Osteoarthritis (OA) and Rheumatoid Arthritis (RA) are diseases commonly classified under Rheumatological disorders.

OA is the commonest form of arthritis, most commonly occurring in the middle aged and older adults with marked variability in disease expression. It was previously thought to be part of the normal process of ageing thereby leading them to degenerative joint disease, however, it has been now realized that it is an interplay of multiple factors. Common factors include age, sex, trauma and repetitive, small insults over time. RA is a chronic systemic inflammatory disease, characterised by a symmetrical deforming, peripheral polyarthritis of unknown aetiology with. Chief complaints are usually joint tenderness and functional limitations. The onset of the disease, sequence of joint involved, and disease progression varies in both diseases. The differences of both the diseases are illustrated in the table below:

Generally, as a rule of thumb, diagnosis for either of the diseases are made after a thorough history taking and physical examination followed by appropriate laboratory findings and imaging modalities. If you experience any of the said symptoms above, please visit your nearest clinic for evaluation. As of any medical conditions, early intervention is the key for better prognosis.

References:

Arthritis Foundation
UpToDate