Interpretation of puzzling thyroid function tests

With the generalized use of highly sensitive thyroid stimulating hormone (TSH) and free thyroid hormone assays, most thyroid function tests (TFTs) are straightforward to interpret and confirm the clinical impressions of thyroid diseases. However, in some patients, TFT results can be perplexing because the clinical picture is not compatible with the tests or because TSH and free T4 are discordant with each other. Optimizing the interpretation of TFTs requires a complete knowledge of thyroid hormone homeostasis, an understanding of the range of tests available to the clinician, and the ability to interpret biochemical abnormalities in the context of the patient's clinical thyroid status. The common etiologic factors causing puzzling TFT results include intercurrent illness (sick euthyroid syndrome), drugs, alteration in normal physiology (pregnancy), hypothalamic-pituitary diseases, rare genetic disorders, and assay interference. Sick euthyroid syndrome is the most common cause of TFT abnormalities encountered in the hospital. In hypothalamic-pituitary diseases, TSH levels are unreliable. Therefore, it is not uncommon to see marginally high TSH levels in central hypothyroidism. Drugs may be the culprit of TFT abnormalities through various mechanisms. Patients with inappropriate TSH levels need a differential diagnosis between TSH-secreting pituitary adenoma and resistance to thyroid hormone. Sellar magnetic resonance imaging, serum α-subunit levels, serum sex hormone-binding globulin levels, a thyrotropin-releasing hormone stimulation test, trial of somatostatin analogues, and TR-β sequencing are helpful for the diagnosis, but it may be challenging. TFTs should be interpreted based on the clinical context of the patient, not just the numbers and reference ranges of the tests, to avoid various pitfalls of TFTs and unnecessary costly evaluations and therapies.

Low Dose Exposure to Di-2-Ethylhexylphthalate in Juvenile Rats Alters the Expression of Genes Related with Thyroid Hormone Regulation

Phthalates widely used in the manufacture of plastics have deeply penetrated into our everyday lives. Recently, a concern over the toxicity of phthalates on thyroid, has been raised but in most of cases, the doses employed were unrealistically high. To investigate the effects of phthalates on thyroid, we investigated the effects of the repeated oral exposure to low to high doses (0.3, 3, 30 and 150 mg/kg) di-2-ethylhexylphthalate (DEHP) from weaning to maturity for 90 days in juvenile rats on the thyroid. The histological examination revealed that DEHP significantly induced hyperplasia in the thyroid from the doses of 30 mg/kg, which was confirmed with Ki67 staining. In line with this finding, increased mRNA expression of thyrotropin releasing hormone (Trh) was observed in the thyroid of female at 0.3 mg/kg and 150 mg/kg as determined by RNAseq analysis. Moreover, significantly increased expression of parathyroid hormone (Pth) in the female at 0.3 mg/kg, and thyroglobulin (Tg) and thyroid hormone responsive (Thrsp) in the male at 0.3 mg/kg were noted in the blood, of which changes were substantially attenuated at 150 m/kg, alluding the meaningful effects of low dose DEHP on the thyroid hormone regulation. Urinary excretion of mono-2-ethylhexyl-phthalate (MEHP), a major metabolite of DEHP was determined to be 4.10 and 12.26 ppb in male, 6.65 and 324 ppb in female at 0.3 and 30 mg/kg DEHP, respectively, which fell within reported human urine levels. Collectively, these results suggest a potential adverse effects of low dose phthalates on the thyroid.

Lentivirus-mediated microRNA-124 gene-modified bone marrow mesenchymal stem cell transplantation promotes the repair of spinal cord injury in rats

