Ignacio Sánchez D

Relación entre bronquiolitis aguda con factores climáticos y contaminación ambiental

Background: Annually, acute bronchiolitis (AB) occurrence peaks during winter and is probably associated with air pollution. Aim: To relate the number of ambulatory consultations, emergency and hospital admission due to AB with climatic factors and air pollution. Patients and methods: Patients of less than 1 year old with AB that consulted to outpatient clinics, the emergency room or were admitted to the Pediatrics ward of the Catholic University Hospital, were enrolled. Information about respiratory syncytial virus (RSV) was obtained from the Catholic University Medical Investigation Center. Indices of air pollution such as particulate matters of less than 10 microns/m 3 (PM 10), of less than 2.5 microns/m3 (PM 2.5), CO, SO 3 and O 3 were obtained from the Metropolitan Environmental Service. Temperature, humidity and precipitations were obtained from the Chilean Meteorological Service. Results: Ninety nine consultations in out patient clinics and 442 in emergency rooms were collected (55% male, mean age 4.8 months). One hundred fifty two were admitted (34.4%). Thirty percent of children consulting in emergency rooms were younger than 3 months and 43% of them were hospitalized. The RSV study was made in 307 patients and 52% were positive. There was a higher rate of hospital admissions among RSV positive than RSV negative patients (52.5 and 22% respectively, p<0.001). No association between environmental variables or air pollution and the number of consultations was observed. Young age and smoking inside the household were the main risk factors for hospital admission due to acute bronchiolitis. Conclusions: Environmental variables did not influence the number of cases of acute brochiolitis. Young age and exposure to tobacco smoke were risk factors for hospital admission (Rev Med Chile 2003; 131: 1117-22). (Key Words: Air pollutants, environmental; Bronchiolitis; Tobacco smoke pollution)

Pruebas cutáneas de hipersensibilidad inmediata en una población pediátrica seleccionada

Background: Skin prick test (SPT) of immediate hypersensitivity is a main instrument in the diagnosis of allergy. Aim: To demonstrate the applicability of skin prick test in different age groups. Patients and Methods: We studied children and adolescents with the diagnosis of allergy in the Pediatric Respiratory Laboratory of the Catholic University of Chile, from January 2001 to March 2002. The SPT was performed using a standardized technique. The allergens were applied on the volar surface of the forearm in children older than 4 years of age and in younger children it was applied on their back. For study purposes we separated them into three age groups: GI ≤2 years and 11 months, GII from 3 to 4 years and 11 months, GIII ≥5 years. Results: We studied 408 children, aged between 8 months and 15 years. The SPT was applied to all patients with no adverse effects of any kind. There was a positive reaction in 57.7% of children. The reaction was positive in 37% in G1, 39% in GII and 65% in GIII (p <0.001). The predominant allergens for each group were dust mites (Dermatophagoides pteronissinus and farinae). Conclusions: SPT was useful when used on a selected pediatric population. The frequency of sensitization increased significantly with age. However, more than one third of children between 2 and 4 years of age tested positive to one or more allergen, demonstrating its applicability in this age group (Rev Med Chile 2005; 133: 195-201). (Key Words: Antigens, Dermatophagoides; House dust mites; Hypersensitivity; Skin tests)

Apoyo ventilatorio domiciliario en niños con insuficiencia respiratoria crónica: Experiencia clínica

