Also make sure your posture is correct no matter if you are playing your keyboard or driving your car. Don't lean forward, which can put added pressure on your wrists - I have to be very careful about this when going on long bike treks or my hands will go totally numb. And, place your hands below your heart when possible, something that's easy to forget when driving with your hands at the normal "10 and 2 o'clock" position. I don't know how you have your keyboard(s) placed but instead of having my two keyboards on a single two-tier stand I prefer to have them on two seperate stands ata right angle to each other to help with proper posture and hand/wrist placement.

Just some tips - always see a doctor as others here have suggested.