Cold Therapy, Clear Airways: Pediatric Cryotherapy for Airway Obstruction Due to Non-tuberculous Mycobacteria

Abstract INTRODUCTION: Cryotherapy has emerged as a valuable tool in managing central airway obstruction, utilizing extreme cold to facilitate the minimally invasive removal of obstructive lesions to alleviate airway compromise. The development of cryoprobes as small as 1.1 mm has broadened applicability of this technique in pediatrics during flexible bronchoscopy. We highlight the effectiveness of cryotherapy in a pediatric patient with worsening respiratory symptoms from a left mainstem bronchus (LMSB) mass linked to non-tuberculous mycobacterial (NTM) infection. CASE PRESENTATION: A 22-month-old previously healthy female presented to the emergency room with five weeks of worsening productive cough, unresponsive to multiple antibiotic courses. A chest X-ray revealed left lower lobe consolidation, raising suspicion for retained foreign body with post-obstructive pneumonia. She was admitted for antibiotic therapy and flexible bronchoscopy, which revealed a soft tissue mass in the LMSB with mucosal edema and purulent secretions; no foreign body was visualized (Figure-1a). A bronchoalveolar lavage (BAL) was performed and cryobiopsy was used for tissue sampling. A subsequent CT chest showed a 3.6 cm posterior mediastinal/subcarinal mass causing significant LMSB narrowing and partial lung collapse (Figure-1b). Respiratory culture from the BAL specimen grew Haemophilus influenzae and she was treated with ampicillin-sulbactam. Pathology from the cryobiopsy identified granulation tissue, inflammation, and granulomas. An acid-fast bacillus (AFB) stain revealed rod-like profiles suspicious for acid-fast bacilli. Despite negative results from the tuberculin skin test (TST), interferon-gamma release assay (IGRA), and AFB smear/culture, there remained a high clinical suspicion for NTM infection. Infectious Disease specialists recommended initiation of an anti-mycobacterial regimen with ethambutol, rifampin, and azithromycin. After four months, a follow-up CT demonstrated reduced mass size but persistent narrowing of the LMSB. She remained symptomatic with intermittent cough and wheeze requiring bronchodilator therapy and systemic steroids, leading to repeat bronchoscopy with cryobiopsy. During the procedure, the LMSB mass was visualized causing near complete airway obstruction. Cryotherapy was employed and the mass was successfully removed piece by piece (Figure-1c). Pathology showed necrotizing granulomatous inflammation concerning for atypical mycobacterial infection, though without visible bacteria. A month later, follow-up CT showed improved LMSB narrowing and reduced mass size (Figure-1d), with the patient reporting resolution of respiratory symptoms. DISCUSSION: Cryotherapy proved effective in removing an obstructive mass due to suspected NTM infection, improving airway patency and respiratory symptoms in this young child. Its potential as a first-line or adjunctive therapy for airway obstructions, especially those involving NTM infections, is significant.