Hypersensitivity Pneumonitis Associated with Intravesical BCG Therapy
Mechanism and Presentation
- BCG induces a systemic non-specific immunostimulatory response leading to secretion of pro-inflammatory cytokines, which can trigger hypersensitivity reactions beyond the bladder, according to the National Comprehensive Cancer Network 1, 2
- The immune response includes activation of neutrophils, monocytes, macrophages, T cells, and natural killer cells, which can lead to granulomatous inflammation in the lungs, as reported by the National Comprehensive Cancer Network 1
Management
- Immediate suspension of BCG instillations is necessary when hypersensitivity pneumonitis is suspected, as recommended by the Military Medical Research and the National Comprehensive Cancer Network 3, 4
- Patients with a history of BCG-induced hypersensitivity pneumonitis should not receive further BCG therapy, according to Praxis Medical Insights 4
Risk Factors and Prevention
- Traumatic catheterization or instillation within 2 weeks of TURBT increases risk of systemic absorption, as noted by the National Comprehensive Cancer Network and Praxis Medical Insights 1, 4
- Patients should be monitored for persistent flu-like symptoms lasting more than 48-72 hours after instillation, as advised by the National Comprehensive Cancer Network 2, 5
- Symptom management with single-dose, short-term quinolones may help reduce adverse events but won't prevent hypersensitivity pneumonitis, according to the National Comprehensive Cancer Network 1