Low Radioactive Iodine Uptake Research Articles

Autoimmune Thyroiditis with Transient Thyrotoxicosis: Comparison between Painful Thyroiditis and Painless Thyroiditis

Clinical and laboratory findings and long-term outcomes in 8 patients (7 women) with autoimmune thyroiditis (AT), aged 34-59 years, who had a painful tender goiter and a transient thyrotoxicosis with a low thyroid radioactive iodine uptake (RAIU), were compared with those in 15 patients (13 women) with painless thyroiditis (PT), aged 23-69 years. Six painful AT and 6 PT patients had a history of prior awareness of goiter. All patients with painful AT had a moderate or marked elevation of erythrocyte sedimentation rate and a positive result for C-reactive protein, while only 3 PT patients (group B) did. There were no significant differences between the mean age, duration of symptoms, white blood cell count, serum triiodothyronine (T3) and thyroxine (T4) concentrations, serum T3/T4 ratio and duration of thyrotoxicosis after the initial examination and prevalences of positive results for antithyroglobulin and -microsomal antibodies in the two diseases. Two of 8 painful AT patients showed a histologically chronic fibrous variant and 6 others showed chronic lymphocytic thyroiditis. All PT patients examined also showed lymphocytic thyroiditis. Two and 5 painful AT patients developed transient and persistent hypothyroidism, respectively, while 8 [7 in group A (normal ESR), 1 in group B] and 3 PT patients (1 in group A, 2 in group B) did, respectively. The mean serum thyroid-stimulating hormone level in the hypothyroid phase in painful AT patients was higher than that in PT patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Thyroid Amyloidosis With Recurrent Subacute Thyroiditis-Like Syndrome

We studied 2 men with a subacute thyroiditis-like syndrome (STLS) associated with systemic amyloidosis. Both had very tender, diffuse, firm goiters, low thyroidal radioactive iodine uptake values, and increased erythrocyte sedimentation rates. Glucocorticoid therapy resulted in dramatic improvement. Compared to 18 patients with subacute thyroiditis, these 2 men had 1) persistence of goiter even in remission, 2) repeated exacerbation of STLS, 3) pain always localized in the same site, and 4) gastrointestinal, renal, and cardiac abnormalities. Histological examination of the patients' thyroid glands revealed amyloid deposition and no evidence of subacute thyroiditis. In addition, 1 man had low T3 thyrotoxicosis with an elevated rT3/T3 ratio, suggesting impaired peripheral conversion of T4 to T3, and immunological and histological evidence of Hashimoto's thyroiditis. These findings suggest that thyroid amyloidosis may be associated with STLS. When patients with clinical features of subacute thyroiditis have an unusual course, the possibility of thyroid amyloidosis should be considered.

Postpartum Thyroid Dysfunction

Until recently, postpartum thyroid dysfunction generally referred to secondary hypothyroidism due to pituitary failure (Sheehan's syndrome). Although cases of postpartum primary hypothyroidism have been previously reported, 1 the pioneering work of Amino and colleagues 2-4 in Osaka, Japan, followed by three series from Canada, 5 England, 6 and the United States, 7 has led to recognition of the syndrome of postpartum thyroid dysfunction. What is postpartum thyroid dysfunction? This usually refers to postpartum silent (painless) thyroiditis, a syndrome of transient low radioactive iodine uptake thyrotoxicosis followed by hypothyroidism, usually followed by a return to a euthyroid state. The thyrotoxic phase usually occurs between one to three months post partum and lasts for one to two months, while the hypothyroid phase usually occurs between three to six months post partum and lasts for three to five months. This syndrome appears to be the same as the syndrome of silent (painless) thyroiditis,

The various presentations of thyroiditis. Diagnostic considerations.

The syndromes of thyroiditis include five disorders. Hashimoto's thyroiditis, the commonest, is an autoimmune disease whose principal manifestations are goiter and hypothyroidism. Subacute granulomatous thyroiditis is probably viral in origin and usually presents with a tender goiter. Subacute lymphocytic thyroiditis is of unknown pathogenesis, but the postpartum form may be autoimmune. Its principal manifestations are goiter and spontaneously reversible hyperthyroidism. Acute suppurative thyroiditis results from bacterial or fungal infection causing abscess. Riedel's struma, a disease of unknown cause, presents with a goiter and thoracic inlet obstruction. Thyroiditis may require differentiation from other diseases. The goiter may resemble that of Graves' disease or thyroid lymphoma. Thyroid nodules may resemble neoplasms. Hyperthyroidism may suggest Graves' disease or other hyperthyroid syndromes with low radioactive iodine uptake. Neck pain can also occur with some thyroid malignancies. Local abscess is usually infectious but may be undifferentiated thyroid carcinoma. Finally, hypothyroidism may be transient or permanent.

