Severe Respiratory Failure Due to Pulmonary BCGosis in a Patient Treated for Superficial Bladder Cancer

Molecular Identification of Extrapulmonary Vaccine Adverse Events after BCG in Paraffin-Embedded Specimens

According to the World Health Organization (WHO), around 1 million children worldwide are diagnosed with tuberculosis each year. The Bacillus Calmette-Guérin (BCG) vaccine has been used around the world for over 100 years. The complications of the BCG vaccination can occur in about 0,06% of children and include local or systemic adverse reactions. Due to the close analogy between the vaccine strain and other species of the Mycobacterium tuberculosis complex (MTBC), molecular methods are recommended for differential diagnosis of Vaccine adverse events (VAE) after BCG. The ability to quickly and specifically identify BCG is important in view of different treatment regimens. The aim of the study was to assess the usefulness of genetic testing for Mycobacterium bovis BCG in the paraffin-embedded specimens' methods. We describe two cases of VAE in immune-compromised children presenting with osteoarticular changes that had been clinically suspected of tuberculosis and led to molecular identification through GeneXpert, GenoType MTBC, and Spoligotyping. Results: Mycobacterium bovis BCG was detected in osteoarticular changes embedded in paraffin block of two patients. Conclusion: Genetic tests using paraffin-embedded materials allow for quick identification and differential diagnosis of patients with Tuberculosis and VAE after BCG. This is an important issue, especially in cases where the tissue has only been submitted for histopathological examination without microbiological diagnostics for tuberculosis.

Disseminated Bacillus Calmette-Guérin (BCG) infection presenting as severe respiratory failure and septic shock

Introduction

Intravesical Bacillus Calmette-Guérin (BCG) instillation is the most effective adjuvant therapy for superficial urinary bladder carcinoma, prolonging disease-free survival. Although it is usually well tolerated, moderate to severe local or systemic infectious complications, including sepsis involving multiple organs, may occur.

Case report

We report the unusual case of a man in his mid '70s who presented with septic shock and severe acute respiratory failure requiring intubation. Lack of response to antibiotics, history of intravesical BCG instillation and consistent imaging findings led to further investigations, with bronchoalveolar lavage (BAL) fluid polymerase chain reaction (PCR) results indicating pneumonitis due to Mycobacterium bovis dissemination. Prompt anti-tuberculosis treatment combined with corticosteroids resulted in significant clinical and radiological improvement, supporting the diagnosis of disseminated BCG infection.

Conclusions

Due to its non-specific clinical presentation and the relatively low diagnostic yield of conventional microbiological tests, a high index of suspicion is required for prompt diagnosis and treatment of systemic BCG infection. PCR-based assays for mycobacterial DNA identification may represent a valuable tool facilitating timely diagnosis of this uncommon, yet potentially life-threatening infection.