Indian Pediatrics 2002; 39:478-483
Clinical Evaluation of Acute Respiratory Distress and Chest Wheezing in Infants
Acute respiratory infections (ARI) are responsible for quite a high morbidity and mortality in children of developing countries(1). It is estimated that about 13.6% hospital admissions and 13% inpatient deaths in pediatric wards are due to several anatomical and physiological characteristics of their respiratory tract. Respiratory distress with wheezing in infants is quite common and presents substantial diagnostic problems. Acute respiratory distress and chest wheezing in infants is commonly seen in bronchial asthma, bronchiolitis and bronchopneumonia. Many times it is difficult to distinguish between these three conditions as clinical picture is overlapping. The management will differ in these conditions as antibiotics are required for bacterial pneumonias, broncho-dilators and/or steroids for asthma and supportive therapy for bronchiolitis and viral pneumonias.
Because of lack of investigative facilities in most centers like viral studies, skin tests for allergens, bronchoscopic aspirates and lung puncture, it is of utmost importance to dignose respiratory distress with wheezing on clinical grounds.
This study was designed to differentiate beacterial bronchopneumonia, bronchiolitis or viral pneumonia and bronchial asthma on the basis of clinical parameters and to correlate clinical findings with simple laboratory data.
Subjects and Methods
This study was conducted among 100 children aged 2 months to 1 year presenting with acute respiratory distress and chest wheezing admitted in pediatric ward during year 1994-95. Cases of foreign body inhala-tion, congestive cardiac failure, congenital heart disease, congenital malformations of ariways, croup syndrome and pulmonary tuberculosis were excluded from the study after taking detailed history and performing clinical examination. Infant was said to have respiratory distress when the respiratory rate was more than 50 per minute and/or the presence of various signs of respiratory distress in form of flaring of alae nasi, subcostal and intercostal retractions.
Wheezing was defined as infant having audible wheezing sounds from chest, heard with or without the help of stethoscope. These cases were provisionally diagnosed as bacterial bronchopneumonia, bronchiolitis or bronchial asthma on the basis of following clinical criteria:
Supportive therapy in the form of intravenous fluids and oxygen inhalation was started in all the cases. Total and differential leukocyte count and chest skiagram were done in all the cases. Chest skiagram was taken within 48 hours of admission. Regarding white blood cell counts, following gold standards (for 2 months to 1 year of age) were followed(3): (i) Leukocytosis - Total leuko-cyte count >17500 per cu mm; (ii) Neutro-philia - Absolute neutrophil count >8500 per cu mm; (iii) Lymphocytosis - Absolute lymphocyte count >13500 per cu mm; and (iv) Eosinophilia - Absolute eosinophil count >400 per cu mm.
The provisional diagnosis was revised on the basis of leukocytic counts. Patients of bronchopneumonia having normal leukocyte and neutrophil counts were excluded from bacterial pneumonia group while patients of bronchiolitis who showed neutrophilia were shifted to bacterial bronchopneumonia group. All the patients underwent radiological examination of the chest and only one radiologist read the skiagrams. Response to appropriate treatment according to final diagnosis was noted.
Sensitivity, specificity and positive predictive value were calculated using standard statistical techniques(4).
One hundred infants between the age of 2 months to 1 year having respiratory distress and wheeze were studied. Fifty two infants had fever >100º F and hence were provisionally diagnosed as having bronchopneumonia. Forty eight cases had fever <100º F or were afebrile. Sixteen cases had recurrence of attacks and out of these 8 cases had positive family history of asthma/allergic disorders. The cases without recurrence of attacks were 32 and were diagnosed provisionally as bronchiolitis (Fig. 1). Forty four patients out of 52 who were provisionally diagnosed as bronchopneumonia, had neutrophilia, while 8 cases had normal neutrophilic counts. These 8 cases were shifted to bronchiolitis group.
Out of 32 cases who were provisionally diagnosed as suffering from bronchiolitis, 6 cases had neutrophilia on peripheral blood counts and hence were shifted to broncho-pneumonia group. Radiological examination of all 50 cases finally diagnosed as pneumonia showed opacities in lung fields. In patients of bronchiolitis, 12 (35.3%) had opacities, 15 (44.2%) showed hyperinflation and 7 (20.5%) had prominent bronchovascular markings. In 16 cases of bronchial asthma, 4 (25%) showed hyperinflation, 5 (31.2%) had prominent bronchovascular markings and 7 (43.8%) had normal radiological picture of chest.
