Median Thyroid Volume Research Articles

Thyroid volume measured by ultrasonography and CT.

To evaluate measurements of thyroid volume by two different US methods and CT in a blinded design. Four observers evaluated 27 patients. Observer 1 used US and calculated thyroid volume based on recordings of cross-sections through the gland. Observer 2 used US and calculated the volume of each lobe as a rotation ellipsoid. Observers A and B used CT images and calculated thyroid volume based on recordings of cross-sections through the gland. All measurements were made twice. The median thyroid volume was 81 ml (range 7-470 ml) evaluated by CT. All three methods had fair reproducibility. When correlating the two different methods using US, an r of 0.837 was found. When correlating data from patients without intrathoracic goitre evaluated by US (Observer 1) and CT, r = 0.945. The method based on a rotation ellipsoid systematically produced smaller thyroid volumes than those of the cross-sectional method. Evaluation by US systematically produced smaller thyroid volumes than CT. Calculation of thyroid volume based on US recordings of cross-sectional areas is a reproducible method in patients without substernal goitre extension. The US method calculating thyroid volume as a rotation ellipsoid is less reproducible, especially in large goitres. Measurement of thyroid volume using CT should be preferred in goitres with substernal extension.

Goitre prevalence and thyroid abnormalities at ultrasonography: a comparative epidemiological study in two regions with slightly different iodine status

The association between severe iodine deficiency and endemic goitre is well established, but little information is available on the relation between milder degrees of iodine deficiency and goitre prevalence. In a comparative epidemiological study performed in two regions in Denmark, we examined 4649 subjects from the general population, women aged 18-65 years and men aged 60-65 years. Ultrasonography and palpation of the thyroid was performed in all participants. Iodine excretion was measured in casual urine samples. Previous thyroid disease was detected by questionnaires, personal interviews and tracing of records. The median iodine excretion was 61 microg/l (mild iodine deficiency (ID)) and 45 microg/l (moderate ID) in the two regions. Median thyroid volume at ultrasonography was 11. 9 ml (mild ID) and 13.6 ml (moderate ID), P <0.001, and thyroid enlargement was found in 15.0% (mild ID) and 22.6% (moderate ID), P<0.001. Goitre prevalence increased in both regions with age to the age group 40-45 years, but not after that age. Subjects who had moved from the moderate ID to the mild ID area had the same prevalence of thyroid enlargement as the subjects staying permanently in the mild ID area. Thyroid nodules at ultrasonography were found in 30% in both regions, but nodules were larger and more often palpable in the moderate ID area. Palpable goitre was found in 9.8% (mild ID) and 14.6% (moderate ID), P<0.001. The greatest regional difference in thyroid abnormalities was found among men. Marked differences in the prevalence of thyroid abnormalities were found in these regions with modest differences in iodine excretion.

Increased prevalence of thyroglobulin antibodies in Sri Lankan schoolgirls--is iodine the cause?

Iodine deficiency was the likely cause of a high prevalence of goitre previously in Sri Lankan schoolchildren. Salt iodination was made compulsory in 1993 but there has been no recent study, using modern techniques, of its benefits or harmful effects. Three hundred and sixty-seven schoolgirls between the ages of 11 and 16 years had ultrasound thyroid volume, free thyroxine (T4), free tri-iodothyronine (T3), thyrotrophin (TSH), anti-thyroglobulin (TgAb) and thyroid peroxidase (TPOAb) antibodies, and urine iodine concentrations measured. Median ultrasound thyroid volume ranged from 4.8 ml (11-year-old girls) to 8.6 ml (16-year-old girls) with an age-related increase. Median urine iodine concentrations ranged from 105 to 152 microg/l. Free T4 and free T3 were normal in all, but TSH was elevated in four subjects (5. 53-41.29 mU/l). However, the prevalence of TgAb was markedly raised, ranging between 14.3% (11-year-old girls) and 69.7% (16-year-old girls) (P<0.03). In contrast, the prevalence of TPOAb was 10% or less in all age groups. Normal median thyroid volumes, iodine concentrations and thyroid function would indicate that iodine deficiency is not a major problem in this group. The high prevalence of TgAb, hitherto unreported, most likely reflects excessive iodination of Tg resulting in increased immunogenicity. There is an urgent need to continuously monitor the adequacy and risks of iodination in this population.

