Acute Acalculous Cholecystitis in a Multiple Sclerosis Patient Treated with Natalizumab.

Natalizumab is a disease-modifying drug that has proved greatly effective and well-tolerated in highly-active Multiple Sclerosis (MS). However, it may increase the risk for opportunistic infections, such as viral ones. We describe a 37-year-old woman treated with Natalizumab for Relapsing-Remitting Multiple Sclerosis (RR-MS) who presented to our clinic with malaise, arthromyalgias, rash, and fever.