Hand and Arm Numbness in Water: Possible Causes & What to Do

Question
I have high blood pressure. I am on norvasc 5 mg. I am on phentermine 37.5 mg and have lost 90 lb. since last november. I have some lower back and hip problems from a car accident about 5 years ago. The last 2 times I went swimming my hands went numb starting with my fingertips after I had been standing in about chest deep water for about 10 minutes. When this happened my fingertips got a slight purplish tinge and the veins in my fingers became very distended. The water is not cold. My doctor is stumped. Have you ever heard of anything like this?

Answer
fingertips numb and purple sounds like Raynaud's phenomena where the artery (inflow of blood) spasms and slows down blood flow to the hands and/or feet.  Sticking a hand in pretty warm water for 2 minutes or so should reverse it if that is occurring.  But, I would want to make sure your blood levels of thyroid hormones, T4, TSH and B12 vitamins levels were checked recently also.