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Objectives: We describe the clinical spectrum, etiology, and progression of children with post-infectious bronchiolitis obliterans (PIBO) from a low- and middle-income setting for which there is limited literature. Materials and Methods: A cross-sectional, retrospective, and descriptive study between November 2019 and October 2020 of all PIBO patients aged 6 months to 15 years managed at pediatric pulmonology service in Cape Town, South Africa. Results: Fifty-one patients with PIBO were enrolled; 78% were males, median age of 60 months (IQR 33-107). Median age at disease presentation was 6 months (IQR 3-12), 80% presented with cough; 94% required hospital admission, 92% needed supplemental oxygen therapy and 75% needed ventilatory support. Reported cigarette smoke exposure was high (47%). Adenovirus infection was the most common etiology (64%). Chest radiographic findings included lung hyperinflation (43 [84.3%]) and bronchiectasis (23 [45%]). Twenty-seven patients had spirometry and showed mixed (41% [n = 8]) or obstructive (27% [n = 12]) pattern with mean (standard deviation) forced expiratory volume in 1s (FEV1) z-score -3.3 (± 1.4), forced vital capacity (FVC) z-scores -2.4 (± 1.6), and FEV1/FVC z-score -3.1 (± 2.4). Systemic corticosteroids were used during initial presentation in 47 patients (92%). Forty-four patients (86%) required two or more subsequent hospital admissions. Improvement of symptoms was reported in 82% of patients with a mean follow-up period of 5 years. Cough (43% [n = 22]) and wheeze (39% [n = 20)]) were the most common reported current symptoms. Conclusion: PIBO is a recognized cause of pediatric obstructive lung disease in South African settings, with adenovirus pneumonia being the most common preceding illness. Symptoms of airway obstruction persist over time, but improvement was observed with treatment including corticosteroids. [ABSTRACT FROM AUTHOR]

Children with post-infectious bronchiolitis obliterans (PIBO) are frequently hospitalized with acute exacerbation, but clinical differentiation of PIBO exacerbation from acute bronchiolitis is often challenging, which may result in treatment delay and chronic lung function impairment. We aimed to examine whether serum YKL-40 and growth factors could be markers for PIBO exacerbation. Thirty-seven children admitted with acute exacerbation of PIBO were enrolled and studied retrospectively. Diagnosis of PIBO was based on clinical history of acute respiratory infection followed by persistent airway obstruction and characteristic findings in high-resolution computed tomography. Serum levels of YKL-40, vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β1, and platelet-derived growth factor (PDGF)-BB were measured on admission. The biomarkers were also examined in children admitted with acute bronchiolitis serving as positive controls ( N = 30) and in age-matched controls ( N = 20). Only YKL-40 levels were found to be significantly higher in PIBO patients with exacerbation compared with that in bronchiolitis patients and showed a positive correlation with the severity of disease before diagnosis of PIBO. Conclusion: Our results suggest that measuring serum YKL-40 levels might help distinguish exacerbation of PIBO from acute bronchiolitis in young children. [ABSTRACT FROM AUTHOR]

Background and objective Post-infectious bronchiolitis obliterans ( PIBO) is a severe disorder following acute lower pulmonary infection in young children, especially caused by adenovirus. Mannose-binding lectin ( MBL) deficiency arising from polymorphisms in the coding and non-coding region on the MBL2 gene has been associated with more frequent and severe respiratory infections. Our aim was to evaluate the influence of MBL variants in the susceptibility and evolution of children with PIBO. Methods One hundred eleven children with PIBO diagnosis were studied. The coding A, B, D and X promoter variants of MBL2 gene were assessed by PCR-RFLP. B and D alleles were pooled as O. The combined genotypes A / A and YA / O were grouped as sufficient MBL (s MBL), and O / O and XA / O as insufficient MBL (i MBL) groups. To evaluate the frequency of MBL2 polymorphisms in the general population, we studied DNA samples from 127 healthy donors from the blood bank of the hospital (control group). Results iMBL variants were significantly more frequent in PIBO children compared with controls (21.6% vs 10.2%, P = 0.01). PIBO patients with i MBL required intensive care unit ( P = 0.001) and mechanical assistance at the moment of viral injury ( P = 0.001) more frequently than those with sMBL. Conclusions Insufficiency of MBL was more common in PIBO children than in healthy controls. This genetic condition was significantly associated with more severe initial disease, illustrating the relevance of innate immune defence factors prior to the maturation of the adaptative immune system. [ABSTRACT FROM AUTHOR]

The aim of the present study was to outline any predisposing factors and clinical and radiological features of post-infectious bronchiolitis obliterans (PIBO) in pediatric patients, and to determine the effect of long-term azithromycin treatment on these factors. In total, 16 cases of children with PIBO were retrospectively reviewed. Adenovirus and Mycoplasma pneumoniae were the most common etiological agents (12/16) in the children with PIBO. The patients presented with persistent dyspnea, a chronic cough, sputum production and wheezing following the initial lung infection. Chest X-rays indicated pulmonary overinflation and patchy ground-glass opacity. In addition, high-resolution computed tomography (HRCT) scans revealed patchy ground-glass opacity, bronchiectasis, bronchial wall thickening and mosaic perfusion in all 16 cases. A unilateral hyperlucent lung was observed in two cases. All the patients underwent treatment with low-dose azithromycin and prednisone. Follow-up examinations of the 16 cases, varying in duration between 7 and 31 months, showed that the disease condition had improved in 10 cases. However, no significant improvements were identified from the HRCT scans or were observed in the patient condition in the additional six cases. The diagnosis of BO is primarily based on a typical clinical presentation and HRCT observations. Therefore, a typical clinical history and patchy ground-glass opacity features on HRCT scans are screening indices that predict BO development. Steroids are the cornerstone of BO treatment; however, long-term azithromycin treatment can improve the condition of the patients. In summary, PIBO is a disease with a high morbidity rate and should be treated by a multidisciplinary team. Patients should receive follow-up examination for an extended period. Patchy ground-glass opacity features on HRCT scans indicate that clinical suspicion of BO is necessary in children with persistent and severe wheezing. [ABSTRACT FROM AUTHOR]

Aim: Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, but it is also frequently demonstrated by children and adults with chronic obstructive lung diseases. BHR is usually measured by bronchial challenges using direct or indirect stimuli. The aim of this study was to compare these two types of bronchial challenge in young children with post-infectious bronchiolitis obliterans (BO). Methods: Methacholine and adenosine 5′-monophosphate (AMP) bronchial challenges were performed on preschool children with post-infectious BO ( n =18), those with asthma ( n =23) and in controls ( n =20), using a modified auscultation method. The endpoint was defined as the appearance of wheezing and/or oxygen desaturation. Results: A positive response to methacholine (an endpoint concentration ≤8  mg/ml) was observed in 88.9% (16/18) of the patients with post-infectious BO, but a positive response to AMP (an endpoint concentration ≤200  mg/ml) was observed in only 22.2% (4/18). All patients with asthma responded positively to methacholine, and most (21/23, 91.3%) of them also responded positively to AMP. The majority of the controls were insensitive to both challenges. Conclusion: BHR to methacholine is a frequent, but by no means universal, finding in young children with post-infectious BO, but is usually not accompanied by BHR to AMP. [ABSTRACT FROM AUTHOR]