Thyroid ultrasound is the best prevalence indicator for assessment of iodine deficiency disorders: a study in rural/tribal schoolchildren from Gujarat (Western India).

(i) To assess the severity of iodine deficiency disorders (IDD), (ii) to determine the aetiology of IDD in Gujarat, (iii) to identify the best prevalence indicator of IDD, and (iv) to compare thyroid volume (TV) results with the WHO International reference. Five hundred and thirty schoolchildren (6-15 years) were studied from two districts (Baroda and Dang) and data were collected on dietary habits and parameters such as height, weight, thyroid size by palpation and ultrasonography, urinary iodine (UI), and blood thyroid stimulating hormone (TSH). Drinking water was analyzed for iodine content and food articles for goitrogens. In Gujarat children median UI (interquartile range)=56 (30-96)microg/l, mean TSH=1.71 +/- 2.10mU/l, goiter by palpatio n = 30%, and median TV = 27.8 (23-35)ml. Females had lower median UI (48 (27-82) microg/l) and higher mean TSH levels (2.0 +/- 2.5mU/l) than males. Applying the WHO ultrasonography reference to Gujarat children resulted in an enlarged TV-for-body surface area in almost 100% of subjects. Ninety-nine percent of females and 95% of males had enlarged TV-for-age. Three to eight times larger TV were seen in all subjects as compared with European children. Dang children were severely malnourished. Flavonoids like vitexin, glucosyl vitexin and apigenin were detected in pearl millet. Apigenin was never identified in pearl millet. Dang district water was lacking in iodine content. IDD is a severe public health problem in Gujarat. Baroda district is a new pocket of IDD. High amounts of dietary flavonoids in Baroda and Dang districts, and lack of iodine in Dang water, account for IDD. TV measurement by ultrasound is the best prevalence indicator of IDD.

Thyroid structure and size and two-year follow-up of solitary cold thyroid nodules in an unselected population with borderline iodine deficiency.

Multinodular goitre has been found with a high prevalence in iodine-deficient areas, but less frequently in iodine-replete areas; the iodine intake sufficient to prevent goitre has not been established, however. We report data from an ultrasonic investigation of the thyroid glands of 2656 randomly selected subjects aged 41 to 71 years in an area with borderline iodine deficiency. Median iodine concentration in spot urine samples was 70microg/l. Multinodular thyroid structure was found in 23% of the population, increasing in women from 20 to 46% with increasing age, and in men from 7 to 23%. Solitary, scintigraphically cold, thyroid nodules >10mm were found in 2.4% of the population with the same prevalence in the different age and sex groups. Two years of follow-up of these cold nodules revealed no signs of malignancies. Median thyroid volume was 11.0ml. Thyroid enlargement (>18ml for women and >25ml for men) was found among 13. 1% of the women and 6.2% of the men, and the prevalence increased with age. The presence of thyroid nodules was related to positive anti-thyroperoxidase antibody (TPO Ab) titres, whereas thyroid enlargement was associated with iodine excretion <50microg/day. Thyroid enlargement was associated with low iodine excretion and median thyroid volume was slightly increased compared with iodine-replete areas. Multinodular thyroid structure was found with a high prevalence and was associated with TPO Ab >200kU/l. Cold thyroid nodules were moderately prevalent, with no cases of detected malignancies during 2 years of follow-up.

Dermatitis herpetiformis is associated with atrophic but not with goitrous variant of Hashimoto's thyroiditis.

Dermatitis herpetiformis (DH) is a gluten-sensitive skin disease that is associated with a variety of autoimmune disorders. Several investigations demonstrated an association between DH and autoimmune thyroid disease. However, it has not been shown if DH is associated with atrophic or goitrous variant of Hashimoto's thyroiditis. We investigated a cohort of 41 DH patients (18 male, 23 female) and a control group (11 male, 19 female; sex and age matched healthy volunteers) to find out which variant of Hashimoto's thyroiditis is associated with DH. All patients had thyroid hormones and antibodies measured. In addition to that, thyroid sonography as well as detailed history-taking of previous thyroid disease were performed. In the control group no individual with elevated levels of thyroid antibodies nor abnormal thyroid hormones nor thyroid atrophy was found. Median thyroid volume in the control group was 11 mL (range 4.8-24.7 mL). However, in nine DH patients (22%) elevated levels of antithyroid microsomal (TM) antibodies were seen (P < 0.01). Three of them had abnormal thyroid hormones (7%). In the group of DH patients a significantly smaller thyroid volume was found (median 8 mL, range 1. 6-25.2 mL; P < 0001). Thyroid atrophy (volume < 4.4 mL) was found in 10 DH patients (24%) of whom 9 were females. All patients with elevated levels of TM antibodies or abnormal thyroid hormones and all patients with a history of previous hypothyroidism had a thyroid volume < 7 mL. Goitrous variant of Hashimoto's thyroiditis was not seen in any of the DH patients. Our findings demonstrate that DH is associated with atrophic but not with goitrous variant of Hashimoto's thyroiditis.

