Laboratorio de función tiroidea en pediatría. Ventajas y limitaciones de los métodos indirectos para la obtención de intervalos de referencia / Thyroid function laboratory in pediatrics. Advantages and limitations of indirect methods to obtain reference intervals

Obtener intervalos de referencia (IRs) confiables para pruebas de laboratorio en pediatría es particularmente complejo y costoso. Una alternativa a este problema es el uso de métodos indirectos, donde se usan grandes bases de datos preexistentes de pacientes. Nuestros objetivos fueron: calcular IR para TSH y hormonas tiroideas (Perfil tiroideo, PT) en población pediátrica que asiste al Hospital de Pediatría Juan P. Garrahan, por método indirecto y verificar la confiabilidad de los mismos para su aplicación. Se recolectaron datos de 19.842 pacientes entre enero de 2020 y diciembre de 2021. Se aplicaron filtros para eliminar los pacientes que pudieran tener afectado el PT. Los 4.861 pacientes incorporados al análisis fueron divididos en 3 grupos: G1: 0-12 meses (n: 551), G2:13 meses- 7 años (n: 1347) y G3: 8 -18 años (n: 2963). Los IR fueron calculados por 2 métodos: el de Hoffman adaptado y el de CLSI EP28A3, para cada grupo de edad. TSH, TT3 y T4L se analizaron con Architect i4000-Abbott y TT4 con Immulite 2000XPi-Siemens. Para la primera etapa de verificación se utilizaron 20 sueros de pacientes provenientes de análisis prequirúrgicos. Los outliers se detectaron aplicando el método de Tukey. Los datos fueron procesados según CLSI EP28A3c. Los IR obtenidos fueron similares a los previamente publicados obtenidos por método directo. Los resultados de la verificación fueron en su mayoría aceptados. Por lo tanto, los métodos indirectos son una buena alternativa de cálculo de IR en pediatría (AU)

Obtaining reliable reference ranges (RRs) for laboratory tests in pediatrics is particularly complex and costly. An alternative to this problem is to use of indirect methods, where large pre-existing patient databases are used. Our aims were to calculate RRs for TSH and thyroid hormones (thyroid profile, PT) in children seen at Hospital de Pediatría Juan P. Garrahan by indirect methods and to verify their reliability for their application. Data were collected from 19,842 patients seen between January 2020 and December 2021. Filters were applied to eliminate patients in whom the PT was potentially affected. The remaining 4,861 patients included in the analysis were divided into 3 groups: G1: 0-12 months (n: 551), G2: 13 months-7 years (n: 1347) and G3: 8-18 years (n: 2963). RRs were calculated by 2 methods: the adapted Hoffman method and the CLSI EP28A3 method, for each age group. TSH, TT3, and FT4 were analyzed with Architect i4000-Abbott and TT4 with Immulite 2000XPi-Siemens. For the first stage of verification, 20 patient sera from pre-surgical analysis were used. Outliers were detected by applying the Tukey method. The data were processed according to CLSI EP28A3c. The RRs obtained were similar to those previously published using the direct method. The verification results were mostly acceptable. Therefore, indirect methods are a good option for calculating RRs in children (AU)

Uso adecuado de las pruebas de laboratorio para la evaluación de la función tiroidea en pediatría / Appropriate use of laboratory tests for evaluation of thyroid function in pediatrics

Las pruebas de función tiroidea (PFT) son esenciales para el diagnóstico preciso y el seguimiento eficaz de la disfunción tiroidea. Existe un incremento progresivo y estable de los pedidos de PFT, incluso se han incorporado las mismas a los exámenes de salud anuales en niños sanos. Representan más del 60% de las pruebas realizadas en el laboratorio de endocrinología, tanto en adultos como en los laboratorios especializados en pediatría. Para hacer un uso eficiente de las PFT, antes de solicitarlas debemos preguntarnos… ¿Para quién? ¿Cuándo solicitarlas? ¿Qué pruebas solicitar? ¿Cómo solicitarlas? y ¿Cómo interpretar correctamente los resultados? Un resultado anormal en las PFT no siempre implica patología tiroidea asociada. Las PFT tienen importante variabilidad intra e interindividual lo que hace más compleja su correcta interpretación. La pesquisa de enfermedad tiroidea neonatal es un importante aporte a la prevención de la deficiencia mental en la infancia, su aplicación obligatoria posibilita un diagnóstico temprano, para asegurar su éxito debe considerarse en el marco de un programa integral de detección con estrategias de confirmación, tratamiento temprano y seguimiento a corto, mediano y largo plazo. No debe hacerse un uso indiscriminado de la prueba de estímulo con TRH en el diagnóstico de la patología tiroidea. En pediatría la estrategia de tamiz de enfermedad tiroidea es conveniente realizarla mediante la medición de por lo menos TSH y T4 libre e incluir la determinación de ATPO en grupos de riesgo, a diferencia de la determinación aislada de TSH como es recomendado en adultos. (AU)

