Abstract
Background and aim:
Respiratory distress is one of the most common underlying causes of emergency department visits in children, with a high morbidity and mortality rate which could raise a lot of concerns, acquiring early recognition of the underlying cause and appropriate treatment. The current study aimed to determine the prevalence and distribution of underlying causes of respiratory distress.
Methods:
In this retrospective cohort study, demographic and clinical information of 154 patients older than 1 month who were referred to a tertiary hospital from October 2018 to April 2019 were gathered from Hospital Information System and analyzed with SPSS Statistics 23.0 version.
Results:
154 participants were recruited with a mean age of 33.02 ± 37.21 months, and 66% were male. The most common clinical symptom among these children was tachypnea (90.6%). Asthma (35.1%), pneumonia (31.8%), sepsis (8.4%), bronchiolitis and croup (7.8%), and foreign body (7.1%) were the most common causes of respiratory distress.
Conclusion:
Respiratory distress can be manifested with a variety of signs and symptoms and different underlying causes which may defer in different genders, ages, and regions. Among patients referred to a tertiary center in Tehran, tachypnea was the most common clinical symptom, and asthma was the most frequent cause of respiratory distress. Knowing the underlying causes of this emergent clinical status in pediatrics can help us in developing appropriate treatment approach.
Keywords: asthma, bronchiolitis, pediatric, pneumonia, respiratory distress
Introduction
One of the most frequent conditions for which pediatric patients are seen in the emergency departments of hospitals is respiratory distress[1,2]. When breathing does not correspond to the body’s metabolic need for oxygenation and/or ventilation, respiratory distress develops. It is characterized by increased work of breathing including tachypnea, accessory muscle usage, and muscle retraction[3-5]. Respiratory distress has various causes and is associated with high morbidity and mortality rate; therefore, accurate and early diagnostic and therapeutic efforts should be appropriately performed[4,6]. Previous studies have shown low incidence but high mortality rates of acute distress syndrome among children[7], raising a lot of concerns in pediatric practices.
HIGHLIGHTS
Respiratory distress is still a major concern in pediatric medicine.
In this study we evaluated the symptoms and causes of respiratory distress among children in a tertiary hospital.
We found that tachypnea is the most common symptom and asthma is the most common cause of respiratory distress in children.
Respiratory distress is usually reversible if treated at the right time, and delay in treatment can lead to cardiac arrest with long-term neurological complications and might give rise to other diseases due to tissue hypoxia, leading to children’s morbidity and mortality[8,9]. Hence, evaluating its prevalence and diving deeply into its underlying cause could play an important role in appropriate diagnosis and treatment. Identifying the underlying frequent and common causes of respiratory distress in each region with clinical symptoms and laboratory findings would help prevent unnecessary treatments and reduce costs on the health system of the countries[4,8-10].
In a study from Iran, the most common symptom in respiratory distress was retraction at 97%, tachypnea at 76%, followed by the tail-to-exhalation ratio at 49%, and cyanosis at 12%. Among the causes of respiratory distress, lower airway obstruction (46%) was the most common cause and pneumonia was the second one[11]. In Abed et al study, bronchiolitis was the most frequent underlying cause in 3-4 months old infants (three times more in boys), with over-inflation as the most common symptom[12]. Another study from Iran characterized the most common causes of respiratory distress as 32% asthma, followed by 31% foreign body, and 22% acute laryngitis. The most common age of asthma was under 5 years old, and it was twice as common in boys[13]. Moreover, pneumonia was presented as the most common risk factor in some other surveys among the median age of 6.2 years[14,15], and consistent with that, another study found pneumonia, asthma, and acute bronchiolitis as the most common causes of respiratory distress in children under 5 years old[16]. In a study in North America asthma, croup, bronchiolitis, and pneumonia were the most significant reasons for respiratory distress in children[17] and another study in Spain represented pneumonia and sepsis as the prevalent causes of acute respiratory distress syndrome[18].
