Managing the Pain of Rheumatoid Arthritis

Professor Philip Conaghan, Professor of Musculoskeletal Medicine, University of Leeds & Leeds Teaching Hospitals Trust, Leeds UK
Original article: 08/04/2004
Reviewed: 27/02/2009
Next review due: 27/02/2011 
 

Pain is an extremely personal experience. While this review will try to explain some simple mechanisms for pain and the current treatments for pain in rheumatoid arthritis (RA) patients, such an overview represents a view based on an understanding of the evidence-based literature on current RA therapies and an individual rheumatologist’s experience - it cannot fully explain every individual patient’s pain problems. All pain that is present for a reasonable length of time, no matter what the underlying cause, can be associated with poor sleep patterns and depressed mood. The stress associated with RA-related job loss or relationship problems all impact on how we cope with pain. Mechanistically, pain involves not only the nerves at the site of pain but the nerve pathways leading to the brain and special pain pathways within the brain itself. Very simply, pain is a complex phenomenon.

Why do people with rheumatoid arthritis get pain?

If you are reading this article then you probably already know a little about RA and that it is a chronic inflammatory disease. The disease process seems to start in the joint lining tissue (called the synovium) and this tissue becomes very inflamed – this is termed synovitis. It is widely assumed that synovitis, together with all the inflammatory chemicals and inflammation of local nerve fibres, is the cause of pain in RA. It is most important though to realise that sufferers of RA will have often have pain for a number of co-existing reasons. It is therefore helpful for an individual to learn something about what is causing their individual pain.

Early on in the disease process much of the pain probably arises from RA synovitis. The simplest evidence suggesting that treatment of inflammation relieves pain is seen in the experience of many patients who have had a corticosteroid injection into an inflamed joint, with subsequent quick-onset relief of pain.

However some other important factors cause pain in a lot of RA patients. After having RA for even a few months, sufferers will have a lot of muscle wasting: in the forearms (eg trouble opening jars) if they have arthritis in their hand joints, or in the thighs (eg trouble getting out of chairs) if they have a lot of knee problems. These weak muscles mean excess strain is taken through not only the affected painful joint but also through adjacent joints because of abnormal use of the whole arm or leg

As well, with even the best of modern therapies, prolonged inflammation in individual joints will lead to some joint damage and a process of osteoarthritis (called secondary osteoarthritis because it happens as a result of the RA). Osteoarthritis refers to the process of permanent cartilage and adjacent bone damage, usually associated with ageing and injured joints; the mechanisms of pain in osteoarthritis are probably different from those of RA pain.

So in summary, after a variable length of time but certainly after a few years, most patients with RA will have pain relating to any or all of:

• Active inflammation in a joint (synovitis)
• Mechanical joint pain due to muscle weakness, and
• Secondary osteoarthritis.

This is why it is unusual to find that just one therapy is completely effective at relieving any one person’s pain. It is also important to realise that the cause of pain may differ between joints within an individual patient.

How do we tell what is the cause of joint pain in an RA patient?

When a rheumatologist sees a patient with RA and pain is their primary complaint, the first step is often to assess how active the synovitis or inflammation component of disease is, since treatment of this is important not only to prevent pain but also to prevent further joint damage. Inflammation is often associated with prolonged morning stiffness, whereas an osteoarthritic joint will be painful and stiff for only a few minutes on waking and then get worse with usage over the day.

The rheumatologist will also assess the degree of inflammation by measures such as the number of tender and swollen joints and blood tests that indicate general inflammation levels (called the erythrocyte sedimentation rate or ESR and the C-reactive protein or CRP).

It is often difficult in patients with long-standing disease to determine whether persistent RA synovitis or osteoarthritis is the problem in any one joint, and this may be especially difficult in large joints such as the knee. As stated above, often more than one problem is present.

What can be done for RA pain?

It should be stressed that adequate suppression of inflammation is the usual first step in managing RA pain. However, since the pain in RA may have multiple causes, a combination of treatments is often required. Most patients who have RA will be familiar with many of the treatments listed below:

A. Non-drug therapy of pain

Resting inflamed joints is a well-tried method for assisting in pain relief and the use of splints on the wrist is a commonly used tool to reduce pain in that site. The use of a walking stick helps take weight off an affected knee or hip joint. The use of thick, cushioned-soled shoes and arch-supports can help foot pain, or even getting shoes that fit a rheumatoid-damaged foot!

