According to news delivered on the show earlier this month, Kim Kardashian West’s blood had tested positive for “lupus and rheumatoid arthritis antibodies”. However, a subsequent episode revealed that her symptoms of tiredness and swollen hands were actually due to psoriatic arthritis.

So, what are these autoimmune conditions and why the confusion?

Systemic Lupus Erythematosus usually known as lupus or SLE is a condition that affects more women than men – eight times more in fact.² It is a chronic, inflammatory autoimmune disorder that can affect several organ systems including the kidneys, skin, joints and other internal organs.

Lupus usually begins in one organ but can progress to involve others. Possible symptoms that may be experienced include: joint pain; fatigue, headaches and a skin rash – which often manifests in a butterfly shape across the nose and cheeks. In rare cases serious symptoms can occur such as seizures, psychoses, inflammation in the heart and lungs, and blood clots that could lead to a stroke or pulmonary embolism.

Rheumatoid arthritis is a chronic autoimmune condition affecting around 450,000 Australians.³ It affects the joints when your immune system malfunctions and attacks healthy tissue in or near your joints. Common symptoms include swelling, pain and heat in the joints, joint stiffness and persistent fatigue.

Psoriatic arthritis causes inflammation of the joints which can result in pain, swelling and stiffness in the joints, pain in tendons and thickening or colour changes in the nails. It affects people who have psoriasis and but only between 10 and 30 percent of people with psoriasis will develop this type of arthritis.

What did Kim’s ‘positive’ lupus result mean?

Diagnosing autoimmune conditions like lupus can be complex. Immunopathologist Associate Professor Stephen Adelstein explains:

“People sometimes think that a test alone can diagnose a disease, but it can’t. We must look at a patient’s symptoms, a comprehensive medical and family history, as well as pathology results to understand what is causing the problem.

Results from a range of tests are often needed to reach a diagnosis, particularly when symptoms are similar across several conditions.”

The pathology tests we have available for autoimmune conditions look for clues in the blood that tell us about certain body processes that are happening.

For example, the antinuclear antibody (ANA) test is often ordered by doctors if they suspect lupus. ANAs are a group of special antibodies produced by the patient’s immune system when it malfunctions and cannot tell the difference between ‘self’ and ‘other’. They are known as autoantibodies and can attack the body’s own cells, causing symptoms such as tissue and organ inflammation, joint and muscle pain, and fatigue.

Detecting ANA in the blood shows that an autoimmune process is taking place. The ANA test is most commonly used to indicate lupus but is also associated with other autoimmune disorders. However, a positive result can happen in some people without an autoimmune condition and this is more common as we age, with 30% of women and 20% of men being ANA positive by age 70.⁴

In pathology this is known as a test that is highly sensitive but not highly specific. This means the test is able to pick up close to 100 per cent of people who have the autoantibodies in their blood, but cannot specify that they have lupus, because someone who does not have lupus may still have a positive result.

For this reason, after a positive ANA result, doctors will often order an Anti-dsDNA test that is a more specific test to confirm a lupus diagnosis. We don’t know what tests were ordered in Kim’s specific case, but it certainly highlights the complexities of diagnosing autoimmune diseases.

A/Prof Adelstein says; “This is a constantly evolving area. We are always looking for ways to improve the diagnostic ability of the tests we have and to develop new tests that can be more specific and more sensitive so that patients can be diagnosed and treated more quickly.”

References

1. https://www.allergy.org.au/patients/autoimmunity/systemic-lupus-erythematosus-sle
2. https://www.labtestsonline.org.au/learning/index-of-conditions/lupus
3. https://www.aihw.gov.au/reports/chronic-musculoskeletal-conditions/rheumatoid-arthritis/contents/who-gets-rheumatoid-arthritis
4. https://www.labtestsonline.org.au/learning/test-index/ana

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What is arthritis?

Arthritis is a name for a group of conditions affecting the joints. Symptoms of arthritis include pain, stiffness or reduced movement of a joint, swelling in a joint, redness and warmth in a joint. People may also experience general symptoms such as tiredness, weight loss or feeling unwell.

What tests are there for arthritis and autoimmune disorders?

When diagnosing arthritis, a doctor will first ask you about your symptoms and may examine you for signs of arthritis or other autoimmune features. Then pathology tests may be performed to:

• Confirm a diagnosis of arthritis or another autoimmune disorder
• Monitor disease activity and response to treatment
• Check for side effects from medicines you are taking

Are all types of arthritis diagnosed by blood tests?

Most forms of arthritis can be diagnosed by blood tests. The doctor may use blood tests to support a diagnosis made on the signs and symptoms, or to rule out a different type of arthritis or other condition with similar symptoms. Pathology tests may not be required to diagnose some conditions such as osteoarthritis or chronic back pain. This article focuses on those conditions where pathology tests are used to assist with diagnosis. For more information about osteoarthritis check out this page from Arthritis Australia.

Blood tests

Erythrocyte Sedimentation Rate (ESR): ESR tests measure the level of inflammation in the body but do not determine exactly where in the body the inflammation is or what is causing it. ESR can also be affected by other conditions besides inflammation, so it is used alongside other tests.