Due to all the aforementioned differences in etiology and prognostic factors in different groups and geographical areas, this study was designed and performed to determine the prevalence and distribution of symptoms and underlying causes of acute respiratory distress in a tertiary children’s center in Iran.
Methods
The current retrospective descriptive study was carried out from October 2018 to April 2019. All participants’ legal guardians provided their informed consent, and patient data confidentiality was upheld. The study population was all children older than 1 month that referred to the emergency department of the hospital with the chief complaint of respiratory distress. All patients older than 1 month with the signs or symptoms of respiratory distress, including tachypnea, bradypnea, cyanosis, respiratory muscles retraction, nasal flaring, tachycardia, and bradycardia who were admitted at the hospital during these 6 months were eligible for enrollment. Patients older than 18 years old, the one whose main complaint was apnea due to an underlying disease, and patients whose symptoms were due to known cardiac diseases (with no other causes) were excluded from the study.
From a total of 186 patients who visited the emergency room during the period of the study, 154 included in the study. After the patient’s selection, all demographics, hemodynamic, radiographic, and laboratory data, were collected using a standardized form through the Hospital Information System. The work has been reported in line with the STROCSS criteria.
The obtained information was classified and analyzed with descriptive statistical methods. The Chi-square test was used to evaluate the qualitative variables and the independent t-test was used to investigate the quantitative variables, such as patients’ age. The P ≤ 0.05 was considered significant. Data analysis was performed using SPSS (IBM SPSS Statistics 23).
Results
Totally, 154 patients with respiratory distress complaints were referred to the emergency department of the hospital, of which 102 patients (66%) were male and 52 patients (34%) were female. The mean age of the whole patient was 33.02 ± 37.21 months. The most common clinical symptom in these children was tachypnea (90.6%), followed by respiratory muscle retraction (66.9%), tachycardia (34.4%), nasal flaring (12.3%), cyanosis (9.7%), and bradycardia (3.2%) (Table 1). All in all, 12 patients with symptoms of respiratory distress developed respiratory failure and cardiac respiratory arrest. All the presenting signs and symptoms were compared between male and female participants and as depicted in Table 1, there were no significant differences in terms of clinical presentation among the genders (P > 0.05)
Table 1.
Demographic data and presenting symptoms of the patients, among both genders.
| Variables | Total (154) | Male (102) | Female (52) | P-value |
|---|---|---|---|---|
| Gender | ||||
| Male | 102 (66%) | – | – | |
| Female | 52 (34%) | – | – | |
| Age (mean, in months) | 33.02 ± 37.21 | 33.03 ± 37.85 | 33.00 ± 36.30 | 0.961 |
| Frequency of presenting symptoms (%) | ||||
| Tachypnea | 140 (90.9) | 92 (90.1) | 48 (92.3) | 0.18 |
| Respiratory muscle retraction | 103 (66.9) | 70 (68.6) | 33 (63.5) | 0.51 |
| Tachycardia | 53 (34.4) | 30 (29.4) | 23 (44.2) | 0.06 |
| Nasal flaring | 19 (12.3) | 9 (8.8) | 10 (19.2) | 0.06 |
| Cyanosis | 15 (9.7) | 7 (6.9) | 8 (15.4) | 0.09 |
| Bradycardia | 5 (3.2) | 3 (5.8) | 2 (2) | 0.2 |
Data are presented as mean ± SD or percentage of the frequency.
Evaluating the presence of different clinical symptoms in terms of the average age, there was a statistically significant relationship between nasal flaring and patients’ age (P = 0.04); patients who revealed nasal flaring had noticeably younger ages (26.39 ± 19.29). The difference in mean age for each symptom is presented in Table 2.
Table 2.