Thyroid function tests (TFTs) are essential for accurate diagnosis and effective monitoring of thyroid dysfunction. There is a progressive and steady increase in requests for TFTs, and they have even been incorporated into annual health examinations in healthy children. They represent more than 60% of the tests performed in the endocrinology laboratory, both in adults and in specialized pediatric laboratories. To efficiently use TFTs, before requesting them we should ask ourselves... For whom? When to request them? Which tests to request? How to request them? and How to correctly interpret the results? An abnormal TFT result does not always imply thyroid disease. TFTs have significant intra- and inter-individual variability, which makes their correct interpretation more complex. Screening for newborn thyroid disease is an important contribution to the prevention of intellectual disability in childhood and its mandatory use enables early diagnosis; however, to ensure the test to be successful, it should be considered within the framework of a comprehensive screening program with strategies for confirmation, early treatment, and short-, medium-, and long-term follow-up. The TRH stimulation test in the diagnosis of thyroid disease should not be used indiscriminately. In children, the screening strategy for thyroid disease should be performed by measuring at least TSH and free T4 and include the measurement of TPO-ab in risk groups, as opposed to the isolated measurement of TSH as recommended in adults. (AU)

Short-term outcomes among patients with subclinical hypothyroidism undergoing primary percutaneous coronary intervention

Objectives: This study aimed to examine possible associations between previously undiagnosed subclinical hypothyroidism and short-term outcomes and mortality in a sample of Iraqi patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction. Design: This is a prospective observational cohort study. Setting: The study was conducted in a single tertiary referral centre in Baghdad, Iraq. Participants: Thyroid-stimulating hormone and free T4 levels were measured in 257 patients hospitalised with STelevation myocardial infarction who underwent primary percutaneous coronary intervention between January 2020 and March 2022. Main outcome measures: Adverse cardiovascular and renal events during hospitalisation and 30-day mortality were observed. Results: Previously undiagnosed subclinical hypothyroidism was detected in 36/257 (14%) ST-elevation myocardial infarction patients and observed more commonly in females than males. Patients with subclinical hypothyroidism had significantly worse short-term outcomes, including higher rates of suboptimal TIMI Flow (< III) (p =0.014), left ventricular ejection fraction ≤ 40% (p=0.035), Killip class >I (p=0.042), cardiogenic shock (p =0.016), cardiac arrest in the hospital (p= 0.01), and acute kidney injury (p= 0.044). Additionally, 30-day mortality was significantly higher in patients with subclinical hypothyroidism (p= 0.029). Conclusion: Subclinical hypothyroidism previously undiagnosed and untreated had a significant association with adverse short-term outcomes and higher short-term mortality within 30 days compared to euthyroid patients undergoing primary percutaneous coronary intervention. Routine thyroid function testing during these patients' hospitalisation may be warranted.

Factores clínicos y ambientales asociados a la tiroiditis de Hashimoto / Clinical and environmental factors associated with Hashimoto's thyroiditis

Introducción: La tiroiditis de Hashimoto es una enfermedad tiroidea autoinmune poligénica y multifactorial resultante de una interacción compleja de factores genéticos y ambientales. Objetivo: Determinar la posible asociación de los factores clínicos y ambientales con los niveles de anticuerpos antitiroideos y las pruebas de función tiroidea en la tiroiditis de Hashimoto. Métodos: Estudio observacional, descriptivo y transversal con 120 personas con diagnóstico de tiroiditis de Hashimoto. Variables estudiadas: edad, sexo, color de la piel, estado nutricional, paridad, hábito de fumar, consumo de alcohol, preparados estrogénicos, antecedentes familiares de enfermedad autoinmune tiroidea y personales de otras enfermedades autoinmunes. Se realizaron determinaciones de anticuerpos AbTPO, TSH, T3 y T4. Resultados: Predominio del sexo femenino (92,5 por ciento), de pacientes de piel blanca (50,8 por ciento) y con sobrepeso corporal (40 por ciento). El 73 por ciento no consumían preparados estrogénicos. El 20 por ciento tenían antecedentes familiares de enfermedad tiroidea y personales de diabetes mellitus tipo 1 (7,5 por ciento). La media del anticuerpo en pacientes con antecedentes de infecciones virales fue superior a los que no tuvieron este antecedente (732,6 vs. 624,6). El resto de las variables no mostraron diferencias entre las medias del anticuerpo. Ninguno de los factores estudiados mostró asociación con el estado de la función tiroidea. (p>0,05). Conclusiones: No existió asociación entre los factores clínicos y ambientales en relación a los niveles de Ac TPO y el estado de la función tiroidea, con predominio del hipotiroidismo manifiesto al diagnóstico de la TH(AU)

Introduction: Hashimoto's thyroiditis is a polygenic and multifactorial autoimmune thyroid disease, resulting from a complex interaction of genetic and environmental factors. Objective: To determine the possible association of clinical and environmental factors with antithyroid antibody levels and thyroid function tests in HT. Methods: An observational, descriptive, cross-sectional study was carried out with 120 subjects diagnosed with Hashimoto's thyroiditis. We studied variables such as age, sex, skin color, nutritional status, parity, smoking, alcohol consumption, estrogen preparations, family history of autoimmune thyroid disease and personal history of other autoimmune diseases. Additionally, AbTPO, TSH, T3 and T4 antibody determinations were made. Results: Predominance of the female sex (92.5 percent), white skin (50.8 percent) and body overweight (40 percent). 73 percent did not consume estrogenic preparations. Twenty percent had family history of thyroid disease and personal history of type 1 diabetes mellitus (7.5 percent). The mean antibody in patients with history of viral infections was higher than those without this history (732.6 vs. 624.6). The rest of the variables did not show differences between the means of the antibody. None of the factors studied showed association with the state of thyroid function. (p > 0.05). Conclusions: There was no association between clinical and environmental factors in relation to Ac TPO levels and the state of thyroid function, with a predominance of overt hypothyroidism at diagnosis of HT(AU)

