Abstract

Aim: To compare the frequency, demographic, clinical, radiological and treatment characteristics of pediatric cases with a diagnosis of Parapneumonic Effusion (PPE)/empyema in the winter and spring of 2022-2023 after the strict restrictions of COVID-19 Pandemic lifted up, with the PPE/empyema cases hospitalized in the winter and autumn months of 2021-2022 during the continuation of COVID-19 Pandemic restrictions.

Materials and Methods: Pediatric cases with a diagnosis of PPE/empyema in the winter and spring of 2021-2022 (during the restrictions continuation; the controlled normalization period in Turkiye) and winter and spring of 2022-2023 (after the lifting up all restrictions) were included and compared in this study. Demographic, clinical, radiological and treatments of patients were discussed.

Results: In the study group, a total of 58 patients with PPE/empyema were included, with 15 in the 2021-2022 group and 43 in the 2022-2023 group. Although the number of PPE/empyema cases were more in 2022-2023 than 2021-2022 group there was no statistically significant difference between the frequencies of PPE/empyema cases (p=0.588). Additionally, there were no statictically significant differences in the demographic, clinical, laboratory and outcomes of patients between the two groups.

Conclusion: The number of PPE/empyema cases increased through the end of COVID-19 Pandemic with the ease of health-care restrictions together with immunity debt which children acquired during pandemic lockdown periods. Our study is the first to document the increased PPE/ empyema cases hospitalized in the post-pandemic period from a single center. Multicenter studies with larger numbers of patients are needed.

Keywords: Parapneumonic Effusion; COVID-19; Pandemic; Empyema Cases

Introduction

The strict public health measures implemented during the COVID-19 pandemic have caused changes in the epidemic patterns of many infectious diseases. Implementation of these measures resulted in low incidences of influenza, respiratory syncytial virus, pneumococcus, enterovirus and parainfluenza infections [1]. The lack of exposure to various microorganisms in children during the COVID-19 pandemic lockdown caused a paucity in their immunity that lead to susceptibility to infectious diseases, the so-called ‘‘immunity debt’’ [2]. Towards the end of COVID-19 pandemic immunity debt together with removal of strict restriction measures lead to off-season resurgence of respiratory infections in several countries.

In our country, the strict public health restrictions were followed until 1^st July, 2021 [3]. During the 2021-2022 school year, controlled normalization period was continuing and face-to-face education started on September 6, 2021, for 5 days a week. Mask wearing was mandatory for both teachers and children in schools at that time. Additionally, teachers not been vaccinated with any of the vaccines against SARS-CoV-2 were required to undergo weekly nasopharyngeal PCR tests [4]. After the lifting up of all rectrictive measures by July 1^st, 2022; the 2022-2023 school year began allowing children and teachers to attend their classes without masks. The removal of these restrictions resulted in more pulmonary infections and more parapneumonic effusion (PPE)/ empyema cases we observed.

PPEs are the most significant complications leading to mortality and morbidity caused by lower respiratory infections [5]. While some PPEs can be resolved with antibiotic therapy alone, others may require drainage due to failure of resolution, resulting in complicated PPE called empyema [6]. PPEs and empyema not only prolong hospital stays but also increase mortality rates [7]. Despite the significant reduction in mortality observed through appropriate antibiotic use, along with repeated therapeutic thoracentesis, closed-chest drainage, fibrinolytic treatment, Video-Assisted Thoracoscopic Surgery (VATS) and open thoracotomy procedures for draining pleural effusion, there is no complete consensus on the treatment approach for parapneumonic effusions [8].

In this study, we aimed to evaluate the epidemiological, clinical, laboratory and radiological characteristics of children presenting to our hospital with PPE/empyema during the two consecutive winter and autumn seasons of COVID-19 pandemic. We hope that the data we obtained would contribute to the monitoring and treatment of parapneumonic effusions and empyema, a commonly observed complication in children.

Materials and Methods

This study was conducted retrospectively in a single center with pediatric patients (under the age of 18) diagnosed with parapneumonic effusion and empyema who were admitted to the hospital. All patients were hospitalized between October 1^st, 2021 and May 31^st, 2023 at the Children’s Infectious Diseases Service of Bursa Medical Faculty City Practice and Research Hospital, which is a tertiary care hospital. The study was approved by the local ethics committee (Approval Number: 2019-KAEK-140 2023-8/3). Written informed consent was obtained from all parents or legal guardians before inclusion in the study. The diagnosis of parapneumonic effusion and empyema was made based on the patient’s history, physical examination, radiological evidence of pleural fluid, and/or evaluation of the pleural fluid obtained by thoracentesis according to Light criteria [9]. Patients or legal guardians who refused to participate in the study and/or those with insufficient information in their hospital records were excluded from the study. Patients diagnosed with PPE and empyema included in our study were categorized as Group 1 if they were diagnosed between October 1^st, 2021 and May 31^st, 2022. Patients diagnosed between October 1^st, 2022 and May 31^st, 2023, were considered as Group 2.