Our study aims to explore the effects of lentivirus-mediated microRNA-124 (miR-124) gene-modified bone marrow mesenchymal stem cell (BMSC) transplantation on the repair of spinal cord injury (SCI) in rats. BMSCs were isolated from the bone marrow of rats. The target gene miR-124 was identified using a luciferase-reporter gene assay. Seventy-two rats were selected for construction of the SCI model, and the rats were randomly divided into the blank group, sham group, SCI group, negative control (NC) group, overexpressed miR-124 group and si-PDXK group. The mRNA expression of miR-124 and the mRNA and protein expression of pyridoxal kinase (PDXK) were detected by quantitative real-time polymerase chain reaction and western blotting. The locomotor capacity of the rats was evaluated using the Basso, Beattie and Bresnahan (BBB) scale. Brdu, neuron-specific enolase (NSE), neurofilament (NF) and microtubule-associated protein 2 (MAP2) were detected using immunohistochemistry. The expression levels of thyrotropin-releasing hormone (TRH), prostacyclin (PGI2) and gangliosides (GM) were measured using an enzyme-linked immunosorbent assay. PDXK was identified as the target gene of miR-124. The overexpressed miR-124 group exhibited higher miR-124 expression than the SCI, NC and si-PDXK groups. Compared with the SCI and NC groups, the PDXK expression was downregulated in the overexpressed miR-124 and si-PDXK groups, and the BBB scores were significantly increased 7, 21 and 35 days after transplantation. The double-labeled positive cell densities (Brdu+NSE/NF/MAP2) and the expression levels of TRH, PGI2 and GM in the overexpressed miR-124 group were significantly higher than those in the NC and SCI groups. These results indicated that miR-124 targeted PDXK to accelerate the differentiation of BMSCs into neurocytes and promote SCI repair.

Hypopituitarism Presenting as Adrenal Insufficiency and Hypothyroidism in a Patient with Wilson's Disease: a Case Report

Wilson's disease typically presents symptoms associated with liver damage or neuropsychiatric disturbances, while endocrinologic abnormalities are rare. We report an unprecedented case of hypopituitarism in a patient with Wilson's disease. A 40-year-old woman presented with depression, general weakness and anorexia. Laboratory tests and imaging studies were compatible with liver cirrhosis due to Wilson's disease. Basal hormone levels and pituitary function tests indicated secondary hypothyroidism and adrenal insufficiency due to hypopituitarism. Brain MRI showed T2 hyperintense signals in both basal ganglia and midbrain but the pituitary imaging was normal. She is currently receiving chelation therapy along with thyroid hormone and steroid replacement. There may be a relationship between Wilson's disease and hypopituitarism. Copper deposition or secondary neuronal damage in the pituitary may be a possible explanation for this theory.

Hypopituitarism Presenting as Adrenal Insufficiency and Hypothyroidism in a Patient with Wilson's Disease: a Case Report

Wilson's disease typically presents symptoms associated with liver damage or neuropsychiatric disturbances, while endocrinologic abnormalities are rare. We report an unprecedented case of hypopituitarism in a patient with Wilson's disease. A 40-year-old woman presented with depression, general weakness and anorexia. Laboratory tests and imaging studies were compatible with liver cirrhosis due to Wilson's disease. Basal hormone levels and pituitary function tests indicated secondary hypothyroidism and adrenal insufficiency due to hypopituitarism. Brain MRI showed T2 hyperintense signals in both basal ganglia and midbrain but the pituitary imaging was normal. She is currently receiving chelation therapy along with thyroid hormone and steroid replacement. There may be a relationship between Wilson's disease and hypopituitarism. Copper deposition or secondary neuronal damage in the pituitary may be a possible explanation for this theory.

The Effects of an Extract of Atractylodes Japonica Rhizome, SKI3246 on Gastrointestinal Motility in Guinea Pigs

BACKGROUND/AIMS: There are limited therapeutic options available for irritable bowel syndrome with diarrhea (IBS-D). We tested the effects of Atractylodes japonica rhizome, a perennial plant native to North Asia, on both upper and lower gastrointestinal (GI) motility in guinea pigs. METHODS: The extract of A. japonica rhizome was administered orally at different doses to test its effects on upper GI motility as determined from charcoal transit in native guinea pigs and in guinea pigs pretreated with thyrotropin-releasing hormone or mustard oil. Regarding its effect on lower GI motility, the removed guinea pig colon was suspended in a chamber containing Krebs-Henseleit solution and the transit time of artificial feces was measured with various dilutions of the extract. As for in vivo assay, weight and number of fecal pellets expelled were determined under the same drug preparation used in upper GI motility experiment. RESULTS: The extract of A. japonica rhizome had no significant effect on upper GI motility in either normal or altered physiological states. However, the extract increased colonic transit time in the in vitro model. In the fecal expulsion study, the cumulative weight and number of pellets did not differ significantly between the control group and groups treated with the extracts. In the animals pretreated in vivo with thyrotropin-releasing hormone, however, the weight and number of fecal pellets were significantly decreased in animals treated with 300 mg/kg and 600 mg/kg doses of extract. CONCLUSIONS: Our findings suggest that the extract of A. japonica rhizome can be a potential agent for IBS-D.

