Utilidad de la proteína C reactiva para el diagnóstico de infección bacteriana en el paciente pediátrico con cáncer, fiebre y neutropenia / Usefulness of C-reactive protein in the diagnosis of bacterial infection in the pediatric patient with cancer, fever and neutropenia

Introducción. El diagnóstico de infección bacteriana en el paciente con cáncer, fiebre y neutropenia se dificulta debido a una pobre respuesta inflamatoria. Se han realizado evaluaciones con reactantes de fase aguda, como la proteína C reactiva, con resultados variables. El objetivo de este trabajo fue calcular la sensibilidad, especificidad, valores predictivos positivos y negativos y razones de verosimilitud de la proteína C reactiva para el diagnóstico de infección bacteriana en pacientes con cáncer y neutropenia febril. Métodos. Se realizó el estudio de la prueba diagnóstica. Se incluyeron pacientes pediátricos con cáncer, y neutropenia (<500 NA/mm³). La proteína C reactiva se cuantificó por nefelometría. Los episodios se clasificaron en cuatro grupos: grupo I, infección microbiológicamente documentada; grupo II, infección clínicamente documentada; grupo III, fiebre por otras causas; y grupo IV, pacientes con neutropenia sin fiebre. Se realizó el cálculo de sensibilidad, especificidad, valores predictivos positivos y negativos, curvas operantes del receptor y razones de verosimilitud. Para la comparación de variables cuantitativas se emplearon la U de Mann-Whitney y Kruskal-Wallis y para variables cualitativas, χ². Resultados. Se incluyeron 127 episodios que se distribuyeron en: 29, 47, 20 y 31 episodios para los grupos I, II, III y IV, respectivamente. Las medianas de la proteína C reactiva fueron 282 mg/L para el grupo I, 205 mg/L grupo II, 27.3 mg/L grupo III y 5.1 mg/L para el grupo IV (p < 0.001). Con la proteína C reactiva de 60 mg/L se obtuvo una sensibilidad de 94%, especificidad de 94%, valor predictivo positivo 96% y valor predictivo negativo 92%; razón de verosimilitud para un resultado positivo 15.6 y de 0.06 para resultado negativo. Conclusiones. La proteína C reactiva es una prueba útil y económica para el diagnóstico de infección bacteriana en el paciente con cáncer, fiebre y neutropenia.

Background. Diagnosis of bacterial infection in the patient with cancer, fever and neutropenia is difficult due to the poor inflammatory response. Several evaluations of acute phase reactants such as C-reactive protein (C-RP) have been performed with diverse results. The aim of this study was to calculate the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), and likelihood ratios (LR) for C-RP in the diagnosis of bacterial infection of patients with cancer, neutropenia and fever. Methods. We carried out a diagnostic test study. Pediatric patients with cancer and neutropenia (<500 NA/mm³) were selected. C-RP was determined by nephelometry. Episodes were classified into the following groups: group I: microbiologically documented infection; group II: clinically documented infection; group III: fever of unknown origin; group IV: patients with neutropenia without fever. Sensitivity, specificity, PPV, NPV, receiving operating curves (ROC) and LR were calculated. Mann-Whitney U test and Kruskal-Wallis test were used for comparison of quantitative variables. For qualitative variables, χ2 test was used. Results. There were 127 episodes distributed as follows: 29, 47, 20 and 31 for groups I, II, III and IV, respectively. Median of C-RP values were 282 mg/L for group I, 205 mg/L group II, 27.3 mg/L group III and 5.1 mg/L group IV (p <0.001). With a C-RP value of 60 mg/L, we obtained a sensitivity of 94%, specificity 94%, PPV 6% and NPV 92%. LR for a positive test was 15.6 and LR for a negative test was 0.06. Conclusions. C-RP is a useful and economically feasible test for diagnosis of bacterial infection in patients with cancer, neutropenia and fever.

[Physiopathological alterations secondary to extracorporeal circulation in cardiac surgery]. / Alteraciones fisiopatólogicas secundarias a circulación extracorpórea en cirugía cardíaca.

Cardiopulmonary bypass (CPB) is one of the methods used in myocardial revascularization and can be associated with adverse events that are uncommon, but CPB induces high morbidity and mortality. Cardiac surgery and CPB activate a systemic inflammatory response characterized by tissular lesions, cells movements and blood flow toward the interstice where the harmful stimulus has begun, under the influence of the mediators. The systemic inflammatory response may be initiated during cardiac surgery by a number of processes, including blood contact with the foreign surface of the CPB apparatus, development of ischemia and reperfusion injury, and presence of endotoxemia. In the course of cardiac surgery using CPB, all three processes are present and contribute concurrently to the systemic inflammatory response. The term "systemic inflammatory response syndrome" (SIRS) has been proposed to describe an entity that continually overlaps with normal postoperative physiology. A frequent complication of SIRS is the development of organ dysfunction, including acute lung injury, shock, renal failure, and multiple organ dysfunction syndrome. Finally, long-term survival in patients developing SIRS may also be adversely affected. The purpose of this review is to examine and understand the pathological mechanisms for inflammatory response that occur following cardiopulmonary bypass.