Perinatal effects of maternal FT3/FT4 ratio on gestational transient thyrotoxicosis

ABSTRACT Objective: The effects of maternal thyroid hormone levels on the course of pregnancy and birth weight have attracted interest. The aim of the present study was to consider FT3 and FT3/FT4 ratio in the evaluation of the effects of maternal thyroid functions in gestational transient thyrotoxicosis (GTT). Materials and methods: This case-control study included 45 patients with GTT and 45 healthy pregnant women. Maternal history before pregnancy, thyroid function tests, thyroid autoantibodies, and thyroid ultrasonography results in 6th to 10th weeks of pregnancy were used in the differential diagnosis of GTT. In both groups, the effects of FT3, FT4 and FT3/FT4 ratios on gestational age and birth weight were evaluated. Results: There was no significant difference in the gestational age between the GTT and control groups (39,3±1,0 weeks and 39,2±1,2 weeks, respectively). Birth weights were similar in both groups (3205,2±4899 g and 3196,6±309,3 g, respectively). When maternal weight was adjusted, a positive correlation was observed between maternal FT3/FT4 ratio and birth weight (r=0,317, p=0,017). Additionally there was a positive correlation between the gestational age and the birth weight in the control group (ρ=0,726, p=0,001). Conclusion: GTT had no significant effect on the gestational age and the birth weight. On the other hand an increase in the maternal FT3/FT4 ratio had a positive effect on the birth weight in the patient with GTT. Maternal characteristics (age, weight, BMI) and FT3/FT4 ratio should be taken into consideration in future impact assessment studies on this issue.

Historia familiar de enfermedad tiroidea y riesgo de hipotiroidismo congénito en neonatos con síndrome de Down / Family history of thyroid disease and risk of congenital hypothyroidism in neonates with Down syndrome

Resumen Introducción: La historia familiar de enfermedad tiroidea (HFET) como factor de riesgo para hipotiroidismo congénito (HC), en síndrome de Down (SD) aún no ha sido explorada. Objetivo: Determinar si la HFET está asociada a mayor riesgo de HC en neonatos con SD. Método: Estudio de casos y controles en 220 neonatos con SD. Se compararon las pruebas de función tiroidea (PFT) de 37 con SD e HFET (casos), frente a las PFT de 183 recién nacidos con SD sin HFET (grupo de referencia). Se realizó análisis de regresión logística multivariante y se calculó la razón de momios (RM) y sus respectivos intervalos de confianza del 95 % (IC 95 %). Resultados: Nueve casos HC (4.1 %). El HC mostró asociación con la HFET (RMa = 8.3, IC 95 %: 2.0-34.3), particularmente en los varones (RMa = 9.0, IC 95 %: 1.6-49.6). La ausencia de HFET tuvo una RM de protección para HC (RMa = 0.4, IC 95 %: 0.1-0.8). Conclusiones: La HFET puede es una estrategia fácil y accesible para identificar pacientes con SD con mayor riesgo de HC.

Abstract Introduction: Family history of thyroid disease (FHTD) as risk factor for congenital hypothyroidism (CH) in patients with Down syndrome (DS) has not yet been explored. Objective: To determine whether FHTD is associated with an increased risk for CH in DS. Method: Case-control study in 220 neonates with DS. Thyroid function tests of 37 infants with DS and FHTD (cases) were compared with those of 183 DS newborns without FHTD (reference group). Data were analyzed using multivariate logistic regression analysis and adjusted odds ratios (aORs) with their respective 95 % confidence intervals (CI) were calculated. Results: Nine newborns with DS in our sample had CH (4.1 %). FHTD showed an association with CH in neonates with DS (aOR = 8.3, 95 % CI: 2.0-34.3), particularly in males (aOR = 9.0, 95 % CI: 1.6-49.6). In contrast, newborns with DS without FHTD were less likely to suffer from CH (aOR = 0.4, 95 % CI: 0.1-0.8). Conclusions: FHTD detailed evaluation can be an easy and accessible strategy to identify those newborns with DS at higher risk for CH.

Clinical characteristics of Graves / 中南大学学报(医学版)

OBJECTIVES@#A variety of causes can lead to cholestasis, however, cholestasis caused by Graves' disease is usually overlooked clinically. Here we analyze the clinical characteristics of Graves' disease associated cholestasis so as to have a better understanding for the disease.@*METHODS@#We retrospectively collected 13 inpatients' data who suffered from the Graves' disease associated cholestasis in the Department of Infectious Disease of Xiangya Hospital from January 2000 to December 2018. The characteristics of the patients' age, gender, liver function, thyroid function, coagulation function, the special cardiac examination, treatment, and follow-up data were analyzed.@*RESULTS@#Thirteen patients, including 10 males and 3 females with the age range from 33 to 55 (median 43) years old presented cholestasis, pruritus, and hypermetabolic symptoms. The levels of total bilirubin (TBIL), direct bilirubin (DBIL), glutamic-pyruvic transferase, glutamic-oxaloacetic transferase, alkaline phosphosphatase, and gamma glutamyl transpeptidase were 170.4-976.7 (median 388.8) µmol/L, 93.2-418.1 (median 199.2) µmol/L, 25.1-182.1 (median 106.4) U/L, 38.2-265.7 (median 59.7) U/L, 105.3-332.0 (median 184.5) U/L, and 20.7-345.1 (median 47.6) U/L, respectively. The levels of free triiodothyronine (FT@*CONCLUSIONS@#Graves' disease can cause cholestasis, with the low incidence. The symptoms of cholestasis can be improved or even eradicated with the cure of the Graves' disease. The cholestasis may be idiopathic. For patients with cholestasis and hyperthyroidism, Graves' disease should be considered for differential diagnosis.

