Anyone experiencing joint pain that has been present for more than 6 weeks, associated with early morning stiffness lasting more than half an hour, or who has noticed that their joints are red, hot, or swollen should be screened for inflammatory arthritis.
Inflammation is the way in which the body fights infection, and usually occurs in tissues that have been exposed to infection such as the throat. It causes pain, heat, redness and swelling. This is a normal response, and as the infection resolves the inflammation goes away. Sometimes an inflammatory response occurs abnormally when there is no infection present and the inflammation can persist. When this occurs in the joint it is called an inflammatory arthritis and often many joints can be involved. Inflammation such as this can also occur in other organs in the body and these types of disease are usually called autoimmune diseases. They are associated with characteristic elevations of proteins in the blood called antibodies; the presence of inflammation can be detected by a blood test which measures elevations in a protein (CRP) or in lots of proteins (ESR.)
Currently, there are a number of treatments available to treat autoimmune inflammatory arthritis. These include pain killers (analgesics), steroids, disease modifying anti-rheumatic drugs (DMARD) such as methotrexate and sulfasalazine, and newer biological agents such as anti-TNF and rituximab. Biological agents are generally expensive but have been approved by the UK Regulatory Body, NICE, for the treatment of some patients with inflammatory disease such as rheumatoid arthritis that has not responded to DMARD. Biological agents and DMARDs affect the underlying disease process as opposed to merely reducing pain and prevent the long-term joint damage which can occur when joints are chronically inflamed. There is now good evidence that early treatment in inflammatory arthritis leads to a better long term outcome.
There are many causes of inflammatory arthritis and the commonest examples are listed below with their clinical features.
This is a symmetrical arthritis typically involving the knuckles, balls of the feet, wrists, shoulders, knees and ankles. In most people it starts slowly but in about 20% it develops very rapidly. The inflammation can also affect the tendons, particularly in the hands, which may rupture. Associated antibodies are Rheumatoid Factor and anti-CCP antibodies.
This is characterised by inflammation in the joints in people who also have a skin rash called psoriasis. Several patterns can occur and sometimes only 1 or 2 joints are involved (eg the ankle or knee), but often several joints are affected including fingers and toes. About one third of patients also have a painful, stiff back or neck caused by inflammation in the spine (spondylitis). Sometimes the arthritis can precede the development of the rash
This is characterised by inflammation in a joint which occurs following an infection; typically of the throat, gut, or genito-urinary system. The infection clears but leaves residual inflammation in the joint. The infection can precede the development of the joint problem by days or weeks. Often only 1 joint is involved but the problem can also affect many joints.
Systemic Lupus Erythematosus (SLE)
This is a systemic rheumatic disorder where inflammation affects areas other than the joints, such as the skin (causing a characteristic butterfly rash over the cheeks), the kidneys and lungs. Patients with lupus can also experience cold sensitivity of the extremities, usually the hands, with a typical colour change on exposure to cold (white to blue to red). This is called Raynaud ’s Phenomenon. SLE is associated with anti-bodies to DNA.
This is a systemic rheumatic disorder where inflammation affects the secretory glands, most frequently the salivary and lacrimal glands, causing dry eyes and dry mouth. Patients can also commonly develop joint pain, skin rashes and Raynauds’s phenomenon.