My Son Was In A Minor Motorcycle Accident Five Days

My son was in a minor motorcycle accident five days ago with no apparent injuries other than bruising on his foot and soreness except for a line of blurred vision in one eye. The blurred vision lasted about an hour he said. He was wearing a helmet. Since that time, he has noticed an increase in frequency of urination. There is no burning. He said he has to go about every two hours. HE described it as feeling like his bladder was going to explode only to urinate about a fourth cup. A few minutes later, he feels the need to urinate again with the same results. There is no increase in thirst.