Rheumatoid Arthritis: An Overview of Risk Factors, Symptoms and Diagnosis

Rheumatoid arthritis causes inflammation, pain, and swelling of joints. Persistent inflammation over time can damage affected joints. The severity can vary from mild to severe. Treatments include disease-modifying medicines to suppress inflammation, which can prevent or delay the progression of the disease, and medication to ease pain. The earlier treatment is started, the less joint damage is likely to occur. Surgery is needed in some cases if a joint becomes badly damaged.

In this article:
An overview of rheumatoid arthritis
Risk factors for rheumatoid arthritis
Clinical features of rheumatoid arthritis
Diagnosis of rheumatoid arthritis
Treatment of rheumatoid arthritis
Natural disease course of rheumatoid arthritis
Where do I get more information about rheumatoid arthritis?

An overview of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory condition. The term rheumatoid arthritis is based on the Greek for watery and inflamed joints. RA can affect many different parts of the body, but most commonly affects the joints. The cause of RA is unknown. It is different from osteoarthritis (OA), which is the most common form of arthritis; OA occurs when the cartilage protecting the joints wears down over time. See the separate article, Osteoarthritis: Risk Factors, Symptoms, Diagnosis and Natural Course for more information.

In people with RA, symptoms develop gradually. Many people have symptoms that are present continuously, some have symptoms that completely resolve, and others have alternating periods of bothersome symptoms and complete resolution. The onset, severity, and specific symptoms of this condition can vary greatly from person to person.

RA was affecting about 24.5 million people as of 2015. This is between 0.5 and 1% of adults in the developed world with 5 and 50 per 100,000 people newly developing the condition each year. RA affects about 1 percent of people in the United States and northern Europe. Onset is most frequent during middle age and women are affected 2.5 times as frequently as men. It resulted in 38,000 deaths in 2013, up from 28,000 deaths in 1990.

This article discusses the risk factors, symptoms, and diagnosis of rheumatoid arthritis. See the separate articles, Rheumatoid arthritis treatment, and also Complementary and alternative therapies for rheumatoid arthritis, for more information.

Risk factors for rheumatoid arthritis

The specific cause of rheumatoid arthritis (RA) is not known. Researchers, however, suspect that two types of factors affect a person's risk: susceptibility factors and initiating factors.

Susceptibility factors — RA most likely occurs when a susceptible person is exposed to factors that start the inflammatory process. Factors that increase a person's susceptibility include:

• Older age – RA typically occurs in people who are middle-aged or older.
• Female sex – Women are about twice as likely as men to develop RA.
• Genetics – People who have a relative with RA have an increased risk of getting it themselves. This is because certain genes affect the likelihood of developing the disease.

Initiating factors — Many people with the above susceptibility factors never develop RA. Several other things appear to increase the chances that a susceptible person will eventually get the disease, including:

• Infection – Researchers suspect that alterations of bacteria in the gut or mouth may be among the factors that initiate RA. There is accumulating evidence that periodontitis (infection of the gums) is also a risk factor.
• Cigarette smoking – Smoking is a recognized factor that increases the risk of developing RA.
• Stress – People often report episodes of emotional stress or trauma (such as divorce, accidents, or grief) during the months preceding the onset of their RA.

Clinical features of rheumatoid arthritis

In most cases, symptoms come on gradually, and weeks or months may pass before becoming bothersome enough to cause a person to seek medical care. Early symptoms may include fatigue, muscle pain, a low-grade fever, weight loss, and numbness and tingling in the hands. In some cases, these symptoms occur before joint pain or stiffness is noticeable.

Pattern of joints affected — Rheumatoid arthritis (RA) usually affects the same joints on both sides of the body; this is often described as "symmetrical arthritis."

In the early stages, small joints are typically affected, especially the joints at the base of the fingers, the middle of the fingers, and the base of the toes. It may also begin in a single, large joint, such as the knee or shoulder, or it may move from one joint to another.

As the condition progresses, most people eventually have inflammation of the joints in the arms or legs. Some people have inflammation of the hips and in the spine, especially the neck.

Joint symptoms — Joint-related symptoms typically include stiffness, pain, redness, warmth to the touch, and swelling. Joint stiffness is most bothersome in the morning and after being still for a period of time. The stiffness can persist for more than one hour.

Joints that may be affected include:

• Hands – The joints of the hands are often the very first joints affected by RA. These joints are tender when squeezed, and the hand's grip strength is often reduced. Occasionally, visible redness and swelling can affect the entire hand.
  
  In 1 to 5 percent of people with RA, swelling compresses a nerve that runs through the wrist, leading to a condition called carpal tunnel syndrome. This causes weakness, tingling, and numbness in the hand and fingers.
  
  Certain characteristic hand deformities can occur over time in people with RA. The fingers may appear bent, called "boutonniere" or "swan neck" deformities (see image below), or point toward the direction of the little finger. The tendons on the back of the hand may become very prominent and tight; this is called the "bowstring sign."
  
