What is Rheumatoid Arthritis?
Rheumatoid arthritis (RA) is a chronic autoimmune and inflammatory disease that causes a person’s immune system to attack the healthy cells in the body by mistake. The result is inflammation and swelling in the affected body parts, mainly the joints.
Frequently, rheumatoid arthritis affects joints in the hands, wrists, and knees but can also spread to other joints. According to the CDC, inflammation starts in the lining of the joint, and the joint tissue becomes damaged, potentially causing chronic pain, lack of balance, and deformity. RA can also affect other tissues throughout the body and lead to problems in organs such as the lungs, heart, and eyes.
- Rheumatoid arthritis is the most common type of autoimmune arthritis.
- Approximately 1.3 million adults in the U.S. suffer from RA, representing 0.6% to 1% of the adult population.
- RA often begins in middle age and affects two to three times as many women as men. Young children and the elderly can also get RA.
- Approximately 40% of people with RA also experience signs and symptoms that do not involve the joints, such as the skin, eyes, lungs, heart, and blood vessels.
RA can begin slowly, often obscure and nonspecific. Other times, the symptoms can worsen and cause intense joint pain and stiffness. These episodes are known as flares. When the symptoms subside, the RA is in remission.
The Arthritis Foundation reports the signs and symptoms of RA include:
- Joint tenderness, pain, swelling, or stiffness that lasts for six weeks or longer
- Morning stiffness that lasts for 30 minutes or longer
- More than one joint is affected
- Small joints are usually affected first. These include the hands, wrists, and feet.
- The same symptoms on both sides of the body, such as both hands or both feet
- Low-grade fever
A person with RA for an extended period may suffer from emotional symptoms due to severe pain and the inability to function. A person may become depressed and anxious, develop low self-esteem, and feel helpless.
Causes and Risk Factors
The exact cause of the autoimmune disease is unknown. However, what is known is that an abnormality in the immune system causes rheumatoid arthritis and is primarily an inflammatory disease of the synovium found inside the joint capsule.
Specific factors that may put a person at increased risk of RA include:
Age. RA is most common in adults in their sixties, but it can begin at any age.
Sex. Women typically get RA more than men.
Genetics/inherited traits. Individuals born with a specific gene are more likely to develop RA.
Smoking. Cigarette smoking increases a person’s risk of developing RA and can worsen the disease.
History of live births. Women who have never given birth may have an increased risk of developing the condition.
Early life exposures. Children of lower-income parents and children with mothers who smoked are at increased risk of developing RA as adults.
Obesity. Obesity can put a person at an increased risk of developing RA. Also, the more overweight a person is, the higher the chances of developing the condition.
Diagnosing Rheumatoid Arthritis
Rheumatoid arthritis can be challenging to diagnose because the symptoms are similar to other disorders. Furthermore, no single blood test is available to diagnose RA definitively, according to the Arthritis Foundation.
According to the Mayo Clinic, some of the most common blood tests used when rheumatoid arthritis is suspected include:
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CPR)
- Antinuclear antibody
- Rheumatoid factor
- Cyclic citrullinated peptide (CCP)
Blood tests can show if the patient’s body has inflammation and is making specific antibodies called anti-cyclic citrullinated peptides (anti-CCPs). These antibodies are often seen in rheumatoid arthritis. However, one person with RA could test positive for anti-CCPs, while another patient with RA may test negative for anti-CCPs.
Either way, with or without these antibodies, a patient may be diagnosed with rheumatoid arthritis according to the patient’s symptoms, physical exam, and x-rays. A good indicator of RA is when the patient has joint pain and swelling, bone and cartilage damage shown on an x-ray, and high levels of antibodies on a blood test.
The Arthritis Foundation reports that physicians often use a rheumatoid factor (RF) test in conjunction with anti-CCP blood work to determine if the patient is positive for anti-CCPs. The two tests combined provide the most accurate results. Still, the anti-CCP test is now the preferred test.
Below is a two-minute video on the difference between seropositive and seronegative rheumatoid arthritis.
Types of Rheumatoid Arthritis
The two main types of rheumatoid arthritis in adults are seropositive RA and seronegative RA, according to Very Well Health. The most common of the two types is Seropositive RA.