A Case of Thyrotropin (TSH)-Secreting Pituitary Adenoma in a Patient with Ankylosing Spondylitis / 대한내과학회지

A thyrotropin (TSH)-secreting pituitary adenoma is a rare cause of hyperthyroidism, with an incidence of one case per million. Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease of the axial skeleton. Extra-articular manifestations, such as anterior uveitis, may also be prominent features in AS but little is known about the association between AS and thyroid diseases including TSH-secreting pituitary adenomas. We present a case study of a 26-year-old male AS patient who was diagnosed with a TSH-secreting pituitary adenoma using a thyrotropin releasing hormone stimulation test, measurement of the TSH alpha-subunit, and magnetic resonance imaging, and subsequently treated with a transsphenoidal tumor resection.

Subclinical hypothyroidism diagnosed by thyrotropin-releasing hormone stimulation test in infertile women with basal thyroid-stimulating hormone levels of 2.5 to 5.0 mIU/L

OBJECTIVE: To investigate the prevalence of subclinical hypothyroidism (SH) diagnosed by thyrotropin-releasing hormone (TRH) stimulating test in infertile women with basal thyroid-stimulating hormone (TSH) levels of 2.5 to 5.0 mIU/L. METHODS: This study was performed in 39 infertile women with ovulatory disorders (group 1) and 27 infertile women with male infertility only (group 2, controls) who had basal serum TSH levels of 2.5 to 5.0 mIU/L and a TRH stimulating test. Serum TSH levels were measured before TRH injection (TSH0) and also measured at 20 minutes (TSH1) and 40 minutes (TSH2) following intravenous injection of 400 microg TRH. Exaggerated TSH response above 30 mIU/L following TRH injection was diagnosed as SH. Group 1 was composed of poor responders (subgroup A), patients with polycystic ovary syndrome (subgroup B) and patients with WHO group II anovulation except poor responder or polycystic ovary syndrome (subgroup C). RESULTS: The prevalence of SH was significantly higher in group 1 of 46.2% (18/39) compared with 7.4% (2/27) in group 2 (P=0.001). TSH0, TSH1, and TSH2 levels were significantly higher in group 1 than the corresponding values in group 2 (P<0.001, P<0.001, P<0.001). In group 1, TSH1 and TSH2 levels were significantly lower in subgroup C compared with those in subgroup A and B (P=0.008, P=0.006, respectively). CONCLUSION: TRH stimulation test had better be performed in infertile women with ovulatory disorders who have TSH levels between 2.5 and 5.0 mIU/L for early detection and appropriate treatment of SH.

Neonatal screening and a new cause of congenital central hypothyroidism

Congenital central hypothyroidism (C-CH) is a rare disease in which thyroid hormone deficiency is caused by insufficient thyrotropin (TSH) stimulation of a normally-located thyroid gland. Most patients with C-CH have low free thyroxine levels and inappropriately low or normal TSH levels, although a few have slightly elevated TSH levels. Autosomal recessive TSH deficiency and thyrotropin-releasing hormone receptor-inactivating mutations are known to be genetic causes of C-CH presenting in the absence of other syndromes. Recently, deficiency of the immunoglobulin superfamily member 1 (IGSF1) has also been demonstrated to cause C-CH. IGSF1 is a plasma membrane glycoprotein highly expressed in the pituitary. Its physiological role in humans remains unknown. IGSF1 deficiency causes TSH deficiency, leading to hypothyroidism. In addition, approximately 60% of patients also suffer a prolactin deficiency. Moreover, macroorchidism and delayed puberty are characteristic features. Thus, although the precise pathophysiology of IGSF1 deficiency is not established, IGSF1 is considered to be a new factor controlling growth and puberty in children.

Diamond Blackfan Anaemia with Hypothyroidism and CNS Malformations.

Diamond Black fan Anemia (DBA) is a congenital erythroid aplasia that usually presents in infancy. The DBA patients have low red blood cell count (Anaemia). The rest of their blood cells (Platelets & WBCs) are normal. We present a 14 month old male child who presented with severe anaemia. The patient was transfusion dependent since 4 months of age. Clinical examination revealed delayed mile stones and a couple of congenital deformities. Haematological parameters showed elevated foetal haemoglobin level (Hb F – 11.8% ) and elevated serum TSH (thyroid stimulating hormone) level. Peripheral blood picture showed gross microcytic hypochromic red blood cells and absence of reticulocytes with normal levels of leucocytes and platelets. A bone marrow showed gross suppression of Erythroid series with M:E ratio of 30:1. Some large pronormoblasts were found. Family history was not significant. Compiling the clinical features, haematological parameters, PS and bone marrow findings, a diagnosis of DBA was given.

