Tuesday, January 22, 2008

Diagnosing Lupus

Lupus is chronic, complex, and difficult to diagnose. No single lab test can tell if you have lupus. Many lupus symptoms imitate symptoms of other diseases and often come and go. Your primary care doctor or rheumatologist will use your medical history, a physical exam, and many routine as well as special tests to rule out other diseases.
Many physicians also use the American College of Rheumatology's "Eleven Criteria of Lupus" to aid in the diagnosis of lupus. The criteria include symptoms as well as specific laboratory findings that provide information about the functioning of a person's immune system. In most cases, the diagnosis of lupus is made when four or more of the criteria have occurred at some time.

The "Eleven Criteria"

  1. Malar rash: butterfly-shaped rash across cheeks and nose

  2. Discoid (skin) rash: raised red patches

  3. Photosensitivity: skin rash as result of unusual reaction to sunlight

  4. Mouth or nose ulcers: usually painless

  5. Nonerosive Arthritis (bones around joints do not get destroyed): in 2 or more joints with tenderness, swelling, or effusion

  6. Cardio-pulmonary involvement: inflammation of the lining around the heart (pericarditis) and/or lungs (pleuritis)

  7. Neurologic disorder: seizures and/or psychosis

  8. Renal (kidney) disorder: excessive protein in the urine, or cellular casts in the urine

  9. Hematologic (blood) disorder: hemolytic anemia, low white blood cell count, or low platelet count

  10. Immunologic disorder: antibodies to double stranded DNA, antibodies to Sm, or antibodies to cardiolipin

  11. Antinuclear antibodies (ANA): positive test in absence of drugs known to induce it

A Positive ANA Test: Should You Worry?

If you have positive antinuclear antibody (ANA) test, it does not automatically mean you have lupus. Your immune system is your body's natural defense against disease. A positive ANA blood test shows that your immune system is making an antibody (protein) that reacts with components of your body's cells. This is called autoimmunity and may or may not be harmful to your body.
While a positive ANA may be associated with an autoimmune illness like lupus, it does not mean you have the disease. Approximately 20% of the normal population will have a positive ANA test; positive tests are also seen in other conditions, such as thyroid disease, certain liver conditions, and other autoimmune diseases.
Before making a diagnosis, your doctor should be able to find objective physical or laboratory evidence of the condition, such as swelling of your joints, protein in your urine, fluid around your lungs or heart, or a positive skin biopsy.

If You Are Diagosed With Lupus

For many lupus patients, following their doctors' instructions very carefully is the first step in the right direction. While lupus can be disruptive to everyday life and even life-threatening, the good news is that, with the correct medication and a healthy lifestyle, many lupus patients can enjoy an improved quality of life.