Euthyroid Atypical Subacute Thyroiditis Simulating Systemic or Malignant Disease

An unusual form of atypical subacute thyroiditis (SAT) occurred in 13 patients. The clinical presentation in all patients simulated systemic or malignant disease, involving fever of long duration and loss of weight without localized thyroid tenderness and without signs or symptoms of thyrotoxicosis. Eleven of the 13 patients had normal serum free thyroxine values. In the ten patients in whom a needle biopsy was done, the histologic findings were the same as in typical SAT. In the other three patients, the diagnosis was made based on the following clinical findings: high erythrocyte sedimentation rate, low radioactive iodine uptake, and good response to salicylate (aspirin, 2 g/day) or steroid (prednisone, 30 mg/day) treatment. Early recognition of this variation of atypical SAT may save the patients unnecessary investigations in search of systemic or malignant disease.

Silent (Painless) Thyroiditis

• Recent reports suggest that 14% to 23% of thyrotoxic patients have silent (painless) thyroiditis, a newly described syndrome characterized by transient thyrotoxicosis with a low radioactive iodine uptake. A three-year review at a Brooklyn (NY) hospital showed only one definite and three possible cases of silent thyroiditis among 86 thyrotoxic patients. At most, 4% to 5% of thyrotoxic patients had silent thyroiditis. We suggest a geographic variation in this syndrome. Most cases and the largest series are from Japan and the Great Lakes area of North America. The latter may be related to increased iodine intake over many years in a previously endemic area of hypoiodidism and goiter, although other local factors may also be involved. (<i>Arch Intern Med</i>1985;145:473-475)

Silent (painless) thyroiditis. Evidence of a geographic variation in frequency.

Recent reports suggest that 14% to 23% of thyrotoxic patients have silent (painless) thyroiditis, a newly described syndrome characterized by transient thyrotoxicosis with a low radioactive iodine uptake. A three-year review at a Brooklyn (NY) hospital showed only one definite and three possible cases of silent thyroiditis among 86 thyrotoxic patients. At most, 4% to 5% of thyrotoxic patients had silent thyroiditis. We suggest a geographic variation in this syndrome. Most cases and the largest series are from Japan and the Great Lakes area of North America. The latter may be related to increased iodine intake over many years in a previously endemic area of hypoiodidism and goiter, although other local factors may also be involved.

Immunologic studies in two patients with persistent lymphocytic thyroiditis, thyrotoxicosis, and low radioactive iodine uptake

Two patients with persistent lymphocytic thyroiditis and thyrotoxicosis were studied. Both patients presented with severe hyperthyroidism of nine months' duration and had nontender, small thyroid glands. Uptake of radioactive iodine ( 131I) was consistently low. Serum thyroxine and triiodothyronine levels remained elevated without remission until thyroidectomy. The serum thyroglobulin level was normal, but testing for microsomal antibody gave weakly positive results in one case. Thyroglobulin and thyroid stimulatory antibodies were not found. The ratio of helper to suppressor T cells was elevated in one case. Neither patient showed response to propranoiol, prednisone, or iodine. Light microscopic and immunohistologic studies showed severe lymphocytic thyroiditis with formation of secondary lymphoid follicles. Lymphocytes were predominately T cells (OKT11-positive), primarily helper/inducer T cells (OKT4-positive). Hyperplastic nodules contained high immunoreactive thyroglobulin and thyroxine levels. Aberrant thymus was seen within the thyroid. These studies suggest the possibility of intrathyroidal stimulation and hydrolysis of thyroglobulin within thyroid cells and also support the hypothesis that T and B cell immunoregulatory defects are important in the pathogenesis of this disease.

Thyrotoxic Lymphocytic Thyroiditis-Reply

In Reply. —Dr Nusynowitz expresses his amazement that my recent review of thyroiditis failed to reference an article he coauthored in 1975. My review was not an attempt to provide an exhaustive, historic perspective. Almost all of the references on painless thyroiditis were from 1980 or later. Dr Nusynowitz also comments that the authors of reference 33 in my review mistakenly considered their patients with painless thyroiditis to have a variant of subacute thyroiditis. In contrast, Dr Nusynowitz, in his report, concluded that the patients had a variant of Hashimoto's thyroiditis. Both interpretations, although quite reasonable based on the information available in 1975, would raise considerable controversy in 1983. More than a dozen terms have been used to describe the condition of transient thyrotoxicosis associated with a low radioactive iodine uptake and lymphocytic infiltration. I prefer painless thyroiditis , since the term is commonly employed (including in the sixth edition of

