Dr Clare Price looks at the causes and treatment of arthritis, differentiating between the two most common forms of the condition seen in primary care – osteoarthritis and rheumatoid arthritis
What is arthritis?
Arthritis means ‘inflammation of the joints’ and can be broadly divided into two main types, both of which are frequently seen in primary care. It’s important to differentiate between the two types as they are managed entirely differently.
How do joints work?
A healthy joint consists of two bony surfaces which are held together by support structures (muscles, tendons and ligaments) with a layer of ‘cushioning’ between them. This cushioning is made up of cartilage, which lines the bony surfaces, and sacs of fluid – a combination which allows the bones to move smoothly past each other giving us a wide range of movement in different joints.
Osteoarthritis is the commonest form of arthritis and will affect most adults, to some degree, as they get older. It is the result of ‘wear and tear’ and the body’s attempts to repair that damage. Typically, it affects the weight-bearing joints, such as hips, knees and spine, although it can affect any joint which is frequently used because, with use, the cartilage can be gradually worn away, reducing the cushioning space between the bones.
When bony surfaces lie too close to each other they can be damaged – causing pain, stiffness, inflammation and swelling of the fluid sacs. The symptoms are, typically, worse at the end of the day and, in severe cases, can impact hugely on a patient’s mobility. Osteoarthritis is usually a clinical diagnosis in the early stages and X-ray imaging may be used in more severe cases to understand the degree of damage.
How is osteoarthritis treated?
Osteoarthritis cannot be reversed but its progression can be slowed. Treatment is aimed at reducing the stress on the joint and managing pain; conservative measures include weight loss, gentle exercise and physiotherapy, all of which strengthen the support structures of the joint, reducing the contact between the bony surfaces. Painkillers are given to relieve symptoms and facilitate movement which, in turn, reduces stiffness and improves mobility. Steroid injections are sometimes used to reduce inflammation within the joint. As the disease progresses it is sometimes impossible to control symptoms with these simple measures – joint replacement is the definitive ‘cure’ for osteoarthritis.
Rheumatoid arthritis is the second most common form of arthritis. It is an autoimmune condition in which the body mistakenly attacks the cells that line the joint, causing inflammation and pain. It’s more common in the small joints, such as the hands and feet, and is usually symmetrical. It’s essential to diagnose rheumatoid arthritis early as, if left untreated, it can result in severe joint damage with deformity and loss of function. Joints affected by rheumatoid arthritis are often hot, red, stiff and swollen and symptoms are worse in the morning, with function improving over the course of the day. It is a condition that ‘flares and settles’ and treatment aims to reduce flares.
Rheumatoid arthritis is definitively diagnosed with blood tests for autoimmune markers in conjunction with XR/MRI imaging which will reveal erosion of the bony surfaces. If rheumatoid arthritis is suspected or diagnosed in primary care the patient should be urgently referred to a rheumatologist for specialist treatment, which must be started expediently.
How is rheumatoid arthritis treated?
In the initial stages rheumatoid arthritis is treated with anti-inflammatory medications; whilst these offer symptomatic relief, they do not control the underlying disease process. Other conservative measures include physiotherapy and occupational therapy and patients should be managed by a multidisciplinary team within secondary care. Most patients will be need steroids to control flares and settle inflammation.
In the longer term patients are often started on DMARDs (disease-modifying anti-rheumatic drugs) such as methotrexate, sulfasalazine or hydroxychloroquine. These drugs can only be initiated by a hospital specialist and require regular blood tests to ensure there is no damage to the liver or kidneys. Often, these medications are used under a ‘shared care protocol’ such that responsibility for initiation lies with secondary care but monitoring and longer term prescribing falls within the remit of the patient’s GP. Biological agents – drugs which modulate the autoimmune process – are a newer development and are used in patients whose disease is resistant to DMARDs.