Variation in iodine handling during normal pregnancy.

Reports in the literature are divided on changes in thyroid volume and urinary iodine excretion (UI) during normal pregnancy. Reports from Ireland, an area of modest dietary iodine intake (median UI 70 microg/L) showed an increase in UI that rose to a median value of 135 microg/L in the first trimester (T1) and continued at 124 microg/L in the second (T2) and 122 microg/L in the third trimester (T3). In parallel with the increase in UI, mean ultrasound measured thyroid volume increased by a maximum of 47% over nonpregnant values in the third trimester (T3). Although these findings were consistent with studies in Cardiff, UK (median UI 73 microg/L), which also showed a pregnancy-associated rise in UI excretion (maximum 176 microg/L) accompanied by a 30% increase in median thyroid volume, they differed from findings in Sri Lanka (median UI 146 microg/L), a country in which a successful program of salt iodination has recently been implemented, which showed no significant changes in UI excretion (T3 maximum 154 microg/L) but did show a modest (20%) maximum increase in median thyroid volume at T3. Prospective studies on Irish subjects showed that median UI fell precipitously to nonpregnant control values (76 microg/L) at delivery. In addition, UI in neonates sampled at 3-days postdelivery showed that excretion was greater in breast-fed than in bottle fed infants. Differences in reported UI excretion patterns during pregnancy may may reflect the existence of a threshold above which increased renal clearance results in increased iodine loss but that is masked at higher iodine intakes. Assuming constant dietary iodine intake during pregnancy, any increased urine loss will inevitably lead to negative iodine balance and thyroid depletion. In these circumstances, increased thyroid volume may in part be a compensatory mechanism to allow for greater iodine storage.

Radioiodine therapy for multinodular toxic goiter.

Radiolabeled iodine 131 therapy is used for treatment of multinodular toxic goiter, but long-term follow-up studies are lacking. A prospective study of 130 consecutive patients (115 women) treated with 131I for multinodular toxic goiter and followed by evaluation of thyroid volume (determined using ultrasound) and thyroid function variables. The patients were observed for a median of 72 months (range, 12-180 months). Sixty-six patients received antithyroid drug pretreatment; 64 did not. Iodine 131 treatment (3.7 MBq/g thyroid tissue corrected to a 100% 24-hour 131I uptake) was given as a single dose in 81 patients, 2 doses in 38, and 3 to 5 doses in 11. One or 2 treatments cured 119 patients (92%), and 68 (52%) became euthyroid within 3 months after 131I treatment. The median 131I dose was 370 MBq (range, 93-1850 MBq). Forty-nine patients needing more than 131I dose had a reduction in median thyroid volume from 56 mL (range, 21-430 mL) to 44 mL (range, 15-108 mL), representing a 24% reduction related to the insufficient 131I dose. In all patients, the initial median thyroid volume of 44 mL (range, 16-430 mL) decreased to 25 mL (range, 8-120 mL) (P<.005), representing a median reduction of 43%, 24 months after the last 131I dose. Hypothyroidism evaluated using life-table analysis developed in 6% of patients who did not receive antithyroid pretreatment and 20% who did (P<.005) after a median of 42 months (range, 3-60 months), the total hypothyroidism frequency being 14% within 5 years of treatment. Ninety-two percent of patients with multinodular toxic goiter were cured with 1 or 2 treatments. The thyroid volume was reduced by 43%, with few side effects. Iodine 131 should be the choice of treatment in patients with multinodular toxic goiter.

