Aorto-enteric fistula development secondary to mycotic abdominal aortic aneurysm following intravesical bacillus Calmette-Guerin (BCG) treatment for transitional cell carcinoma of the bladder.

INTRODUCTION: Intravesical BCG-instillation for bladder cancer is considered safe but is not without risk. While most side-effects are localised and self-limiting, the development of secondary vascular pathology is a rare but significant complication.

PRESENTATION OF CASE: A 77-year-old male presented with a mycotic abdominal aortic aneurysm and associated aorto-enteric fistula 18 months after receiving intravesical BCG-instillations for early stage transitional cell carcinoma.

DISCUSSION: Response rates to intravesical BCG for early stage transitional cell carcinoma are high. The procedure produces a localised inflammatory response in the bladder but the exact mechanism of action is unclear. The treatment is generally well tolerated but BCG-sepsis and secondary vascular complications have been documented. Mycotic abdominal aortic aneurysm with associated aorto-enteric fistula secondary to BCG is very rare. Few examples have been documented internationally and the extent of corresponding research and associated management proposals is limited. Surgical options include in situ repair with prosthetic graft, debridement with extra-anatomical bypass and, occasionally, endovascular stent grafting. Recommended medical therapy for systemic BCG infection is Isoniazid, Rifampicin and Ethambutol.

CONCLUSION: Current screening methods must be updated with clarification regarding duration of anti-tuberculous therapy and impact of concomitant anti-tuberculous medication on the therapeutic action of intravesical BCG. Long-term outcomes for patients post graft repair for mycotic aneurysm are unknown and more research is required regarding the susceptibility of vascular grafts to mycobacterial infection. Recognition of the risks associated with BCG-instillations, even in immunocompetent subjects, is paramount and must be considered even several months or years after receiving the therapy.