Low Serum Thyroglobulin as a Clue to the Diagnosis of Thyrotoxicosis Factitia

Mariotti, Stefano; Martino, Enio; C, Cupini; Lari, Riccardo; Giani, Carlotta; Baschieri, L; Pinchera, Aldo

doi:10.1056/nejm198208123070705

Cited by 134 publications

(36 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…thyroid disease, such as subacute thyroiditis (Hidaka et al, 1994), Graves' disease (Izumi and Larsen, 1978), and thyrotoxicosis factitia (Mariotti et al, 1982), or among people with a history of thyroid cancer (Ericsson et al, 1984;Haugen et al, 2016;Heemstra et al, 2007;McGrath et al, 2015;Molinaro et al, 2013;Rosario et al, 2013;Trimboli et al, 2015). While several epidemiologic studies have examined factors related to serum Tg in large population-based settings (Krejbjerg et al, 2016;Ma and Skeaff, 5 2014), only one other study has examined factors related to Tg in a radiation exposed population with mild-to-moderate iodine deficiency (Cahoon et al, 2013).…”

Section: Most Studies Of Serum Tg Have Been Conducted Among Individuamentioning

confidence: 99%

Factors associated with serum thyroglobulin in a Ukrainian cohort exposed to iodine-131 from the accident at the Chernobyl Nuclear Plant

Peters

Тronko

Hatch

et al. 2017

Environmental Research

View full text Add to dashboard Cite

Background: Serum thyroglobulin (Tg) is associated with the presence of thyroid disease and has been proposed as a biomarker of iodine status. Few studies have examined factors related to serum Tg in populations environmentally exposed to ionizing radiation and living in regions with endemic mild-tomoderate iodine deficiency. Methods:We screened 10,430 individuals who were living in Ukraine and under 18 years of age at the time of the 1986 Chernobyl Nuclear Power Plant accident for thyroid disease from 2001 to 2003. We estimated the percent change (PC) in serum Tg associated with demographic factors, iodine-131 thyroid dose, and indicators of thyroid structure and function using linear regression. We also examined these relationships for individuals with and without indications of thyroid abnormality.Results: Mean and median serum Tg levels were higher among participants with abnormal thyroid structure/function. Percent change in serum Tg increased among females, smokers and with older age (pvalues < 0.001), and Tg increased with increasing thyroid volume, and serum thyrotropin (p-values for trend < 0.001). We found no evidence of significant associations between iodine-131 thyroid dose and Tg. Serum Tg levels were inversely associated with iodized salt intake (PC= -7.90, 95% confidence interval: -12.08, -3.52), and over the range of urinary iodine concentration, the odds of having elevated serum Tg showed a U-shaped curve with elevated Tg at low and high urinary iodine concentrations. Conclusion:Serum Tg may be a useful indicator of population iodine status and a non-specific biomarker of structural and functional thyroid abnormalities in epidemiological studies.

show abstract

Section: Most Studies Of Serum Tg Have Been Conducted Among Individuamentioning

confidence: 99%

Factors associated with serum thyroglobulin in a Ukrainian cohort exposed to iodine-131 from the accident at the Chernobyl Nuclear Plant

Peters

Тronko

Hatch

et al. 2017

Environmental Research

View full text Add to dashboard Cite

show abstract

“…Patients with toxic adenoma had a single hot thyroid nodule at scintiscan with absent radioiodine uptake in the extranodular tissue. Patients with thyrotoxicosis factitia had low/suppressed thyroidal 24-h radioiodine uptake values (3 Ϯ 1%), normal urinary iodine excretion, and undetectable serum Tg (18). All patients admitted surreptitious thyroid hormone pill intake.…”

Section: Conventional and Cfd Sonographymentioning

confidence: 99%

Thyroid vascularity and blood flow are not dependent on serum thyroid hormone levels: studies in vivo by color flow doppler sonography

