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BACKGROUND: We hypothesized that the serum TRX-1 in extremely preterm infants (EPIs) after birth was associated with the development of severe bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP). METHODS: This single-centered retrospective study enrolled EPIs treated at our institution. Serum TRX-1 concentrations of the residual samples taken on admission, day 10-20 of life, and 36-40 weeks of postmenstrual age (PMA) were measured with an enzyme-linked immunosorbent assay. RESULTS: The serum TRX-1 levels on admission were not different between the severe BPD (n = 46) and non-severe BPD groups (n = 67): [median (interquartile range) 147 (73.0-231) vs. 164 (80.5-248) ng/mL] (P = 0.57). These had no significant difference between the severe ROP (n = 47) and non-severe ROP groups (n = 66): [164 (71.3-237) vs. 150 (80.9-250) ng/mL] (P = 0.93). The TRX-1 levels at 10-20 days of life and 36-40 weeks of PMA also had no association with the development of severe BPD and ROP. CONCLUSION: The serum TRX-1 levels after birth are not predictive of severe BPD and ROP. IMPACT: Serum thioredoxin-1 levels in extremely preterm infants on the day of birth are lower than those in term or near-term infants hospitalized for transient tachypnea of the newborn. In extremely preterm infants, the serum thioredoxin-1 levels on the day of birth, at 10-20 days of life, and at postmenstrual age of 36-40 weeks were not associated with severe bronchopulmonary dysplasia and retinopathy of prematurity. The thioredoxin system is under development in extremely preterm infants; however, the serum thioredoxin-1 level is not predictive for severe bronchopulmonary dysplasia and retinopathy of prematurity.
Assuntos
Displasia Broncopulmonar , Lactente Extremamente Prematuro , Retinopatia da Prematuridade , Tiorredoxinas , Humanos , Displasia Broncopulmonar/sangue , Displasia Broncopulmonar/diagnóstico , Tiorredoxinas/sangue , Retinopatia da Prematuridade/sangue , Recém-Nascido , Estudos Retrospectivos , Feminino , Masculino , Lactente Extremamente Prematuro/sangue , Idade Gestacional , Biomarcadores/sangue , Fatores de RiscoRESUMO
PURPOSE: Personalized pharmacotherapy, including for the pediatric population, provides optimal treatment and has emerged as a major trend owing to advanced drug therapeutics and diversified drug selection. However, it is essential to understand the growth and developmental characteristics of this population to provide appropriate drug therapy. In recent years, clinical pharmacogenetics has accumulated knowledge in pediatric pharmacotherapy, and guidelines from professional organizations, such as the Clinical Pharmacogenetics Implementation Consortium, can be consulted to determine the efficacy of specific drugs and the risk of adverse effects. However, the existence of a large knowledge gap hinders the use of these findings in clinical practice. METHODS: We provide a narrative review of the knowledge gaps in pharmacokinetics (PK) and pharmacodynamics (PD) in the pediatric population, focusing on the differences from the perspective of growth and developmental characteristics. In addition, we explored PK/PD in relation to pediatric clinical pharmacogenetics. RESULTS: The lack of direct and indirect biomarkers for more accurate assessment of the effects of drug administration limits the current knowledge of PD. In addition, incorporating pharmacogenetic insights as pivotal covariates is indispensable in this comprehensive synthesis for precision therapy; therefore, we have provided recommendations regarding the current status and challenges of personalized pediatric pharmacotherapy. The integration of clinical pharmacogenetics with the health care system and institution of educational programs for health care providers is necessary for its safe and effective implementation. A comprehensive understanding of the physiological and genetic complexities of the pediatric population will facilitate the development of effective and personalized pharmacotherapeutic strategies.
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Farmacogenética , Farmacocinética , Criança , Humanos , Preparações FarmacêuticasRESUMO
We examined whether the administration of growth hormone (GH) improves insulin resistance in females of a non-obese hyperglycemic mouse model after birth with low birth weight (LBW), given that GH is known to increase muscle mass. The intrauterine Ischemia group underwent uterine artery occlusion for 15 min on day 16.5 of gestation. At 4 weeks of age, female mice in the Ischemia group were divided into the GH-treated (Ischemia-GH) and non-GH-treated (Ischemia) groups. At 8 weeks of age, the glucose metabolism, muscle pathology, and metabolome of liver were assessed. The insulin resistance index improved in the Ischemia-GH group compared with the Ischemia group (p = 0.034). The percentage of type 1 muscle fibers was higher in the Ischemia-GH group than the Ischemia group (p < 0.001); the muscle fiber type was altered by GH. In the liver, oxidative stress factors were reduced, and ATP production was increased in the Ischemia-GH group compared to the Ischemia group (p = 0.014), indicating the improved mitochondrial function of liver. GH administration is effective in improving insulin resistance by increasing the content of type 1 muscle fibers and improving mitochondrial function of liver in our non-obese hyperglycemic mouse model after birth with LBW.