Assessment of causal association between thyroid function and lipid metabolism: a Mendelian randomization study / 中华医学杂志(英文版)

BACKGROUND@#Thyroid dysfunction is associated with cardiovascular diseases. However, the role of thyroid function in lipid metabolism remains partly unknown. The present study aimed to investigate the causal association between thyroid function and serum lipid metabolism via a genetic analysis termed Mendelian randomization (MR).@*METHODS@#The MR approach uses a genetic variant as the instrumental variable in epidemiological studies to mimic a randomized controlled trial. A two-sample MR was performed to assess the causal association, using summary statistics from the Atrial Fibrillation Genetics Consortium (n = 537,409) and the Global Lipids Genetics Consortium (n = 188,577). The clinical measures of thyroid function include thyrotropin (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) levels, FT3:FT4 ratio and concentration of thyroid peroxidase antibodies (TPOAb). The serum lipid metabolism traits include total cholesterol (TC) and triglycerides, high-density lipoprotein, and low-density lipoprotein (LDL) levels. The MR estimate and MR inverse variance-weighted method were used to assess the association between thyroid function and serum lipid metabolism.@*RESULTS@#The results demonstrated that increased TSH levels were significantly associated with higher TC (β = 0.052, P = 0.002) and LDL (β = 0.041, P = 0.018) levels. In addition, the FT3:FT4 ratio was significantly associated with TC (β = 0.240, P = 0.033) and LDL (β = 0.025, P = 0.027) levels. However, no significant differences were observed between genetically predicted FT4 and TPOAb and serum lipids.@*CONCLUSION@#Taken together, the results of the present study suggest an association between thyroid function and serum lipid metabolism, highlighting the importance of the pituitary-thyroid-cardiac axis in dyslipidemia susceptibility.

Thyroid gland changes in patients with acromegaly

ABSTRACT Objective Acromegaly is characterized by high neoplastic morbidity as a side effect of growth hormone (GH) hypersecretion. Increased incidence of goiter, thyroid carcinoma, and thyroid dysfunction is also reported. The aim of the present study was to find the prevalence of thyroid dysfunction and goiter in patients with acromegaly and determine its relationship to disease activity, disease duration, and the presence of secondary hypothyroidism. Subjects and methods In a cross-sectional study of the period 2008-2012 were included 146 patients with acromegaly (56 men, 90 women) of mean age 50.3 ± 12.4 years. Acromegaly disease activity and thyroid function were evaluated in all patients. Thyroid ultrasonography was performed to calculate thyroid volume and detect the presence of nodular goiter. Results Ninety-one patients were determined to have an active disease, and 55, a controlled disease. The mean thyroid volume in patients without previous thyroid surgery was 37.6 ± 38.8 mL. According to disease activity, thyroid volume was significantly higher in patients with active disease (38.5 ± 45.4 mL vs. 27.2 ± 18.4 mL, p = 0.036). A weak positive correlation was found between thyroid volume and insulin-like growth factor 1 (IGF-1) in the whole group and in females (R = 0.218; p = 0.013, and R = 0.238; p = 0.037, respectively). There was no significant correlation of thyroid volume with disease duration and GH level in the whole group and in both sexes. The patients with secondary hypothyroidism had twofold smaller thyroid volume, relative to the rest of the group. The prevalence of thyroid dysfunction was 39%, with a female to male percentage ratio of 1.73. Goiter was diagnosed in 87% of patients, including diffuse goiter (17.1%) and nodular (69.9%), with no significant difference between patients with active and controlled disease or the presence of secondary hypothyroidism. Conclusions Thyroid volume in patients with acromegaly depends on disease activity and the presence of secondary hypothyroidism as a complication. The increased prevalence of nodular goiter determines the need of regular ultrasound thyroid evaluation in the follow-up of patients with acromegaly. Arch Endocrinol Metab. 2020;64(3):269-75

Selective case finding versus universal screening for detecting hypothyroidism in the first trimester of pregnancy: a comparative evaluation of a group of pregnant women from Rio de Janeiro

