INTRODUCTION: Endobronchial stenosis has been documented in a variety of conditions. Disease can be focal or diffuse, and may be related to infection, trauma, inflammation or idiopathic in nature. A recent literature review on endobronchial lesions reveals associations with bacterial, mycobacterial, fungal or viral infections, connective tissue diseases, sarcoidosis, Behcet’s syndrome, Wegener’s granulomatosis, papillomatosis, and others. Endobronchial stenosis in systemic disease is often a late stage presentation. However, it is difficult to find reports of obstructing membranous stenosis, and no reports associated with influenza have been published. Presented here is the case of a Hispanic female found to have extensive and visually striking endobronchial membranous obstructions after a documented case of H1N1 influenza A.
CASE PRESENTATION: A 61 year old woman, with well controlled diabetes, was transferred to our facility with numerous thin membranous endobronchial stenoses noted during admission for adult respiratory distress syndrome (ARDS), septic shock, and H1N1 influenza A. At an outside hospital, H1N1 was diagnosed by nasopharyngeal swab, and confirmed by polymerase chain reaction (PCR). All other bacterial, fungal, and mycobacterial cultures from sputum and bronchoscopy were negative prior to transfer. Hospital course was notable for acute kidney injury requiring transient hemodialysis and multiple embolic strokes due to a large atheromatous aortic plaque. She was discharged home, only to return to the outside hospital several days later with recurrent dyspnea. She was treated for hospital acquired pneumonia, but remained persistently hypoxic. Ventilation/perfusion scan reported severely impaired ventilation on the left and low probability for pulmonary embolism. Bronchoscopic findings were described as multiple web-like endobronchial membranous lesions on the left. The patient was then transferred to our facility for bronchoscopic intervention. At our facility, the patient had hypoxemic respiratory failure, requiring oscillatory ventilation with inhaled nitric oxide. Her endobronchial findings were striking, with profound involvement of the left-sided bronchial tree with thin membranous webs occluding numerous subsegmental bronchi. Over a two month period, she received serial bronchoscopy with numerous dilatations. Multiple biopsies were obtained and consistently demonstrated the presence of inflammation with granulation tissue without evidence of infection. On serial evaluation, the lesions appeared to recur and thicken over time, so a course of high dose IV steroids was given. Evaluation for primary immunodeficiency including immunoglobulin subclass analysis was unremarkable. The patient was eventually discharged home after a prolonged hospital stay, tracheostomy placement, percutaneous endoscopic gastrostomy placement, and aggressive inpatient rehabilitation.
DISCUSSION: Influenza A has multiple documented presentations. Previous literature has often focused on influenza presenting as ARDS or hemorrhage, and complicated by bacterial infection. The mechanism of serious bacterial super-infection is hypothesized to be related to inflammatory mediator release resulting in damaged bronchial epithelial layers and increased bacterial binding sites. Application of these concepts in our case suggests that an exaggerated inflammatory response to the influenza infection resulted in mucosal hypertrophy, scarring, and the formation of fibrous web-like membranes. With well-controlled diabetes as her only comorbidity, our patient was essentially immunocompetent. It is unclear why she developed such an exaggerated inflammatory response following influenza A infection, and such extensive and recurrent endobronchial disease.
CONCLUSIONS: Diffuse web-like membranous endobronchial stenosis is a newly described presentation and complication of H1N1 influenza A infection. Management of the fibrous obstructions with repetitive dilatation was effective in our patient. Further studies are needed to outline the frequency of these findings, prognostic significance and best treatment approaches.
Reference #1 Prince, J., Duhamel, D., Levin, D., Harrell, J., Friedman, P. (2002). Nonneoplastic Lesions of the Tracheobronchial Wall: Radiologic Findings with Bronchoscopic Correlation. Radiographics (special Issue); 22:S215-S230.
Reference #2 Rothberg, M., Haessler, S., and Brown, R. (2008). Complications of Viral Influenza. The American Journal of Medicine; 121(4):258-264.
DISCLOSURE: The following authors have nothing to disclose: Breion Mailloux, Sergio Burguete, John Stupka, David Sonetti
No Product/Research Disclosure Information