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Modelos Animais de Doenças , Hiperglicemia , Resistência à Insulina , Fígado , Animais , Feminino , Humanos , Camundongos , Gravidez , Hormônio do Crescimento Humano/farmacologia , Hormônio do Crescimento Humano/administração & dosagem , Hiperglicemia/tratamento farmacológico , Hiperglicemia/metabolismo , Fígado/metabolismo , Fígado/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Proteínas Recombinantes/farmacologiaRESUMO
Islet-cell associated antibodies are predictive and diagnostic markers for type 1 diabetes. We studied the differences in the early clinical course of children with type 1 diabetes with a single antibody and those with multiple antibodies against pancreatic ß-cells. Sixty-seven children with type 1 diabetes aged less than 15 years diagnosed between 2010 and 2021 were included in the study and subdivided into two subgroups: children who were single positive for either glutamic acid decarboxylase (GAD) antibodies (n = 16) or insulinoma-associated antigen-2 (IA-2) antibodies (n = 13) and those positive for both antibodies (n = 38) at diagnosis. We compared the patients' clinical characteristics, pancreatic ß-cell function, and glycemic control during the 5 years after diagnosis. All clinical characteristics at diagnosis were similar between the two groups. One and two years after diagnosis, children who tested positive for both antibodies showed significantly lower postprandial serum C-peptide (CPR) levels than those who tested positive for either GAD or IA-2 antibodies (p < 0.05). In other periods, there was no significant difference in CPR levels between the two groups. There was a significant improvement in glycosylated hemoglobin (HbA1c) levels after starting insulin treatment in both groups (p < 0.05), but no significant difference in HbA1c levels between the groups. Residual endogenous insulin secretion may be predicted based on the number of positive islet-cell associated antibodies at diagnosis. Although there are differences in serum CPR levels, optimal glycemic control can be achieved by individualized appropriate insulin treatment, even in children with type 1 diabetes.
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Autoanticorpos , Diabetes Mellitus Tipo 1 , Glutamato Descarboxilase , Insulina , Insulinoma , Humanos , Diabetes Mellitus Tipo 1/tratamento farmacológico , Masculino , Feminino , Criança , Adolescente , Hemoglobinas Glicadas , Insulinoma/tratamento farmacológico , Peptídeo C/sangue , Insulina/uso terapêuticoRESUMO
Since it was proposed in this journal in 2001, the cranial vault asymmetry index (CVAI) has been an important parameter for assessing cranial shape. However, different publications currently use different variables in the denominator of the CVAI formula. We thus investigated the use of long and short diagonal lengths as variables in the denominator of the CVAI formula. We searched the databases of PubMed, Google Scholar, and Scopus for articles published between 2016 and 2022 that cited the original work article of CVAI. Articles were included if they were written in English and if the denominator of the CVAI formula was specified. For multiple articles by the same author, only the most recent article was included. In total, 30 articles were included; 10 articles used the longer diagonal length as the denominator and 20 articles used the shorter diagonal length. No uniform trend was observed by a country or journal of publication. Application of the CVAI formula using different denominators yielded interchangeable results, and the resulting values had only negligible differences clinically. However, it would be necessary to create a standard formula for using the CVAI as a parameter for reporting cranial shape assessments consistently.
