The Subglottic Obstructive Acute Laryngitis Biology Essay

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the detection of the viruses responsible of the subglottic obstructive acute laryngitis in children and the establishment of clinical-etiological and epidemiological correlations. Material and method. There have been investigated 88 children, between 3-36 months, during two consecutive seasons (2004-2005 and 2005-2006), pursuing the identification of 8 viruses: influenza A and B, parainfluenza 1,2,3, adenovirus, measles and respiratory syncytial virus. Results.The etiology has been identified for 79.54% of the cases, most frequent being the parainfluenza 3 (27.14%) and measles (21.42%) viruses, and the less detectable influenza A (5.71%) and B (4.28%) viruses. There have been observed differences between the age groups, the patients' provenience environment and regarding the distribution between genders. The measles and parainfluenza 3 viruses have determined the most severe forms of disease. Conclusions.Assessing viral etiology of laryngitis allows us to conclude specific peculiarities between etiological, clinical and demographic spread.

INTRODUCTION The subglottic obstructive acute laryngitis of the infant and small child has an almost exclusively viral aetiology. They represent a consistent segment of the respiratory pathology of the referential children and are responsible for a large number of hospitalizations.

OBJECTIVE Our objective is to identify with accuracy the viral etiology of the laryngitis and to explore the possibility of outlining clinical-etiological and epidemiological correlations.

MATERIAL AND METHODS The study has been performed upon 73 children hospitalized in the Children's Clinical Hospital "Gavril Curteanu" Oradea, for a clinical picture of subglottic obstructive acute laryngitis, and upon 15 patients infected with measles, complicated with laryngitis, hospitalized in the Clinical Hospital of Infectious Diseases Oradea. The inclusion criteria have been:

- age: 3 - 36 months;

- children without malformative pathology of laryngotracheobronchitis sphere;

- children, hospitalized or home observed for a 14 days period after release, for a correct evaluation of the studied material, respectively the monitorization of the IgM antibody titre in dynamics.

The exclusion criteria have been:

- the existence of malfor mative syndromes of laryngotracheobronchitis sphere;

- other forms of obstructive laryngitis (spastic laryngitis, epiglottitis);

- children which, after release, could not be monitorized for reevaluation up to a total of 14 days.

The design of the research: The selected patients have been clinically examined in the first day of hospitalization, establishing the diagnosis of subglottic obstructive acute laryngitis and including them in a certain severity score.

Therefore, there have been described 3 stages of severity:

- light, score 1: the child has a good general condition, accepts the food, has no stridor in repose and no retraction;

- medium, score 2-7: the stridor is present and in repose, the retraction is moderate, tachypnea, tachycardia, maintains interest for people and the surrounding environment. If a child with medium obstruction becomes agitated or tired, it is a sign of progression to the severe form;

- severe, score > 7: stridor and ample retraction, also present in repose, cyanosis, tachycardia, convulsion or obnubilation, loss of interest for the people around, can not feed or hydrate, presents tiredness, exhaustion. The respiratory distress can be less pronounced than in the medium form due to exhaustion. The children have been monitorized under the clinical evolution report and the response to treatment, also noting the length of hospitalization. If the hospitalization period has been shorter than 14 days, those children were monitorized ambulatory and were recalled on the 14th day at the ambulatory service of the hospital, for the second sampling of blood. The samples taken from the same patient (in day 1 and 14) have been analyzed concomitantly, to confirm the etiology. The tests for the virus diagnosis have been performed for the following etiological agents: the respiratory syncytial virus, the adenovirus, the influenza A virus, the influenza B virus, the parainfluenza 1 virus, the parainfluenza 2 virus, the parainfluenza 3 virus, the measles virus. For identification there has been used the ELISA technique (enzyme-linked immunosorbent assay). For statistics data there has been used the EPIINFO aplication, 6.0 version, a program of The Center of Disease Control and Prevention - Atlanta, with the Student method (test t) and χ2.

