Rheumatoid arthritis (RA) - Affects joints and is the most common inflammatory arthritis

What is RA?

Joints become warm, swollen, painful and stiff.   Usually worse early morning after waking and also following prolonged activity. RA can cause weakness, fatigue, loss of appetite, muscle pain, and weight loss.

Usually affects hands, but can affect most joints.   Eventually affecting multiple joints: small joints in wrists, fingers (usually middle joints and where fingers attach to hand),  feet and cervical spine, but also larger shoulder and knee joints;

RA can also occur systemically.    E.g manifesting as spleen enlargement, blood vessel inflammation (vasculitis), heart / lung inflammation, muscle wasting, skin nodules, low white blood cell count.

Tends to affect the same joints on both left and right sides of body (i.e. symmetrically)

Affects 1 out of 100 people worldwide.  Women 3x more than men, typical onset 40-60 years of age (although not a normal part of aging).

Caused by a pathogenic bacteria or a dietary substance that may have "escaped" from the gut  that has been deposited in the affected joint.   This can be a bacteria, virus or dietary antinutrient, such as lectins, found in wheat, peanuts and other grains and legumes.

RA Causes

At least 50% Increased risk of RA with repetitive movement.   According to research involving self-reporting of 3680 RA patients and 5935 controls; this was especially evident in the construction industry with manual work above the shoulder level or below the knee level.

Pingling Zeng et al, Physical workload is associated with increased risk of rheumatoid arthritis: results from a Swedish population, BMJ Vol 3, Issue 1

What is happening in the body?

RA is an autoimmune disease.   i.e. the body loses the ability to discriminate self proteins from non-self proteins, which ultimately results in the destruction of self tissues by the immune system. The synovial membrane (synovium) is a layer of cells that lines the joints and produces synovial fluid, a clear fluid that nourishes and lubricates the bone and cartilage in the joint.  Cartilage is an elastic connective tissue covering the ends of bones to cushion and protect the bone from getting damaged during movement.

 RA begins when infection-fighting white blood cells (WBCs) of the immune system (IS) accumulate in the synovial tissue, most likely in response to dietary or pathogenic antigens that have been deposited there (probably having "escaped" from a damaged/ "leaky" gut). Your body can confuse these "invaders" with your own tissue (in a process called molecular mimicry), and cause damage to your body tissue. Proinflammatory cytokines produced by the WBCs and IS acute phase proteins can cause inflammation (such proteins include interferons (IFNs), interleukins (ILs) IL-1, IL-6, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP)), and other immune cells attending the "party" can cause over-production of synovial fluid. Inflammation can spread to the entire joint and destroy cartilage.

Diagnosis

C-reactive protein (CRP) is a marker for tissue damage / inflammation.   CRP is a blood protein mainly produced in the liver, which increases dramatically during the acute phase inflammatory response. Even CRP>1mg/dL is high, but most inflammation results in CRP >10.