Alteraciones del neurodesarrollo en pacientes con hipotiroidismo congénito: Recomendaciones para el seguimiento / Neurodevelopmental assessment of patients with congenital hypothyroidism

Congenital hypothyroidism (CH) is the most common cause of preventable cognitive disability worldwide. Generally, it is produced by an alteration in the embryogenesis of the thyroid gland or by an alteration in the synthesis of thyroid hormones, which determine that affected patients have low or absent thyroid hormone concentrations. The importance of this fact is that brain development during the first three years of life is highly dependent on thyroid hormones. Prior to the implementation of national neonatal screening programs around the world, 8 to 27% of children with CH had an IQ lower than 70. Nowadays, this percentage is close to 0 in countries that have implemented the program. In Chile, CH neonatal screening program achieved national coverage in 1996. Currently, the incidence of the disease in our country is 1: 3163. The degree of disability produced by CH not only depends on the time of detection of the disease and the prompt start of therapy, but also on an adequate monitoring. Despite screening programs, neurocognitive impairment in schoolchildren and teenagers with CH is still observed, reflected in lower scores in cognitive, language and gross motor assessments, receptive communication, expressive communication, fine motor and gross motor skills compared to healthy children. Also, lesser achievements in learning and language disorders are observed. The objective of this review is to update the information available on neurodevelopment of patients with CH.

Hipotiroidismo congénito: un diagnóstico que no debemos olvidar / Congenital hypothyroidism: a diagnosis not to forget

Summary: Congenital hypothyroidism (CH) is the most common cause of preventable mental retardation. Since 1994, Chile has a national plan for mass screening all newborns to diagnose the disease. Currently, the CH incidence is approximately 1:3163 newborn (NB). Approximately, 10 percent of these cannot be identified by screening programs, so the clinical suspicion is fundamental in the diagnosis. The most frequently clinical features observed in neonates or young infants are the presence of a posterior fontanelle greater than 5 mm, umbilical hernia and dry skin. It is important to determine the etiology of CH, but the etiological study should not delay the start of treatment. Early treatment determines a better prognosis of neurological development. A review of the CH screening program, pathophysiology, clinical presentation, and aspects of the study and treatment are presented in this study.

El hipotiroidismo congénito (HTC) es la causa más frecuente de discapacidad intelectual prevenible. Desde el año 1994 existe en Chile un plan nacional de tamizaje masivo a todos los recién nacidos para el diagnóstico de la enfermedad. Actualmente, la incidencia de HTC es de aproximadamente 1:3 163 recién nacidos (RN). Hasta un 10 por ciento de éstos puede no ser identificado por los programas de tamizaje, por lo que es importante la sospecha clínica del diagnóstico. Las características clínicas más frecuentemente observadas en RN o lactantes pequeños son la presencia de una fontanela posterior mayor de 5 mm, hernia umbilical y piel seca. Es importante determinar la etiología del HTC, pero el estudio etiológico no debe retrasar el inicio del tratamiento. El inicio precoz de éste determina un mejor pronóstico de desarrollo neurológico. Se presenta una revisión del programa de tamizaje de HTC, su fisiopatología, presentación clínica, y aspectos del estudio y tratamiento.

Absceso tiroideo con fístula del seno piriforme: tres casos clínicos / Thyroid abscess with pyriform sinus fistulae: 3 clinical cases

Thyroid abscess is an infrequent, potentially life-threatening condition. It accounts for 0,1 to 0,7 percent of thyroid pathology, usually occurring in patients with preexisting disease of the gland or more commonly, associated to local anatomical defects, such pyriform sinus fistulae. Three cases of thyroid abscess in children are presented, in which no bacterial etiology was confirmed. Intravenous antibiotics were used, cefotaxime, cloxacillin or clindamicin. Recurrence was confirmed in 2 of them, and a pyriform sinus fistulae was demostrated by esophagogram.

El absceso tiroideo es un cuadro infrecuente y una emergencia endocrina potencialmente fatal. Representa el 0,1 a 0,7 por ciento de las patologías tiroideas. Habitualmente se produce en pacientes con patología preexistente de la glándula o más frecuentemente, asociado a defectos anatómicos locales, como una fístula del seno piriforme. Presentamos 3 casos de abscesos tiroideos en escolares. Recibieron tratamiento antibiótico endovenoso de amplio espectro, a pesar de lo cual dos de ellos recidivaron precozmente. En dos de ellos se demostró una fístula del seno piriforme con esofagograma que se manejó quirúrgicamente.

Sensibilidad diagnóstica de los distintos tiempos de la prueba de estímulo con clonidina, indicada para descartar deficiencia de hormona de crecimiento en niños con talla baja / Timing of growth hormone peaks during the clonidine provocation test

Background: Clonidine provocative test is used for the diagnosis of growth hormone (GH) deficiency. The duration of the test is not uniform across places where it is performed. Aim: To evaluate the frequency and timing of GH peaks during the clonidine test. To determine the timing with the highest diagnostic yield for GH deficiency. Patients and Methods: Analysis of the GH response during a clonidine test performed to 93 children with low stature, aged 11 +/- 3 years (41 percent women), with mean z scores of -2.3 +/- 0.8 for height and of 0.4 +/- 0.9 for body mass index, that were consecutively studied. A oral dose of 0.15 mg/m2 of clonidine was administered and GH levels were determined by the chemiluminescent enzyme immunoassay method of solid phase at 0, +30, +60, +90 and +120 minutes after. The cut-off point for GH deficiency was set at 7 ng/dL. Results: In ten children GH levels were lower than 7 ng/dL during the test and were considered as having GH deficiency. In 86 percent of the 83 patients without GH deficiency, the peak over 7 ng/mL appeared at +60 minutes and in 89 percent the peak had appeared at +90 minutes. In only 11 percent of these children, the peak appeared at +120 minutes. Conclusions: The timing with the highest diagnostic yield for GH is +60 minutes after the administration of clonidine. However the sample at +120 minutes should not be eliminated, considering that the highest GH peak appears at that time in 11 percent of children.