Understanding Inflammatory Arthritis: An Introduction

Inflammatory arthritis is the name used to describe a group of diseases caused by an overactive immune system that results in inflammation. Many forms of these diseases manifest mainly with inflammation of the joints felt as joint pain and stiffness, but inflammatory arthritis can also affect other connective tissues, including the lungs, heart, eyes, skin and other organs. Importantly, when inflammation affects any part of the body it can result in damage which is irreversible.

Inflammation is a
reaction to an irritant,
causing redness,
swelling & pain.

In usual situations, the body responds to infection or the presence of a foreign substance, such as bacteria, a virus or fungus, by producing special cells called lymphocytes that kill and clean up harmful "invaders." Inflammation is normally a process that occurs when the body recruits those special cells and uses complex proteins ("cytokines and other chemical messengers") to do this job. The term inflammation comes from the Latin word inflammare, which means "to set on fire."

Signs and symptoms of inflammation include:

  • heat
  • swelling
  • tenderness
  • altered function of the affected area

In a healthy person, inflammation is a limited and ultimately helpful response to fight off a foreign substance. Once the infection or virus has been eliminated, inflammation and the swelling, heat and tenderness that come with it resolves. (For example, consider a minor infection of a cut or scrape, which is tender, pink and swollen, then resumes its normal appearance and sensation as the body fights the infection.)

In a person with inflammatory arthritis, the immune response has "gone wrong" and lacks the ability to self-regulate or stop, and the immune system turns on one’s self. This is the meaning of "auto-immunity". Different kinds of inflammatory arthritis reflect a set of "auto-immune" diseases where the body cannot distinguish between its own healthy cells and tissues (i.e. itself) and a foreign substance.

Autoimmunity means
the immune system has
turned on one’s self.

As a result, inflammation occurs where it is not "needed" and can intermittently and chronically affect the joint tissues of other organs such as the tendons, skin, eyes or even the heart and lungs. The prolonged tissue invasion of immune cells (such as lymphocytes or macrophages) - and the messenger and effector chemicals these cells produce - begins to damage the affected area(s), usually the joint structures. People who get inflammatory arthritis most frequently will experience pain, stiffness, and limited movement in one or more joints, and in some types of inflammatory arthritis, even the spine. Depending on the type of inflammatory arthritis present, they may also feel fatigue; they will usually have difficulty with functioning. As mentioned, all types of inflammatory arthritis can affect other organs and tissues.

Inflammatory arthritis can often be well controlled using medication and, when treated earlier, put into remission. Initially people with inflammatory arthritis can experience intermittent symptoms (flare-ups) of their condition, alternating with resolution, periods when they do not experience symptoms. However in most, the condition will eventually become chronic and ongoing medical care is needed.

Inflammatory arthritis is not the same disease as osteoarthritis, the type of arthritis many people associate with aging. (See the sidebar for more on these differences.)

Inflammatory Arthritis vs. Osteoarthritis

It’s important to realize the differences between these two types of arthritis. Osteoarthritis - which many people commonly refer to simply as arthritis - is a condition in which breakdown of the cartilage occurs in one or more joints resulting in pain as well as some stiffness and inflammation, but this does not occur as a result of the body’s altered immune response. While the cause of all osteoarthritis is not completely understood, it is generally associated with aging, "wear and tear", or in some cases with traumatic injury to the joint. Unlike inflammatory arthritis, osteoarthritis is limited to the joints including small joints in the spine. However, the limited mobility that is a consequence of osteoarthritis can have an impact on one’s general health. For instance if osteoarthritis affects the knees, and one cannot move about as easily, weight gain may occur, which in turn could impact risks for high blood pressure or diabetes.

Individuals diagnosed with osteoarthritis are treated by various specialists including physiatrists, sports medicine physicians, and physical therapists. When surgery is needed orthopedic surgeons will treat this condition. However most people with inflammatory arthritis should be seen by a rheumatologist, a physician who specializes in autoimmune disorders, and as needed, by other specialists who can address symptoms of the disease that affect specific organs or parts of the body other than the joints. It is possible that people who have had inflammatory arthritis for a long time will end up with enough joint destruction that orthopedic surgery is needed. This is more common in those who developed the disease years ago, before more effective treatment regimens to control inflammatory arthritis were available.