Seropositive Rheumatoid Arthritis
Seropositive rheumatoid arthritis refers to positive anti-cyclic citrullinated peptide (anti-CCP) antibodies and/or rheumatoid factor (RF) blood tests. An anti-CCP blood test identifies antibodies that attack the body’s healthy cells, resulting in inflammation.
The symptoms are everlasting and can improve or flare up at times, causing joint pain, swelling, and stiffness. More than one joint will be affected, usually on both sides of the body, such as the bilateral knees.
Seropositive rheumatoid arthritis tends to be more progressive and severe than seronegative rheumatoid arthritis. It is also associated with more joint damage, deformity, rheumatoid nodules, vasculitis, lung issues, and organ and tissue damage outside the joints, such as heart attack and stroke.
Seronegative Rheumatoid Arthritis
Seronegative rheumatoid arthritis is less frequent than seropositive rheumatoid arthritis and lacks anti-CCP and rheumatoid factor (RF). The classic symptoms are like those seen in seropositive RA but are often less severe and unforeseeable.
Diagnosing seronegative RA is made according to the signs and symptoms, including morning stiffness, joint stiffness, pain, swelling, and multiple symmetrical joints being affected.
Like seropositive RA, seronegative RA is associated with systemic conditions, such as fever and fatigue. Seronegative RA is less likely to be associated with rheumatoid nodules, vasculitis, and lung issues.
Almost half of the people with rheumatoid arthritis will experience other problems in the body other than the joints. The inflammation associated with rheumatoid arthritis can affect areas including the skin, eyes, lungs, heart, kidneys, salivary glands, nerve tissue, bone marrow, and blood vessels.
Rheumatoid Arthritis in ICD-10-CM
Diagnosis codes for rheumatoid arthritis are in Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) of the ICD-10-CM coding manual. Specifically, the codes are listed under Arthropathies (M00-M25) and block M05-M14 (Inflammatory polyarthropathies).
The two different types of rheumatoid arthritis (seropositive and seronegative) are assigned codes from these categories:
- M05 (Rheumatoid arthritis with rheumatoid factor)
- M06 (Other rheumatoid arthritis)
Selecting a code from categories M05 and M06 depends on whether or not the blood test is positive for rheumatoid factor and/or anti-CCP antibodies. A positive blood test indicates the patient has seropositive rheumatoid arthritis and is assigned a code from M05. A blood test without these antibodies is called seronegative RA and is assigned a code from M06.
M05 – Rheumatoid arthritis with Rheumatoid Factor (Seropositive)
Codes for rheumatoid arthritis with rheumatoid factor are located in category M05 and are broken down further into subcategories based on the joint(s) affected and laterality (right, left, unspecified). Affected joints may include the shoulder, elbow, wrist, hand, hip, knee, ankle, and foot, or multiple sites.
Since RA not only affects the joint but also may be systemic, a coder must also consider the combination codes that include organ or systems involvement (i.e., lung disease).
The code blocks and their descriptions for each subcategory of M05 (Rheumatoid arthritis with rheumatoid factor) are as follows:
- M05.00‑M05.09 M05.0 Felty’s syndrome
- M05.10‑M05.19 M05.1 Rheumatoid lung disease with rheumatoid arthritis
- M05.20‑M05.29 M05.2 Rheumatoid vasculitis with rheumatoid arthritis
- M05.30‑M05.39 M05.3 Rheumatoid heart disease with rheumatoid arthritis
- M05.40‑M05.49 M05.4 Rheumatoid myopathy with rheumatoid arthritis
- M05.50‑M05.59 M05.5 Rheumatoid polyneuropathy with rheumatoid arthritis
- M05.60‑M05.69 M05.6 Rheumatoid arthritis with involvement of other organs and systems
- M05.70‑M05.7A M05.7 Rheumatoid arthritis with rheumatoid factor without organ or systems involvement
- M05.80‑M05.8A M05.8 Other rheumatoid arthritis with rheumatoid factor
- M05.9 Rheumatoid arthritis with rheumatoid factor, unspecified
The individual codes within the code blocks indicate the side of the body being affected. For example, the codes listed under subcategory M05.1 (Rheumatoid lung disease with rheumatoid arthritis) include:
- M05.111, Rheumatoid lung disease with rheumatoid arthritis of right shoulder
- M05.112, Rheumatoid lung disease with rheumatoid arthritis of left shoulder
- M05.119, Rheumatoid lung disease with rheumatoid arthritis of unspecified shoulder
There are also code options for unspecified, multiple sites, and other site. Examples of these include:
- M05.00, Felty’s syndrome, unspecified site
- M05.69, Rheumatoid arthritis of multiple sites with involvement of other organs and systems
- M05.8A, Other rheumatoid arthritis with rheumatoid factor of other specified site
According to the ICD-10-CM Official Guidelines for Coding and Reporting, when the condition involves “more than one bone, joint, or muscle, there is a “multiple sites” code available. For categories where no multiple site code is provided and more than one bone, joint or muscle is involved, multiple codes should be used to indicate the different sites involved.”
