My 13 year old son, who was diagnosed with type 1 diabetes four months ago, weighed 74 pounds at diagnosis and gained 17 pounds in five weeks. His blood sugars have been in the normal range, and his A1c is 6.7%, but he has experienced light to heavy swelling in both legs and feet. Kidney, liver, and heart tests are normal. The only change in diet is a larger consumption of peanut butter and jelly and a stark reduction in sugar. Is juvenile rheumatoid arthritis a possibility? His endocrinologist says it can’t be that because of the swelling. Where can we go for additional tests?

While JRA perhaps is a consideration, given the autoimmune nature of that disorder and the autoimmune nature of type 1 diabetes, based on the history, I think that disorder is unlikely. JRA is less common in boys and is usually clearly a joint issue, rather than an extremity issue. It also often is associated with redness and pain of the joint, and fever.

It sounds as if there has been incredible “catch-up” weight for your son. Not uncommonly, recently diagnosed patients will experience a bit of fluid retention (edema), often in the face, but also in gravity-dependent areas (ankles, legs, lower back after sleeping) that is usually temporary. The mechanism is uncertain and perhaps relates to insulin directly. As long as the liver and kidney functions were normal, I would try to ride this one out.

DS