C-Reactive Protein (CRP): CRP tests measure the amount of C-reactive protein in the blood, which shows the level of inflammation in the body. The test is not specific enough to diagnose a particular type of arthritis or disease, so is used alongside other tests.

Rheumatoid Factor (RF): The RF test is commonly used to help diagnose rheumatoid arthritis (RA). However, a positive RF test does not always mean a person has RA, as several conditions can give positive RF results. People without RA can also test positive for RF, particularly older people, but this does not mean they will develop the condition.

Anti-Cyclic Citrullinated Peptide antibody (anti-CCP):  Anti-CCP antibodies (proteins made by the body’s immune system) are commonly present in people with RA. This test is useful in the early stages of RA or in borderline cases, as it is a stronger indicator of RA than the rheumatoid factor test. As not all people with early RA test positive, the doctor will use other tests and examinations so the diagnosis is more reliable.

Antinuclear Antibody (ANA): The ANA test is used to screen for autoimmune disorders. In particular, almost 100% of people with systemic lupus erythematosus (SLE) have a positive ANA test. People with conditions such as Sjögren’s syndrome, scleroderma, Raynaud’s disease and rheumatoid arthritis can also have a positive ANA result, so further testing, plus the patient’s symptoms and signs, is usually needed for a final diagnosis.

• Anti-dsDNA test: This test helps diagnose and monitor SLE. It is ordered after a positive ANA test to confirm a diagnosis of SLE.
• Extractable Nuclear Antigen Antibodies (ENA) panel: This test comes after a positive ANA test to help diagnose a specific autoimmune disorder. The number of tests done on the blood sample will depend on the clinical symptoms and the doctor’s assessment.

HLA typing: This test looks for the presence of certain genetic markers in the blood that are associated with an increased risk of developing certain types of arthritis.

Uric Acid test: Levels of uric acid in the blood are measured to test for gout. As high levels of uric acid can occur in people without gout, other tests (arthrocentesis, X-ray and ultrasound) might be needed to confirm diagnosis.

Other pathology tests

Arthrocentesis: Arthrocentesis is the process of extracting some fluid from a joint, usually using a needle and syringe. Although infections can be identified with a blood test, arthrocentesis, if possible, is usually better. It is also the most specific test for gout.

• The fluid is cultured to check for an infection.
• The fluid is observed under a polarised microscope to look for uric acid crystals to check for gout.

Forms of arthritis diagnosed by pathology tests

Autoimmune disorders

Rheumatoid Arthritis (RA): A common inflammatory form of arthritis that causes pain and swelling of the joints and other organs in the body, such as the lungs and skin. In RA, the immune system attacks healthy tissues, specifically the lining of the joints, causing inflammation and joint damage.

Spondyloarthritis: Includes inflammatory diseases that involve both the joints and the entheses (the sites where the ligaments and tendons attach to the bones; for example, around joints, at the edges of the vertebral bodies of the spine and where tendons attach to the heel bone).

• Ankylosing Spondylitis (AS): The most common symptoms of AS are chronic pain and stiffness in the lower back, buttocks and hips. AS usually develops slowly over several weeks or months.
• Reactive arthritis: Reactive arthritis follows certain infections. The most common symptoms are inflammation in the joints, eyes and urethra (the tube that helps remove urine from the body). Mouth sores and skin rashes sometimes occur.
• Psoriatic Arthritis (PsA): Approximately 30% of people with psoriasis (a skin condition characterised by itchy, scaly rashes and crumbling nails) also develop PsA. The symptoms of PsA include joint pain and stiffness, skin rashes, nail changes, fatigue, eye problems, and swelling and tenderness in fingers and feet. PsA may be indistinguishable from other types of arthritis, except that the patient has psoriasis.

Systemic Lupus Erythematosus (SLE):  The immune system attacks healthy tissues, including the joints and skin. In some people, the lungs, kidneys, blood vessels, brain or other parts of the body are also affected.

Sjögren’s syndrome: Abnormal dryness of the mouth, eyes and/or other tissues. Around half the people who have Sjögren’s syndrome also have another form of arthritis

Scleroderma:  Scleroderma affects the connective tissues of the body (tissues that hold together joints, muscles, blood vessels and internal organs), causing skin thickening. Many different areas of the body can be affected. Raynaud’s phenomenon is common in people with scleroderma.

Raynaud’s disease: Raynaud’s phenomenon is a condition that can cause discomfort as the blood supply to the fingers and toes becomes reduced. When this happens, the person’s fingers or toes change colour. It can happen in cold temperatures or emotionally stressful situations.

Inflammation and other forms of arthritis

Septic arthritis: Some infections can lead to joint destruction and this occurs much quicker than with other forms of arthritis. It is crucial to rule out an infection when arthritis affects a single joint.

Gout: A common and painful condition that affects the joints and tendons. Small crystals of uric acid form in and around the joint which causes inflammation, pain and swelling. An attack of gout usually comes on very quickly, often overnight. The joint becomes red, swollen and painful. It often affects one joint at a time, such as the big toe.

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