ABSTRACT Objective Maternal hypothyroidism during pregnancy may lead to adverse outcomes. Recently published guidelines by the American Thyroid Association (ATA) do not advocate for universal screening but recommend a case-finding approach in high-risk pregnant women. The present study aims to evaluate the accuracy of this approach in identifying women with thyroid dysfunction during early pregnancy. Subjects and methods This is a multiple-center, cross-sectional study. Three hundred and one pregnant women were enrolled. Anamnesis and a physical examination were performed to detect which women fulfilled the criteria to undergo laboratory screening of thyroid dysfunction, according to the ATA's 2017 guidelines. The Zulewski's validated clinical score was applied to assess signs and symptoms of hypothyroidism. Serum levels of thyrotropin (TSH), free thyroxine (FT4), anti-thyroperoxidase (TPO-Ab), and anti-thyroglobulin (Tg-Ab) antibodies were determined. Results Two hundred and thirty one women (78%) were classified as high risk, and 65 (22%) were classified as low risk for thyroid dysfunction. Regarding the clinical score, 75 patients (31.2%) presented mild symptoms that were compatible with SCH, of which 22 (7.4%) had symptoms as the only risk factor for thyroid disease. 17 patients (5.7%) had SCH, of which 10 (58.8%) belonged to the high-risk group, and 7 (41.2%) belonged to the low-risk group. OH was found in 4 patients (1.4%): 3 (75%) in the high-risk group and 1 (25%) in the low-risk group. Conclusions The ATA's proposed screening criteria were not accurate in the diagnosis of thyroid dysfunction in pregnancy. Testing only the high-risk pregnant women would miss approximately 40% of all hypothyroid patients.

Relationship of gender and age on thyroid hormone parameters in a large Chinese population

ABSTRACT Objective This study aimed to present the impact of age and gender on thyroid hormone levels in a large Chinese population with sufficient iodine intake. Subjects and methods A total of 83643 individuals were included and were stratified by age and gender. The median, 2.5th and 97.5th of thyrotropin (TSH), free triiodothyronine (FT3), free thyroxine (FT4) and FT3/FT4 ratio were calculated for both genders for every decade from 18 to over 80 years. TSH, FT3, FT4, FT3/FT4 distribution in each age group was evaluated for females and males using smoothing splines in the generalized additive models (GAM). TSH concentrations were compared in the different age groups in gender. Results In the over 80s age group, the TSH level (median: 2.57 mIU/L, 2.5th-97.5th: 0.86-7.56 mIU/L) was significantly higher than other age groups, irrespective to gender (P<0.001). Females had a higher TSH value than males in all age groups (P<0.001). Results of the smoothing curves showed that TSH increased with age, FT3 concentration was higher in males than in females and the tendency of the FT3/FT4 ratio was basically similar to that of FT3. TSH concentration in the 50s age group (median 2.48 mIU/L for females versus 2.00 mIU/L for males) was significantly higher than that in the 30s age group (median 2.18 mIU/L for females versus median 1.85 mIU/L for males). Conclusions In accord with increasing TSH values during aging, females and older adults have lower FT3 values and lower FT3/FT4 ratios, while the FT4 values remain stable.

Outpatient analytic assessment of anorexia nervosa — the importance of venous blood gases / Avaliação laboratorial em ambulatório na anorexia nervosa: a importância da gasometria venosa

ABSTRACT Objective: To evaluate serum biochemical parameters' evolution, especially venous blood gas (VBG), in anorexia nervosa (AN), correlating with clinical parameters. Methods: Retrospective study including out-patient AN adolescents, between January 2014 and May 2017. Three evaluations were compared: t1) first consultation; t2) consultation with the lowest body mass index (BMI) z-score and t3) with the highest BMI z-score. Results: A total of 24 adolescents (87.5% females) were included, mean age of presentation of 14.9±1.7 years, onset of symptoms 6.4±3.2 months before the first visit. In t1, BMI z-score of -1.91±1.11 kg/m2 and ideal weight % of 84.3±9.2. Amenorrhea was present in 88%. In t2 the analytical alterations were: altered VBG in 100%, altered ferritin (72% elevated), altered thyroid function (53% with thyroxine decrease), dyslipidemia (31% elevation of high density lipoprotein, 25% hypercholesterolemia), elevation of urea (25%), elevation of alanine aminotransferase (14%), hypoglycemia (14%), anemia (9%). Respiratory acidosis was present in 91% in t1, 100% in t2 and 94% in t3. There was a significant decrease between t2 and t3 in mean pCO2 (57.2 versus 53.6 mmHg; p=0.009) and mean HCO3 (30.0 versus 28.8 mEq/L; p=0.023). Conclusions: Respiratory acidosis and increased ferritin were common in this group. Respiratory acidosis was the most frequent abnormality with significant pCO2 and HCO3 variation in the recovery phase. VBG should be considered in AN evaluation, once it seems to be important in assessing the severity of the disease and its subsequent follow-up.

RESUMO Objetivo: Avaliar a evolução laboratorial, particularmente da gasometria venosa, na anorexia nervosa (AN), correlacionando os achados com parâmetros clínicos. Métodos: Estudo retrospetivo com adolescentes com AN seguidos em ambulatório, entre janeiro de 2014 e maio de 2017. Foram comparadas três avaliações: (t1) primeira consulta; (t2) consulta com escore Z de índice de massa corpórea (IMC) mais baixo; e (t3) consulta com escore Z de IMC mais elevado. Resultados: Incluídos 24 adolescentes, 87,5% do sexo feminino, idade média de apresentação de 14,9±1,7 anos, início dos sintomas 6,4±3,2 meses antes da primeira consulta. Em t1, escore Z de IMC de -1,91±1,11 kg/m2 e % de peso ideal de 84,3±9,2. Tinham amenorreia 88%. Em t2 as alterações laboratoriais encontradas foram: gasometria venosa alterada em 100%, ferritina alterada (72% elevada), função tiroideia alterada (53% com diminuição da tiroxina), dislipidemia (31% com elevação de lipoproteína de alta densidade, 25% com hipercolesterolemia), elevação da ureia (25%), elevação da alanina aminotransferase (14%), hipoglicemia (14%) e anemia (9%). A acidose respiratória esteve presente em 91% em t1, 100% em t2 e 94% em t3. Verificou-se diminuição significativa entre t2 e t3 da pressão parcial de CO2 (pCO2) média (57,2 versus 53,6 mmHg; p=0,009) e HCO3 médio (30,0 versus 28,8 mEq/L; p=0,023). Conclusões: A acidose respiratória e o aumento da ferritina foram comuns nesse grupo. Acidose respiratória foi a alteração mais frequente, com variação significativa de pCO2 e HCO3 na fase de recuperação. A gasometria venosa deve ser considerada na avaliação laboratorial na AN, pois parece ser importante na avaliação da gravidade e monitorização da doença.

