease of the thyroid gland is not common and the CT and MR imaging findings are similar as described under neck infection. Other types of inflammatory disorders including Hashimoto's thyroiditis, granulomatous thyroiditis, and Riedel's struma display no specific imaging features. Imaging studies may, however, be indicated to confirm a suspected clinical diagnosis and assess compromise of the airway (Riedel's struma). HPT is a clinical diagnosis in which hypercalcemia is the most important finding. Parathyroid hyperplasia, adenoma, and carcinoma represent underlying lesions. To relieve the patient's symptoms surgical extirpation is indicated. The surgical success rate without imaging is 95%. The indications for imaging studies vary but it is generally agreed that reoperation after a previous failed surgical attempt and suspicion of an ectopic parathyroid adenoma should be investigated by imaging. These consist of US, nuclear medicine studies, CT and MR imaging. US and technetium sestamibi scanning have the highest accuracy rate for localizing an adenomatous gland at and near the thyroid gland. Ectopic adenomas, particularly if they are located in the mediastinum, are preferrably investigated with CT and MR imaging with gadolinium and fat suppression. Carcinomas and parathyroid cysts are optimally evaluated by CT and MR imaging. On MR imaging adenomas are low in signal intensity on T1-weighted images, high in signal intensity on T2-weighted images, and enhance post introduction of gadolinium.

Diagnosis and Management of Infectious Thyroiditis

A broad range of disorders can cause inflammation of the thyroid gland. True thyroid infections are rare and can result from a variety of microorganisms, of which bacteria are the most common. Other rarer pathogens include fungi, parasites, and viruses. Gram-positive bacteria, especially staphylococci, predominate as causative agents in adults and children. In immunocompromised patients, opportunistic pathogens have been isolated. Most infections in adults occur as a result of hematogenous or lymphatic seeding of the thyroid gland. In children, congenital anomalies can lead to thyroid infection and require surgical correction to prevent recurrence. Fine-needle aspiration of the thyroid is usually required to identify the infecting agent, and prolonged antimicrobial therapy with or without surgical drainage is the cornerstone of management. This review outlines the pathogenesis, microbiology, diagnosis, and management of infectious thyroiditis in adults and children and compares this disorder with other, more common causes of thyroid inflammation.