Strong muscles take weight off painful joints. Simple forearm exercises may help reduce hand pain whereas straight leg raising (quadriceps) exercises will help reduce knee pain. Some patients with RA will of course find it difficult to exercise because of the malaise and lethargy resulting from the inflammatory chemicals produced by their inflamed joints. However for many patients, gentle exercise will be beneficial; for example, walking laps in a swimming pool allows for muscle strengthening while reducing load through an inflamed or damaged joint.

If joint damage is severe then sometimes the only therapy that will help relieve pain significantly is to surgically replace the joint. Joint replacement is successful treatment for severe arthritis involving the knee and hip, but can also sometimes be used in the shoulder and small joints of the hand.

B. Drug therapy of RA pain

The usual drugs used for treating the inflammation of RA are non-steroidal anti-inflammatory drugs (NSAIDs), disease modifying drugs (such as methotrexate or sulphasalazine and more recently the biologics including those called anti-TNF therapies) and corticosteroids (which may be used orally as prednisolone or via joint injections).

Most studies of RA focus on anti-inflammation therapies, and in large studies it is not always practical to work out how much of an individual’s pain is due to mechanical factors. The evidence for treating the mechanical causes of joint pain is essentially that derived from osteoarthritis studies, and there are few such long-term studies.

It is uncommon to find one drug that relieves all arthritis pain for any one person. The pharmacological agents commonly used to treat musculoskeletal pain, including that associated with RA, are:

Paracetamol

This is the commonest drug used for joint pains. It is generally safe in doses up to 4 grams daily. Very high doses or use together with heavy alcohol intake can lead to liver damage.

NSAIDs

These agents may be used orally or as topical preparations and act not only as anti-inflammatory agents but also as analgesics. They have typical quick onset of action, need to be taken at least once a day and their analgesic effect lasts for a number of hours, depending on the particular drug used. The major side effects of NSAIDs include dyspepsia (upper abdominal burning or bloating sensation, often described as indigestion) and very uncommonly stomach ulcers and bleeding. A new class of NSAIDs called COX-2 selective drugs (sometimes referred to as coxibs) were developed and may have fewer serious stomach side effects. As well, your doctor can prescribe another drug with the NSAID (called a proton pump inhibitor or PPI) that may reduce stomach problems. All NSAIDs and COX-2 drugs may cause aggravation of blood pressure and ankle swelling (by causing fluid retention) and importantly they may increase risk of angina and stroke, so they should not be used in people with (or at high risk of) heart problems or stroke.

Opioid analgesics

Codeine-containing drugs (known as weak opioids – examples include paracetamol/codeine combinations, dihydrocodeine and tramadol) are the commonest used in this category but stronger painkillers, (eg buprenorphine and fentanyl in topical patches) have been used in patients with moderate to severe musculoskeletal pain. Unlike paracetamol and NSAIDs, which work in the joints themselves, opiate-derived drugs seem to work in the central nervous system. The term “opiates” is often associated with fears of addiction. However the vast majority of patients using such drugs for chronic pain never become addicted. Doses of these drugs are usually increased slowly to get a balance between pain reduction and unwanted side-effects. The common side-effects of this class of drugs are constipation, nausea and drowsiness. High fibre diet and laxatives may be useful if the drugs are helping pain but causing constipation and some opioids are less constipating than others. Drowsiness may be helpful if the drugs are used at night in people with sleep disturbance due to pain, but care must be taken during daytime activities such as driving (if you are on stronger analgesics you should check with your doctor to see if the drug is licensed for people who want to drive).

Combinations of the above drugs may be useful in many patients since the drugs work in different ways. It is common for patients with chronic arthritis pain to be using both a NSAID and paracetamol or NSAID and paracetamol/codeine combination tablets.

Certain antidepressants may help pain, not only through analgesic effect but also through positive effects on sleep and mood.

When is the best time of day to take my painkillers?

It is worth thinking about what type of analgesic you are using and how long it works for. Paracetamol and many of the other analgesics listed above will have effects lasting a few hours and therefore require multiple daily dosing. If your worst symptoms are first thing in the morning, it may be worth trying drugs that last many hours (slow release or modified release preparations) and taking them before you go to bed. This can be discussed with your doctor.

Summary

Pain is complex and the causes of pain in RA may be due to inflammation and/or related mechanical factors. Hopefully this article has provided some information on the cause of RA joint pain and an understanding that inflammation control, analgesics and non-drug therapies are all important in helping reduce the burden of pain.

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