Thus, 50 cases finally diagnosed as bronchopneumonia on the basis of neutro-philia were given antibiotics while 34 cases with normal blood counts or lymphocytosis were presumed to be that of bronchiolitis or viral pneumonia and were not given any antibiotics and only supportive therapy was given.
In cases of bacterial pneumonia, fever >100º F was seen in 44 (88%) cases while 6 cases were having fever <100º F or were afebrile. Out of 34 cases of bronchiolitis, 26 (67.7%) cases were having fever <100º F or absence of fever. Response to appropriate therapy was observed in 2-3 days, 1-2 days and 6-8 hours in cases of bronchopneumonia, bronchiolitis and bronchial asthma, respect-ively. Three (6%) cases having broncho-pneumonia expired. Clinical profile and hematological data of patients after final diagnosis is shown in Table I. Sensitivity, specificity and predictive value of criteria for diagnosis of bronchopneumonia is shown in Table II.
In the present study bacterial broncho-pneumonia, bronchiolitis and bronchial asthma were differentiated on the basis of clinical parameters like fever, recurrence of attacks and simple investigations like total and differential leukocyte counts.Table I-Clinical and Hematological Picture of Cases Finally Diagnosed as Bronchopneumonia, Bronchiolitis and Bronchial Asthma
Table II-Sensitivity, Specificity and Predictive Value of Criteria for Diagnosis of Bronchopneumonia
In infants who present with respiratory distress and wheezing if fever >100º F is associated, one can safely assume a dignosis of bacterial bronchopneumonias and manage accordingly with antibiotics, as in our study 88% infants having bronchopneumonia had fever >100º F and only 12% infants had fever <100º F. Presence of fever >100º F had 88% sensitivity and 76.4% specificity for diag- nosis of bronchopneumonia in an infant having respiratory distress and wheezing. Similar observations have been made earlier also(5-7).
Fever was absent or less than 100º F in 67.7% cases of bronchiolitis(8-10) and in these children antibiotics were avoided. Past history of similar wheezing episodes was observed in 100% infants who had bronchial asthma and in our study recurrence of attacks had 100% sensitivity and specificity. Sachdev et al. observed recurrence of attacks in 96% cases of bronchial asthma with 84% sensitivity and specificity(11). Family history of asthma or allergic disorders was observed to be an important finding as was found to be present in 50% of patients of bronchial asthma. Cough is a common symptom in patients of broncho-pneumonia, bronchiolitis and bronchial asthma(7,10,12,13). Preceding history of upper respiratory infection was present in 61.7% cases of bronchiolitis and it may help in differentiating cases of bronchiolitis(13).
Neutrophilia can be accepted as a useful criteria of identifying infants with bacterial infections. However, sensitivity and specifi-city of neutrophilia for bacterial pneumonia could not be assessed in the current design. Other workers have reported normal leukocyte counts to be 94.1% specific and sensitive for bronchiolitis(3,9,14). Eosinophilia was present in 68.7% cases of bronchial asthma with 68.7% sensitivity and 100% specifi-city(15). So, eosinophilia along with recurrence of attacks and positive family history can be considered as a useful criteria to diagnose bronchial asthma in a wheezing infant having respiratory distress. Opacities in chest roentogenograms were observed in all cases of bronchopneumonia and 35.3% cases of bronchiolitis. It was 100% sensitive and 64.7% specific in cases of bronchopneumonia.
It can be concluded from the present study that bronchopneumonia, bronchiolitis and bronchial asthma can be differentiated upto a reasonable extent on the basis of clinical features like fever, recurrence of attacks supported by simple investigations like total and differential leukocyte counts. This may prove to be helpful in the early and rational management with antibiotics, bronchodilators and/or steroids in these comon disease found in infancy which otherwise are difficult to differentiate in the setting where specific investigative facilities like bacterial culture, viral studies and antibodies titer, etc. are not available.
Contributors: KKL coordinated the study, and will act as the guarantor for the paper. NK and NS participated in the data collection. RG and DS helped in drafting the paper.
Funding: None stated.
Competing interests: None.