Clinical symptoms and signs useful in the early diagnosis of ankylosing spondylitis.

Seventy patients between the ages of 18 to 30 with early spondylitis (eAS), with bilateral grade II-III sacroiliitis without syndesmophytes were examined. The control group comprised 32 patients of the same age range with lumbar disc disease (LDD) confirmed by radiculography, without changes in the sacroiliac joints. In both groups the same clinical parameters were evaluated, calculating for each the specificity, sensitivity and Youden index.