A Case Series of Patients With Central Hypothyroidism From Oxcarbazepine Therapy

2020 ◽  
pp. 088307382096292 ◽  
Author(s):  
Bahareh Michelle Schweiger ◽  
Aaron-James Lao ◽  
Jane Tavyev
Keyword(s):  
Thyroid Function ◽  
Pediatric Population ◽  
Case Series ◽  
Metabolic Enzymes ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Central Hypothyroidism ◽  
Serum Free ◽  
Serum Free Thyroxine ◽  
Stimulating Hormone

Many medications can impact thyroid function. Antiseizure medications have been shown to disrupt thyroid function in adults, but information is limited about how antiseizure medications may affect thyroid function in children. Oxcarbazepine is an analog of carbamazepine designed to minimize effects from the hepatic P450 metabolic enzymes. We have found that in the pediatric population, serum free thyroxine is reduced and thyroid-stimulating hormone concentrations are unchanged in patients taking oxcarbazepine with the mechanism thus being central hypothyroidism.

scholarly journals Misleading results from immunoassays of serum free thyroxine in the presence of rheumatoid factor

1997 ◽  
Vol 43 (6) ◽  
pp. 957-962 ◽  
Author(s):  
Anthony G W Norden ◽  
Rodwin A Jackson ◽  
Lorraine E Norden ◽  
A Jane Griffin ◽  
Margaret A Barnes ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Rheumatoid Factor ◽  
Equilibrium Dialysis ◽  
Thyroid Stimulating Hormone ◽  
Normal Serum ◽  
Free Thyroxine ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Serum Free Thyroxine ◽  
Stimulating Hormone

Abstract A novel interference with measurements of serum free thyroxine (FT4) caused by rheumatoid factor (RhF) is described. We found misleading, sometimes gross, increases of FT4 results in 5 clinically euthyroid elderly female patients with high RhF concentrations. All 5 patients had high FT4 on Abbott AxSYM® or IMx® analyzers. “NETRIA” immunoassays gave misleading results in 4 of the 5 patients; Amerlex-MAB® in 2 of 4 patients; AutoDELFIA®in 2 of the 5; and Corning ACS-180® and Bayer Diagnostics Immuno 1® in 1 of the 5. BM-ES700® system results for FT4 in these women remained within the reference range. Results for serum T4, thyroid-stimulating hormone, free triiodothyronine, thyroid-hormone-binding globulin, and FT4 measured by equilibrium dialysis were normal in all 5 patients. Drugs, albumin-binding variants, and anti-thyroid-hormone antibodies were excluded as interferences. Addition to normal serum of the RhF isolated from each of the 5 patients increased the apparent FT4 (Abbott AxSYM). Screening of 83 unselected patients demonstrated a highly significant positive correlation between FT4 (Abbott AxSYM) and RhF concentrations. Discrepant, apparently increased FT4 with a normal result for thyroid-stimulating hormone should lead to measurement of the patient’s RhF concentration.

scholarly journals L-T4 Therapy in the Presence of Pharmacological Interferents

2020 ◽  
Vol 11 ◽  
Author(s):  
Salvatore Benvenga
Keyword(s):  
Thyroid Function ◽  
Cardiovascular Complications ◽  
Primary Hypothyroidism ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Central Hypothyroidism ◽  
Serum Free ◽  
Function Tests ◽  
Frequent Monitoring ◽  
Serum Free Thyroxine

Pharmacological interference on L-thyroxine (L-T4) therapy can be exerted at several levels, namely from the hypothalamus/pituitary through the intestine, where the absorption of exogenous L-T4 takes place. A number of medications interfere with L-T4 therapy, some of them also being the cause of hypothyroidism. The clinician should be aware that some medications simply affect thyroid function tests with no need of modifying the dose of L-T4 that the patient was taking prior to their prescription. Usually, the topic of pharmacological interference on L-T4 therapy addresses the patient with primary hypothyroidism, in whom periodic measurement of serum thyrotropin (TSH) is the biochemical target. However, this minireview also addresses the patient with central hypothyroidism, in whom the biochemical target is serum free thyroxine (FT4). This minireview also addresses two additional topics. One is the costs associated with frequent monitoring of the biochemical target when L-T4 is taken simultaneously with the interfering drug. The second topic is the issue of metabolic/cardiovascular complications associated with undertreated hypothyroidism.