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Plagiocefalia não Sinostótica , Humanos , Crânio , Bibliometria , Bases de Dados FactuaisRESUMO
Background and Objectives: Baloxavir marboxil is a novel cap-dependent endonuclease inhibitor prescribed for influenza treatment. Unlike neuraminidase inhibitors like oseltamivir, which impair viral release from infected host cells, baloxavir blocks influenza virus proliferation by inhibiting viral mRNA transcription. This study aimed to compare the effectiveness of baloxavir and oseltamivir for the treatment of early childhood influenza. Materials and Methods: Of 1410 patients diagnosed with influenza between 2015 and 2018 at a Japanese primary care outpatient clinic, 1111 pediatric patients aged 0-6 years who were treated with baloxavir (n = 555) or oseltamivir (n = 556) were enrolled retrospectively. The following clinical factors were compared between patients treated with baloxavir and oseltamivir: age, sex, time from fever onset to drug administration (<24 h or 24-48 h), time from drug administration to fever reduction, influenza type (A or B), and influenza vaccination before disease onset. The duration of the fever, which was used as an index of clinical effectiveness, was compared using the log-rank test. Clinical factors associated with fever duration were determined using multivariate logistic regression analysis. Results: Median age (3.0 vs. 2.5 years), influenza type A (99% vs. 47%), median duration from drug administration to fever resolution (1 day vs. 2 days), and influenza vaccination (done, 41% vs. not done, 65%) were significantly different between the baloxavir and oseltamivir groups (p < 0.001). The number of patients with a fever duration of one day was 553 (99.6%) in the baloxavir group and 6 (1.1%) in the oseltamivir group (p < 0.001). Baloxavir use was only significantly associated with fever duration in the multivariate analysis (odds ratio 50,201, p < 0.001). Apparent adverse effects were not observed in the baloxavir-treated group. Conclusions: Baloxavir treatment resulted in a shorter fever duration than oseltamivir treatment in early childhood influenza.
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Dibenzotiepinas , Influenza Humana , Pré-Escolar , Humanos , Criança , Oseltamivir/uso terapêutico , Influenza Humana/tratamento farmacológico , Estudos Retrospectivos , Dibenzotiepinas/uso terapêutico , Febre/tratamento farmacológicoRESUMO
A standard treatment for disseminated intravascular coagulation in neonates has not yet been established. We analyzed the outcomes of 23 neonates who developed disseminated intravascular coagulation due to infection or asphyxia between 2004 and 2017. The overall survival rate was 95.7% on day 28 after anticoagulant therapy. In contrast, the bleeding-free survival rate was 69.6% (95% confidence interval, 53.1%-91.2%). Of the 6 neonates with intracranial bleeding, 2 developed neurological sequelae. The current study showed that intracranial bleeding remained a major problem in the early 2000s, despite the introduction of a new anticoagulant drug, recombinant thrombomodulin, at our institution since 2009.
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Coagulação Intravascular Disseminada , Trombomodulina , Anticoagulantes/uso terapêutico , Coagulação Intravascular Disseminada/tratamento farmacológico , Coagulação Intravascular Disseminada/etiologia , Hemorragia/tratamento farmacológico , Humanos , Recém-Nascido , Hemorragias Intracranianas/induzido quimicamente , Hemorragias Intracranianas/tratamento farmacológico , Proteínas Recombinantes/efeitos adversos , Trombomodulina/uso terapêuticoRESUMO
BACKGROUND: There is insufficient research on cholesterol uptake capacity (CUC) in preterm infants; therefore, the relationship between CUC and cholesterol transport in preterm infants is unclear. This study aimed to clarify the relationship between CUC and anthropometric measurements, high-density lipoprotein cholesterol (HDL-C) levels, and HDL-C subclasses in preterm infants. METHODS: Fifty-eight preterm infants were divided into small-for-gestational age (n = 20) (SGA) and appropriate-for-gestational age (AGA) (n = 38). CUC was measured using a fully automated immunoassay system, HI-1000. HDL-C subclasses were measured using high-performance liquid chromatography. RESULTS: SGA showed significantly lower HDL-C and CUC levels than AGA. We found a positive correlation between CUC and birth weight, birth height, and birth head circumference in preterm infants. Moreover, CUC had a strong relationship with HDL-C and very large, large, and medium HDL-C in preterm infants. CONCLUSIONS: In preterm infants, CUC is associated with normal growth and may indicate the ability to transport cholesterol forward by large-or medium-size HDL.