Systemic Conditions Related to RA
Below is a brief description of each of the systemic manifestations of RA assigned with codes M05.00-M05.69.
- Felty’s syndrome (M05.00-M05.09) is a rare manifestation of seropositive RA disorder that includes rheumatoid arthritis, an enlarged spleen (splenomegaly), and a decreased white blood cell count (neutropenia).
- Rheumatoid lung disease (M05.10‑M05.19) is a group of RA-related lung problems that causes lung inflammation and is associated with RA of a specific anatomic site.
- Rheumatoid vasculitis (M05.20‑M05.29) is an unusual complication of prolonged severe rheumatoid arthritis. Blood vessels become inflamed and, at times, cause complete blockage.
- Rheumatoid (rheumatic) heart disease (M05.30‑M05.39) is inflammation of the various anatomical features of the heart that may lead to a severe cardiovascular event such as a heart attack or stroke.
- Rheumatoid myopathy (M05.40‑M05.49) is inflammation and weakness of the muscles, potentially resulting in chronic muscle pain, disability, and paralysis.
- Rheumatoid polyneuropathy (M05.50‑M05.59) is inflammation of the peripheral nerves and the central nervous system due to a specific affected joint.
- Rheumatoid with involvement of other organ systems (M05.60‑M05.69) is inflammation of other specified body areas due to rheumatoid arthritis.
M06 – Other Rheumatoid Arthritis (Seronegative)
Similar to the codes in category M05, the codes for rheumatoid arthritis without rheumatoid factor in category M06 are based on the joint(s) affected and laterality. The joints affected are the same here, but an additional joint code is listed for rheumatoid arthritis without rheumatoid factor of the vertebrae (M06.08).
The code blocks and their descriptions for each subcategory of M06.0 (Rheumatoid arthritis without rheumatoid factor) are as follows:
- M06.00 Rheumatoid arthritis without rheumatoid factor, unspecified site
- M06.011‑M06.019 M06.01 Rheumatoid arthritis without rheumatoid factor, shoulder
- M06.021‑M06.029 M06.02 Rheumatoid arthritis without rheumatoid factor, elbow
- M06.031‑M06.039 M06.03 Rheumatoid arthritis without rheumatoid factor, wrist
- M06.041‑M06.049 M06.04 Rheumatoid arthritis without rheumatoid factor, hand
- M06.051‑M06.059 M06.05 Rheumatoid arthritis without rheumatoid factor, hip
- M06.061‑M06.069 M06.06 Rheumatoid arthritis without rheumatoid factor, knee
- M06.071‑M06.079 M06.07 Rheumatoid arthritis without rheumatoid factor, ankle and foot
- M06.08 Rheumatoid arthritis without rheumatoid factor, vertebrae
- M06.09 Rheumatoid arthritis without rheumatoid factor, multiple sites
- M06.0A Rheumatoid arthritis without rheumatoid factor, other site
Again, the individual codes within the code blocks indicate laterality (right, left, unspecified).
When assigning the appropriate codes for RA, review the documentation for the type of arthritis (e.g., rheumatoid, rheumatoid myopathy, juvenile rheumatoid, etc.), affected joint(s), laterality, any organ or systems involvement, and whether or not rheumatoid factor has been identified in the blood test.
Laterality. If the documentation indicates both sides of the body are affected, assign a code for both the right and left sides, as no bilateral codes are available.