Serum free thyroxine concentrations measured by chemiluminescence in hyperthyroid and euthyroid cats

1996 ◽  
Vol 32 (6) ◽  
pp. 489-494 ◽  
Author(s):  
M Paradis ◽  
N Page
Keyword(s):  
Thyroid Function ◽  
Reference Values ◽  
Free Thyroxine ◽  
Radioactive Materials ◽  
Serum Free ◽  
Clinically Normal ◽  
Serum Free Thyroxine

Serum free thyroxine (FT4) concentrations using chemiluminescence were measured in hyperthyroid cats (n = 72) and clinically normal cats (n = 129) to establish reference values and to determine if this method could be a useful alternative to total T4 (TT4) measurement by radioimmunoassay (RIA). Mean serum FT4 concentration (68.3 +/- 26.8 pmol/L) of hyperthyroid cats was significantly higher than that of euthyroid cats (22.9 +/- 4.8 pmol/L). Reference values for basal FT4 of hyperthyroid and healthy cats were 33 to 114 pmol/L and 16 to 30 pmol/L, respectively. The results of the present study suggest that FT4 measured by chemiluminescence could be a useful alternative to TT4 measured by RIA when evaluating thyroid function in cats, since the hazardous effects of radioactive materials on the manipulators and the environment could be avoided. Further studies are required to corroborate these preliminary findings.

scholarly journals Measurement of Serum Free Thyroxine Index May Provide Additional Case Detection Compared to Free Thyroxine in the Diagnosis of Central Hypothyroidism

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Kevin M. Pantalone ◽  
Betul Hatipoglu ◽  
Manjula K. Gupta ◽  
Laurence Kennedy ◽  
Amir H. Hamrahian
Keyword(s):  
Elevated Serum ◽  
Free Thyroxine ◽  
Pituitary Hormone ◽  
Normal Range ◽  
Free T4 ◽  
Central Hypothyroidism ◽  
Serum Free ◽  
Free Thyroxine Index ◽  
Serum Tsh ◽  
Serum Free Thyroxine

The diagnosis of central hypothyroidism is often suspected in patients with hypothalamic/pituitary pathology, in the setting of low, normal, or even slightly elevated serum TSH and low free thyroxine (FT4). We present four cases of central hypothyroidism (three had known pituitary pathology) in whom central hypothyroidism was diagnosed after the serum free thyroxine index (FTI) was found to be low. All had normal range serum TSH and free thyroxine levels. This report illustrates that the assessment of the serum FTI may be helpful in making the diagnosis of central hypothyroidism in the appropriate clinical setting and when free T4 is in the low-normal range, particularly in patients with multiple anterior pituitary hormone deficiencies and/or with symptoms suggestive of hypothyroidism.

scholarly journals A CASE OF FAMILIAL NONAUTOIMMUNE HYPERTHYROIDISM DURING PREGNANCY

2020 ◽  
Vol 6 (2) ◽  
pp. e94-e97
Author(s):  
Yuka Okazaki ◽  
Naoko Arata ◽  
Nagayoshi Umehara ◽  
Taisuke Yamauchi ◽  
Junnichi Tajiri ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Germ Line ◽  
Thyroid Volume ◽  
Thyroid Stimulating Hormone ◽  
Free T4 ◽  
Serum Free ◽  
Free T3 ◽  
Gestational Week ◽  
Tshr Gene ◽  
Stimulating Hormone