Effect of iodized salt on thyroid volume of children living in an area previously characterized by moderate iodine deficiency.

It is well established that an adequate iodine intake prevents iodine deficiency disorders. Prophylaxis through iodized salt is able to correct urinary iodine deficiency and to prevent goiter endemia, but scanty data are available about its effect on decreasing the thyroid size in goitrous children born before prophylaxis. The prevalence of goiter was evaluated by ultrasound in the school-children population of an area of Eastern Tuscany (Tiberina Valley) characterized by moderate iodine deficiency in 1985. At present, after the implementation of voluntary iodized salt consumption, iodine urinary excretion was borderline sufficient (median, 98 micrograms/L). Goiter prevalence was higher at ultrasound (17%) than by palpation (10%). The median thyroid volume ranged from 3.1 mL in 7-yr-old children to 9.2 mL in 14-yr-old children. In the 7-10 yr age class (i.e. in children born after iodine prophylaxis), no statistical difference in thyroid volume was found with respect to controls. In older children (11-14 yr) born before the institution of iodine prophylaxis, the median thyroid volume was significantly higher than that in age-matched controls. Moreover, in this cluster of subjects, the median thyroid volume in nongoitrous children was higher than that in controls. In conclusion, the data of the present study indicate that the iodized salt prophylaxis is able to prevent the development of goiter in children born after the implementation of iodized salt consumption and to further control thyroid enlargement in older children, but is less effective (or rapid) in reducing goiter size in children exposed to iodine deficiency in the first years of life.

Influence of compensated radioiodine therapy on thyroid volume and incidence of hypothyroidism in Graves' disease.

To investigate the long-term effect of radioactive iodine (131I) on thyroid function and size in patients with Graves' disease. Out-patient clinic in Herlev Hospital. One hundred and seventeen consecutive patients (104 women) with Graves' disease selected for 131I treatment and followed for a minimum of 12 months (range 1-10 years, median 5 years). 131I dose was calculated based on thyroid volume and 24-h 131I uptake. Standard thyroid function variables and ultrasonically determined thyroid volume before treatment as well as 0.75, 1.5, 3, 6 and 12 months after treatment, and then once a year were investigated. Seventy-eight patients were cured by one 131I dose and 30 by two doses, while the remaining nine patients received additional doses (range one to five doses, median one dose). Within one year, 25% developed hypothyroidism, and hereafter, hypothyroidism developed at a constant rate of 3% per year independent of antithyroid pretreatment. The cumulative 10-year risk of hypothyroidism was 60%. Initial median thyroid volume was 33 mL (range 9-106 mL). At 12 months after the last 131I dose, median thyroid volume was reduced to 14 mL (range 6-36 mL) (P < 0.00001). The median reduction being 58% (range 0-80%), hereafter no further reduction occurred. A significant reduction in thyroid volume was also noted in patients needing subsequent 131I doses and in those developing hypothyroidism within the first year. 131I normalizes thyroid volume in patients with Graves' disease. Hypothyroidism seems an inevitable end result of this treatment. The present study suggests that it will be impossible to modify 131I therapy in a way to achieve both early control of hyperthyroidism and a low incidence of hypothyroidism.

Thyroid cytotoxic antibodies in atrophic and goitrous autoimmune thyroiditis

It is unknown whether in chronic lymphocytic thyroiditis the goitrous (Hashimoto's thyroiditis) and atrophic forms (primary myxedema) are variants of the same disease or different pathogenic entities. Conventional thyroid-related autoimmune parameters are unable to separate both diseases serologically. It is assumed that cellular and humoral cytotoxic events induce gland atrophy and thus should be detectable more often in non-goitrous than goitrous autoimmune thyroiditis. We determined antibody-dependent cell-mediated cytotoxicity in 67 patients with autoimmune thyroiditis, using a 51chromium-release assay against human thyroid cells. Thyroid volume had been measured by ultrasonography. Other thyroid-specific antibodies, like TSH binding-inhibiting antibodies, TSH function-blocking antibodies, thyroglobulin antibodies and thyroid peroxidase antibodies, were determined. Cytotoxic antibody activity was 20.5% (median, range 0-54.5%) in patients with autoimmune thyroiditis and 8.3% (median, range 0-18.4%) in controls (p < 0.0001). Analysis of cytotoxicity regarding thyroid size showed a high incidence of cytotoxic antibodies in atrophic disease (median thyroid volume 6 ml), where cytotoxic antibodies were detectable in 80% versus 39% (x2 = 9.6; p < 0.0001) in goitrous disease (median thyroid volume 36 ml). The specific lysis of 30% (median; 95% confidence limit 23.9-32.9) in non-goitrous thyroiditis patients was significantly higher than in goitrous patients (16.9%; 95% confidence limit 13.2-20.4) (p = 0.0006).(ABSTRACT TRUNCATED AT 250 WORDS)