Prevalência de alterações dos hormônios TSH e T4 livre empacientes atendidos em um laboratório de análises clínicas do município de Carazinho, RS / Prevalence of alterations in hormones TSH and free T4 in patientes attended in a laboratory clinical analyses in Carazinho, RS

O TSH comanda todos os processos que envolvem a síntese e secreção da tireoide, além de manter seu metabolismo. O objetivo deste estudo foi verificar a prevalência de alterações nas dosagens séricas dos hormônios TSH e T4 livre em pacientes atendidos em um laboratório de análises clínicas do município de Carazinho - RS. O estudo foi composto por mil amostras de ambos os sexos, sendo realizado no período de junho 2007 a junho 2008. Nas mulheres, a faixa etária mais atingida pelo hipotireoidismo ficou entre 41 e 70 anos, representando 13,5%; nos homens, entre 51 e 70 anos, representando 12,6%. Com relação ao hipertireoidismo, não houve faixa etária prevalente nos sexos. No hipotireoidismo subclínico, obteve-se um percentual maior de alterações, tanto no sexo feminino quanto no masculino, representando, respectivamente, 25% e 36,4% dasalterações, quando comparado ao hipotireoidismo em sua apresentação clínica. A partir do estudo realizado, constatou-se que a principal alteração detectada nos hormônios da tireoide foi a forma subclínica, o que está de acordo com relatos encontrados na literaturamundial. Sabendo-se da importância destes hormônios em todo o metabolismo, torna-se fundamental o rastreamento para diagnóstico destas alterações a fim de evitar possíveisdanos decorrentes dessa patologia...

Hypothalamic Hypopituitarism Caused by Pituitary Stalk Dysgenesis / 대한내과학회지

Functional defects of the pituitary gland are a rare cause of pubertal delay. The pituitary stalk is an important structure that connects the hypothalamus and pituitary gland. A defect in fusion of the pituitary stalk and anterior pituitary gland will block the function of the anterior pituitary gland. A 28-year-old man was referred to our clinic with poorly developed secondary sexual characteristics. He had undeveloped facial, axillary, and pubic hair and was Tanner stage I. Laboratory tests gave random serum testosterone < 0.025 ng/mL, luteinizing hormone (LH) < 0.1 mIU/mL, follicle-stimulating hormone (FSH) 0.626 mIU/mL, thyroid-stimulating hormone (TSH) 6.85 microIU/mL, and fT4 6.96 pmol/L. Sella magnetic resonance imaging (MRI) showed no pituitary stalk enhancement. The response in the combined pituitary function test revealed multiple hormonal defects, while the TSH response to thyrotropin-releasing hormone (TRH) was exaggerated and delayed. Therefore, we concluded that pituitary stalk dysgenesis had led to hypothalamic-type panhypopituitarism.

Effects of Ramosetron on Gastrointestinal Transit of Guinea Pig

BACKGROUND/AIMS: A selective 5-hydroxytryptamine (5-HT) type 3 receptor antagonist, ramosetron, inhibits stress-induced abnormal defecation in animals and is currently used as a therapeutic drug for irritable bowel syndrome with diarrhea. The aim of this study is to investigate the effect of ramosetron on altered gastrointestinal (GI) transit. METHODS: Male guinea pigs weighing approximately 300 g were used. The effect of ramosetron was investigated on altered GI transit induced by thyrotropin-releasing hormone (TRH), 5-HT, or mustard oil (MO). GI transit was evaluated by the migration of charcoal mixture from the pylorus to the most distal point, and expressed as a percentage (%) of charcoal migration (cm) of the total length of total small intestine (cm). RESULTS: The average charcoal transit was 51.3 +/- 20.1% in the control (vehicle) group, whereas in the ramosetron group charcoal moved 56.6 +/- 21.9%, 46.9 +/- 9.14% and 8.4 +/- 5.6% of the total small intestine at the concentrations of 10, 30 and 100 microg/kg, respectively. GI transit after administration of TRH (100 microg/kg), 5-HT (10 mg/kg) or MO (10 mg/kg) was accelerated compared to vehicle (5-HT, 94.9 +/- 9.22%; TRH, 73.4 +/- 14.7%; MO, 81.0 +/- 13.7%). Ramosetron inhibited GI transit altered by 5-HT, TRH or MO. CONCLUSIONS: Ramosetron modulated GI transit. We suggest that ramosetron may be therapeutically useful for those with accelerated upper GI transit.