In many, but not all cases, people become aware that they have inflammatory arthritis when they develop symptoms of inflammation in one or more joints. On a simple level, joints are where two bones are attached. A joint can be fibrous and a simple connection without movement, such as joints in the pelvis. However, most joints are "ball and socket joints", which are covered with a smooth layer of specialized tissue called cartilage - allowing for a gliding motion; examples are the knees, elbows, shoulders, hips or elbows. Other structures that attach the bones to each other and to muscles include the tendons, tissue that attaches muscles to bones and the ligaments, tissues that attach bone to bone. These can also be targets of inflammation in inflammatory arthritis. Furthermore, the joints are held together by a capsule, a kind of protective container that is lined with a membrane called the synovium. In inflammatory arthritis inflammation of the synovium is what usually causes pain, stiffness and swelling. This is called "synovitis".

It’s also helpful to understand that not all joints are the same. They vary in shape and size, as well as the kind of movement they permit. For example, the knee, which is a hinge joint, allows movement in only one direction, bending and straightening. Hips and shoulders which are ball joints, allow for a greater range of motion. The wrist and mid-foot are complex joints with many bones and joints in one area.

Types of Inflammatory Arthritis

In order to make an accurate diagnosis, rheumatologists rely on a person’s history of his or her joint and other symptoms, a physical examination, blood tests and, where needed, imaging techniques. Imaging can include X-Rays, ultrasounds of joints or MRI exams if a better understanding of a patients’ disease is required. If damage is already seen in the joints, this indicates that the type of inflammatory arthritis that is present may be more aggressive with a higher risk for more damage. There are many types of inflammatory arthritis. However, the following conditions are the most common:

Rheumatoid Arthritis (RA): the most common form of inflammatory arthritis, tends to involve the small joints in the hands and feet and most often more than one joint is affected. The focus of inflammation is in the synovium (joint or tendon lining), which can become swollen, warm, painful, and stiff, and eventually becomes damaged when inflammation is prolonged. In 30-60% of patients with RA, blood tests such as rheumatoid factor (RF) or anti-cyclic citrullinated peptide antibodies (anti-CCP) are positive, helping to confirm the diagnosis. RA can be a very destructive and disfiguring form of arthritis. It is important to control the inflammation in the synovium to stop joint destruction. In RA, other organs and systems in the body may also be affected, including the heart, lungs and eyes.

rheumatoid arthritis in the hands rheumatoid arthritis in the hands

Spondyloarthropathies make up another group of types of inflammatory arthritis where inflammation of the ligaments attaching to vertebrae - the bones in the spine - is often prominent. Very typically inflammation of the ligaments occurs at the site of insertion into the bones. These types of arthritis can also affect joints throughout the spine, ligaments around the toes and fingers, and involve both large and small joints. In addition to affecting the peripheral joints and joints in the pelvis or in the spine, people with spondyloarthropathies can have other organ systems involved. For instance, they may also have inflammatory bowel disease which affects the colon and small intestine, causing pain and other gastrointestinal symptoms. There can be inflammation of the eyes, or involvement of the skin, a condition known as psoriasis.

Although patients with spondyloarthropathies can have features of all the subtypes, they are typically named according to the predominant pattern of arthritis, and other organs involved. These include:

  • Psoriatic arthritis: a form of inflammatory arthritis that occurs with psoriasis, a skin condition that shows up as a red scaly, sometime itchy rash that typically occurs over the knees, elbows and scalp, but can occur anywhere on the body including the inside of the ears, groins and buttock creases. It can also cause changes to the nail itself.
    psoriatic arthritis psoriatic arthritis

The disease can affect large joints as well as the distal small joints in the hands or feet, and may cause complete swelling of a finger or toe, a condition that is also called dactylitis. (A diagnosis of psoriasis refers only to the skin disease.) People with psoriatic arthritis can also have spinal inflammation.

