CL-350 Captain reported encountering wake turbulence on descent into BWI in trail of a heavy jet.

Narrative

While on arrival on the RAVNN 6 RNAV into BWI; we were instructed to fly from RAVNN direct to SPLAT which is on the ILS for 33L. As we were descending from 5000 ft. to 4000 ft. all of a sudden and without any warning signs the aircraft rolled to the right approximately 45 to 50 degrees. The autopilot was engaged at the time. I immediately held the control wheel and as I began to disengage the autopilot the aircraft began to roll back to normal. From that point on I flew the aircraft with the autopilot disengaged. We were following a heavy which on TCAS was at least 5 miles ahead and approximately 2000 ft. below. While on final approach on the ILS I stayed no less than half a dot above the glideslope to avoid another upset. Continued the approach and landed normally.In all my years flying jets this was the first time that I encountered such a pronounced event. I'm always very aware of the dangers of following a heavy and plan to stay as high above their wake as possible. Given our spacing and altitude difference I'm not quite sure why we encountered the wake in such dramatic fashion. It's quite possible the wake did not dissipate fast enough as we were going through the same path. Once on the ground I followed up with couple of phone calls first to the Tower and then Potomac Approach to find more details.