Mean age in different presenting symptoms.
| Symptoms | Result | Age (months) | P-value |
|---|---|---|---|
| Tachypnea | Positive | 33.37 ± 02.21 | 0.48 |
| Negative | 42.54 ± 01.45 | ||
| Cyanosis | Positive | 39.48 ± 86.92 | 0.56 |
| Negative | 32.35 ± 28.87 | ||
| Tachycardia | Positive | 27.32 ± 49.78 | 0.18 |
| Negative | 35.39 ± 93.18 | ||
| Bradycardia | Positive | 46.66 ± 00.00 | 0.67 |
| Negative | 32.36 ± 59.16 | ||
| Muscles retraction | Positive | 28.34 ± 87.28 | 0.06 |
| Negative | 41.41 ± 41.63 | ||
| Nasal flaring | Positive | 19.29 ± 26.39 | 0.04 |
| Negative | 34.37 ± 96.87 |
Data are presented as mean ± SD
Asthma (35.1%), pneumonia (31.8%), sepsis (8.4%), bronchiolitis (7.8), and croup (7.8%) were the most common causes of respiratory distress among all the participants, respectively. Figure 1 represents the frequency of underlying causes of respiratory distress among all the participants.
Figure 1.
The frequency of all underlying causes among the participants. The number on the bars demonstrates the percentage of each condition.
Considering the differences among the genders in terms of underlying causes, structural defects of the chest were significantly higher in girls compared to boys (P = 0.03). The results indicate that in other causes of respiratory distress, there are no statistically significant differences among the genders (P > 0.05). Table 3 shows frequency of underlying diseases among genders.
Table 3.
The frequency of underlying disease among the genders.
| Frequency of underlying disease (%) | Male (102) | Female (52) | P-value |
|---|---|---|---|
| Foreign body aspiration | 7 (6.9) | 4 (7.7) | 0.85 |
| Pneumonia | 28 (27.5) | 21 (40.4) | 0.10 |
| Bronchiolitis | 8 (7.8) | 4 (7.7) | 0.97 |
| Respiratory airway malformation | 5 (4.9) | 3 (5.8) | 0.81 |
| Chest wall deformity | 2 (2) | 5 (9.6) | 0.03 |
| Pulmonary edema | 1 (1) | 1 (1.9) | 0.62 |
| Respiratory muscle weakness | 2 (2) | 3 (5.8) | 0.20 |
| Sepsis | 7 (6.9) | 6 (11.5) | 0.32 |
| Asthma | 40 (39.2) | 14 (26.9) | 0.12 |
| Croup | 11 (10.8) | 1 (1.9) | 0.05 |
| Cancer | 7 (6.9) | 2 (3.8) | 0.45 |
| Pleural effusion | 5 (4.9) | 2 (3.8) | 0.76 |
| Mediastinal tumor | 2 (2) | 1 (1.9) | 0.98 |
| Cardiac disease | 4 (3.9) | 3 (5.8) | 0.60 |
Patients with structural defects of the chest were significantly older (P = 0.01); meanwhile, patients with bronchiolitis and airway malformations were significantly younger than the patients without those conditions (P < 0.001). Table 4 presents the underlying cause in terms of age in detail.
Table 4.
The median age of the participants based on the underlying diseases.
| Underlying Cause | Result | Age (months) | P-value |
|---|---|---|---|
| Foreign body aspiration | Positive | 34.45 ± 72.45 | 0.87 |
| Negative | 32.36 ± 89.69 | ||
| Pneumonia | Positive | 28.34 ± 55.70 | 0.31 |
| Negative | 35.38 ± 11.31 | ||
| Bronchiolitis | Positive | 5.2 ± 25.8 | <0.001 |
| Negative | 35.37 ± 37.82 | ||
| Respiratory airway malformation | Positive | 7.8 ± 62.05 | <0.001 |
| Negative | 34.37 ± 41.69 | ||
| Chest wall deformity | Positive | 68 ± 49 ± 00.44 | 0.01 |
| Negative | 31.35 ± 36.90 | ||
| Pulmonary edema | Positive | 66.59 ± 00.39 | 0.2 |
| Negative | 32.36 ± 59.95 | ||
| Respiratory muscle weakness | Positive | 16.24 ± 40.50 | 0.31 |
| Negative | 33.37 ± 58.49 | ||
| Sepsis | Positive | 16.31 ± 76.50 | 0.10 |
| Negative | 34.37 ± 52.43 | ||
| Asthma | Positive | 36.31 ± 29.87 | 0.42 |
| Negative | 31.39 ± 26.84 | ||
| Croup | Positive | 39.40 ± 25.95 | 0.54 |
| Negative | 32.36 ± 50.99 | ||
| Cancer | Positive | 56.55 ± 33.18 | 0.21 |
| Negative | 31.35 ± 57.58 | ||
| Pleural effusion | Positive | 52.36 ± 00.84 | 0.16 |
| Negative | 32.27 ± 12.11 | ||
| Mediastinal tumors | Positive | 32.37 ± 57.01 | 0.28 |
| Negative | 55.48 ± 66.95 | ||
| Cardiac diseases | Positive | 40.53 ± 14.80 | 0.6 |
| Negative | 32.36 ± 68.46 |
Data are presented as mean ± SD.