Data Collection

The records of all patients were examined in terms of age, gender, pre-admission complaints and durations, history of comorbid diseases, use of antibiotics and the presence of risk factors for Parapneumonic Effusion (PPE)/empyema. Symptoms and signs of PPE and empyema, vital signs (respiratory and heart rates, blood pressure and oxygen saturation) and other physical examination findings were evaluated. Complete blood count, liver-kidney function tests, albumin, Erythrocyte Sedimentation Rate (ESR), C-Reactive Protein (CRP) and procalcitonin results obtained from all PPE and empyema patients at the time of admission were recorded from their files. From the pleural fluids obtained by thoracentesis; total leukocyte count, protein, glucose, lactate dehidrogenase, albumin, gram staining results and thoracentesis culture results which grew on specific and non-specific media, as well as simultaneous blood culture results, were recorded. During the follow-up of the patients; posteroanterior-lateral and decubitus lung X-ray findings, thoracic ultrasound and if any, thoracic CT findings were recorded from the files. In addition, oxygen support, admission to the Pediatric Intensive Care Unit (PICU) for mechanical ventilation need, presence of closed-chest tube drainage, antibiotic treatments, fibrinolytic treatment and their outcomes were evaluated.

Statistical Analysis

The characteristic data were presented as n (%) for categorical variables and, when appropriate, as mean ± SD or median (minimum-maximum values) for continuous variables. Chi-square tests or Fisher’s exact tests were used for comparing categorical variables. In the presence of parametric test conditions to assess differences between two groups, independent T-tests were used and when the conditions could not be met, the Mann-Whitney U test was used. All tests were two-tailed, p-values <0.05 were considered statistically significant and Bonferroni correction was applied when appropriate. Statistical analyses were performed using SPSS version 22.0 (SPSS Inc., Chicago, IL, USA).

Results

Characteristics of the Study Group

In our study, which included 58 pediatric patients admitted with the diagnosis of PPE/empyema the median age was 75 months (min-max, 4-210 months) and 62% of the patients were male. There were 15 patients in Group 1 and 43 patients in Group 2. No statistically significant difference was found according to the frequency of PPE/empyema cases between the two groups (p=0.588). While 93% of the patients presented with fever, 62% had cough and 50% had difficulty in breathing upon hospital admission. One or more comorbid conditions were observed in 13 (22%) of our patients. Of these patients; four were CP-epilepsy, two Down Sydnrome, one Menkes disease, one dilated cardiomyopathy, one selective Ig M deficiency, one hypotonic infant, one hydrocephaly with VP shunt, one with right renal agenesis, one with ASD. Detailed baseline characteristics and laboratory results of all patients are listed in Table 1. No significant differences were found between the two groups in terms of demographic characteristics, symptoms, signs and laboratory results (p > 0.05).

Radiological Characteristics

In 42 cases (73%) included in our study, pleural effusion was detected on the chest X-ray taken in the AP-lateral and decubitus position at the time of admission. Thoracic Ultrasound (USG) was performed in 51 patients (88%). Isolated pleural effusion was most commonly reported in the patients (63%), with varying proportions of associated consolidated parenchymal areas and atelectasis. Thoracic CT was performed in 28 cases (48%) and the combination of pleural effusion and consolidation (71%) was the most frequently reported condition. Detailed radiological characteristics of the study patients in both groups are presented in Table 2. There was no statistically significant difference between the two groups.

Pleural Fluid and Culture Results

Pleural effusion was observed bilaterally in 23 cases (40%), only on the left side in 23 cases (40%) and only on the right side in 12 cases (21%). The median value of pleural effusion fluid volume was reported as 17 mm (min-max, 5-100 mm). Among all the cases 20 (34%) were diagnosed with empyema and pleural fluid samples were obtained. There was no significant difference in pleural fluid sample results between Group 1 and Group 2 (p > 0.05). Cultures were positive in 3 out of 17 pleural fluid samples (18%). The cultured organisms were reported as Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus pyogenes in individual patients. Blood cultures were taken in 32 cases (55%). Positive cultures were detected in a total of four patients (12%), all in Group 2; with one case each of Acinetobacter baumannii, Streptococcus pneumoniae, Streptococcus mitis and Staphylococcus epidermidis (Table 3).

Clinical Outcomes and Treatments

The median length of hospital stay of the cases was 11 days (min-max, 3-61 days). Intensive Care Unit (ICU) admission was required for 21 cases (36%), with a median duration of 7 days (min-max, 1-58 days) in the ICU. The most preferred antibiotic treatment protocol in the patient groups included in our study was a combination of 3rd generation cephalosporin + vancomycin, accounting for 43% of all cases. This was followed by the combination of 3rd generation cephalosporin + clindamycin (24%). Chest tube placement was performed in 16 (36%) cases. Intrapleural fibrinolytic therapy was administered in 13 patients (22%). Alteplase of 2 to 5 mg in 25 to 100 ml normal saline with a dwell time of 4 hours followed by drainage was used for intrapleural fibrinolitic treatment. This protocol was given 3 consecutive days. Detailed clinical characteristics of the patients are presented in Table 4. No significant differences were observed in the clinical characteristics and treatment modalities of the study patients when compared by periods (p > 0.05).