Other. When the documentation provides a specific diagnosis description for a specific code that does not exist, assign a code from code block M05.80‑M05.8A (Other rheumatoid arthritis with rheumatoid factor).
Unspecified. An unspecified diagnosis code should be used only when the provider does not have enough medical information at the time of the encounter. Only then should the coder assign M05.9 (Rheumatoid arthritis with rheumatoid factor, unspecified).
Instructional Notes. Before making your final code assignment, review the instructional notes (Includes, Excludes, etc.) provided in ICD-10-CM. In particular, a note at code range M00-M99 states, “Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition. ”
Adult RA vs. Juvenile RA. Do not confuse coding for adult rheumatoid arthritis with the child’s version of the disorder. Juvenile RA is reported with codes from category M08 and is only to be used for patients ages 16 years and younger.
RA abbreviation. “RA” is often used as an abbreviation for rheumatoid arthritis. However, the acronym can also have other meanings. The coder should be careful to make sure the documentation is clear in its meaning before selecting the appropriate code.
Past medical history. Since RA is a lifelong disease, the documentation should not state “a history of rheumatoid arthritis.” Instead, RA may be described as “rheumatoid arthritis in remission.”
Test your skill on the following five coding examples by assigning the appropriate ICD-10-CM code for each. The correct answers are posted below.
- A 65-year-old male patient is diagnosed with seronegative rheumatoid arthritis affecting the right hip.
- A 59-year old with RF-positive rheumatoid vasculitis disease presents with rash and tingling in the left hand. The symptoms are due to RA.
- Patient is seen for treatment of suspected rheumatoid arthritis in both hands. Test results confirm a diagnosis of RA with rheumatoid factor, bilaterally.
- A 72-year-old female patient presents to the rheumatologist’s office to discuss treatment of her seropositive rheumatoid arthritis of multiple sites and associated polyneuropathy.
- Patient sees the physician with complaints of pain and swelling in the left hand and wrist. The diagnosis is rheumatoid arthritis without rheumatoid factor of the left hand and wrist.
- Seronegative RA means no rheumatoid factor is found in the blood test and is reported with a code from M06. The RA is affecting the right hip. Look up Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute)/rheumatoid/seronegative/hip M06.05-. In the Tabular, we can verify the correct code as
M06.051, Rheumatoid arthritis without rheumatoid factor, right hip
- RF-positive refers to seropositive RA. The blood test shows rheumatoid factor; therefore, the code we are looking for is in category M05. The vasculitis is associated with the RA. Look up Rheumatoid/vasculitis/hand joint M05.24-. In the Tabular, we can verify the correct code as
M05.242, Rheumatoid vasculitis with rheumatoid arthritis of left hand
The rash and tingling are integral to rheumatoid vasculitis and should not be coded.
- RA with rheumatoid factor tells us that the RA is seropositive, which means we need a code from category M05. There is no mention of organ or systems failure. Two codes are needed to code for the bilateral hands. Look up arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute)/rheumatoid/without organ involvement/hand joint M05.74-. In the Tabular, we can verify the correct codes as
M05.741, Rheumatoid arthritis with rheumatoid factor of right hand without organ or systems involvement and
M05.742, Rheumatoid arthritis with rheumatoid factor of left hand without organ or systems involvement
- Polyneuropathy has been documented as being associated with the patient’s seropositive rheumatoid arthritis. Again, seropositive RA is coded to category M05. Multiple sites are affected. This is reported with a combination code. Look up Rheumatoid/polyneuropathy/multiple sites M05.59. In the Tabular, our correct code is
M05.59, Rheumatoid polyneuropathy with rheumatoid arthritis of multiple sites
- Rheumatoid arthritis without rheumatoid factor is reported with a code from category M06, because it is lacking RF. A code for both the left wrist and hand joint must be assigned to indicate the two different sites. Look up Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute)/rheumatoid/seronegative/hand joint M06.04-. To look up the wrist joint, follow the same process and go to wrist M06.03-. In the Tabular, we can verify the correct codes as
M06.042, Rheumatoid arthritis without rheumatoid factor, left hand and
M06.032 , Rheumatoid arthritis without rheumatoid factor, left wrist
Pain and swelling are symptoms integral to RA and should not be coded as secondary codes.