Resumen Introduccion: En los ultimos anos se han desarrollado sistemas de apoyo ventilatorio en domicilio (SAVED), que han logrado tratar pacientes con insuficiencia respiratoria cronica en su hogar. Objetivo: revisar nuestra experiencia en los pacientes con SAVED. Pacientes y Metodo: Se revisaron las fichas de los 15 pacientes (9 mujeres) con SAVED dados de alta del Servicio de Pediatria del Hospital Clinico de la Pontificia Universidad Catolica de Chile, entre enero de 1993 y diciembre 2000. Se describen las caracteristicas del grupo y su seguimiento. Resultados: Sus edades al alta fluctuaron entre 5 meses y 15 anos; 6 tenian enfermedad neuromuscular, 4 dano pulmonar cronico, 1 deformidad toracica y 4 traqueobroncomalacia grave. Doce requirieron traqueostomia, de estos, 4 utilizaron ventilacion mecanica (PLV-102, LifeCare) y 8 CPAP con generador de flujo (Downs) y valvula de PEEP, y 3 ventilacion nasal a traves de BiPAP. El alta fue entre 2 y 4 meses desde el ingreso y la implementacion del SAVED entre 1 y 4 meses, de acuerdo a la realidad familiar y previsional. El periodo de seguimiento fue de 3 meses a 8 anos. La tasa de reingreso fue 2,5 y 0,4 ingresos/paciente/ano por morbilidad y por falla de sistema respectivamente; el tiempo promedio de estadia en el hospital fue de 16,5 ± 9 dias/ano. Se logro la retirada del SAVED en 5 pacientes y 1 nino fallecio debido a su enfermedad neurologica. En resumen, nuestra experiencia demuestra que los SAVED son una alternativa real en el manejo de pacientes con insuficiencia respiratoria cronica grave. Esta terapia presenta escasas complicaciones, permite enviar al paciente a su casa y disminuye en forma significativa los costos del tratamiento

Prevalencia de síntomas de rinitis alérgica y su relación con factores de riesgo en escolares de Santiago, Chile

Background: The prevalence of asthma and allergic rhinitis experienced a steady increase in the last years, probably associated to changes in lifestyles. Aim: To assess the prevalence of allergic rhinitis, to evaluate changes over time (1994-2000), and to describe risk factors. Material and Methods: The International Study of Asthma and Allergies in Childhood (ISAAC) core questionnaire, with questions added about socioeconomic status (SES), was applied to 4594 children between 6-7 years old and 13-14 years old during october-december 2000. Attendance to public or private schools was also used a SES proxy. The results were compared with those of a similar survey in 5281 children, performed in 1994. Rhinitis symptoms (ever) (SR), rhinitis symptoms within last 12 months (SR12) and medical diagnosis of rhinitis (DR) were assessed. Results: There was a significant increase in the prevalence of SR, SR 12 and DR in both age groups in 2000, compared to 1994. SR older children showed a higher prevalence of SR compared with the youngest group (p=0.003). No age differences were observed in the prevalence of SR12 and DR. Both SR and SR12 were more prevalent at schools of medium and low-medium SES (p=0.003 and p=0.002 respectively). DR was significantly more prevalent among children of high SES. A better mother educational level was associated to higher prevalence of SR and SR12 (p=0.03 and p=0.04). Father educational level was associated to DR (p=0.007). The prevalence of SR12 was higher in households with carpets (p=0.017). The prevalence of DR was higher in houses with smokers (p=0.03) and gas heating (p=0.005). None of the three variables were related to gender. Conclusions: The prevalence of SR, SR12 and DR increased significantly in a short time period (6 years). Our results support a positive association between DR and high SES (Rev Med Chile 2006; 134: 456-64).

Identificación de mutaciones en el gen CFTR en pacientes chilenos con fibrosis quística

Background: Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CFTR gene, that codes for a chloride channel located in the apical surface of epithelial cells. The main role of this protein is the regulation of chloride transport, and secondarily, of sodium and water to the extracellular space. More than 900 gene mutations have been described, and their relative frequency in different populations depends on their ethnic origin. Aim: To report the findings of Chilean patients with cystic fibrosis, in whom the presence of 20 common mutations was analyzed. Patients and methods: Fifty seven patients with established diagnosis or suspicion of CF were studied. The simultaneous identification of 20 mutations and the normal DF508 allele was done using polymerase chain reactions with a commercial assay. Results: Eight mutations were found. Fifty patients fulfilled diagnostic criteria proposed by the Consensus Panel of the CF Foundation and 66% of alleles were identified in this group. ∆F508 mutation was found in 45%. We did not identify mutations in any of the remaining 7 patients. Conclusions: Our results suggest that the majority of undetected mutations are associated with atypical phenotypes or that some patients in this series could have other diseases. We recommend to include mutation analysis in the evaluation of Chilean patients with CF. It is useful to establish prognosis and genetic counselling (Rev Med Chile 2001; 129: 841-7).

