What is the appropriate management for a patient with vaping‑related bronchiolitis obliterans who has developed a pneumomediastinum?

Management of Vaping-Related Bronchiolitis Obliterans with Pneumomediastinum

Immediately cease all vaping exposure permanently and provide supportive care for the pneumomediastinum with observation, while initiating high-dose systemic corticosteroids for the bronchiolitis obliterans if physiological deterioration is present. 1, 2

Immediate Management of Pneumomediastinum

The pneumomediastinum component requires conservative management with observation in most cases, as vaping-induced spontaneous pneumomediastinum typically resolves without intervention. 3, 4

• Monitor vital signs and respiratory status closely during observation period 3
• Serial chest radiographs to document resolution of air in the mediastinum 3
• Most patients can be discharged after 24 hours of observation if clinically stable 3
• Supplemental oxygen if hypoxemic, though avoid positive pressure ventilation unless absolutely necessary as this can worsen air leak 4

A critical caveat: While rare, tension pneumomediastinum can progress to life-threatening complications including pneumothorax or tension pneumoperitoneum with abdominal compartment syndrome, requiring immediate decompression. 5 Monitor for persistent hypotension, distended abdomen, or hemodynamic instability that would necessitate urgent surgical consultation. 5

Management of Bronchiolitis Obliterans

High-dose systemic corticosteroids are indicated for patients with physiological deterioration from vaping-induced bronchiolitis obliterans. 1, 2

• The case report demonstrating successful treatment used high-dose corticosteroids in a patient requiring ECMO support, with subsequent improvement allowing weaning from mechanical ventilation 2
• Avoid long-term high-dose corticosteroids (>30 mg/day prednisone) beyond the acute phase, as they provide minimal benefit and increase adverse effects in chronic bronchiolitis obliterans 6, 7

Absolute and permanent cessation of all vaping products is non-negotiable and forms the cornerstone of treatment. 1, 2

Diagnostic Evaluation Required

Before finalizing treatment, complete the following assessments:

• Spirometry, lung volumes, and gas exchange testing to quantify the degree of obstruction and gas trapping 1
• High-resolution CT chest to evaluate for centrilobular "tree-in-bud" nodularity, air trapping, and mosaic attenuation patterns characteristic of bronchiolitis 2, 8
• Bronchoscopy with bronchoalveolar lavage to exclude bacterial suppurative airway disease and infectious etiologies 1, 2
• Comprehensive infectious workup including cultures from BAL, as multiple negative cultures support the diagnosis of toxic injury rather than infection 2
• Surgical lung biopsy may be necessary if the clinical syndrome, physiology, and imaging do not provide diagnostic certainty 1

Critical Distinction from Post-Transplant Bronchiolitis Obliterans

Azithromycin therapy, which is recommended for post-transplantation bronchiolitis obliterans syndrome, has no documented role in toxic/antigenic exposure-related bronchiolitis obliterans such as vaping-induced disease. 1, 9

This is a crucial distinction because:

• Azithromycin (250 mg three times weekly) is effective for BOS in lung transplant recipients, particularly those with neutrophilic BAL 9, 6
• However, this benefit has not been demonstrated for diacetyl-induced or other toxic inhalation-related bronchiolitis obliterans 1
• The pathophysiology differs: transplant-related BOS involves alloimmune mechanisms, while vaping-related disease results from direct toxic injury to small airways 1, 2

Long-Term Monitoring and Prognosis

Regular spirometric monitoring is essential to assess disease progression, as vaping-induced bronchiolitis obliterans often results in persistent, fixed airflow obstruction. 1, 2

• The reported case showed persistent fixed airflow obstruction with gas trapping several months after hospital discharge despite aggressive treatment 2
• Exercise tolerance may remain permanently limited 2
• Serial pulmonary function tests should be performed at 3-month intervals initially, then every 6 months once stable 1

Severe Disease Requiring Advanced Support

For life-threatening hypercapnic respiratory failure refractory to conventional mechanical ventilation, venovenous ECMO may be necessary as a bridge to recovery. 2

• The published case required 47 days of hospitalization including ECMO support for refractory hypercapnia 2
• Intubation and invasive mechanical ventilation should be avoided if possible due to risk of worsening pneumomediastinum, but may be unavoidable in severe bronchiolitis 2, 4
• Use lung-protective ventilation strategies with low tidal volumes and plateau pressures if mechanical ventilation is required 2

Mechanism of Injury

Vaping causes bronchiolitis obliterans through subepithelial inflammatory and fibrotic narrowing of small airways, likely from inhaled flavoring agents such as diacetyl, though the exact causative agent and mechanism remain incompletely understood. 1, 2, 8

• The exaggerated Valsalva maneuver performed during vaping (deep inhalation followed by forceful exhalation) contributes to pneumomediastinum development 4
• Diacetyl and other flavoring compounds cause direct toxic injury to bronchiolar epithelium 1
• The pattern differs from the predominantly alveolar injury seen in the 2019 EVALI outbreak 2