How does the diurnal variation in joint pain aid in diagnosis?
Stiffness and pain on range of motion (ROM) immediately upon arising in the morning (morning stiffness) and after periods of inactivity (“gelling”) are classic findings for the inflammatory arthritides. Morning stiffness will be relieved by heat and ROM exercises. The duration of morning stiffness is an excellent gauge of the severity of the arthritis and the efficacy of therapy. In contrast, mechanical joint pain will worsen over the course of the day and with activity. Finally, nighttime pain and/or awakening with pain are red flags for neoplasia or, on a less serious note, for “growing pains.”