My daughter is a very athletic 23 year old woman who recently has been feeling ill. She has had headaches and nausea after exercise. She had an ultrasound and was told that she has a thinning of the cortex of the kidney. She also has an inflamed and her blood work tested positive for ANA. The little research I've done on the internet suggest lupus as a possible cause. However, she has none of the other typical symptoms. Is there another possible explanation for the test results?