1. Morning Stiffness
Definition and clinical significance
Morning stiffness is a subjective feeling of difficulty or reluctance in moving a joint after waking, usually occurring after a period of rest. It may be associated with pain, swelling, restriction of movement or a sensation of “gelling.” It is not a diagnosis by itself; its duration, distribution and associated findings help distinguish inflammatory, degenerative, traumatic and periarticular disorders.
The most useful clinical discriminator is the duration of stiffness. Prolonged stiffness, particularly lasting more than 30–60 minutes, suggests synovitis or another inflammatory process. Brief stiffness, generally lasting less than 30 minutes and improving rapidly with activity, is more typical of osteoarthritis, although this distinction is not absolute. Morning stiffness may also occur in endocrine, metabolic and periarticular conditions, and therefore must be interpreted with the complete history and examination.
Pathophysiological basis
During inactivity, synovial fluid is distributed less effectively and inflamed synovium becomes relatively congested. Inflammatory exudate, cytokines, synovial hypertrophy and accumulation of fluid within a joint produce pain and resistance to movement. In rheumatoid arthritis and other inflammatory arthritides, overnight persistence of inflammation causes pronounced early-morning stiffness. In osteoarthritis, stiffness is related mainly to cartilage loss, osteophytes, capsular contracture, altered joint mechanics…