Biochemical pattern of thyroid function test and clinical impression of thyroid disorder in a rural tertiary health institution in Nigeria

Thyroid disorders are one of the most common endocrine disorders seen globally. Diagnostic challenge may arise both clinically and biochemically because of the multiple function of thyroid hormones (THs). Request for thyroid function test (TFT s) may be based on clinical impression that may suggest thyroid dysfunction or obvious symptoms and signs that are diagnostic of hyperthyroidism or hypothyroidism. Materials and Methods: This retrospective study looks at the biochemical patterns of TFTs and the clinical impression of thyroid disorders in a rural tertiary institution. Information extracted from the laboratory register includes indication for the test, the hospital number, the gender, the age, and the THs assayed. The corresponding biochemical pattern of the TFT result was established. Results: A total of 297 requests were submitted for TH assay; 34 were excluded from the present study because there were no clinical information. There were 239 females and 24 males giving a female-to-male ratio of 9.9:1. Majority of the requests (36.5%) were for goiters, followed by gynecological disorders (20.9%) and clinical thyroid disorders (17.9%). About 46% (45.8%) of the goiter cases were biochemically euthyroid, whereas 13.5% were biochemically primary hyperthyroid. Among the 47 cases of thyroid disorders by the physician's clinical impression, 27.7% were euthyroid, 17% were biochemically hyperthyroid, and 10.6% were hypothyroid. Of the 55 gynecological disorders assessed, only 7.3% show biochemical evidence of TH alteration with 56.4% being euthyroid. About 47% (46.6%) of those that did routine medical examination had altered TH level that includes hyperthyroidism and hypothyroidism. Conclusion: Goiter is the most prevalent thyroid disorder in this environment. Biochemical pattern of thyroid function test in our environment was mostly euthyroid despites clinical features suggestive of thyroid disorders

Association between Serum Free Thyroxine and Anemia in Euthyroid Adults: A Nationwide Study

BACKGROUND: Studies on the relationship between thyroid function and anemia in the euthyroid range are scarce. We aimed to evaluate the association between anemia and serum free thyroxine (fT4) and thyrotropin (TSH) in euthyroid adults.METHODS: Data on 5,352 participants aged ≥19 years were obtained from the Korea National Health and Nutrition Examination Survey VI (2013 to 2015). Anemia was defined as hemoglobin (Hb) <13 and <12 g/dL for men and women, respectively.RESULTS: Overall, 6.1% of participants had anemia, and more women (9.9%) had anemia than men (2.8%, P<0.001). In multivariate analysis, serum fT4 levels, but not TSH, were positively associated with serum Hb levels in both sexes (P<0.001, each). Serum Hb levels linearly reduced across decreasing serum fT4 quartile groups in both sexes (P<0.001, each). After adjusting for potential confounding factors, participants with low-normal fT4 had 4.4 (P=0.003) and 2.8 times (P<0.001) higher risk for anemia than those with high-normal fT4 among men and women, respectively. When participants were divided into two groups at 50 years of age, in younger participants, men and women with the first quartile were at higher risk of anemia than men with the second quartile (odds ratio [OR], 3.3; P=0.029) and women with the forth quartile (OR, 3.2; P<0.001), respectively. This association was not observed in older participants.CONCLUSION: These results suggest that a low-normal level of serum fT4 was associated with a lower serum Hb level and a higher risk of anemia in euthyroid adults, especially in younger participants.

Historia de las pruebas de función tiroidea / History of thyroid function tests

El desarrollo de las pruebas de función tiroidea no ha sido fácil, con múltiples retos para mejorar algunas características que son insatisfactorias, incluso en la actualidad. En 1960 se logró la medición de tiroxina total (T4 total), y aunque fue un gran avance, los investigadores sabían que era insuficiente para una evaluación precisa de la función tiroidea. Uno de los problemas importantes radica en que existen diferencias marcadas interindividuales en la composición y en las cantidades de las proteínas de transporte de la T4 y la triyodotironina (T3). Por lo tanto, los depósitos de T4 y T3 son muy diferentes a los valores de T4 libre (T4L) y T3 libre (T3L). Por ejemplo, la mujer embarazada tiene el doble de globulina fijadora de tiroxina (TBG) y tres cuartas partes de la cantidad de albúmina que tenía cuando no estaba embarazada. También se pierde transtiretina y albúmina en enfermedades graves o con traumas, como quemaduras o sepsis. Entre 1963 y 1965 se desarrolló una prueba para tratar de obtener una estimación de la T4L, con el método de absorción de la hormona tiroidea a partir de la T4 total. Sin embargo, este análisis no funcionó correctamente, especialmente teniendo en cuenta la variabilidad en la TBG