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Sangue Fetal , Recém-Nascido Prematuro , Colesterol , HDL-Colesterol , Feminino , Humanos , Lactente , Recém-Nascido , Recém-Nascido Pequeno para a Idade GestacionalRESUMO
BACKGROUND: In the original glucose oxidase-peroxidase (GOD-POD) protocol, the time required to decrease the initial total bilirubin (TB) level by 20% is used for unbound bilirubin (UB) calculation. However, it needs to continuously monitor the TB levels by spectrometry. METHODS: Here, we hypothesized that the TB decrease during fixed time periods can also be used to extrapolate UB values (fixed-time protocol). Serum UB levels measured by the different protocols were compared using 10 newborn serum samples. RESULTS: Serum UB levels determined using the fixed-time protocol, especially using periods of 10 - 40 seconds, were strongly correlated with those determined using the original protocol (coefficient of determination > 0.9). The fixed-time protocol, using periods of 20 - 60 seconds, showed the high measurement precision (coefficient of variation < 5%). CONCLUSIONS: The fixed-time protocol, using periods of 20 - 40 seconds, can help determine serum UB levels as effectively as the original protocol.
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Glucose Oxidase , Peroxidase , Bilirrubina , Humanos , Recém-Nascido , Oxirredutases , PeroxidasesRESUMO
INTRODUCTION: The aims were to investigate the clinical characteristics of Toxoplasma gondii (T. gondii) immunoglobulin (Ig) M-positive mothers and to clarify the incidences of serum T. gondii IgM or blood T. gondii DNA positivity in newborns born to the mothers and the actual congenital T. gondii infection. METHODS: Mothers with T. gondii IgM positivity and newborns born to the mothers from 2013 to 2020 were prospectively investigated. Serum T. gondii IgG and IgM were measured by enzyme-linked immunosorbent assay. Blood T. gondii DNA was detected by semi-nested polymerase chain reaction. Congenital T. gondii infection was diagnosed based on clinical characteristic manifestations with serum T. gondii IgG positivity at any age or T. gondii IgG positivity after 12 months of age. RESULTS: Among 71 T. gondii IgM-positive mothers, including one with triplets, 41% had low T. gondii IgG avidity index and 73% received maternal therapy. Among 73 newborns who were examined for serum T. gondii IgG and IgM at birth, none had clinical manifestations, and one (1.4%) had T. gondii IgM positivity. Among 32 newborns who were examined for blood T. gondii DNA at birth, two (6.3%) were positive. All patients with serum T. gondii IgM or blood T. gondii DNA positivity showed T. gondii IgG negativity within 12 months of age. CONCLUSIONS: A few newborns born to T. gondii IgM-positive mothers were suspected of having congenital T. gondii infection based on serum T. gondii IgM or blood T. gondii DNA testing at birth. However, none developed congenital T. gondii infection.
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Toxoplasma , Anticorpos Antiprotozoários , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina M , Recém-Nascido , Mães , Gravidez , Estudos Prospectivos , Toxoplasma/genéticaRESUMO
Beckwith-Wiedemann syndrome (BWS) is infrequently associated with adrenocortical carcinoma (ACC) or non-hormone-producing adrenal cytomegaly, but we recently, encountered a single case of adrenal cytomegaly in a patient with BWS, which was difficult to distinguish from androgen-producing adrenocortical carcinoma (ACC). Here, we describe the case of a 4-month-old female who presented with clitoromegaly, hemihypertrophy, and an adrenal mass identified during the prenatal period. The mass was located in detected at the left suprarenal region and detected at 20 weeks of gestational age. At birth, she also presented with clitoromegaly and elevated serum levels of 17α-hydroxyprogesterone, dehydroepiandrosterone, and testosterone at birth and experienced hyper-insulinemic hypoglycemia, which improved following diazoxide therapy. We initially suspected androgen-producing ACC with metastasis and the left adrenal mass was resected accordingly when the patient reached 4 months of age. However, histological examination revealed adrenal cytomegaly. Genetic analysis revealed paternal uniparental disomy, and the patient was finally diagnosed as having BWS. Resection of the left adrenal gland restored the serum androgen levels to normal physiological levels without any recurrence. While it is reasonably well known that BWS is sometimes accompanied by virilization due to androgen-producing ACC, our findings are among the first to suggest that adrenal cytomegaly can also increase androgen hormone production. Thus, we propose that adrenal cytomegaly should be considered one of the differential diagnoses when accompanied with hyperandrogenism in BWS patients.
