There are two major types of arthritis: rheumatoid, which usually makes a first appearance between the ages of 25 and 50; and osteo-, or wear-and-tear arthritis, which tends to be a phenomenon of later life.
By no means every painful or swollen joint is due to arthritis, but in the absence of recent trauma to the joint or a family history of joint problems, a hot, swollen joint that is difficult to move could herald the onset of arthritis.
Arthritis can also be associated with other conditions, such as psoriasis or infection, but this review will focus on the two principal types.
Although rheumatoid arthritis (RA) can strike at any age, it is most common in the 40-60 age group. Estimated to affect up to two in every 100 people, it causes disability for about one in 10 of those who suffer from it. RA particularly affects the small joints of the hands, wrists and feet, but can also affect larger joints such as the knee, shoulder, ankle and neck. It is an autoimmune condition, which means the person’s own immune system has attacked the cells that line the affected joint. Over time, this can damage the joint itself, the cartilage and nearby bone. RA is three times more common in women than in men.
Osteoarthritis is the ‘wear-and-tear’ damage that joints experience as part of the ageing process. It tends to affect larger, weight-bearing joints such as the knees and hips. However, injury to a joint due to sports or accidental damage can bring the condition on earlier in life.
In someone with osteoarthritis, the covering at the ends of the bones, called the cartilage, gradually roughens and becomes thin. The bone underneath the cartilage reacts by growing thicker. All the tissues within the joint are more active than normal as the body tries to repair the damage; the bone at the edge of the joint grows outwards, forming bony spurs called osteophytes.
The synovial membrane may produce extra fluid, causing the joint to swell. The capsule and ligaments around the joint also thicken and contract.
CAUSES, SIGNS, SYMPTOMS AND DIAGNOSIS
The exact cause of rheumatoid arthritis is unknown. The condition may run in families; however even an identical twin of someone with RA has only a one in five chance of developing it, suggesting genes are only part of the story.
Because RA affects more women than men, a possible causative role for female hormones such as oestrogen has been suggested. But there is no strong evidence yet.
There is no evidence to suggest an infection can trigger RA. And no one knows why the immune system suddenly turns on the cells lining an affected joint.
Most people with RA will experience stiffness, particularly in the mornings, swelling and tenderness of the small joints. Tiredness is also a feature.
Your doctor will carry out a blood test to see if a specific antibody, known as the rheumatoid factor, is present in your blood. This antibody is present in eight out of 10 people with rheumatoid arthritis. However, it cannot always be detected in the early stages of the condition. The antibody is also found in one in 20 people who do not have rheumatoid arthritis, so this test cannot absolutely confirm rheumatoid arthritis.
X-rays of your joints will show characteristic changes depending on the type of arthritis you have.
So a diagnosis of RA is made by combining your symptoms, the clinical signs found by the doctor on examination and the results of various tests.
The main symptoms of osteoarthritis are pain and stiffness in the hips or knees. Typically, the knees may feel stiff at particular times such as first thing in the morning or after a period of rest. Pain may be felt around the joint or at the front and sides of the knee. It may be exacerbated by certain movements or activities, such as climbing stairs. The pain usually improves with rest. Osteoarthritis pain can vary from day to day.
In some people, osteoarthritis can develop earlier in life in a single joint. This joint may have suffered a significant sports injury or it may have been damaged years earlier in a road traffic accident, for example. But most cases are caused by the wear and tear of decades of use, although as this wear and tear will be exacerbated in those who are overweight, they may experience osteoarthritis some years earlier than their peers.
Blood tests do not help in the diagnosis of osteoarthritis. It is made primarily on the basis of your symptoms, your clinical signs and sometimes with the help of an x-ray.
PREVENTION AND TREATMENT
The best way of delaying the onset of osteoarthritis is to avoid being obese or overweight. Avoiding trauma to your joints from either sports or accidents earlier in life will also help.
The treatment for osteoarthritis includes a combination of lifestyle changes such as losing weight and exercising, as well as pain medication.
Exercise does not have to be too strenuous as even gentle yoga has been shown to result in improvements in controlling pain and fatigue, as well as enhancing joint mobility. Simple, non-opiate pain analgesia such as paracetemol or a non-steroidal anti-inflammatory drug works best. In some cases, steroids may be injected into the joint to provide pain relief.
Physiotherapy will provide exercises to condition muscles and improve flexibility and joint mobility. An occupational therapist will be able to advise on changes to routines and the environment to reduce the stresses put on joints during daily activities.
Surgery is an option when other treatments have failed: this may involve resurfacing the damaged joint surfaces, or replacement of the joint may be considered when joint pain and stiffness remain severe.
There is nothing you can do to prevent the onset of rheumatoid arthritis. Apart from the analgesics mentioned above, the main drugs used to treat RA are disease-modifying anti-rheumatic drugs (DMARDS) and biological treatments.
DMARDs help to ease symptoms and slow down the progression of rheumatoid arthritis. DMARDs work by blocking the effects of chemicals produced by antibodies attacking the tissue in the joints. The earlier you start taking a DMARD, the more effective it will be.
Methotrexate, a DMARD, is often the first drug given for rheumatoid arthritis. You will have regular blood tests to monitor the drug’s effect on your blood count and your liver. It may take four to six months for a drug like methotrexate to start working.
Biological treatments are a relatively new form of treatment for RA. They include TNF-alpha inhibitors (etanercept, infliximab, adalimumab and certolizumab), rituximab and tocilizumab.
They work by stopping particular chemicals in the blood from activating your immune system to attack the lining of your joints.
Side-effects from biological treatments include skin reactions at the site of injection, infections, nausea and headaches. If you have had TB or hepatitis B in the past, the biological agents may rarely reactivate these.
If you have a single inflamed joint, your doctor may inject a steroid directly into the joint.
Ask for a referral to a physiotherapist who will teach you exercises to do at home to prevent muscle weakness and maintain joint mobility. He or she will also advise on the correct use of heat and cold packs to help reduce inflammation and control pain.
You should also see an occupational therapist for an assessment of your current functional ability, and to get advice on a wide range of issues including joint-protection techniques, energy conservation, splinting and fatigue/pain management.
USEFUL RESOURCES
Arthritis Ireland provides information and support for people with arthritis. It can be contacted on 1890-252846 and www.arthritisireland.ie
Arthritus Foundation www.arthritis.org
Arthritus on Web MD www.webmd.com/arthritis
Dr Muiris Houston is a specialist in general practice and occupational medicine and a medical education consultant