Keywords
TSH
pseudomalabsorción
levotiroxina
levothyroxine
pseudo malabsorption
hypothyroidism
How to Cite
Abstract
Se presentan cinco casos de pacientes con hipotiroidismo primario y altos requerimientos de levotiroxina, que luego de haber tenido un abordaje convencional en el ajuste de las dosis necesarias de levotiroxina por el peso y etiología de hipotiroidismo, recomendación y educación para el consumo adecuado de levotiroxina, optimización de la calidad del medicamento recibido, eliminación de interferencias con la absorción por medicamentos o alimentos, reposición de deficiencia de vitamina B12, desparasitación, descartar enfermedad celíaca y gastritis autoinmune atrófica, persisten con TSH elevada pese al uso de dosis altas de levotiroxina (mayores de 2,5 µg/kg/día). Se les practicó prueba de absorción de levotiroxina con 1.000 µg en dosis única de carga y evaluación de los incrementos de T4 libre a las 2 y 4 horas en cuatro pacientes y en uno con suministro semanal de la dosis de levotiroxina y evaluación semanal de T4 libre. Se confirmó en los cinco pacientes la capacidad de absorción de levotiroxina, constituyendo cinco casos de pseudomalabsorción de levotiroxina.
Abstract
Five patients with primary hypothyroidism and high levothyroxine dose requirements (>2.5 µg/kg/day) are presented.
All patients had usual adjustment of the levothyroxine dose according to weight and hypothyroidism etiology. Patients were educated about the appropriate way of drug intake, the quality of the hormone replacement was assessed and withdrawal of all medications potentially interrupting with the levothyroxine absorption was done. All patients had vitamin B12 replacement, were treated for gastrointestinal parasites and celiac disease and autoimmune atrophic gastritis was ruled out. Despite correction of all this factors these patients had elevated TSH. To evaluate a potential mala-absorptive case all patients underwent a levothyroxine absorption test. In 4 cases, 1000 µg of levothyroxine was administered and free T4 was evaluated at 2 and 4 hours after intake of the drug. In 1 case, the levothyroxine was administered weekly with free t4 evaluation. Appropriate levothyroxine absorption was confirmed in all cases and the diagnosis of pseudo mal-absorption of levothyroxine was done.
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