MACROPHAGE ACTIVATION SYNDROME (MAS) SECONDARY TO MYCOBACTERIUM BOVIS CYSTITIS FOLLOWING INTRAVESICAL INSTILLATION OF BACILLUS CALMETTE-GUERIN (BCG) VACCINE: A CASE REPORT WITH REVIEW OF LITERATURE

Background: Intravesical Bacillus Calmette-Guerin (BCG) vaccine instillation is widely used for the treatment of superficial bladder cancer. While mild non-infectious problems have mostly been reported with intravesical BCG instillation, significant local and systemic complications, albeit low, have also been documented. Macrophage activation syndrome (MAS) is a potentially serious condition characterized by a hyperinflammatory state occurring secondary to infections, malignancies, and autoimmune diseases. Intravesical BCG is internalized into tumor cells, initiating local and systemic immune responses, leading to MAS. Case Summary: We report the case of a 61-year-old male patient with high-grade papillary bladder carcinoma who was diagnosed with macrophage activation syndrome (MAS) in association with Mycobacterium bovis (M bovis) cystitis following the fifth dose of intravesical BCG instillation. He was put on high-dose oral steroids prednisolone 1mg/kg/day for MAS along with antitubercular targeting M bovis infection. There was a dramatic clinical responsefrom Day 7 of treatment with a drastic reduction in serum ferritin levels from day 12. There are only 6 cases of MAS in association with intravesical BCG instillation reported in the literature to date. All were male patients with the median age being 67 years which was similar to our patients age. Intravenous Immunoglobulin (IVIG) (5/6, 83.33%), high-dose steroids (6/6, 100%), and antitubercular drugs (2/6, 33.33%), Vinblastine (1/6, 16.66%) were used in these cases for the treatment of the same. Conclusion: The diagnosis of MAS in a setting of intravesical BCG immunotherapy requires a high index of suspicion as MAS has been rarely found to be associated with BCG therapy and there is an increased risk of mortality when this condition remains untreated.