Which type of arthritis do I have?
There are many types of arthritis. For The UK, Europe and N America the commonest are described here. Arthritis means ‘inflammation’ or ‘disease’ of joints. The commonest type of arthritis is osteoarthritis. The prevalence of this broadly correlates with age, and simply, we all would get it, in virtually all our joints, if we lived long enough. This would be the mechanical form of osteoarthritis (OA), made worse by factors which accelerate cartilage and bone damage (e.g. obesity/excess weight or previous damage to the internal joint structures). A generalised form of OA, influenced by genetics, can evolve typically in the small hand joints any time after the age of 40y. This type of arthritis – very much an inflammatory arthritis in its initial stages – needs to be discriminated from rheumatoid arthritis (about 1% of the population get this type) and Calcium Pyrophosphate (CPP) Crystal induced arthritis (the latter often affects wrists and both the index and middle finger knuckle joints). Rheumatoid arthritis is associated with high levels of inflammatory markers in the blood (CRP, ESR) and positive autoantibodies (anti-CCP, rheumatoid factor). A third common arthritis type is Psoriatic Arthritis (PsA). This type of arthritis is highly variable in how it occurs, not always present at the same time as the skin rash psoriasis, and is often associated with nail changes, bowel disturbance (‘IBS’ a bit like celiac disease) and runs in families. Psoriatic arthritis is broadly considered one of the Spondyloarthritis (SpA) conditions (axial SpA, PsA, inflammatory bowel disease related SpA, Reactive SpA) – so about 1-2% of the population. SpAs are all associated with inflammatory back, enthesitis (see next blog!) and posterior pelvis (buttock / posterior thigh) symptoms (with stiffness, worse at rest, eases with movement). Both PsA, and the SpAs generally, are not always associated with abnormal blood tests and people with pains from PsA or SpA can often be dismissed (by the unwary) if blood tests are normal and may be wrongly told… ’you have fibromyalgia…’. The final common type of arthritis is gout. In men this mainly appears as a sudden very painful red swollen joint (or limb extremity) but in women often occurs less acutely as multiple joint pains together – in fingers and toes. Gout is associated with, but not defined by, a high blood uric acid. Proper diagnosis requires examination of joint fluid or specific signs on imaging the joint.