Medicina

101.- La primera causa de hipertiroidismo en adolescentes es:

a) Tiroditis subaguda
b) Bocio toxico difuso (enfermedad de Graves)
c) Bocio toxico nodular
d) Adenoma toxico

Respuesta correcta: B, bocio toxico difuso.
Thyrotoxicosis is the hypermetabolic condition associated with elevated levels of free thyroxine (FT4), free triiodothyronine (FT3), or both. Hyperthyroidismincludes diseases that are a subset of thyrotoxicosis (excludes exogenous thyroid hormone intake and subacute thyroiditis) that is caused by excess synthesis and secretion of thyroid hormone by the thyroid. Most clinicians, exclusive of endocrinologists, use the terms hyperthyroidism and thyrotoxicosis interchangeably. The most common forms of hyperthyroidism include diffuse toxic goiter (Gravesdisease), toxic multinodular goiter (Plummer disease), and toxic adenoma. The most common cause of thyrotoxicosis is Graves disease (50-60%). Graves disease is an organ-specific autoimmune disorder characterized by a variety of circulating antibodies, including common autoimmune antibodies, antithyroperoxidase (anti-TPO), and antithyroglobulin (anti-TG) antibodies. The most important autoantibody isthyroid-stimulating immunoglobulin (TSI). TSI is directed toward epitopes of the thyroid-stimulating hormone (TSH) receptor and acts as a TSH-receptor agonist. Similar to TSH, TSI binds to the TSH receptor on the thyroid follicular cells to activate thyroid hormone synthesis and release and thyroid growth (hypertrophy). This results in the characteristic picture of Graves thyrotoxicosis, with adiffusely enlarged thyroid, very high radioactive iodine uptake, and excessive thyroid hormone levels compared to a healthy thyroid with subacute thyroiditis, these conditions constitute 85-90% of all causes of thyrotoxicosis.

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102.- El principal neurotransmisor implicado en la de etiopatogenesis de la ansiedad es:

a) Serotonina
b) Noradrenalina
c) GABA
d) Glutamato.Respuesta correcta: A, serotonina.
Serotonin and its receptors have long been implicated in memory and anxiety in both humans and animals. In addition to receptors, other factors include serotonin homeostasis and metabolism. Serotonin is removed from the synaptic cleft by a specific membrane transporter protein (SERT), representing an important target for various manipulations. For example,pharmacological inhibition of SERT leads to elevated hippocampal serotonin levels and improved memory. While genetic ablation of SERT in mice is widely used as a model of anxiety, these mice display increased poststress responsivity, indirectly implying a better memory for aversive stimuli. Clearly, further studies are needed to assess the link between SERT and cognitive abilities in animals, and itsrelevance to human brain dysfunctions. Overall, human anxiety-related traits seem to generally facilitate cognitive functions (e.g., acquisition of conditioned fear), and such interplay is partially serotonergically mediated.

Allan V. Kalueff*
Neurobiology of Memory and Anxiety: From Genes to Behavior
Neural Plast. 2007; 2007: 78171.

103.- Caso clínico. Un jugador de fútbol soccer que selesiona al ir corriendo, al parar bruscamente y rotar sobre su propia rodilla, a la exploración física existe signo de tempano de hielo positivo, el diagnóstico más probable es:
a) Lesión de meniscos
b) Hemartrosis
c) Lesión del ligamento cruzado anterior
d) Lesión de ligamentos colaterales

Respuesta correcta: B, hemartrosis.
El futbolista lesionado tiene una rodilla "ocupada"(signo de tempano de hielo positivo) y la única respuesta probable por la falta de datos específicos es "hemartrosis". Ahora bien, si les dijera que tuvo cajones positivos seria una lesión a ligamentos cruzados, y si les dijeran bostezos positivos seria una lesión de colaterales. La rotación sobre la rodilla causa lesión meniscal, la carga excesiva en la articulación de la rodilla al detenerse de...