Scientific Papers

Plastic bronchitis associated with respiratory syncytial virus infection: a case report | BMC Pediatrics

A 2-year-old female patient was admitted to Shenzhen Children’s Hospital in July 2021 because of a cough, fever for 5 days, and worsening shortness of breath for 1 day. Five days before admission, the child presented with paroxysmal productive cough, cyanosis, and fever. The highest temperature was 40.0 ℃. Four days later, the child had a worse cough and significant shortness of breath, then she was admitted to the hospital with presumptive pneumonia.

She was previously diagnosed with acute myeloid leukemia (M5, CR1) and was in the induction phase of chemotherapy, The chemotherapy regimen was cytarabine (Ara-c) 100 mg/m2 d1-7, etoposide (VP-16) 150 mg/m2 d3, cladribine (Cla) 5 mg/m2 d1-5, and granulocyte colony-stimulating factor (G-CSF) 200 µg/m2 d1-7. The patient had no history of eczema or wheezing. There was no special birth history, personal history, or family history.

The physical examination on admission was as follows: temperature 38.9 °C, heart rate 138 beats/min, respiratory rate 50 beats/min, blood pressure 104/60 mmHg, weight 12 kg, and 94% arterial oxygen saturation (with supplemental oxygen concentration 65%). The patient had poor mental status, dysphoria, shortness of breath, cyanosis, nasal flaring, retraction, wheezing, and rales on auscultation. Examinations on the heart, abdomen, and nervous system were unremarkable. The capillary refill time was 2 s.

Laboratory tests were as follows: The white blood cell counts 0.83*109/L, neutrophils 0.21*109/L, lymphocytes 0.62*109/L, hemoglobin 105 g/L, platelet 50*109/L, hypersensitive C-reactive protein 22.71 mg/L; procalcitonin 2.95 ng/ml; blood gas analysis: pH 7.403, carbon dioxide partial pressure 43.5 mmHg, oxygen partial pressure 87.4 mmHg, and standard bicarbonate 26.3 mmol/L. The standard residual base was 2.2 mmol/L. The liver and kidney function, creatinase, Brain Natriuretic Peptide, electrolyte, and coagulation function were normal; The blood culture and sputum culture were negative. The throat swab and alveolar lavage fluid PCR for respiratory pathogens (including metapneumovirus, influenza B virus, influenza A virus H3N2, Chlamydia, Mycoplasma pneumonia, bocavirus, coronavirus, respiratory syncytial virus (RSV), influenza A virus H1N1, adenovirus, rhinovirus, parainfluenza virus) indicated positive only for RSV only. A Chest CT (Fig. 1) suggested consolidation of both lungs with segmental atelectasis.

Fig. 1
figure 1

Chest CT on admission: It shows consolidation of both lungs with segmental atelectasis, centrilobular nodules, and a sign of tree-in-bud (yellow arrow)

Treatment and follow-up: During hospitalization, the child was in the induction phase of M5 chemotherapy with neutropenia and fever. Therefore, the intravenous meropenem (20 mg/kg q8 h) was given, with high-flow nasal catheter oxygen (HFNC), nebulization (with budesonide 2 ml ipratropium 2 ml salbutamol aerosol 1.25 ml once/8 h), rehydration and antipyretic. On the 6th day of hospitalization, the difficulty breathing, and retraction were worsening, and the oxygen saturation was 88% on HFNC, then she was transferred to the Pediatric Intensive Care Unit (PICU). By intubation and mechanical ventilation, the oxygen saturation was still lower than 90%, and mechanical ventilation-related lung injuries such as subcutaneous emphysema and mediastinal pneumatosis occurred (Fig. 2A). On the 9th day of hospitalization, extracorporeal membrane oxygenation (ECMO) was given, by which the tidal volume was still low, and manual lung recruitment was ineffective. Repeated chest radiographs indicated signs of “white lung” (Fig. 2B). Airway obstruction was considered, the bronchoscopy was performed on the 10th, 13th, 15th, and 19th days of ECMO operation, respectively, and many plastic plugs were aspirated during the first two procedures (Fig. 3A). After that, the tidal volume increased. The alveolar lavage fluid was sent for a high-throughput etiology test by next-generation sequencing, which was only positive for RSV. The pathology of the plastic plugs indicated fibrinous secretions, as well as red blood cells, lymphocytes, and neutrophils (Fig. 3B C). The ECMO was withdrawn 35 days later. At discharge, she was on HFNC (FiO2 34%, flow 13 L/min) with, an oxygen saturation maintained above 95%.

Fig. 2
figure 2

Chest X-ray during hospitalization. It shows consolidation and segmental atelectasis of both lungs (A), subcutaneous emphysema (red arrow), and a small amount of pneumatosis of the mediastinum (yellow arrow); It shows diffuse consolidation of both lungs (B), with air bronchogram sign, indicating “white lung”

Fig. 3
figure 3

A1-A2 Plastic secretion; B Low-magnification pathological image. It shows abundant fibrin and inflammatory cells (as shown by black arrows) (HE staining, ×100) (C) High-magnification pathological image. It shows visible neutrophils (black arrows) lymphocytes (red arrows) red blood cells (blue arrows) (HE staining, ×400)

After discharge, the child had a cough, exercise intolerance, and persistent moist rales on lung auscultation. A chest CT scan performed six months post-discharge (February 2022) revealed uneven inflation, hyperinflation, ground-glass opacity, atelectasis, and interlobular septal thickening in both lungs (Fig. 4). Consequently, bronchiolitis obliterans (BO) was diagnosed. oral montelukast sodium and low-dose azithromycin, as well as budesonide nebulization, were given. A follow-up CT scan performed 19 months post-discharge (March 2023)still indicated a mosaic attenuation pattern, atelectasis, and interlobular septal thickening (Fig. 5). In October 2022, oral pirfenidone was initiated for the treatment of pulmonary fibrosis. Currently, during more than two years of monitoring, no exacerbation of BO has been observed.

Fig. 4
figure 4

A follow-up CT scan 6 months after discharge. It shows a mosaic attenuation pattern, (hyperinflation (yellow circle) and ground glass opacity (red circle)), atelectasis (blue circle), and interlobular septal thickening (yellow arrow) in both lungs

Fig. 5
figure 5

A follow-up CT scan 19 months after discharge. It still shows mosaic attenuation pattern, (hyperinflation (yellow circle) and ground glass opacity (red circle)), atelectasis (blue circle), and interlobular septal thickening (yellow arrow) in both lungs

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