Painless Thyroiditis: Diagnostic Essentials

To the Editor.— It is important for therapeutic as well as academic reasons to identify patients who have the newly described silent, or painless, thyroiditis and to differentiate them from patients with hyperthyroidism of other cause. The former condition is usually self-limiting, occasionally recurring, and rarely may lead to long-term hyperthyroidism or hypothyroidism. Symptomatic treatment is all that is usually required, and methods that destroy thyroid tissue or interfere with hormone production should not be employed. Elevated concentration of thyroid hormone, a low radioactive iodine uptake (RAIU), and a normal ESR are prerequisites for a reliable diagnosis of the condition. However, ingestion of thyroid hormone or an expanded iodine pool also reduces RAIU and therefore can confuse the diagnosis. Subacute thyroiditis can usually be differentiated by the high ESR and on clinical grounds. Recently, Check and Avellino (1980; 244:1361) reported as an example of painless thyroiditis and transient thyrotoxicosis after

Postpartum thyrotoxicosis in a patient with Graves' disease. Association with low radioactive iodine uptake

A patient with previously diagnosed Graves' hyperthyroidism had a transient episode of thyrotoxicosis three months postpartum. This was associated with a diffusely enlarged thyroid gland, a rise in antithyroid microsomal antibody titer, a 24-hour radioactive iodine uptake (RAIU) of 1%, and an aspiration biopsy specimen suggestive of chronic lymphocytic thyroiditis. An alternative cause for the depressed RAIU was not discovered. This case would suggest that patients with previously diagnosed Graves' disease can have thyrotoxicosis without an enhanced RAIU and that the postpartum thyrotoxic syndrome may involve an immunologic injury causing a release of preformed thyroid hormone. (<i>JAMA</i>243:1454-1456, 1980)

Thyrotoxicosis due to Metastatic Involvement of the Thyroid-Reply

Dr Shimaoka correctly notes that metastatic cancer may cause hyperthyroidism with low radioactive iodine uptake. However, this is rare and seldom a diagnostic problem. The patients usually have widespread disease and do not survive long. 1 The radioactive iodine uptake is low because discharged thyroid hormone suppresses pituitary thyroid-stimulating hormone (TSH) release. After parenteral TSH administration, the image will demonstrate the size and sites of uninvolved areas of thyroid tissue, findings quite dissimilar to those of subacute thyroiditis. Unfortunately, Dr Shimaoka did not perform this study. 2 Also, his patient's return to normal thyroid status contrasts sharply with the persistent thyroid involvement characteristic of metastatic cancer. Perhaps a remarkable recovery is possible with lymphoma, but I agree with Dr Shimaoka that the thyroid findings he reported are identical to those seen with spontaneously resolving silent subacute thyroiditis (or silent chronic thyroiditis, as some readers may prefer). This patient might have

Thyrotoxicosis due to Metastatic Involvement of the Thyroid

To the Editor. —The article on atypical hyperthyroidism by Joel I. Hamburger, MD, in the JanuaryArchives(139:96-98, 1979) did not refer to another condition that may cause thyrotoxicosis. Involvement of the thyroid by metastatic neoplasm is relatively common in patients with cancer, but seldom causes thyroid dysfunction.1Hypothyroidism may develop after complete replacement of the thyroid by a tumor.1Although rare, thyrotoxicosis could also result from destruction of the thyroid by a rapidly growing metastatic tumor; we have reported such occurrence in a patient with a nodular, poorly differentiated lymphocytic lymphoma.2Since then, two additional cases appeared in the literature; one case was a pancreatic adenocarcinoma3and the other, a breast carcinoma.4However, such a phenomenon has not been observed in a primary thyroid cancer. Nontender, firm, and diffuse enlargement of the thyroid is found in association with a very low radioactive iodine uptake,

Transient Thyrotoxicosis Associated With Painless Thyroiditis and Low Radioactive Iodine Uptake

We describe a patient with transient thyrotoxicosis and low radioactive iodine uptake by the thyroid. Although the clinical course in this patient was compatible with subacute thyroiditis, she did not experience pain or tenderness in the neck. The use of thyroid hormones or iodine was excluded. The substantial level of thyroid antibody in serum was present during the entire phase of the disease. Histological findings on thyroid biopsy were characteristic of chronic lymphocytic thyroiditis. Furthermore, it was remarkable that the histological abnormalities improved spontaneously during the course of several months, with the spontaneous recovery of clinical signs and biochemical abnormalities.