Interpretación de las pruebas de función tiroidea / Interpretation of thyroid function tests

Los desórdenes de la glándula tiroides son comunes y pueden afectar hasta el 10% de la población en general. En muchas ocasiones los síntomas pueden ser inespecíficos, por lo que el médico en busca de un trastorno tiroideo debe llegar a un diagnóstico funcional y anatómico. Las mediciones séricas de las hormonas tiroideas confirman si hay un exceso, un déficit o si las concentraciones son normales. Para ello, se requiere un rango de referencia de la población local, y específicamente por grupos de edad, para una correcta interpretación de las pruebas de función tiroidea. Las hormonas tiroideas juegan un papel fundamental en el sistema endocrino, controlan el metabolismo general del cuerpo, el desarrollo neural, el crecimiento normal y la maduración de los huesos, así como funciones cardiovasculares y renales, entre otras. En esta revisión se pretende dar una aproximación a las pruebas tiroideas más relevantes, partiendo de la biosíntesis y secreción de las hormonas tiroideas, hasta llegar al abordaje para un diagnóstico inicial del paciente con trastorno tiroideo, mencionando los aspectos más importantes de los diferentes patrones tiroideos. El tratamiento detallado de cada uno de ellos, supera las expectativas de esta revisión

Thyroid gland disorders are common and can affect up to 10% of the general population. In many cases the symptoms can be nonspecific, so the physician in search for a thyroid disorder should reach a functional and anatomical diagnosis. Serum measurements of thyroid hormones confirm if there is an excess, a deficit, or if concentrations are normal. For this, reference ranges of the local population, and specifically by age groups, are required for a correct interpretation of thyroid function tests. Thyroid hormones play a fundamental role in the endocrine system, control of the general metabolism of the body, neural development, normal growth and maturation of bones, as well as in cardiovascular and renal functions, among others. In this review, the most relevant thyroid tests will be described, starting with the biosynthesis and secretion of thyroid hormones, and continuing with an approach to reach an initial diagnosis. Finally, the most important aspects of the different thyroid patterns will be mentioned. It is beyond the scope of this review, to describe the treatment for thyroid disorders.

Profile of necessary thyroid tests in a Colombian university hospital / Caracterización del perfil de pruebas tiroideas en un hospital universitario colombiano

Abstract Introduction: There are no clear clinical guidelines for requesting thyroid tests in hospitalized patients. The necessity and profile of requested tests in hospitalized patients at the San Vicente Foundation University Hospital were evaluated. Methods: This retrospective study included patients over 14 years of age who were nonpregnant and hospitalized at the Hospital Universitario de San Vicente Fundación. A total of 351 records were evaluated in the clinical history system, six necessity groups were defined: categories 1 to 4 were considered necessary test requests, and 5 and 6 were considered unnecessary test requests. Demographic and clinical variables were recorded. Quantitative statistical variables were evaluated with the Mann-Whitney U test, and qualitative variables were evaluated with Pearson's chi square and Fisher's tests. Results: Normal values were obtained for 67% of the measured thyroid stimulating hormone (TSH), 80% of the measured thyroxine (T4) and 53% of the measured triiodothyronine (T3). The most frequent abnormality in TSH was an elevation, observed in 24% of tests, the most frequent abnormality for free T4 (T4L) was a decline, observed in 11.5% of tests, and the most frequent abnormality for T3 was an elevation, as observed in 27% of tests. TSH ≤ 0.1 was found in 3.5% and ≥ 20 in 3.9% of tests. Of the 60 patients with elevated TSH, 75% had values between 5 and 9.99 mUI/mL; 11.5% had T4L values ≤ 0.7 ng/dL, and 8.6% had T4L values ≥ 1.48. In total, 95% of T4L measured in the unnecessary category was normal. Conclusions: Requests for necessary thy3roid tests during hospitalization should be improved. An initial approach is proposed only with TSH. (Acta Med Colomb 2019; 44. DOI: https://doi.org/10.36104/amc.2019.1057).

Resumen Introducción: se carece de guías clínicas claras para la solicitud de pruebas tiroideas en pacientes hospitalizados. Se evaluó el nivel de pertinencia y tipos de perfil solicitados en pacientes hospitalizados en el Hospital Universitario de San Vicente Fundación. Métodos: estudio retrospectivo en pacientes mayores de 14 años, no gestantes, hospitalizados en el Hospital Universitario de San Vicente Fundación. Se evaluaron 351 registros en el sistema de historia clínica, se definieron seis grupos de pertinencia, las categorías 1 a 4 se consideraron como pertinente, y la 5 y 6 como solicitudes de pruebas no pertinentes. Se registraron variables demográficas y clínicas. Las variables estadísticas cuantitativas fueron evaluadas con la prueba U Mann-Whitney, las variables cualitativas con chi2 Pearson y Estadístico de Fisher. Resultados: se obtuvieron valores normales en 67% de las TSH medidas, en 80% de las T4 y el 53% de las T3. La anormalidad más frecuente de la TSH fue elevación en 24%, para la T4 libre fue su reducción en 11.5% y para la T3 elevación en 27%. Se encontró TSH ≤ 0.1 en 3.5% y ≥ 20 en 3.9%. De los 60 pacientes con TSH elevada el 75% están entre 5 y 9.99 mUI/mL. La T4L ≤ de 0.7 ng/dL fue 11.5% y ≥ 1.48 en 8.6%. El 95% de las T4L medidas en la categoría no pertinente fueron normales. Conclusiones: se debe mejorar la pertinencia de solicitud de pruebas tiroideas en hospitalización. Se propone abordaje inicial solo con TSH. (Acta Med Colomb 2019; 44. DOI: https://doi.org/10.36104/amc.2019.1057).