Objective: Familial nonautoimmune hyperthyroidism (FNAH) is a rare disease. To date there are few, if any, reports of pregnancies in women with FNAH. Our objective here is to present such a case. Methods: Free thyroxine (free T4), free triiodothyronine (free T3), thyroid-stimulating hormone (TSH), and antibodies related to the thyroid were measured. Fetal thyroid function indicators including thyroid volume and ossification were checked using ultrasound. Thyroid-stimulating hormone receptor (TSHR) gene analyses were performed. Results: The patient was a 30-year-old woman with no past medical history. She was introduced to our hospital in the fifth gestational week for pregnancy care because her family history revealed that her mother had nonautoimmune hyperthyroidism with a TSHR-activating germ-line mutation (Asn406Ser). The serum free T4 was 1.88 ng/dL (normal, 0.62 to 1.19 ng/dL), free T3 was 3.27 pg/mL (normal, 2.55 to 3.88 pg/mL), TSH was 0.02 μIU/mL (normal, 0.007 to 3.619 μIU/mL), and TSHR was negative which were considered to be consistent with mild primary hyperthyroidism. Serum free T4, free T3, and TSH concentrations were monitored every 4 to 6 weeks with a peak free T4 of 2.23 ng/dL noted at gestational week 9. The patient had no signs related to hyperthyroidism throughout pregnancy. The patient delivered a 3,518 g girl at 40 weeks of gestation. Genetic analysis of her TSHR gene showed heterozygous Asn406Ser mutation. The offspring did not show any signs of prenatal hyperthyroidism, and thyroid function at day 6 after delivery revealed a free T4 of 2.41 ng/dL (normal, 1.83 to 2.91 ng/dL) and a TSH of 3.55 μIU/mL (normal, 0.51 to 4.57 μIU/mL). Conclusion: Women with FNAH and mild thyrotoxicosis prior to pregnancy may have continuous hyperthyroidism with additional change due to the series of human chorionic gonadotropin secretion during pregnancy.

Detecting Congenital Central Hypothyroidism by Newborn Screening: Difficulty in Distinguishing from Congenital Thyroxine-Binding Globulin Deficiency

2017 ◽  
Vol 88 (5) ◽  
pp. 331-338 ◽  
Author(s):  
Kara J. Connelly ◽  
Melinda J. Pierce ◽  
Cheryl Hanna ◽  
Stephen H. LaFranchi
Keyword(s):  
Newborn Screening ◽  
Thyroid Function ◽  
Thyroid Stimulating Hormone ◽  
Pituitary Hormone ◽  
Thyroid Function Tests ◽  
Free T4 ◽  
Central Hypothyroidism ◽  
Serum Free ◽  
Thyroxine Binding Globulin ◽  
Healthy Infants

Background/Aims: Congenital central hypothyroidism (CH-C) can be detected on newborn screening (NBS) by programs using thyroxine (T4)-reflex thyroid-stimulating hormone (TSH) test approach. CH-C must be distinguished from T4-binding globulin (TBG) deficiency. We sought to determine whether thyroid function tests reliably separate CH-C from TBG deficiency. Methods: We analyzed NBS and serum free and total T4, T3 resin uptake (T3RU) or TBG, and TSH for infants in the Northwest Regional NBS Program (NWRSP) between the years 2008 and 2015 with either CH-C or TBG deficiency. Results: We discovered a significant overlap in T3RU and TBG levels amongst 21 cases of CH-C and 250 cases of TBG deficiency. Mean serum TBG levels were lower in CH-C cases (20.3 µg/mL, range 14.2–33.3) than what is reported in healthy infants (28.6 µg/mL, range 19.1–44.6). Serum free T4 was lower in CH-C cases than TBG deficiency but did not always differentiate between the two conditions. Conclusion: CH-C benefits from detection on NBS but must be distinguished from TBG deficiency. The diagnosis of CH-C rests solely on subnormal serum free T4, but is supported by the demonstration of other pituitary hormone deficiencies. As an overlap exists, serum TBG (or T3RU) levels do not play a role in the diagnosis of CH-C.

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