Computed tomography findings, temporal course, and clinical relevance of subpleural pulmonary interstitial emphysema in patients with pneumomediastinum

Background Subpleural pulmonary interstitial emphysema is defined as the air in the subpleural portion of the lung, and the clinical relevance is not well understood. Purpose to evaluate the frequency, temporal course, risk factors, and clinical significance of subpleural pulmonary interstitial emphysema (PIE) in patients with pneumomediastinum resulting from ruptured alveoli and other causes. Material and Methods This was a retrospective study of 130 patients with pneumomediastinum on CT between January 2009 and December 2019 at 2 hospitals. Patients were divided into 3 groups as follows: spontaneous pneumomediastinum ( n = 101), pneumomediastinum due to blunt trauma ( n = 16), and pneumomediastinum due to another known cause ( n = 13). The frequencies of radiographic features (subpleural PIE, peribronchovascular PIE, pneumothorax, pulmonary fibrosis, and emphysematous changes) between the 3 groups were compared by the χ2 or Kruskal–Wallis test. Odds ratios were calculated to evaluate candidate risk factors for subpleural and peribronchovascular PIE. Results Subpleural PIE was observed in 0%, 15.8%, and 31.3% of patients with pneumomediastinum due to another cause, spontaneous mediastinum, and blunt trauma, respectively. In most patients, subpleural PIE resolved spontaneously (85.7% within 8 days). Two patients with pulmonary fibrosis showed recurrent subpleural PIE on follow-up. Young age showed increased risk for subpleural PIE (odds ratio [OR] 0.9, 95% confidence interval [CI] 0–0.99). Conclusion Subpleural PIE was only detected in patients with pneumomediastinum due to ruptured alveoli and resolved spontaneously and rapidly. Subpleural PIE may be one route the air from ruptured alveoli to the mediastinum.

Giant Pulmonary Bulla Underlying Bronchopulmonary Dysplasia in a Very Low-birth-weight Infant: a Case Report

Background: Acquired cystic lung disease is a serious respiratory complication of bronchopulmonary dysplasia in premature infants. Most cases of acquired cystic lung disease underlying bronchopulmonary dysplasia involve pulmonary interstitial emphysema. Although this is a reversible condition, there are a few instances where surgery might be necessary. An accurate diagnosis is important to decide the therapeutic strategy for acquired cystic lung disease. Here, we report a rare case of a giant pulmonary bulla in an infant treated with bullectomy. Case presentation: A male infant born at 23 weeks of gestation with a birth weight of 524 g was initially diagnosed with respiratory distress syndrome. During mechanical ventilatory support, he presented with recurrent pneumothorax and a gradually expanding pulmonary cyst in the right lung. Chest CT at 5 months of age revealed a large cyst located in the subpleural area adjacent to the multiple cystic air spaces. These findings are consistent with the diagnosis of giant pulmonary bulla with pulmonary interstitial emphysema underlying bronchopulmonary dysplasia . At 9 months of age, the giant pulmonary bulla expanded further due to acute bronchitis for which he developed respiratory failure and obstructive shock. This warranted a bullectomy for the giant pulmonary bulla. After the operation, the unresected pulmonary interstitial emphysema lesion did not expand further. He is currently three years old and has no respiratory problems. Conclusions: This case demonstrated that chest CT is useful for providing valuable anatomical information necessary in deciding the treatment strategy for acquired cystic lung disease in infants.

Refractory Pulmonary Interstitial Emphysema in Extreme Premature Newborn

Pulmonary interstitial emphysema (PIE) occurs when air leaks into the pulmonary interstitium due to overdistension of distal airways, it occurs mainly in neonates with respiratory distress syndrome who need positive pressure ventilation but has also been reported in spontaneously breathing infants. Herein, we report on an extremely low birth weight infant with severe persistent PIE, while on invasive mechanical ventilation (high-frequency oscillatory ventilation, high-frequency jet ventilation, and neurally adjust ventilator assist) managed successfully with 2 weeks of selective right lung ventilation after failure of more conservative measures, including shorter periods of right mainstem intubation, before the prolonged trial that was successful.

A case of neonatal diabetes insipidus following dexamethasone for bronchopulmonary dysplasia

BACKGROUND: Diabetes insipidus (DI) is a disease resulting from defects in the arginine vasopressin system responsible for regulating body water homeostasis. It is characterized by polyuria with increased serum osmolality and sodium and can result from congenital or acquired disorders. CLINICAL PRESENTATION: A baby was admitted to NICU for extreme prematurity (25 weeks gestation), extreme low birth weight (900 grams) and respiratory distress. He received one dose of Surfactant and was ventilated using high frequency jet ventilation for development of pulmonary interstitial emphysema. After nine days, he still required high settings with development of early chronic lung changes in the form of atelectasis. Therefore, he was started on a course of dexamethasone following the DART study protocol (Dexamethasone: A Randomized Trial). However, after six days (cumulative dose of 0.75 mg/kg/day) he developed polyuria (7.4 ml/kg/h) with increased serum sodium (150 mmol/L) and osmolality (348 mmol/L). He lost 85 grams of his weight in 24 hours, which represented a 9.8 %weight loss. The findings were suggestive of DI and given there were no apparent causes other than dexamethasone, it was discontinued. Over the following 48 hours, polyuria and hypernatremia gradually resolved, reaching 3.5 ml/kg/h, and 140 mmol/L respectively. CONCLUSION: The use of dexamethasone is not an uncommon practice in tertiary care neonatal units. To our knowledge, our case is the first report of neonatal DI secondary to the use of dexamethasone. We recommend closely monitoring urine output and serum electrolytes in preterm infants receiving dexamethasone.

Management of severe right lung cystic pulmonary interstitial emphysema in an infant at 24 weeks gestation with bedside selective left main stem bronchial intubation: Case report and review of the literature

Pulmonary interstitial emphysema (PIE) is a severe complication of mechanical ventilation in preterm infants. Selective bronchial intubation is a rarely used treatment strategy, as it is challenging, especially left main stem bronchial intubation. We report our experience in an infant at 24 weeks gestation with bedside left main stem bronchial intubation using flexible fiberoptic bronchoscopy. We also describe in detail the procedural details involved in the selective left main stem bronchial intubation including the helpful technique of gently bending the tip of the endotracheal tube to create “memory” to better direct the tube into the left main-stem bronchus while using the flexible fiberoptic bronchoscope. A review of the literature regarding selective bronchial intubation in newborn infants is presented. This case report and literature review suggest that bedside left main stem bronchial intubation using a flexible fiberoptic bronchoscope is a viable option to successfully manage even the most unstable extreme premature infant with unilateral right lung cystic PIE. This may potentially prevent a rare but necessary invasive surgical procedure like lobectomy or even death.