Evaluation of Prevalence of Changes in Thyroid Functional Tests in Mole Hydatiforme

Introduction: Mole hydatiforme is the most common type of gestational trophoblast disease (GTI) and the aim of this study, is evaluation the frequency of changes in thyroid function test in mole hydatidiform patients. Materials and Methods: In this retrospective study, 63 patients with mole hydatidiform who reffering to gynecolgy ward of Ali ibn Abitaleb Hospital in Zahedan from April 2016 to March 2017, were studied. Information such as age, gravidity and laboratory findings inclluding thyroid function test (TFT) and the presence or absence of clinical sympltoms were recorded in the information forms and analyzed by SPSS software. Results: In this study, 63 patients with mole hydatidiform were studied. The mean age of the patients was 26.6 ± 7.7 years. The most common clinical manifestations of hyperthyroidism in patients with mole hydatidorme was tachycardia (39.7%). There was no relationschip between age and gravidity with the hyperthyroid simptoms and thyroid function test. Conclusion: Overall, the results of this study showed ttat 67% of patients with mole hydatidiform hay reduced TSH and more than 50% of cases hay increased free T3 and T4. There was no relationship between maternal age and gravidity with changes in thyroid functional test (AU)

Propylthiouracil-induced agranulocytosis as a rare complication of antithyroid drugs in a patient with Graves' disease

SUMMARY INTRODUCTION: Graves' disease (GD) is an autoimmune disorder characterized by hyperthyroidism. Antithyroid drugs (ATDs) are available as therapy. Agranulocytosis is a rare but potentially fatal complication of this therapy. In this study, we report agranulocytosis induced by propylthiouracil (PTU) in a patient with GD and the difficulties of clinical management. CASE: RNBA, male, 30 years old, with GD, treated with propylthiouracil (PTU). He progressed with pharyngotonsillitis. Then, PTU was suspended and antibiotic, filgrastim, propranolol, and prednisone were initiated. Due to the decompensation of hyperthyroidism, lithium carbonate, dexamethasone, and Lugol's solution were introduced. Total thyroidectomy (TT) was performed with satisfactory postoperative progression. DISCUSSION: We describe here the case of a young male patient with GD. For the treatment of hyperthyroidism, thioamides are effective options. Agranulocytosis induced by ATDs is a rare complication defined as the occurrence of a granulocyte count <500/mm3 after the use of ATDs. PTU was suspended, and filgrastim and antibiotics were prescribed. Radioiodine (RAI) or surgery are therapeutic alternatives. Due to problems with ATD use, a total thyroidectomy was proposed. The preoperative preparation was performed with beta-blocker, glucocorticoid, lithium carbonate, and Lugol solution. Cholestyramine is also an option for controlling hyperthyroidism. TT was performed without postoperative complications. CONCLUSION: Thionamide-induced agranulocytosis is a rare complication. With a contraindication to ATDs, RAI and surgery are definitive therapeutic options in GD. Beta-blockers, glucocorticoids, lithium carbonate, iodine, and cholestyramine may be an adjunctive therapy for hyperthyroidism.

RESUMO INTRODUÇÃO: A doença de Graves (DG) é uma doença autoimune caracterizada por hipertireoidismo. As drogas antitireoidianas (DAT) são opções terapêuticas disponíveis. A agranulocitose é uma complicação rara, potencialmente fatal desta terapia. Neste estudo, relatamos um caso de agranulocitose induzida por propiltiouracil (PTU) em paciente com DG e as dificuldades do manejo clínico. RELATO DE CASO: RNBA, sexo masculino, 30 anos, com DG, tratado com PTU. Evoluiu com faringoamigdalite, sendo o PTU suspenso e antibióticos, filgrastim, propranolol e prednisona, iniciados. Devido à descompensação do hipertireoidismo, iniciou carbonato de lítio (CL), dexametasona e a solução de Lugol. A tireoidectomia total (TT) foi realizada com boa evolução pós-operatória. DISCUSSÃO: Descrevemos caso de paciente jovem, sexo masculino, com DG. Para o tratamento do hipertireoidismo, as tionamidas são opções efetivas. A agranulocitose induzida por DATs é uma complicação rara, definida como a ocorrência de contagem de granulócitos <500/mm3 após uso de dats. PTU foi suspenso e foram prescritos filgrastim e antibiótico. O radioiodo (RAI) ou a cirurgia são alternativas terapêuticas. Devido a problemas com o uso de DAT, a TT foi proposta. A preparação pré-operatória foi realizada com betabloqueador, glicocorticoide, CL e solução de Lugol. A colestiramina também é uma opção para controlar o hipertireoidismo. A TT foi realizada sem complicações pós-operatórias. CONCLUSÃO: A agranulocitose induzida por drogas antitireoidianas é uma complicação rara. Com a contraindicação às DATs, RAI e cirurgia são opções terapêuticas definitivas para DG. Os betabloqueadores, glicocorticoides, CL, iodo e a colestiramina podem ser uma terapia adjuvante para o hipertireoidismo.