Radioiodine treatment of multinodular non-toxic goitre.

To investigate the long term effect of radioactive iodine on thyroid function and size in patients with non-toxic multinodular goitre. Consecutive patients with multinodular non-toxic goitre selected for radioactive iodine treatment and followed for a minimum of 12 months (median 48 months) after an intended dose of 3.7 MBq/g thyroid tissue corrected to a 100% uptake of iodine-131 in 24 hours. 69 patients with a growing multinodular non-toxic goitre causing local compression symptoms or cosmetic inconveniences. The treatment was chosen because of a high operative risk, previous thyroidectomy, or refusal to be operated on. Standard thyroid function variables and ultrasonically determined thyroid volume before treatment as well as 1, 2, 3, 6, and 12 months after treatment and then once a year. 56 patients were treated with a single dose of 131I, 12 with two doses, and one with four doses. In 45 patients treated with one dose and remaining euthyroid the median thyroid volume was reduced from 73 (interquartile range 50-106) ml to 29 (23-48) ml at 24 months in the 39 patients in whom this was measured during follow up. The median reduction was 40 (22-48) ml (60% reduction, p < 0.0001), half of which occurred within three months. Patients treated with two doses as well as those developing hypothyroidism and hyperthyroidism had a significant reduction in thyroid volume. Eleven patients developed hypothyroidism (cumulative five year risk 22%, 95% confidence interval 4.8% to 38.4%). Side effects were few: three cases of hyperthyroidism and two cases of radiation thyroiditis. Only one patient was dissatisfied with the result; she was referred for operation six months after treatment. A substantial reduction in thyroid volume accompanied by a low incidence of hypothyroidism and few side effects makes the use of radioactive iodine an attractive alternative to surgery in selected cases of non-toxic multinodular goitre.

Influence of rifampicin on thyroid gland volume, thyroid hormones, and antipyrine metabolism.

The influence of rifampicin (450 mg/day for 28 days) on the hepatic microsomal enzymes and thyroid function variables were investigated in 13 healthy male volunteers. After 14 and 28 days of treatment a significant increase in median thyroid volume (determined ultrasonically) was demonstrated (20 ml, range 13-28 before; 26 ml, range 18-48 at day 14, and 24 ml, range 17-40 at day 28) (p less than 0.01). A significant decrease in median serum free T4 index levels was seen (94.1 arbitrary units, range 80.1-123.4 before treatment; 86.8, range 71.7-102.0 at day 14, and 85.3, range 65.5-131.3 at day 28) (p less than 0.01). Serum T4, T3, T3 resin uptake, free T3 index and TSH levels were not significantly altered. Hepatic microsomal enzyme activity assessed by antipyrine clearance was significantly increased (approximately by 85%) at day 14 and 28, whereafter it normalized. The study supports the hypothesis that the increase in thyroid volume after treatment with rifampicin and other hepatic enzyme system inducers (e.g. phenytoin and carbamazepine) is a compensatory mechanism caused by an increased hepatic degradation of thyroid hormones.

Independent effects of liver disease and chronic alcoholism on thyroid function and size: The possibility of a toxic effect of alcohol on the thyroid gland