The Effect of Octreotide LAR on GH and TSH Co-Secreting Pituitary Adenoma

Growth hormone (GH) and thyroid stimulating hormone (TSH)-secreting pituitary adenomas are very rare and they account for only 0.5% for all pituitary adenomas. These adenomas are usually treated with surgery, but this surgery is not easy because the tumor is usually huge and invasive. We reported here on a case of a GH-TSH-secreting adenoma in a 23-year-old male patient who was initially treated with octreotide LAR. He presented with symptoms of headache, palpitation and a visual defect that he had for the 3 months. He had hypertrophy of the frontal bone and enlargement of both the hands and feet. The visual field test showed bitemporal hemianopsia. The laboratory examinations showed high serum levels of free T4, TSH and free alpha-subunit. Additionally, the serum levels of GH and insulin-like growth factor-I (IGF-I) were increased. GH was not suppressed below 1microg/L by an oral 75g glucose loading test, and TSH was not stimulated by thyrotropin-releasing hormone (TRH). Because sellar MRI showed invasive macroadenoma encasing the vessels, we initially tried octreotide LAR for treatment. A year later, the IGF-I and thyroid function tests were normalized and the size of the tumor was reduced with cystic change. The symptoms of palpitation and headache were improved without a change of the visual field defect.

Remission rate and remission predictors of Graves disease in children and adolescents / 소아과

PURPOSE: Medical therapy is the initial treatment for children with Graves disease to avoid complications of other treatments. However, optimal treatment for childhood Graves disease is controversial because most patients require relatively long periods of medical therapy and relapse is common after medication discontinuation. Therefore, this study aimed to search clinical or biochemical characteristics that could be used as remission predictors in Graves disease. METHODS: We retrospectively studied children diagnosed with Graves disease, treated with anti-thyroid agents, and observed for at least 3 years. Patients were categorized into remission and non-remission groups, and the groups were compared to determine the variables that were predictive of achieving remission. RESULTS: Sixty-four patients were enrolled, of which 37 (57.8%) achieved remission and 27 (42.2%) could not achieve remission until the last visit. Normalization of thyroid-stimulating hormone-binding inhibitory immunoglobulin (TBII) after treatment was faster in the remission group than in the non-remission group (remission group, 15.5+/-12.1 vs. nonremission group, 41.7+/-35.7 months). Thyrotropin-releasing hormone (TRH) stimulation tests were performed in 28 patients. Only 2 (7.7%) of 26 patients who showed normal or hyper-response in TRH stimulation test relapsed. Binary logistic regression analysis identified rapid achievement of TBII normalization after treatment as a significant predictor of remission. Six percent of patients achieved remission within 3 years and 55.8% achieved it within 6 years. CONCLUSION: Rapid achievement of TBII normalization can be a predictor of remission in childhood Graves disease. The TRH stimulation test can be a predictor of maintenance of remission.

Remission rate and remission predictors of Graves disease in children and adolescents / 소아과

PURPOSE: Medical therapy is the initial treatment for children with Graves disease to avoid complications of other treatments. However, optimal treatment for childhood Graves disease is controversial because most patients require relatively long periods of medical therapy and relapse is common after medication discontinuation. Therefore, this study aimed to search clinical or biochemical characteristics that could be used as remission predictors in Graves disease. METHODS: We retrospectively studied children diagnosed with Graves disease, treated with anti-thyroid agents, and observed for at least 3 years. Patients were categorized into remission and non-remission groups, and the groups were compared to determine the variables that were predictive of achieving remission. RESULTS: Sixty-four patients were enrolled, of which 37 (57.8%) achieved remission and 27 (42.2%) could not achieve remission until the last visit. Normalization of thyroid-stimulating hormone-binding inhibitory immunoglobulin (TBII) after treatment was faster in the remission group than in the non-remission group (remission group, 15.5+/-12.1 vs. nonremission group, 41.7+/-35.7 months). Thyrotropin-releasing hormone (TRH) stimulation tests were performed in 28 patients. Only 2 (7.7%) of 26 patients who showed normal or hyper-response in TRH stimulation test relapsed. Binary logistic regression analysis identified rapid achievement of TBII normalization after treatment as a significant predictor of remission. Six percent of patients achieved remission within 3 years and 55.8% achieved it within 6 years. CONCLUSION: Rapid achievement of TBII normalization can be a predictor of remission in childhood Graves disease. The TRH stimulation test can be a predictor of maintenance of remission.

