Final answer:
The nurse should advise the parents to encourage the child with juvenile idiopathic arthritis to do range-of-motion exercises regularly, but to be careful to stop if the exercise becomes too painful, ensuring only gentle movements are carried out within the comfort range.
Step-by-step explanation:
When a child with juvenile idiopathic arthritis (JIA) experiences a painful exacerbation, the nurse's advice should be informed by current treatment principles for inflammatory joint diseases. It is recognized that resting the affected joints during periods of significant inflammation is crucial to minimize further joint damage and reduce pain. However, maintaining range-of-motion exercises is also important to prevent stiffness and preserve joint function, though this should be done with caution and attention to the child's pain levels.
In light of these considerations, the nurse should advise that range-of-motion exercises be performed, but with respect to the child's pain thresholds. Hence, the correct response would be, "Encourage the child to do exercises regularly, but be mindful to stop if the exercise becomes too painful and concentrate on gentle movements within the comfort range." This encourages a balanced approach that promotes joint health without exacerbating pain during an active flare of JIA.