Actualización en Medicina de Familia. Anafilaxia, el riesgo del infradiagnóstico / Up-Date in Family Medicine. Anaphylaxis, the risk of being underdiagnosed

El fenómeno de la anafilaxia fue descrito por primera vez en 1902 por Potier y Richet. Etimológicamente anafilaxia hace referencia a la "falta de protección" en contraposición al término profilaxis. Son reacciones de hipersensibilidad de tipo I o mediadas por IgE, y los agentes etiológicos más frecuentemente implicados son los fármacos, los alimentos y las picaduras de himenópteros. La importancia de la anafilaxia radica en la necesidad de una actitud diagnóstica rápida y una acción terapéutica inmediata. Son reacciones alérgicas de rápida evolución que pueden afectar a diferentes órganos o sistemas, y que implican un potencial riesgo vital. Aunque se describieron hace más de 100 años no se ha llegado a consensuar una definición y unos criterios diagnósticos hasta principios de 2005. Esto ha supuesto históricamente un importante infradiagnóstico y, en consecuencia, una falta de tratamiento adecuado. Por esta misma razón es difícil establecer su prevalencia real

Anaphylaxis was first described in 1902 by Portier and Richet. Etymologically, it refers to "lack of protection" as against the term prophylaxis. Anaphylactic reactions are prototypical allergic reactions that represent an extreme example of type I hypersensitivity (IgE-mediated). Drugs, food and hymenoptera stings are the most frequent causative agents. The importance of anaphylaxis is found in the need for a rapid diagnostic attitude and immediate therapeutic action. They are allergic reactions that occur rapidly and that can affect different organs or systems and imply a potentially fatal risk. Even though anaphylaxis was first described more than 100 years ago, no universal agreement on its definition or criteria for diagnosis was reached until 2005. This has historically meant that it was significantly underdiagnosed, resulting in lack of adequate treatment. That is why it is difficult to establish its real prevalence

Effect of conditions in obtaining blood samples for ECP testing in children.

Eosinophil Cationic Protein (ECP) is a basic protein found in eosinophil granules. This cell and its mediators are currently considered to be potential indicators of the severity of inflammation in the organism. ECP concentration can be reliably tested using several RIA or ELISA methods. It is well known that the conditions of sample obtention can affect the ECP values in blood. The aim of this study is to establish which parameters affect ECP testing during regular blood sample collection and how they affect it. Blood samples taken for the routine study of five children attended in our department were analysed: four were asthmatic and one child had atopic dermatitis. In the results we observed that ECP was not detected in the blood samples taken with EDTA tripotassium. In both the plasma samples taken with heparin as well as with serum, more ECP was released at a higher temperature. In the release of ECP obtained by coagulation, samples at 37 degrees showed values of between 4 and 20 higher than those obtained for an hour at 0 degrees. There is a considerable variability in the testing of ECP depending on the blood test extraction conditions, the range is bigger in the samples with eosinophils. These results imply the need to define a stricter protocol for obtaining samples than that suggested at present.

Specific IgE determination using the CAP system: comparative evaluation with RAST.

The CAP system's main contribution is its solid phase, which consists of a cellulose polymer activated within a capsule (the ImmunoCAP). This solid phase can bind more protein to it, and, in addition, the conditions of reaction seem to make the system more sensitive at detecting antibodies to certain antigens. It is therefore important to assess the new analytical and diagnostic performance in comparison with previous systems. In this context, we studied the reliability and comparison with the RAST and with skin tests carried out on 144 pediatric patients. Skin tests and specific IgE for radioimmunological RAST (radio-allergosorbent test) and for the fluoroimmunological CAP system were performed on all the patients. The RAST/CAP correlation quotients for the different allergens tested varied between 0.971 and 0.991. Diagnostic sensitivity increased for all the allergens studied and specificity remained unchanged. The system provides reliable results, with better diagnostic capacity than RAST, but it must be quantified for each allergen because its results are not interchangeable.

[Reference values for vitamin B12 in blood in a population of children and one of adults using the IMxRB12 method]. / Valores de referencia de la vitamina B12 en sangre en una población de niños y una de adultos con el método IMxRB12.

UNLABELLED: In this study we have performed the reference values of vitamin B12 of a population of 124 children aged 0-18 years and 42 adults aged 19-55 years, assessed by the recent method IMxR B12. Abbott. The population studied included outpatients, some inpatients and groups of subjects undergoing banal examinations in the Hospital Universitario Materno-Infantil of Barcelona. STATISTICS: Data were first tested for goodness-of-fit gaussian distribution by a nonparametric test, by testing skewness and kurtosis coefficients for significance and by Kolmogorov-Smirnov test. The correlation with the age groups was evaluated with Student's-t-test. RESULTS: We show the histograms of the data obtained and a nonparametric approach selecting the central 95th percentile range. Reference limits (5-95th percentile range) were as follows: Premature infants = 365-1568 ng/L; 1-3 years = 345-1154 ng/L; 4-6 years = 330-1236 ng/L; 7-11 years = 312-1237 ng/L; 12-18 years = 328-1185 ng/L; Adults (19-55 years) = 300-964 ng/L. There were no significant differences between both sexes. The goodness-of-fit test for a gaussian distribution showed no departure from normality except for the groups of children 12-18 years old. A simple linear regression analysis showed that age significantly affected the concentration in inverse way. CONCLUSIONS: The importance of establishing the reference values of vitamin B12 lies in the relevance of this serum analyte to some pathophysiological conditions. Considerable racial heterogeneity exists in populations, and these racial differences profoundly affect total values of vitamin B12 so that different racial reference limits have been suggested.