Influencia del nivel socioeconómico (NSE) en el asma bronquial y cambios en su prevalencia en población escolar en un periodo de 6 años

Antecedentes: La prevalencia de asma se encuentra mundialmente en aumento, especialmente en paises en desarrollo. Objetivos: Determinar la prevalencia de asma en escolares de Santiago, estudiando la influencia del nivel socioeconomico (NSE) y describir su evolucion en un periodo de 6 anos. Material y metodos: Estudio transversal en poblacion escolar de la Region Metropolitana. Se encuesto a 4.561 escolares de 6-7 y 13-14 anos provenientes de establecimientos publicos de la comuna de Santiago y de colegios particulares pagados ubicados en el sector oriente de la ciudad. Las variables estudiadas fueron diagnostico de asma (DA), sibilancias en los ultimos 12 meses (SIB12) y frecuencia de episodios de sibilancias (FES). Mediante modelos de regresion se calcularon odds ratios para la ocurrencia de estas variables segun la exposicion a diversas variables independientes. Resultados: La prevalencia de DA en el grupo completo de escolares fue mayor en escolares varones respecto de mujeres (13,2% vs . 10,8%) (p = 0,016), siendo estadisticamente mayor en escolares de 13-14 anos respecto del grupo de 6-7 anos (13,8%: vs .10,1%). (p -4 ). Se encontro una asociacion inversa significativa entre NSE y SIB12. Un mayor nivel de educacion materna se asocio a menor prevalencia de SIB12 en ambos grupos de edad y de FES en ninos de 6-7 anos. Un mayor nivel de instruccion paterna determino un incremento en DA entre los mas pequenos. Incrementos significativos en la prevalencia de SIB12 y FES fueron observados entre 1994 y 2000 unicamente en escolares de 6-7 anos de Santiago Centro. Conclusion: Se encontro asociacion significativa entre NSE y el diagnostico y sintomatologia del asma en escolares de Santiago, asi como un incremento de su prevalencia y severidad en el grupo de 6-7 anos en el periodo 1994–2000.

Empiema y efusión pleural en niños

Introduccion: El empiema pleural (EP) es una complicacion grave de la neumonia adquirida en la comunidad (NAC). Objetivos: Describir las caracteristicas de los pacientes hospitalizados por EP en el Servicio de Pediatria del Hospital de la Universidad Catolica durante el periodo 2000-2005. Se identificaron 86 hospitalizaciones por NAC con efusion pleural, practicandose en 59 (70%), al menos una toracocentesis. Se considero EP a la presencia de pus, tincion de Gram con bacterias, cultivo positivo o pH < 7,10 en el liquido pleural, siendo las efusiones para-neumonicas los controles. Resultados: Se analizaron 24 EP y 25 controles [promedio 2,9 anos (rango: 8 meses - 14,3 anos)], 78% de edad inferior a 5 anos con diferencia entre los grupos EP y controles [1,6 vs 3,3 anos, respectivamente (p = 0,01)]. El promedio global (dias) de sintomas previo al ingreso en los EP fue 7 (rango: 2-21), siendo los mas frecuentes fiebre (100%) y tos (96%). Se identifico algun microorganismo en 15/24 EP, Streptococcus pneumoniae fue el mas frecuente (n: 9). En 48 ninos, el manejo inicial fue conservador, requiriendose cuatro rescates quirurgicos luego del cuarto dia. El promedio (dias) de hospitalizacion fue significativamente superior en el grupo EP vs controles [15 (rango: 5-38) vs 9 (rango: 3-16) (p < 0,01)]. Requirieron drenaje pleural 83% del grupo EP y 36% de los controles (p = 0,002). No hubo diferencia en el numero de dias de empleo de oxigeno [6 vs 4,5 (p = 0,36)] o drenaje pleural [3 vs 2,5 (p = 0,29)]. No se registraron fallecidos. Conclusion: El EP en ninos fue una condicion respiratoria aguda que se asocio a estadias hospitalarias prolongadas, especialmente en los de menor edad, no requiriendose, en la mayoria, una intervencion quirurgica de rescate

