Southern Illinois GI Specialists When you choose to work with Dr. Zahoor Makhdoom you're working with the best staff around. Allow us to diagnose and treat diseases and illnesses such as acid reflux, Crohn's disease / colitis, colon cancer / prevention, diverticulitis, excessive weight gain / loss, gallstones / pancreatic disease, celiac disease, liver diseases (all kinds of hepatitis ...Contact Us‧About SIGIS‧GI Disorders‧Procedures‧Insurance Information‧Patient Forms.