psoriatic arthritis hand
  • Reactive Arthritis: inflammatory arthritis that occurs after contracting an infection such as diarrheal illnesses caused by certain bacteria, some of which are related to food poisoning, or from a sexually transmitted infection such as Chlamydia. Reactive arthritis is the least common of the spondyloarthropathies and can disappear completely within 12 months. This is different from (and does not include) Lyme disease.
  • Ankylosing Spondylitis (AS): This form of inflammatory arthritis primarily affects the spine and pelvic joints, sternum (the breast bone), and large joints in the body. Over time, inflammation can result in noticeably reduced motion in the spine.
  • Sacroiliitis: Rheumatologists will often take an image of the posterior pelvic joints also known as the sacroiliac joints. Inflammation of the joints is called "sacroiliitis". People who have had this for many years will have abnormal sacroiliac joints on specific X-Rays of these joints. If findings cannot be seen by X-Ray, physicians may obtain an MRI to confirm if sacroiliitis is present. About one third to one half of people with AS have a gene called an HLAB27, the presence of which can help to diagnose this condition. However up to 10% of the total population have this gene so having the gene without the symptom of inflammatory back pain is not meaningful and does not necessarily mean AS is present or will develop.
  • Gout: this form of inflammatory arthritis results from an excess of uric acid (a chemical that is created as the body breaks down certain substances in food called purines) in the blood. In people with gout, uric acid crystallizes in the joints causing painful attacks in the affected body part - often, initially, a big toe. Other joints that may be affected include the ankle, foot or knees, and in severe cases, the wrists, elbows and fingers. In gout, as in CPPD (see below), as white blood cells envelop the crystals, chemicals are released that prompt the inflammatory process. Uric acid can also crystallize as kidney stones and can damage the kidneys. People suffering from attacks of gout often need lifelong medications to prevent excess uric acid formation.
    gout hands
  • CPPD (calcium pyrophosphate dehydrate deposition disease): is another form of crystal-induced arthritis. CPPD occurs when calcium salts form in the joints and are engulfed by white blood cells, prompting an inflammatory response. The most commonly affected joints are the wrists and knees.
  • Polymyalgia Rheumatica (PMR): this form of inflammatory arthritis causes pain and stiffness in multiple parts of the body. The word polymyalgia refers to the effect of the disease on several (poly) muscle groups and joint areas (-algia meaning pain.). Typically the shoulder areas, low back, thighs and hips are involved; sometimes other joints are also inflamed, such as the wrist or knee. The onset can be slow or sudden and is particularly associated with marked stiffness in the morning that makes it very difficult for patients to function. A doctor will diagnose this condition based on the patient’s history and a physical examination, as well as by testing blood for markers of inflammation such at the erythrocyte sedimentation rate (ESR) or C-Reactive Protein (CRP), which are typically high in this condition. PMR usually occurs in people over the age of 50, and more frequently in those between the ages of 70 and 90. PMR is thought to affect blood vessels. Consequently, up to 15% of people who develop the condition also have temporal arteritis (TA), a condition in which the temporal artery (the artery at the temple) becomes inflamed and painful. Temporal pain may be experienced as a headache, scalp tenderness, jaw, tongue or arm pain.
    Inflammatory arthritis can
    affect people at any age,
    even children.
  • Juvenile Inflammatory Arthritis (JIA): is inflammatory arthritis that affects young people under the age of 16. Most forms of inflammatory arthritis seen in adults can start in childhood or adolescence although the onset and manifestations may be slightly different in younger patients. Similar treatment approaches are used. However, children and adolescents can have forms of inflammatory arthritis that are unique. As in adults, JIA causes inflammation in the joints or sometimes in the spine and ligaments. When the joints are involved, swelling or problems with mobility may be the only signs of this disorder. For example, in a young child, the first signs of this condition may be a limp. Because young people are still growing, joint damage that may inhibit growth is a particular concern. JIA may be associated with other complications. Most concerning is eye inflammation because it is not easy to detect, can often occur without symptoms, and can cause blindness. Children with JIA may be affected for a finite period of a few months or for a lifetime. It is important that children and adolescents with JIA be assessed by a pediatric rheumatologist.