In an autopsy study we found thyroid volume significantly decreased in alcoholics with liver cirrhosis as compared to matched controls: 15 mL (range, 7 to 37 mL) v 25 mL (range, 13 to 90 mL) ( P < .01). At the same time the amount of fibrosis of the thyroid glands was higher in the alcoholics as compared to the matched controls: 20% (range, 6% to 40%) v 12% (range, 6% to 23%) ( P < .01). In order to evaluate the relative importance of alcohol consumption and liver disease on thyroid function and ultrasonically determined size, three groups of patients and matched controls (sex, age, weight, and smoking habits) were investigated: group 1, 18 patients with nonalcoholic liver cirrhosis; group 2, 21 consecutive chronic alcoholics (>100 g of alcohol daily for >5 years) without liver cirrhosis (all had biopsy proven fatty change or normal liver); group 3, 31 nonalcoholic patients with chronic nonhepatic, nonrenal disease. In group 1 median thyroid volume and serum FT 4I, FT 3I, and TSH levels were unchanged compared with the controls. In group 2 median thyroid volume was 13 mL (range, 9 to 32 mL) compared with 27 mL (range, 12 to 44 mL) in the controls ( P < .005). Serum T 3 and FT 3I levels were reduced, while T 4, FT 4I, and TSH levels were unaltered. In group 3 serum T 3 and FT 3I levels were reduced while serum FT 4I and TSH levels and thyroid volume were unaltered compared with the controls. It is suggested that alcohol may have a toxic effect on the thyroid gland independent of the degree of liver damage.

Thyroid gland volume and thyroid function during and after acute hepatitis infection

Thyroid function, the occurrence of goiter, and ultrasonically determined thyroid gland volume were investigated in 23 consecutive nonalcoholic patients with acute viral hepatitis during and six months after recovery, and compared with data obtained from 23 matched controls. Seven patients had clinically detectable goiter during disease, but only one after recovery ( P < 0.05). Median thyroid volume was 28 mL (range 15 to 42 mL) compared with 18 mL (range 12 to 27 mL) after recovery ( P < 0.001), and 17 mL (range 11 to 24 mL) in the controls ( P < 0.001). During acute hepatitis, serum levels of thyroxine, thyroxine binding globulin, and free thyroxine index were significantly increased while triiodothyronine and thyrotropin levels were unaltered and triiodotryronine resin uptake and free triiodothyronine index levels were decreased. After recovery all thyroid variables were normalized. In conclusion, acute liver disease was associated with a marked increase in thyroid volume, but the study did not clarify the mechanism underlying thyroid enlargement.

Increased frequency of goitre in epileptic patients on long-term phenytoin or carbamazepine treatment.

Thyroid function, the clinical occurrence of goitre and ultrasonically determined thyroid gland volume were investigated in 23 patients with phenytoin- and 28 patients with carbamazepine-treated convulsive disorders and compared with matched healthy controls. In the phenytoin treated group median thyroid volume was 26 ml (range 14-57 ml) compared to 17 ml (range 8-41 ml) in the controls (P less than 0.01). Ten patients and four controls had a goitre (NS). Median serum T4 and FT4I levels were reduced, serum TSH level increased and serum T3, T3RU, FT3I and thyroglobulin levels unaltered compared with the controls. In the carbamazepine treated group median thyroid volume was 25 ml (range 13-66 ml) compared to 16 ml (range 9-44 ml) in the controls (P less than 0.01). Thirteen patients and three controls had a goitre (P less than 0.02). Median serum T4, FT4I and FT3I levels were reduced, serum thyroglobulin increased and serum T3, T3RU and TSH levels unaltered compared with the controls. The increase in thyroid size is probably a compensatory mechanism due to the low free thyroid hormones in serum caused by an increased hepatic degradation of thyroid hormones by phenytoin and carbamazepine.

High frequency of goitre in cigarette smokers.

Thyroid function, the clinical occurrence of goitre and ultrasonically determined thyroid gland volume were investigated in 219 healthy subjects randomly chosen from hospital employees. Thirty-five subjects (16%) had a clinically detectable goitre. The frequency of goitre among smokers was higher (32 of 107, 30%) than among non-smokers (3 of 112, 3%), (P less than 0.001). Median thyroid volume was significantly higher in smokers, 26 ml (range 11-55 ml), compared with non-smokers, 15 ml (range 8-37 ml), (P less than 0.001). The median serum thyroglobulin levels were significantly higher and median serum thyrotropin levels lower in smokers compared with non-smokers. There were no differences between the groups regarding serum levels of T4, T3, rT3, free T4 index, free T3 index, thyroglobulin antibodies and 131I uptake (24 h) in the thyroid gland. It is suggested that these findings could partly be due to inhaled thiocyanate and/or increased adrenergic stimulation of the thyroid gland in smokers.