RESULTS Of the total number of 88 children which were paraclinically analysed, the aetiology could be determined for 70 patients (79.54%), as it results from fig. 1. From the total 70 cases with established etiology, there has been determined a predominance of the parainfluenza 3 virus, which was detected at 19 people (27.14%), followed by the measles virus, which caused 15 cases within the two seasons (21.43%). This aspect is presented in table no. I. The lowest incidence have had the infections caused by the influenza B virus: 3 patients (4.29% of the cases with stated aetiology) and the influenza A virus: 4 patients (5.71% of the cases with identified aetiology), in all, during the two seasons. In our study group, the aetiology has been stated in 31 cases in the urban environment (44.29%) and 39 cases in the rural environment (55.71%), the rural/urban report being of 1.3:1. Regarding the relation etiological agent-origin environment of the patient, the situation can be evaluated based on table no. II, resulting a significant difference between the urban and the rural (p<0.001). Therefore, the VRS prevalence, the parainfluenza 1 and 2 viruses, is 2-2.9 times bigger in the urban area, and the prevalence of the influenza A and B viruses, the parainfluenza 3 and measles viruses is significantly bigger in the rural environment. The distribution on groups of age was the following: 8 cases (11.43%) have had ages between 3-12 months, 39 cases (55.71%) between 13-24 months and 23 cases (32.86%) between 25-36 months. Referring to the groups of age, we have observed that: the age group 3-12 months presents risk of acute laryngitis with VRS (RR=2.44) and adenovirus (RR=1.94), the age group 13-24 months having laryngitis with measles virus (RR=3.18) and the age group 25-36 months having acute laryngitis with parainfluenza1 and 2 virus (RR=2.04). We can not state that one of the age groups presents a higher risk of acute laryngitis with parainfluenza 3 virus. In table IV is presented the distribution of the studied cases, making the correlation between the patients' gender and etiological agent of the laryngitis. One may observe that more male patients have been hospitalized, that is 41 (58.57%), compared to only 29 female (41.42%). We note that the VRS prelevance, of the influenza A and B viruses is significantly bigger with girls (1.4 -2.8 times bigger, p=0.044, 0<0.001), and of the parainfluenza 1 virus with boys (p=0.021) (fig. Fig. 5 shows that the most frequent forms of disease have been those with medium severity (60.00%) and severe (30.00%). One of the very important aspects of this study has been represented by the highlight of the correlation between the severity score and the etiological agent of the disease. Table V shows that for the parainfluenza 3 virus and the measles virus have been encountered more severe forms of disease (52.63%, respectively 73.33%). There is a very tight correlation between the severity score and the number of days of hospitalization. Therefore, the patients with subglottic obstructive acute laryngitis given by the infection with the parainfluenza 3 and measles viruses, which determined the severe forms of disease, have needed a significantly longer period of hospitalization From the analysis of the average number of hospitalization days, are to be noticed 4 groups: the first one includes VRS and adenovirus, the second the parainfluenza 1 and 2 viruses, the third one the influenza A and B viruses, and the forth one the parainfluenza 3 and measles viruses. Within the groups there is no significant difference regarding the average number of hospitalization days, while between the four groups there are significant differences (p=0.042 between groups 1 and 2, p=0.037, between the groups 2 and 3, p=0.024 between the groups 3 and 4 and p<0.01 between the groups 3 and 4).

DISCUSSION Because the incidence of the subglottic acute laryngitis is conditioned mainly by the season, the viral aetiology has been investigated only in the interspace 1st of October- 30 of April (autumn-winter- early spring). The aetiology identified for 79.54% of the cases, presents a structure that is only partially similar with the one presented in other published studies. Still, we note that the high frequency of the infection with measles virus explains through the fact that, in February 2005, in Bihor County started a measles epidemic. According to the data published by the Public Health Authority of Bihor, the epidemics developed along the entire year, the descendent evolution taking place only in 2006, after the intervention in the foyers represented by the less accessible communities, with infant population that was not registered in the family doc- tors' lists and that was not vaccinated. The predominance of the parainfluenza 3 virus represents an ascertainment applicable to other referential works. The study performed by us indicated a predominance of the cases with origins in the rural environment, where certain conditions (agglomeration, housing, general and medical care) have made infants and children more vulnerable in front of the referential viral infections. The ascertainment is correlated with the fact that the biggest number of unvaccinated children that were infected with measles was in the rural environment. It has been observed the predominance of the measles, influenza B and parainfluenza 3 type viruses, in the rural environment, compared to the urban environment. We found no observations in the professional literature that would study the two origin environments in comparison, our work being a premiere in this respect.As other authors did, we signalized a maximum of incidence in the second year of life and an obvious predominance in the male gender. We observed a predominance of the parainfluenza 3 and measles viruses for the age groups 19-24 months and 13-18 months. Also, there has been registered a significantly bigger prevalence of the respiratory syncytial virus and of the influenza A and B viruses in the female gender, and of the parainfluenza 1 virus in the male gender. The most severe forms of subglottic laryngitis have been determined by the parainfluenza 3 virus and especially by the measles virus. The ascertainment is inconsistent with one of the reports, where the most severe forms have been given by the influenza A virus. The longest hospitalization was registered with the cases of laryngitis having as etiology the parainfluenza 3 and measles viruses that also generated the most alarming forms of disease.

CONCLUSIONS 1.The viral aetiology has been analysed for 88 children with ages between 3-36 months, with subglottic obstructive acute laryngitis during 2 seasons (2004-2005 and 2005-2006), with the purpose to identify 8 serological confirmed viruses. 2. The aetiology could be established for 70 cases (79.54%), most detected being the parainfluenza 3 (19 cases, 27.14%) and measles (15 cases, 21.43%) viruses, and less identified were the influenza B and A viruses (3 cases, 4.29%, respectively 4 cases, 5.71%). 3. The most severe forms, that implied the biggest number of hospitalization days, have been determined by the parainfluenza 3 and measles viruses.

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