Discussion
In this retrospective cohort study, we have assessed the incidence, epidemiology, and distribution of various causes of acute respiratory distress in children referred to a tertiary center. Out of a total 154 patients who took a part in the study, 102 patients were male (66%), which indicates a higher incidence of respiratory distress in males consistent with previous studies[11].
The most common clinical symptoms at the time of presentation to the emergency room were tachypnea (90.6%), followed by respiratory muscle retraction (66.9%), cyanosis (9.7%), and bradycardia (3.2%). While our findings were consistent with Anadol et al study showing tachypnea as the most common symptom, contradicts another study in Iran which expressed chest retraction as the most frequent finding followed by tachypnea[11,14]. Although there were no significant differences in terms of clinical symptoms among the genders, considering different presentations at different ages, patients with nasal flaring were significantly younger than others. However, there were no statistically significant differences in the mean ages of patients with and without other clinical symptoms such as tachypnea, use of respiratory muscles, cyanosis, tachycardia, and bradycardia.
We observed that pneumonia, croup, asthma, and bronchiolitis were not significantly different among the gender. This would be partly consistent with another study which showed that approximately 52% of pneumonia patients were male, in contrast to a couple of other studies from Iran that reported a higher rate of bronchiolitis, pneumonia, and asthma in boys[8,9,12,13,16]. However, our findings indicated that structural defects of the chest were significantly higher in girls compared to boys, but there was no statistically significant relationship between other underlying causes and gender.
In terms of age, patients with structural defects of the chest were significantly older; however, patients with bronchiolitis and airway malformations were notably younger than others. We perceived a mean age of 28.34 ± 55.70 months for patients with pneumonia in a total of 49 patients, although in a study in Worabe town, they reported that the mean age of pneumonia in 145 patients was 14.6 months, this discrepancy could be due to the difference in numbers of patients[8]. The mean age of patients in the bronchiolitis group was 5.2 ± 25.8 months, somehow in line with the Abed et al study (n = 49) which reported that the mean age of 3–4 months in bronchiolitis[12].
We can specify the causes of respiratory distress into four categories: upper respiratory tract involvement (croup, epiglottitis, anaphylaxis or angioedema, bacterial tracheitis, foreign body), lower respiratory tract involvement (asthma and bronchiolitis), lung parenchyma involvement, and respiratory center involvement[4,8]. According to our study, the most common cause of respiratory distress was a lower respiratory tract, asthma with a prevalence of 35.1%, and bronchiolitis with a prevalence of 7.8%. This is consistent with Tabatabai et al and another study in 1990 which revealed that the most important causes of respiratory distress were asthma 32%, foreign body 31%, acute laryngitis 22%, and acute bronchiolitis 9%[11,13]. We found that lung parenchymal involvement was the second leading cause of respiratory distress.