Derrame pleural y empiema complicado en niños: Evolución y factores pronósticos

Background: Complicated pleural empyema has a torpid and longer clinical evolution, requiring in some patients surgical management. The predictive factors for surgical treatment are not well known. Aim: To search for clinical, laboratory or radiological predictors for the requirement of surgical treatment in pediatric patients with empyema. Patients and methods: A retrospective review of the charts of 108 patients hospitalized for pneumonia plus pleural effusion at the Pediatric Service of the Catholic University Hospital between January 1985 and July 2000. Results: Eighty one patients had complete radiological evaluation and pleural fluid biochemical analysis. Forty nine (60%) fulfilled the criteria for empyema and 32 (40%) for an exudate. Thirteen patients with empyema required surgery and 36 were treated medically. The mean age was 3 years (range 9 months-6 years) for the surgically treated and 4 years (range 12 months-14 years) for the non-surgical group. The male/female ratio was 5:1 in the surgical group and 1:1 for the non-surgical group. Pleural fluid cultures were positive in 21 of 79 patients. Streptococcus pneumonia was the most frequently isolated agent. No significant differences were found between groups for the average days of fever prior to the diagnosis or total days of fever, days of hospital stay, pleural fluid pH (6.8 and 7.0 respectively) and glucose (21 and 31 mg/dl respectively). No differences were either observed for pleural fluid risk factors (pH < 7 and glucose <20mgdl), the presence of extensive pleural effusions, pleural loculations or bands on pleural ultrasonography and positive Gram stain or cultures in the pleural fluid. Surgical patients required oxygen for more days than medical patients (7.7 and 5.1 days; p=0.037). Conclusions: This study failed to find predictive clinical, radiological or pleural fluid parameters, for the requirement of surgical treatment of empyema (Rev Med Chile 2001; 129: 1289-96).

Fibrosis quística: Actualización en sus aspectos básicos

Los avances en torno al conocimiento de la proteina de regulacion de transmembrana de la fibrosis quistica (CFTR) han permitido entender mejor la fisiopatologia de esta enfermedad y la compleja relacion genotipo-fenotipo. Los diversos fenotipos clinicos estan influenciados no solo por la clase de mutacion registrada, sino tambien por factores ambientales y probablemente otros genes reguladores. CFTR regula la composicion y cantidad de liquido en el epitelio de la via aerea, primariamente por su accion sobre el cloro, pero tambien regula diferentes canales y transporta otras moleculas. Ademas, CFTR regula una respuesta inflamatoria frente a bacterias como Pseudomona aeruginosa y Staphylococcus aureus. Es probable que todos estos factores influyen en la historia natural de la FQ de cada paciente. El entendimiento de los aspectos basicos y sus implicancias clinicas podria brindar futuras y nuevas aproximaciones terapeuticas

Fibrosis quística: enfrentando la transición desde el pediatra hacia el internista

The increased survival of patients with cystic fibrosis (CF) resulted inthe appearance of new pulmonary and non-pulmonary complications. Even though subjects with CFpresent with inflammatory pulmonary changes at birth, several pathogens such as Staphyloccocusaureus, Haemophilus influenzae and Pseudomona aeruginosa contribute to the progression ofpulmonary injury. Clinical presentations vary according to patient age; even though mild forms exist,patients with severe forms, develop respiratory insufficiency and end-stage disease at an early stage.Today, new diagnostic and therapeutic tools, increase the possibility of an early diagnosis and ofgreater survival. Successful management will depend on the timely selection of adequateantimicrobials, the use of pancreatic enzyme supplementation and early institution to respiratoryphysiotherapy. The transition from pediatric care to adult care must occur according to developmentof each patient. This timing must be flexible and there should be a constant communication andcoordination within the different specialists in internal medicine. Thus, it is crucial to recognize thedisease progression as a continuous process, giving the appropriate physiologic support andevaluating the needs of the patient and close relatives (Rev Med Chile 2006; 134: 365-71).(