ABSTRACT
DIFFERENTIAL DIAGNOSIS Rheumatoid Arthritis Rheumatoid arthritis is an autoimmune disease that causes a chronic symmetrical polyarthritis. It is considered a systemic disease but in the early stages it is restricted to articular involvement, with the systemic extra-articular manifestations not developing until late. It affects 1-3% of the population with peak age of onset at 35-45 years and females being affected three times more than their male counterparts. Symptoms include pain and stiffness following periods of inactivity. There is usually morning stiffness which improves as the day draws on. On examination, there may be swelling and tenderness at the MCP and PIP joints. Symmetrical involvement of both hands is common. Hand deformities, which manifest later as the disease progresses, include boutonniere deformity (PIP fl exion and DIP hyperextension), swan-neck deformity (fl exion contracture of MCP with PIP hyperextension and DIP fl exion), ulnar/lateral deviation of fi ngers and MCP and wrist subluxation. If these deformities become fi xed then the patient may need assistance with daily activities involving fi ne fi nger movements e.g. washing, dressing and feeding. Other less common hand features include nail fold infarcts, palmar erythema and carpal tunnel or other compression syndromes.