Transient thyrotoxicosis associated with painless thyroiditis and low radioactive iodine uptake

Transient thyrotoxicosis associated with painless thyroiditis and low radioactive iodine uptake

Thyrotoxicosis with painless goiter may recur or develop into hypothyroidism

About five years ago, reports appeared describing a form of thyrotoxicosis with painless goiter and low radioactive iodine uptake (RAIU) that appeared to resolve spontaneously in two to six months. The initial interpretation was that this condition is a variant of subacute thyroiditis, since the only apparent difference between the two was that in the latter condition the goiter is painful. However, biopsy studies subsequently showed that patients with transient painless goiter and thyrotoxicosis always have a lymphocytic inflammation rather than the granulomatous lesion found in subacute thyroiditis (<i>JAMA</i>240:1520-1521, 1978). New data presented at the recent meeting of the American Thyroid Association now show that there is another major difference: The newly described painless form does not resolve completely, as does subacute thyroiditis, but may recur over a period of years. According to Thomas F. Nikolai, MD, staff physician in the endocrinology section of the Marshfield (Wisconsin) Clinic and

Thyrotoxicosis with painless goiter may recur or develop into hypothyroidism

About five years ago, reports appeared describing a form of thyrotoxicosis with painless goiter and low radioactive iodine uptake (RAIU) that appeared to resolve spontaneously in two to six months. The initial interpretation was that this condition is a variant of subacute thyroiditis, since the only apparent difference between the two was that in the latter condition the goiter is painful. However, biopsy studies subsequently showed that patients with transient painless goiter and thyrotoxicosis always have a lymphocytic inflammation rather than the granulomatous lesion found in subacute thyroiditis (<i>JAMA</i>240:1520-1521, 1978). New data presented at the recent meeting of the American Thyroid Association now show that there is another major difference: The newly described painless form does not resolve completely, as does subacute thyroiditis, but may recur over a period of years. According to Thomas F. Nikolai, MD, staff physician in the endocrinology section of the Marshfield (Wisconsin) Clinic and

'Silent' Subacute Thyroiditis

To the Editor.— In response to the report by Morrison and Caplan, found in the JanuaryArchives(138:45-48, 1978), we do not deny the existence of painless or subacute thyroiditis. Neither do we claim, as Morrison and Caplan do, that the association of thyrotoxicosis, a low radioactive iodine uptake (RAIU), and a nontender thyroid gland is characteristic of subacute thyroiditis (typical atypical subacute thyroiditis?). The features not usually associated with subacute thyroiditis that were common to our reported cases and theirs, such as a normal ESR, painless thyroid glands, and occasional progression to hypothyroidism, led us to perform biopsies in a attempt to better define the disease process. Rather than confirm a clinical impression, Morrison and Caplan would allow for an clinical presentation of subacute thyroiditis in these cases, but have rigorously defined criteria for the clinical presentation of Hashimoto's thyroiditis. This exercise completed, the authors classify our

'Silent' Subacute Thyroiditis-Reply

In Reply.— Recently, investigators have reported 39 cases of hyperthyroidism without thyroid pain and/or tenderness associated with low radioactive iodine uptake (RAIU). Gluck and associates 1 have made a valuable contribution to the understanding of the cause of this syndrome by noting histological changes of chronic thyroiditis on thyroid biopsies performed in four cases. Although the changes of chronic thyroiditis have also been detected by other investigators, 2,3 there remains considerable controversy over whether patients with this thyroid disorder have a form of subacute thyroiditis or chronic thyroiditis. In an editorial in the JanuaryArchives(138:26-27, 1978), Woolf indicates that patients exhibit features of both disorders. The clinical course, low RAIU, and negative or weakly positive thyroid antibodies suggests subacute thyroiditis, while the absence of thyroidal pain, normal ESR and biopsy findings are consistent with chronic thyroiditis. Although the relative merits of these causes are debated in recent reports, editorials,

'Silent' subacute thyroiditis

<h3>To the Editor.—</h3> In response to the report by Morrison and Caplan, found in the JanuaryArchives(138:45-48, 1978), we do not deny the existence of painless or atypical subacute thyroiditis. Neither do we claim, as Morrison and Caplan do, that the association of thyrotoxicosis, a low radioactive iodine uptake (RAIU), and a nontender thyroid gland is characteristic of subacute thyroiditis (typical "atypical" subacute thyroiditis?). The features not usually associated with subacute thyroiditis that were common to our reported cases and theirs, such as a normal ESR, painless thyroid glands, and occasional progression to hypothyroidism, led us to perform biopsies in a attempt to better define the disease process. Rather than confirm a clinical impression, Morrison and Caplan would allow for an atypical clinical presentation of subacute thyroiditis in these cases, but have rigorously defined criteria for the clinical presentation of Hashimoto's thyroiditis. This exercise completed, the authors classify our