Q12 cáncer diferenciado de tiroides (CDT): estimulación de la TSH endógena con múltiples dosis de TRH y su tratamiento con 131I: experiencia de 3 años / Differentiated thyroid carcinoma: endogenous TSH stimulation by multiple dosage of TRH and treatment with 131I

La búsqueda un método alternativo a la rh-TSH para estimular el aumento de la TSH sérica previo al tratamiento con 131I en pacientes con CDT operados con reducción del tiempo del hipotiroidismo pre ablativo fue el propósito del trabajo que iniciamos en el año 2001 en el Paraguay utilizando múltiples dosis de TRH para estimular la TSH endógena de los pacientes para luego lograr la ablación del remanente tiroideo con 131I. Se conoce que la inyección de una dosis única de 200µU de TRH por vía EV logra el aumento de la TSH endógena en los pacientes con carcinoma diferenciado de tiroides logrando elevar la TSH entre 30 - 35 mUI/L al final de la primera hora , sin embargo, no se cuentan con datos estadísticos de los efectos de múltiples inyecciones de TRH aplicadas por vía EV o por vía IM en los pacientes operados de tiroides por CDT previamente a la ablación con 131I. Material y Método: Desde el 2001al 2007 doscientos pacientes operados por CDT fueron estudiados por este método en el Centro de Diagnostico y Tratamiento Nuclear (CEDIN), 120 correspondieron a cáncer papilar y 80 a cáncer folicular. Ciento ochenta no presentaron metástasis a distancia y 20 presentaron metástasis en cuello, tórax, pelvis y columna dorsal. Tiroidectomía total se realizó en 120 y lobectomía total e itsmectomía más hemilobectomía del lado contra lateral en 80. Todos fueron tratados con dosis ablativas (100 mCi (3.700 mBq) de 131I excepto aquellos con metástasis que recibieron 150 mCi (5.500 mBq) previa estimulación con TRH por vía EV en dos dosis diarias por dos días con previa suspensión de L-tiroxina por 25 días antes del tratamiento reemplazándola por triyodotironina 25 mcg/día por 15 días tras lo cual también fue suspendida 10 días antes de la estimulación con TRH y el tratamiento con 131I. Dos pacientes con metástasis recibieron otra dosis extra de 150 mCi (5.550 MBq) 6 meses después...

The search of an alternative method to the rh-TSH to stimulate endogenous rising of TSH previous to thyroid ablation with 131I in patients with CDT operated. The purpose of the work began in 2001 in Paraguay using multiple dose of TRH IV (200µU of TRH Threlea® Argentina) to stimulate the own TSH of patients previous to 131I ablation. It is known that the injection of an unique dose of 200µU of TRH IV achieves the increasing of the endogenous TSH in patients with differentiated thyroid carcinoma up to 30 - 35 mUI/L at the end of the first hour, however, there is not statistical data of the effects of multiple injections of TRH applied IV or IM in operated patients of DTC previous to the ablation with 131I. Since 2001-2007, two hundred patients operated for DTC were studied by this method, 120 were papillary cancer and 80 follicular cancer. One hundred eighty did not have distance metastasis and 20 presented metastasis in thorax, pelvis and dorsal spine. Total thyroidectomy was carried out in 120 and total lobectomy with itsmectomy plus hemilobectomy of the other lobe in 80. All were treated with ablative dose of 100 mCi (3.700 mBq) of 131I, except those with metastasis which receive 150 mCi (5.500 mBq) with the previous stimulation with TRH IV with two daily dose for three days with previous suspension of L-tiroxine for 25 days and replaced by triyodotiroxine 25 mcg/d for 15 days with suspension 10 days before the stimulation with TRH and treatment with 131I. Two patients with metastasis received another extra dose of 150 mCi (5.550 MBq) 6 months later. One presented uptake in thyroid bed one year after the ablation received a new ablative dose of 100 mCi (3.700 mBq) of 131I. All the patients were interned and isolated by 48 hours. Twenty feminine patients had later pregnancies in 1-3 years after their ablative dose with healthy products. TSH was measured during the stimulation with TRH in all patients...