Rheumatologists and researchers have identified additional forms of inflammatory arthritis; however, many are rare. These forms are considered when the clinical information (patient history, tests and images) do not confirm one of the more common types of the disease.

Although the categories presented above are helpful to describe inflammatory arthritis and capture the most common forms, many people with inflammatory arthritis actually have mixed diagnoses (that is, more than one condition) and many different of symptoms. For example, some patients with RA can also have Sjogren’s syndrome, an autoimmune disease of moisture-producing glands, such as the salivary glands and tear glands. In addition, a person may be diagnosed with a single type of inflammatory arthritis and then, over time, develop other forms of the disease. For instance, patients with ankylosing spondylitis may develop features of psoriatic arthritis or eye inflammation. Treatment should therefore be customized to the patient’s specific needs at any given time. This means that a person with Inflammatory Arthritis needs to follow up with a rheumatologist on a regular basis and may need to see more than one type of doctor on a regular basis in order to keep symptoms in check and maintain a good quality of life.

Treatments for Inflammatory Arthritis

Although presently there is no cure for Inflammatory Arthritis, doctors and other healthcare providers can make lifestyle recommendations and prescribe medication that aim to control the inflammatory process and hence reduce its symptoms and signs. In patients in whom the process is well controlled, the progress - and potential damage resulting from the disease - can be slowed and often halted. Treatment is most effective when it begins early in the course of the disease. Over the past two decades, research in this field has resulted in dramatic improvements in care. Recent developments in treatment strategies have also significantly improved the long term outcomes of inflammatory arthritis.

Medications for Inflammatory Arthritis fall into one of the following categories:

  • Non-steroidal Anti-Inflammatory drugs (NSAIDs): as the name suggests, this group of drugs reduces inflammation, specifically by interfering with the production of prostaglandins, chemicals that contribute to pain and inflammation.
  • Corticosteroids such as prednisone have multiple actions. They can both reduce inflammation and suppress the immune system, but may also affect bone strength and make one more susceptible to infection, diabetes, and hypertension. Rheumatologists prefer to limit the duration of therapy with these potent drugs because of the many side effects, or not use them at all.
    In the treatment of almost
    all forms of Inflammatory Arthritis,
    NSAIDs and/or corticosteroid therapy
    are used temporarily to control
    flares and symptoms of the disease.
  • Disease Modifying Anti-Rheumatic Drugs (DMARDs): This group of drugs is essential to the treatment of Inflammatory Arthritis. They have been shown to slow, or modify, the progress of joint damage (as seen on x-ray) in people with forms of inflammatory arthritis such as rheumatoid arthritis, psoriatic arthritis, or juvenile inflammatory arthritis. DMARDs are medications that are used over the long term to keep inflammatory arthritis under control, or in remission and in many cases are known to halt damage from the disease. They typically do not act immediately on the inflammatory response, but can take weeks or even a few months to become fully effective. One of the most commonly used, well-established drugs in this class is methotrexate, which is not only effective in rheumatoid arthritis but also in juvenile inflammatory arthritis and potentially in psoriatic arthritis. Other traditional DMARDs used include hydroxychloroquine, sulfasalazine, minocycline, and leflunomide. Additional types of DMARDs available, include a new generation of drugs called biologics (see below), commonly referred to as biologic DMARDs to distinguish them from the traditional DMARDs. Traditional DMARDs are often used in combination with other traditional DMARDs or biologics to gain control of the disease. Biologics are never combined.
  • Biologics: These newer types of DMARDs, are faster-acting than traditionally used drugs in this category. Biologic drugs target a particular molecule or protein that is involved in the inflammatory process. Most DMARDs are actual antibodies which are proteins and must be given as injections either under the skin (one to four weeks apart) or by intravenous infusion (one to six months apart). Although more costly and sometimes more challenging to use due to the immunosuppression they cause, biologics have been known to dramatically improve the prognosis and function of people living with inflammatory arthritis, especially those who do not respond to treatment with traditional DMARDs.