  

  

  Swan neck deformity in a 65-year old patient with rheumatoid arthritis.
  Credit: Phoenix119 / CC BY-SA

• Wrist – In the early stages of RA, it may become difficult to bend the wrist backward.
• Elbow – Swelling in elbow may compress nerves that travel through the arm and cause numbness or tingling in the fingers.
• Shoulder – The shoulder may be inflamed in the later stages of RA, causing pain and limited motion.
• Foot – The joints of the feet are often affected in the early stages of disease, especially the joints at the base of the toes. Tenderness at these joints may cause a person to stand and walk with their weight on the heels, with the toes bent upward. The top of the foot may be swollen and red, and, occasionally, the heel may be painful.
• Ankle – Inflammation of the ankle may cause nerve damage, leading to numbness and tingling in the foot.
• Knee – Swelling of the knee can lead to difficulty bending the knee, loosening of the ligaments that surround and support the knee, and damage to the ends of the bones that meet at the knee. RA may also cause the formation of a "Baker's cyst" (a fluid-filled cyst in the hollow space at the back of the knee).
• Hips – The hips may become inflamed in the later stages of RA. Hip pain can make it difficult to walk.
• Neck – RA may cause inflammation of the neck (cervical spine). Inflammation of the cervical spine can cause a painful and stiff neck and make it difficult to bend the neck and turn the head. If you need to have surgery for any reason, your healthcare provider may get X-rays of your neck in order to decide whether any precautions are needed to protect the area.
• Cricoarytenoid joint – About 30 percent of people with RA have inflammation of a joint near the windpipe called the cricoarytenoid joint. Inflammation of this joint can cause hoarseness and difficulty breathing.

Other symptoms — Although joint problems are the most common symptoms of RA, the condition can also be associated with a variety of other problems. These can be related to inflammation in the body, a side effect of medications used to treated the disease (eg, steroids), or a combination of factors:

• Bone loss – Many people with RA have a decrease in bone density.
• Muscle weakness – This is also a common symptom. It can affect muscles around the joints (for example, inflammation in the knee can lead to weakness of the thigh muscle, which in turn further stresses the joint) or be more widespread.
• Skin problems – The most common of these are rheumatoid nodules, which are painless lumps that appear beneath the skin. These nodules may move easily when touched, or they may be fixed to deeper tissues. They most often occur on the underside of the forearm and on the elbow, but they can also occur on other pressure points, including the back of the head, the base of the spine, the Achilles tendon, and the tendons of the hand.
• Eye problems – Eye inflammation can cause redness, pain, and vision problems.
• Lung disease – Inflammation of the lung may cause shortness of breath and a dry cough. See the separate articles, Breathlessness and Difficulty Breathing, and also Cough: Types, Causes, Treatment and Prognosis, for more information.
• Pericarditis – This is the term for inflammation of the tissue lining the chest cavity and surrounding the heart; it can cause chest pain and difficulty breathing.
• Vasculitis (inflammation of the blood vessels) – This can cause a wide variety of symptoms, depending upon where the inflamed blood vessels are located.
• Sjögren's syndrome – This is a condition that causes dry eyes and dry mouth.

Diagnosis of rheumatoid arthritis

There is no single test used to diagnose rheumatoid arthritis (RA). Instead, the diagnosis is based upon multiple factors including a person's medical history, physical examination, and results of blood and imaging tests.

Typically, RA is diagnosed when a person has the following (and in whom other potential causes have been ruled out):

• Signs of inflammation in three or more joints, lasting for six weeks or longer
• The presence of specific proteins in the blood (rheumatoid factor and/or anti-citrullinated peptide/protein antibody)
• Elevated blood levels of C-reactive protein or CRP (a marker that suggests inflammation in the body) or the erythrocyte sedimentation rate or ESR (a test that measures how quickly red blood cells settle to the bottom of a test tube containing a blood sample)

In some cases, it may be necessary to monitor a person's condition over time before a diagnosis of RA can be made with certainty.

While X-rays are often done to exclude other conditions, and to monitor disease progression in people with confirmed RA, they are usually not necessary to make the initial diagnosis.

Treatment of rheumatoid arthritis

The goals of treatment in people with rheumatoid arthritis (RA) are controlling symptoms, minimizing joint damage, and improving quality of life. The earlier the disease is recognized, and treatment commenced, the less the amount of damage done to the joints and other affected parts of the body. Treatment is discussed in more detail separately.

Please see the separate article, Rheumatoid arthritis treatment, for more details.

Natural disease course of rheumatoid arthritis

The course of rheumatoid arthritis (RA) varies from person to person. While some people have periods of worsening symptoms that alternate with periods of remission, most people experience progressive disease (although it may progress slowly or quickly).

The inflammation of RA can potentially damage the bones, cartilage, and other structures of the joints. The joint damage typically worsens over time and is irreversible; this can have an impact on a person's ability to do their usual activities, and eventually lead to significant disability. Many people with RA also have other health conditions as well; this can affect quality of life as well as life expectancy.

Treatment with medications, especially when initiated early in the course of disease, is effective in reducing symptoms and slowing damage to joints; this improves quality of life for most people. Occasionally, disease may remit completely, although remission is rare in established disease without drug treatment. See the separate article, Rheumatoid arthritis treatment, and also Disease-modifying antirheumatic drugs (DMARDs) in rheumatoid arthritis.

Where do I get more information about rheumatoid arthritis?

Your health care provider is always the best source of information for the questions and concerns you may have concerning your medical problem.

Treatment of rheumatoid arthritis »

Reference(s)
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2). Smolen JS, Aletaha D, McInnes IB (October 2016). "Rheumatoid arthritis" (PDF). Lancet. 388 (10055): 2023–2038. doi:10.1016/S0140-6736(16)30173-8. PMID 27156434. S2CID 37973054
3). PJW Venables. Patient education: Rheumatoid arthritis symptoms and diagnosis (Beyond the Basics) UpToDate. Feb 2020