[Allergens and risk factors in pediatric patients with allergic seasonal conjunctivitis]. / Alergenos y factores de riesgo en pacientes pediátricos con conjuntivitis alérgica estacional.

BACKGROUND: The seasonal allergic conjunctivitis is an inflammatory disease of the ocular surface that affects mainly children, with predominance of male sex. It is an immunological disease with a typical reaction of hypersensitivity type 1 (IgE), resulted from several biological reactions (antigen-antibody) and it's associated to several risk factors. OBJECTIVE: To determine the more frequently identified allergens and the associated risk factors to the seasonal allergic conjunctivitis in children living in Mexico City. MATERIAL AND METHODS: Ophthalmologic clinical study done to 50 patients with diagnosis of seasonal allergic conjunctivitis, during the months of March to October, 2001, at the Ophthalmology Department of the National Pediatric Institute. A control group was integrated by 50 patients of the consultation of ophthalmology with non-allergic ocular pathology, and percutaneous skin tests were made. A direct interrogation was applied to both groups to investigate associated risk factors of atopy. RESULTS: The associated risk factors to the development of allergic conjunctivitis are: family atopic background, negative antecedent of breast feeding, asthma o rhinitis (statistically significant). The most frequently identified allergens were Dermatophagoides pteronissinus, Dermatophagoides farinae, Lolium perenne and Atriplex bacteosa, of the group of dust mites and pollen, respectively. CONCLUSION: It is important to see our patients in an integral way. In the case of patients with seasonal allergic conjunctivitis, it should not be forgotten to make an interrogation of the factors associated to atopy and, if it is possible, to inform to the patient and their relatives about these, in order to prevent them.

[Frequency of postoperative fever in children with congenital heart disease undergoing cardiovascular surgery and associated risk factors]. / Frecuencia y factores de riesgo asociados con el desarrollo de fiebre postoperatoria en niños con cardiopatía congénita sometidos a cirugía cardiovascular.

OBJECTIVES: To determine the frequency of postoperative fever in children with congenital heart disease who undergo cardiovascular surgery, and the risk factors associated. PATIENTS AND METHODS: In a prospective cohort study, 100 children under the age of less than 9 years were followed-up during hospitalization in order to detect fever after cardiac surgery. Preoperative, perioperative, and postoperative variables were assessed to determine their relationship with postoperative fever. The cases were patients who developed fever. Multivariate analysis was used, and the odds ratio (OR) and 95% confidence intervals (95% CI) were calculated. RESULTS: The frequency of postoperative fever was 46%. Fever appeared within 24 hours of surgery in 56% cases. In 32/46 (70%) cases, fever remitted within 72 hours. Fever was more common in patients who underwent open-heart surgery than in those treated with a closed technique (28 vs. 18, P = 0.045). Prolonged extracorporeal circulation (OR = 1.024; 95% CI, 1.004-1.045), aortic cross-clamping (OR = 2.83; 95% CI, 1.21-6.61) and postoperative infections (OR = 24.07; 95% CI, 7.2-75.0) were the risk factors associated with the development of postoperative fever. CONCLUSIONS: Postoperative fever is common in children with congenital heart disease. The identification of risk factors associated to the development of fever should help clinicians to identify the cause of fever in this group of patients.

Frecuencia y factores de riesgo asociados con el desarrollo de fiebre postoperatoria en niños con cardiopatía congénita sometidos a cirugía cardiovascular / Frecuency of postoperative fever in children with congenital heart disease undergoing cardiovascular surgery and associated risk factors

Objetivos. Determinar la frecuencia y los factores de riesgo asociados al desarrollo de fiebre postoperatoria en niños con cardiopatía congénita sometidos a cirugía cardiovascular. Pacientes y métodos. Estudio de una cohorte prospectiva. Cien niños menores de nueve años sometidos a cirugía cardiovascular fueron vigilados durante su estancia hospitalaria para identificar la presencia de fiebre después de la cirugía. Se registraron variables pre, trans y postoperatorias para determinar su asociación con fiebre. Los casos fueron pacientes que desarrollaron fiebre. Se realizó análisis multivariado , calculándose odds ratio e intervalos de confianza del 95 por ciento (IC del 95 por ciento). Resultados. La frecuencia de fiebre postoperatoria fue del 46 por ciento; en el 56 por ciento de los casos la fiebre ocurrió dentro de las primeras 24 horas después de la cirugía, y en 32/46 (70 por ciento) casos la fiebre se resolvió en menos de 72horas. La frecuencia de fiebre fue mayor en pacientes sometidos a cirugía intracardíaca que en cirugía extracardíaca (28 frente a 18, p= 0,045). Los factores de riesgo asociados a fiebre postoperatoria fueron: mayor tiempo de bomba de circulación extracorpórea (OR= 2.83; IC del 95 por ciento, 1,21-6,61) e infecciones en el período postoperatorio (OR=24,07; IC del 95 por ciento, 7,2-75,0). Conclusiones. El desarrollo de fiebre postoperatoria en niños con cardiopatía congénita es un acontecimiento frecuente. Los factores de riessgo encontrados en este estudio pueden ayudar a los clínicos para orientarlos en la búsqueda de la causa de fiebre en estos pacientes (AU)