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Neoplasias do Córtex Suprarrenal , Doenças das Glândulas Suprarrenais , Carcinoma Adrenocortical , Síndrome de Beckwith-Wiedemann , Androgênios , Feminino , Humanos , Lactente , Recém-Nascido , Gravidez , Dissomia UniparentalRESUMO
BACKGROUND: Bacterial infections and some antibiotics show displacer effects on bilirubin-albumin binding and increase unbound bilirubin (UB) but not total bilirubin (TB) in serum. METHODS: A case study was conducted to show a successful treatment of hyperbilirubinemia by monitoring UB. RESULTS: In an extremely preterm infant with bloodstream bacterial infection caused by methicillin-resistant coagulase-negative staphylococci, 2 days after high-dose ampicillin and regular-dose amikacin were initiated, UB markedly increased, but TB did not. After vancomycin was substituted, UB decreased immediately with phototherapy and intravenous albumin infusion. CONCLUSIONS: When using antibiotics, the clinicians should be mindful regarding the displacer effect on bilirubin-albumin binding.
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Infecções Bacterianas , Lactente Extremamente Prematuro , Bilirrubina , Humanos , Hiperbilirrubinemia/terapia , Lactente , Recém-Nascido , FototerapiaRESUMO
BACKGROUND: Preterm infants sometimes have transient late-onset hemolytic jaundice; however, the etiology has yet to be determined. CASE PRESENTATION: In our case, fetal hemoglobin (HbF) level increased significantly to 100% at 23 days of age. Levels of methemoglobin and carboxyhemoglobin also increased to 2.9% and 3.5%, respectively, following the elevated HbF level. At 26 days, hemolytic jaundice developed. No abnormality of red blood cell membranes and enzyme activities was found. CONCLUSIONS: The etiology of late-onset hemolytic jaundice in preterm infants may associate with an impaired switching from HbF to adult hemoglobin (HbA) or reverse switching from HbA to HbF.
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Hemoglobina Fetal/análise , Recém-Nascido de Peso Extremamente Baixo ao Nascer , Icterícia , Eritrócitos/patologia , Humanos , Recém-Nascido , Masculino , Metemoglobina/análiseRESUMO
OBJECTIVE: We aimed to evaluate immunogenicity following Japanese original delayed hepatitis B (HB) vaccinations for prevention of mother-to-child HB infection in preterm infants. METHODS: A nationwide survey in Japan was conducted at certified neonatology facilities in 2014. Eighty-four preterm infants born from a serum hepatitis B surface (HBs) antigen-positive mother were included. We collected data on the following parameters: gestational age, birth weight (BW), age at HB vaccination, age at examination of serum anti-HBs titer, and serum anti-HBs titer. The delayed HB vaccination schedule was 3 doses of HB vaccines at 2, 3 and 5 months of age. A seropositive immunogenic response to HB vaccination was defined as an anti-HBs titer ≥10 mIU/mL. Seropositive rates were calculated in all participants. Four subgroups based on BW were as follows: <1000 g (n = 13), 1000-1499 g (n = 16), 1500-1999 g (n = 26), and ≥2000 g (n = 29). RESULTS: Among 84 preterm infants who completed the delayed vaccination schedule, 82 (98%) achieved seropositive anti-HBs titer at a median age of 6 months. Seropositive rates of infants <1000 g, 1000-1499 g, 1500-1999 g, and ≥2000 g were 92%, 94%, 100%, and 100%, respectively. CONCLUSION: The Japanese original delayed HB vaccinations achieved sufficient seropositive rates in preterm infants and provide immunogenicity against mother-to-child HB infection.
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Vacinas contra Hepatite B/imunologia , Hepatite B/prevenção & controle , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Feminino , Hepatite B/imunologia , Humanos , Lactente , Recém-Nascido de Peso Extremamente Baixo ao Nascer , Recém-Nascido Prematuro , Japão , Gravidez , Estudos Retrospectivos , Inquéritos e Questionários , Vacinação/métodosRESUMO
BACKGROUND: The objective of the present study was to verify the speed and accuracy of fetal ultrasonic Doppler (fetal Doppler) in measuring heart rate of newborns at rest, including preterm, low-birthweight infants, and its efficacy during neonatal resuscitation, including cases of neonatal asphyxia. METHODS: A three-lead electrocardiogram and fetal Doppler were used to measure resting heart rates in 100 newborns, including 48 preterm, low-birthweight infants, at 0 to 72 h after birth. Times to display heart rate were compared between electrocardiogram and fetal Doppler by the Bland-Altman analysis and Wilcoxon signed-rank test. The time required for the fetal Doppler to measure heart rate during neonatal resuscitation was also assessed. RESULTS: In 100 newborns, the mean error of the resting heart rate in 1,293 measurement points was 0.07 beats/min. To display the heart rate, the fetal Doppler required a median time of 5 s, and electrocardiogram required a median time of 10 s (P < 0.001). During neonatal resuscitation, the heart rate was measured within 10 s in 18 of 21 cases (86%) and displayed with a median time of 5 s; this was measured in all neonatal asphyxia cases (9/9, 100%). CONCLUSIONS: Fetal Doppler can measure heart rate in newborns accurately and rapidly and is useful for evaluating heart rate not only at rest but also during neonatal resuscitation, especially in asphyxia.