To dive more deeply into the pneumonia group, just two patients had no risk factor, while 20% of patients had asthma and 34% had aspiration pneumonia due to the underlying disease and the rest had pneumonia due to immunodeficiency. In a study which is conducted from December 2016 to January 2017 among children aged 2–59 months, pre-existing respiratory illnesses, such as stunting, history of asthma in the child, previous history of acute upper respiratory tract infection, absence of chimney in the cooking room, and carrying the child during cooking were found to be significant risk factors associated with the occurrence of pneumonia[8,9]. In the current study, an H1N1 influenza test was done for 25% of the patients with pneumonia (12 out of 49) and only one of them was positive. Four patients had para-pneumonic effusion and two patients had pneumothorax during hospitalization. In our study 18% of patients with pneumonia died, one with H1N1 influenza and the other with bacterial pneumonia, consistent with World Health Organization statistics which demonstrated pneumonia is accounting for 17.5% of children aged under 5 years and is the main cause of child mortality in the worldwide[19,20].
Upper airway involvement is another cause of respiratory distress, therefore in our study, two cases of angioedema, one case of bacterial tracheitis, 11 cases of foreign body aspiration, 12 cases of croup, and no cases of acute epiglottitis were reported, which showed that despite the high prevalence of croup in autumn and winter, upper airway obstruction was less common than other causes of respiratory distress and national vaccination had been effective in reducing epiglottitis.
One of the most common findings in bronchiolitis and croup was normal radiological imaging. In asthma, the most common finding was peribronchial infiltration, and in pneumonia, the most common finding was bilateral diffuse alveolar infiltration. In the treatment of patients with lower airway obstruction, 40% of patients received Pulmicort nebulization, which had no place in the initial approach in the treatment of acute pediatric attacks[21].
Conclusion
Taken all together, according to the most common cause of respiratory distress which is obstruction of the lower airways of the lungs, attention to clinical symptoms, including increased exhalation-to-tail ratio, wheezing, and a history of allergies in the patient and the patient’s family can lead us to diagnose and treatment of patients at the best time, and avoids unnecessary imaging and treatments that have no place in children’s algorithms. In the current study, among patients referred to a tertiary center in Tehran, tachypnea was the most common clinical symptom, and asthma was the most frequent cause of respiratory distress. Some proposed limitations of our study are missing patient information, being a single center study, and not considering the complete population.
Acknowledgements
All listed authors must have made a significant scientific contribution to the research in the manuscript approved its claims and agreed to be an author. It is important to list everyone who made a significant scientific contribution.
Footnotes
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Published online 19 March 2025
Contributor Information
Mahdis Bayat, Email: dr.mahdisbayat@sbmu.ac.ir.
Fatemeh Shojaeian, Email: fshojae1@jhmi.edu.
Seyed Mohamad Sadegh Mousavi Kiasary, Email: Mosavikia@sums.ac.ir.
Samira Sayyah, Email: drsamirasayah@sbmu.ac.ir.
Ethical approval
Ethical approval has been taken from Shahid Beheshti University of Medical Science’s ethics committee (Ethics ID: 1397640.IR. SBMU) and all methods were carried out in accordance with the relevant guidelines and regulations.
Consent
Written informed consent was obtained from the patient’s parents/legal guardian for publication and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.
Sources of funding
The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.
Author’s contribution
M.B. and F.S. conceptualized and designed the study, carried out the analyses, and wrote the manuscript (original draft). M.B. wrote the manuscript (original draft). F.S. carried out the analyses. S.M.S.M.-K. wrote & revise the manuscript draft. S.S. critically reviewed the manuscript for important intellectual content. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
Conflicts of interest disclosure
The authors declare no competing interests.
Guarantor
Dr Samira Sayyah.
Research registration unique identifying number (UIN)
Registry used: Clinicaltrials.gov (NCT06578377).
Provenance and peer review
Not commissioned, externally peer-reviewed.
Data availability statement
The data and materials are available and can be provided by the corresponding author, if based upon reasonable request.
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Associated Data
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Data Availability Statement
The data and materials are available and can be provided by the corresponding author, if based upon reasonable request.