Infección por Cryptosporidium parvum en niños desnutridos y no desnutridos sin diarrea en una población rural mexicana / Cryptosporidium parvum infection in wellnourished and malnourished children without diarrhea in a Mexican rural population

El Cryptosporidium parvum causa enfermedad diarreica y afecta predominantemente a niños y a hospederos inmunocomprometidos. La mayoría de los casos de criptosporidiosis en sujetos inmunocompetentes son asintomáticos. Los objetivos del estudio fueron determinar la prevalencia de infección asintomática causada por el parásito en niños desnutridos y no desnutridos y determinar los factores de riesgo asociados a la infección. Métodos. Se incluyeron niños de 1 a 15 años de edad, sin diarrea. Se investigaron las condiciones socioeconómicas, sanitarias y de urbanismo tanto familiares como comunitarias y se realizó antropometría. Se buscaron parásitos en heces con técnica de Faust y Cryptosporidium parvum con la técnica de Kinyoun. Se calcularon razón de momios (OR), intervalos de confianza al 95 por ciento (IC95 por ciento), se utilizó c 2 de Mantel-Haenszel, c 2 para tendencias y prueba exacta de Fisher para evaluar asociaciones. Resultados. Se incluyeron a 132 niños. En 10/132 (7.5 por ciento) se encontraron ooquistes de Cryptosporidium, 7/71 en niños con desnutrición (9.8 por ciento) y 3/61 sin desnutrición (4.9 por ciento) (p = 0.23). El 69.7 por ciento de los niños cursaba con algún tipo de parasitosis. Al comparar a los niños de acuerdo a la presencia de C. parvum en heces, se obtuvieron los siguientes OR: Diarrea en familiares 5.82 (IC95 por ciento 0.86 - 39.18), no lavado de manos 5.08 (IC95 por ciento 0.62 - 110.49), edad > 5 años 4.90 (IC95 por ciento 0.60 - 106.9), ingesta de agua no intubada 3.34 (IC95 por ciento 0.40 - 73.01) y desnutrición 2.11 (IC95 por ciento 0.46 - 10.89). Se encontró asociación entre el número de habitantes de la vivienda y el riesgo de presentar infección (p= 0.005). La presencia de diarrea en familiares (OR= 4.15, IC95 por ciento 0.47 - 36.91) y el consumo de agua no intubada (OR= 4.19, IC95 por ciento 0.48 - 36.32) se identificaron como variables relevantes por el modelo de regresión logística. Conclusiones. La frecuencia de la infección por C. parvum fue del 7.5 por ciento. La ingesta de agua no intubada, el hacinamiento y la diarrea en familiares se asociaron significativamente con la infección por C. parvum, la desnutrición no fue un factor de riesgo estadísticamente significativo.

Empirical antimicrobial therapy in pediatric patients with neutropenia and fever. Risk factor for treatment failure

Background. The use of combinations of antibiotics has been the cornerstone of therapy for febrile patients with cancer and severe neutropenia. Each empirical regimen should be selected according to the epidemiology and susceptibility patterns in each center. We describe here the experience wtih empirical antimicrobiial treatments in pediatric patients with cancer, fever and severe neutropenia, and identify the risk factors associated with treatment failure. Methods. This is a prospective study including 145 patients with cancer, and 171 episodes of neutropenia and fever. Blood cultures were taken before initiating empirical treatment: a)carbenicillin (400 mg/kg/day) plus amikacin (21 mg/kg/day) (Cb/ak), and b) ceftazidime (100 mg/kg/day), plus amikacin at the same dosage (Cz/ak). Results. The overall response rate was 54.9 percent and 56.3 percent for Cb/ak and Cz/ak, respectively. Fifty-seven episodes (33.3 percent) were microbiologically documented, gram-positive isolated in 38 percent and gram-negative in 49 percent. Risk factors associated significantly with treatment failure were acute mywlocytic leukemia (AML) (RR 2.59, CI 95 percent 1.42-4.7, p=0.003); bacteriological identification (RR= 4.41, CI 95 percent 2.21 - 8.8, p<0.001), and the presence of two or more sites of infection (RR= 2.89, CI 95 percent 1.03 - 8.11, p=0.03). Conclusions. The rates of response are similar to the combinations used in the hospital (Cb/ak, Cz/ak). The risk factors associated with treatment failure were AML diagnosis, bacteriological identification, and the presence of two or more sites of infection