Because the medications used to treat inflammatory arthritis affect the immune system and can have side effects, rheumatologists monitor their patients carefully throughout treatment. This can involve regular doctor’s visits and blood tests.

In addition to treatment with medication, people with inflammatory arthritis benefit from eating a healthy, balanced diet and maintaining an optimal weight to minimize stress on the joints.

In cases where medication and other measures have not controlled the disease and joint damage has occurred, some people with ongoing pain and limitations on movement may need surgery. Surgery usually involves repair or replacement of completely damaged joints or repair of ruptured tendons or ligaments. However, patients with inflammatory arthritis have complex perioperative needs, as they may have damage to multiple joints which may create challenges for their health care team. Medication regimens used to control the arthritis may need to be modified at the time of surgery to decrease risks of bleeding and infection.

At HSS, the Combined Arthritis Program, or CAP, is comprised of surgeons and rheumatologists who focus on the care of patients with inflammatory arthritis and other rheumatic diseases who require orthopedic surgery, who are familiar with the surgical, medical, and rehabilitative needs of patients with inflammatory arthritis. This collaborative relationship has led to superb results for these complex patients [1, 2]

Questions and Information for Your Rheumatologist

Whether you are planning an initial visit to a rheumatologist for an evaluation or are going to see your long-established healthcare provider, to make the most of a visit to the doctor’s office, consider the following:

  • Bring in a full list of the medications you are taking as well as any vitamins or supplements (Even if you have seen this physician before, if you are seeing other physicians, your medications or supplements may have changed since your last visit).
  • If you are already taking medication, prepare notes about any reactions or side effects that you feel may be related to the drugs that you are taking.
  • Be ready to report any physical or emotional changes that you are experiencing, whether or not they are strictly related to your inflammatory arthritis, and
  • Bring in reports or copies of any blood tests or imaging tests (X-rays, ultrasounds, MRIs of joints that were done to better understand your arthritis.
  • Bring a list of any questions you have about any aspect of your care.
  • If it is your first visit, be ready to provide a list of all health conditions, prior surgeries and any allergies.

Some people also find it helpful to bring a loved one, friend or caregiver along on a doctor’s appointment, in order to have a second "set of ears" for any new information or instructions given. On occasion, close family members cannot fully understand the impact inflammatory arthritis has and it may be helpful for them to join you on a visit to your rheumatologist.

A Final Note

A diagnosis of inflammatory arthritis can initially feel somewhat overwhelming. It can take weeks or even months to come to terms with and understand what having inflammatory arthritis can mean in a person’s life. However, by developing a close working relationship with your rheumatologist and other caregivers, there is much you can do to control inflammatory arthritis and maintain an independent, productive and active lifestyle.

In addition to providing leading-edge medical care, the Inflammatory Arthritis Center offers services for the emotional/psychological aspects of the disease and runs a support group where people with Inflammatory Arthritis can meet and learn from one another. Learn more about the Inflammatory Arthritis Center.

Bykerk VP. Management of Rheumatoid Arthritis: The Newly Diagnosed Patient.  Targeted Treatment of the Rheumatoid Diseases. ed. IBSN: 978-1-4160-9993-2. 2009. 17-26

Bykerk VP, Crow MP:  An Introduction to Rheumatic Disease.  Editor:  Cecil’s Textbook of Medicine, pending publication, submitted 2014.

Goodman SM. Rheumatoid arthritis: pre-operative evaluation for total hip and total knee replacement surgery. J Clin Rheum 2013  Jun;19(4):187-92. doi: 10.1097/RHU.0b013e318289be22.

Goodman SM, Figgie M. Lower Extremity Arthroplasty in Inflammatory Arthritis: Pre-operative and Perioperative Management.  J Am Acad Orthop Surg. 2013 Jun;21(6):355-63.  doi: 10.5435/JAAOS-21-06-355.

Summary by Nancy Novick

Images courtesy of ACR Imagebank


Headshot of Vivian P. Bykerk, BSc, MD, FRCPC
Vivian P. Bykerk, BSc, MD, FRCPC
Director, Inflammatory Arthritis Center of Excellence
Associate Attending Rheumatologist, Hospital for Special Surgery

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