Assuntos
Asfixia Neonatal/terapia , Eletrocardiografia/métodos , Frequência Cardíaca , Ressuscitação/métodos , Ultrassonografia Doppler/métodos , Feminino , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Ultrassonografia Pré-Natal/métodosRESUMO
BACKGROUND: The aim of this study was to investigate cholesterol and triglyceride levels in the chylomicron fraction of preterm infants at birth and during the early postnatal period. METHODS: The subjects consisted of 133 infants (81 boys and 52 girls): 74 were term infants born at 37-41 weeks of gestation and 59 were preterm infants born at 29-36 weeks of gestation. Cholesterol and triglyceride in the chylomicron fraction were measured using high-performance liquid chromatography. RESULTS: Compared with term infants, preterm infants had higher cholesterol and lower triglyceride in the chylomicron fraction, both in cord blood and at 1 month after birth. Thus, the chylomicron triglyceride/cholesterol ratio was significantly lower in preterm infants than in term infants in cord blood and at 1 month of age. On single regression analysis the chylomicron triglyceride/cholesterol ratio correlated positively with gestational age at birth (r = 0.331, P = 0.0003) and at 1 month (r = 0.221, P = 0.0119). CONCLUSIONS: Preterm infants have a less-lipidated chylomicron composition at birth and at 1 month of age. Some prenatal factors may persist to influence chylomicron lipidation during the early postnatal period.
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Colesterol/sangue , Quilomícrons/análise , Recém-Nascido Prematuro/sangue , Triglicerídeos/sangue , Cromatografia Líquida de Alta Pressão , Feminino , Sangue Fetal/metabolismo , Idade Gestacional , Humanos , Recém-Nascido , Masculino , GravidezAssuntos
Infecções por Citomegalovirus , Perda Auditiva Neurossensorial , Doenças do Recém-Nascido , Lactente , Recém-Nascido , Humanos , Valganciclovir/uso terapêutico , Citomegalovirus , Recém-Nascido Prematuro , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/tratamento farmacológico , Infecções por Citomegalovirus/congênito , Antivirais/uso terapêuticoRESUMO
Hypothyroidism is rarely included in the differential diagnosis for fetal sinus bradycardia. We report an infant with congenital hypothyroidism caused by ectopic thyroid tissue, who showed antenatal bradycardia. The baseline fetal heart rate was 100-110 bpm at 30 weeks of gestation, and fetal echocardiography revealed sinus bradycardia but no cardiac anomalies. Maternal thyroid function was normal (thyroid-stimulating hormone [TSH] 2.03 µIU/ml, free T3 2.65 pg/ml, and free T4 0.99 ng/dl) when measured at 31 weeks of gestation. Her serum anti SS-A and SS-B antibodies, anti-thyroglobulin, and microsomal antibodies were negative. A male infant without cardiac anomalies was delivered at 35 weeks and 4 days of gestation and admitted for prematurity and respiratory distress syndrome. The infant's heart rate was 70-110 bpm (normal: 120-160 bpm) on admission. On 8 days of age, thyroid function tests revealed that the infant had severe hypothyroidism (TSH 903.3 µIU/ml, free T3 1.05 pg/ml, and free T4 0.26 ng/dl). The prolonged jaundice assumed to be due to hypothyroidism. Oral levothyroxine sodium hydrate (10 µg/kg/day) was immediately started on day 8. After the treatment, the heart rate was gradually increased to 130-140 bpm as the infant's thyroid function was improved (TSH 79.8 µIU/ml, free T3 2.95 pg/dl, and free T4 1.66 ng/dl on day 22). The infant was diagnosed ectopic thyroid tissue because of the high thyroglobulin level (85.9 µg/l). In conclusion, congenital hypothyroidism should be included in the differential diagnosis in cases of fetal bradycardia without cardiac anomalies or maternal autoimmune diseases.