Función tiroidea en pacientes pediátricos con enfermedad renal crónica / Thyroid function in pediatric patients with chronic renal failure

Objective: To characterize the thyroid function in mild (L), moderate (M), hemodialysis (HD), peritoneal dialysis (PD), chronic renal failure (CRE) and post kidney transplant (TX). Method: 46 children between 9.3 +/- 3.7 years-old with CRF (10 mild (L), 10 moderate (M), 10 peritoneodialysis (PD), 6 hemodialysis (HD), 10 transplants (TX)) were evaluated. Basal total T4 and free T3, TRH test (TSH at 0-30-60 min), creatinine, BUN, creatinine clearance and anthropometric parameters were measured. The statistics analysis included Anova Test to compare group results and correlation coefficients for studied variables. Results: Basal thyroid hormone levéis were normal in all groups and no differences between groups (except higher TSH in L (p < 0.01)) were found. TRH test response was prolonged on L, M, PD and HD and deficient in TX, except 3 TX patients who had normal TRH response, all using Tacrolimus, Micofenolate and Prednisone on altérnate day treatment versus the remaining TX who where on Cyclosporine or Azathioprine, Micofenolate and continuous corticoid régimen. Prolonged TRH response correlates with creatinine (p < 0.001) and creatinine clearance (p < 0,01). Conclusions: Basal thyroid hormones were normal in all groups. TRH test response was predominantly prolonged in L, M, PD and HD, suggesting adaptative phenomena at tertiary level, and correlates with renal function. TX patients had deficient TRH response, suggesting hypofisial dysfunction.

Objetivo: Caracterizar la función tiroidea y la respuesta a test de TRH (thyroid releasing hormone), en niños con enfermedad renal crónica (ERC) leve (L), moderada (M), peritoneodiálisis (PD), hemodiálisis (HD) y trasplantados renales (TX). Pacientes y Método: Se estudiaron 46 pacientes con ERC (10 L, 10 M, 10PD,6HDy 10TX),9,3 +/- 3,7 años. Se midió t4t,t41,t3t, t31,TBGbasalytest de TRH(TSHa 0,30y60min). Se evaluó función renal, antropometría y se consignó tratamiento inmunosupresor (IS) en el grupo TX. Se utilizó anova para comparar los resultados entre los grupos y coeficiente de correlación para las variables estudiadas. Resultados: Los valores basales de hormonas tiroideas fueron normales en todos los grupos, sólo TSH fue significativamente mayor en L aunque dentro del rango normal (p < 0,01). La respuesta al test de TRH fue predominantemente prolongada en L, M, PD y HD y deficiente en TX; los 3 pacientes TX con tacrolimus, micofenolato y prednisona en días alternos tuvieron respuesta normal a diferencia del resto TX que recibían prednisona continua, ciclosporina y micofenolato. La prolongación de respuesta a TRH se correlacionó con creatininemia, BUN y clearance de creatinina (p < 0,01). Conclusiones: Los niveles de hormonas tiroideas basales se encuentran normales en todos los grupos de ERC. La respuesta a TRH fue predominantemente prolongada en L, M, PD y HD, demostrando un fenómeno adaptativo a nivel terciario del eje hipotálamo-hipofisis-tiroides. Los TX presentan una respuesta mayoritoriamente deficiente a TRH, sugerente de disfunción hipofisiaria, la que podría estar relacionada con el tipo de tratamiento inmunosupresor y al uso de corticoides en días continuos.

Effect of non detectable thyroid stimulating hormone [TSH] levels on thyroid activity

Thyroid hormones, triiodothyronine [T3] and thyroxin [T4], affect almost all metabolic activities of tissues and are produced under influence of the anterior pituitary hormone, the thyroid stimulating hormone [TSH], which stimulates secretion of thyroid hormones, and is itself under the control of the hypothalamic thyroid releasing hormone [TRH]. The present study was conducted to observe the effect of non-detectable levels of TSH on thyroid hormones, on the basis of gender and age. Analysis of data through student's 't'-test revealed that prevalence of thyroid disorders in the studied group was more among females. However, the disorders were not age dependent. Most common condition associated with non-detectable TSH levels was hyperactivity of the thyroid gland, followed by sub-clinical hyperthyroidism