Autoimmune disorder affecting joints primarily, though can have systemic impact (i.e. kidneys, heart, lungs, skin, vascular system, GI, eyes, neurologic)

Subacute (>6w), persistent/progressive joint pain, stiffness, swelling
Often worse in AM (x ~1h) due to gelling → improves w/use
Tendency for polyarticular, bilateral involvement, commonly small and medium sized joints (hands, feet, ankles); sometimes atypical involvement, affecting knees/other large joints
At onset, symptoms can be vague and involve one or few joints
Nerve symptoms can be motor, sensory or from compression
SOB/DOE related to interstitial lung disease, nodules, pleural disease, pulmonary hypertension, or pericardial disease

Joint warmth, redness, spongy feeling from joint capsule inflammation (i.e. synovitis)
Pain w/squeezing of joints (hands)
Joint effusion sometimes
Joint deformity if longstanding, in particular MCPs, fingers (e.g. ulnar deviation, swan neck or boutonnierre deformities)
Extra articular findings: episcleritis, pleural/pericardial inflammation, rheumatoid nodules
Peripheral neuropathy related: decreased distal sensation, weakness, diminished reflexes

Diagnostic criteria RA: synovitis at least one joint & 6 or more points: a. Number/Site of involved joints: 2-10 large joints =1 point; 1-3 small joints = 2 points; 4-10 small joints = 3 points; >10 joints including 1 small joint = 5 points b. RF or CCP: low positive (above upper limit of normal, ULN) = 2 points; high positive (>3x ULN) = 3 points c. ESR or CRP elevated above ULN = 1 point d. Symptom duration: > 6 weeks = 1 point
+RF: Sensitivity 70%; 50% + at time of dx, rising to 60-80% over time; Specificity low, w/5-10% healthy patients +
+ ACPA: sensitivity 70-80%, specificity 95-97%
ANA + 1/3 w/RA
X-rays can be suggestive; US (dz activity) and MRI increasingly used

Rheumatoid Arthritis (RA)