Bogazzi

Bartalena

Brogioni

et al. 1999

European Journal of Endocrinology

125

View full text Add to dashboard Cite

Objective: Thyroid blood flow is greatly enhanced in untreated Graves' disease, but it is not known whether it is due to thyroid hormone excess or to thyroid hyperstimulation by TSH-receptor antibody. To address this issue in vivo patients with different thyroid disorders were submitted to color flow doppler sonography (CFDS). Subjects and methods:We investigated 24 normal subjects, and 78 patients with untreated hyperthyroidism (49 with Graves' hyperthyroidism, 24 with toxic adenoma, and 5 patients with TSH-secreting pituitary adenoma (TSHoma)), 19 patients with thyrotoxicosis (7 with thyrotoxicosis factitia, and 12 with subacute thyroiditis), 37 euthyroid patients with goitrous Hashimoto's thyroiditis, and 21 untreated hypothyroid patients with Hashimoto's thyroiditis. Results: Normal subjects had CFDS pattern 0 (absent or minimal intraparenchimal spots) and mean intraparenchimal peak systolic velocity (PSV) of 4.8 Ϯ 1.2 cm/s. Patients with spontaneous hyperthyroidism due to Graves' disease, TSHoma, and toxic adenoma had significantly increased PSV (P < 0.0001, P = 0.0004, P < 0.0001 respectively vs controls) and CFDS pattern. Patients with Graves' disease had CFDS pattern II (mild increase of color flow doppler signal) in 10 (20%) and pattern III (marked increase) in 39 cases (80%). Mean PSV was 15 Ϯ 3 cm/s. Patients with toxic adenoma had CFDS pattern I (presence of parenchymal blood flow with patchy uneven distribution) in 2 (8%), pattern II in 16 (70%) and pattern III in 5 (22%). Mean PSV was 11 Ϯ 2.4 cm/s. Patients with TSHoma showed CFDS pattern I in one case (20%) and pattern II in 4 (80%). Mean PSV was 14.8 Ϯ 4.2 cm/s. Patients with thyrotoxicosis had normal PSV (4.2 Ϯ 1.1 cm/s in subacute thyroiditis, 4 Ϯ 0.8 cm/s in thyrotoxicosis factitia, P = not significant vs controls) and CFDS pattern 0. Untreated euthyroid patients with goitrous Hashimoto's thyroiditis had CFDS pattern 0, and mean PSV (4.3 Ϯ 0.9 cm/s; P = not significant vs controls). Untreated hypothyroid patients with goitrous Hashimoto's thyroiditis had CFDS pattern I in 14 cases (67%), pattern II in 4 (19%) and pattern 0 in 3 (14%) and mean PSV (5.6 Ϯ 1.4 cm/s) was higher than that of controls (P = 0.026). Conclusions: An increase in both intrathyroidal vascularity and blood velocity was observed in patients with spontaneous hyperthyroidism but not in thyrotoxicosis due to either ingestion of thyroid hormones or to a thyroidal destructive process. The slightly increased vascularity and blood velocity observed in patients with hypothyroid Hashimoto's thyroiditis suggests that thyroid stimulation by either TSH-receptor antibody or TSH is responsible for the increased thyroid blood flow.

show abstract

“…The suppressed levels of serum thyroglobulin may occur with the absence of thyroid tissue (after total thyroidectomy, or thyroid atrophy with almost no functional thyroid tissue) or with exogenous thyroid supplementation [6][7][8]. Markedly elevated TSH was consistent with the clinical diagnosis of hypothyroidism and suppressed serum thyroglobulin suggests either complete absence of thyroid tissue or exogenous administration of thyroid hormone.…”

Section: Discussionmentioning

confidence: 88%

Pseudohyperthyroxinemia in a hypothyroid patient secondary to chronic phlegmon

Parmar

2015

Diagnosis

View full text Add to dashboard Cite

Background: Elevated free thyroxine could be primary or secondary, endogenous or exogenous and often presents with symptoms of hyperthyroidism. Thyroxine levels are low in hypothyroidism, where the individual requires exogenous supplementation to maintain a euthyroid state. However, thyroxine levels may be elevated in a hypothyroid patient because of over-supplementation/ over-suppression with exogenous agent(s) or secondary to other pathologies and rarely, laboratory error or assay interference may cause alteration in the levels of the thyroid hormones. Case report: A 44-year-old man with well controlled hypothyroidism was referred for assessment of markedly elevated TSH and free thyroxine levels with low free T 3 . Clinically the patient was hypothyroid with symptoms of fatigue and weight gain of 30 pounds over the past 3-months and the TSH levels were consistent with marked hypothyroidism. However, free thyrxoine was markedly elevated, opposite of what to be expected. A systematic evaluation, presented here, was helpful in the diagnosis of pseudohyperthyroxinemia secondary to assay interferences in a timely fashion, avoiding unnecessary further investigations. Conclusions: Interference in immunoassays is an important clinical problem that is underestimated and can have important clinical consequences. It is important to recognize the possibility of such interferences early in the diagnostic process and to implement protocols to identify these whenever possible, in a timely fashion, to prevent untoward consequences. Vigilance by both the clinician and the laboratory staff is important.

show abstract

Low Serum Thyroglobulin as a Clue to the Diagnosis of Thyrotoxicosis Factitia

Cited by 134 publications

References 13 publications

Factors associated with serum thyroglobulin in a Ukrainian cohort exposed to iodine-131 from the accident at the Chernobyl Nuclear Plant

Factors associated with serum thyroglobulin in a Ukrainian cohort exposed to iodine-131 from the accident at the Chernobyl Nuclear Plant

Thyroid vascularity and blood flow are not dependent on serum thyroid hormone levels: studies in vivo by color flow doppler sonography

Pseudohyperthyroxinemia in a hypothyroid patient secondary to chronic phlegmon

Contact Info

Product

Resources

About