What is the Criteria for Diagnosing Lupus?
What is the criteria for diagnosing Lupus?
Lupus is a chronic autoimmune disease in which the body's immune system becomes hyperactive and attacks the normal, healthy tissue. This results in symptoms such as inflammation, swelling, and damage to joints, skin, kidneys, blood, the heart, and lungs.
Under normal function, the immune system makes proteins called antibodies in order to protect and fight against antigens such as viruses and bacteria.
Lupus makes the immune system unable to make a difference between antigens (a substance capable of inducing a specific immune response) and healthy tissue. This leads the immune system to direct antibodies against the healthy tissue - not just antigens - causing swelling, pain, and tissue damage.
While genetics play a role in the development of Lupus, which we said that is a systemic autoimmune disease that can attack any organ system in the human body, so do environmental triggers, like for example, particulates in air pollution and ultraviolet light.
More than 1.5 million people in the United States are affected by lupus and it occurs in both men and women, though 90 percent of those diagnosed are women, with African-Americans disproportionately impacted by the disease, according to the Lupus Foundation of America. It can cause inflammation, swelling, and damage to joints, skin, kidneys, blood, the heart, and lungs. But, there were several cases where lupus has finished fatal.
So, the main question is – How is lupus diagnosed?
Lupus affects people very differently. In some people, symptoms may come on suddenly or build slowly over time. Symptoms may be mild or severe and depend largely on which systems of the body are affected and to what degree. Most people with lupus have a mild form characterized by “flares,” where the symptoms temporarily worsen and then improve or even disappear completely for a period of time. Other common symptoms include fatigue, fever, pain and stiffness in the joints, a butterfly-shaped rash on the face, skin lesions that typically worsen if you go in the sun, Raynaud’s phenomenon (in which the fingers and/or toes turn white or blue when exposed to cold or during times of stress), headaches, memory loss and shortness of breath.
A diagnosis of lupus is made based on symptoms, a physical examination, and blood tests. Tests can help to rule out other conditions.
Because lupus can produce a variety of symptoms in different individuals, it may take some time for a physician to actually make the diagnosis. Often a doctor will say that lupus might be present, but that the current symptoms are insufficient to signify a firm diagnosis. In this event, s/he will likely monitor the patient’s symptoms, signs, and lab tests closely over time and have him/her return for regular visits.
No single finding qualifies an individual as having SLE. Instead, the American College of Rheumatology (ACR) has devised certain classification criteria, and four or more of these criteria must be present for a classification of lupus. [The term “classification” is not synonymous with “diagnosis.” “Classification” means that reasonable certainty exists for the diagnosis of lupus for research purposes.] Although these criteria are currently being updated, they are believed to be about 90% effective. The ACR criteria include malar rash; discoid rash; photosensitivity (development of a rash after sun exposure); oral or nasal ulcers; arthritis of multiple joints; serositis: (inflammation of the lining around the lungs or heart); kidney disease indicated by protein or casts in the urine; neurological disorders such as seizures and psychosis; and blood disorders such as hemolytic anemia, leukopenia, and lymphopenia. Other signs that are common but not included in the classification criteria are hair loss or breaking, especially around the forehead, and Raynaud’s Phenomenon, a two- or three-color change of the fingertips upon cold exposure.
A number of different blood tests may be used:
Anti-nuclear antibody (ANA) test
About 95% of people with lupus are ANA positive, but the test can sometimes be positive in people who don't have lupus, so it can’t confirm the diagnosis.
Anti-double-stranded DNA (anti-dsDNA) antibody test
About 70% of people with lupus have these antibodies. A positive test means that lupus is highly likely as the test is hardly ever positive in people who don't have lupus. The anti-dsDNA level usually goes up when lupus is more active, so repeat tests may be helpful as a means of monitoring your condition and deciding on treatment.
Anti-Ro antibody test
If you test positive for this autoantibody you may be more likely to get skin rashes and suffer from dry eyes or a dry mouth (Sjögren's syndrome). This autoantibody can pass across the placenta during pregnancy. If you carry the anti-Ro autoantibody and decide to have a baby, your pregnancy will be more closely monitored.
Antiphospholipid antibody test
A positive test for these autoantibodies may mean an increased risk of miscarriage and develop blood clots.
Complement level test
Complement refers to a set of proteins in the blood that protect us from infections. Complement levels go down when lupus is more active.
Erythrocyte sedimentation rate (ESR) test
This test assesses inflammation by measuring how quickly the blood cells settle at the bottom of a test tube. The ESR is often raised in lupus.
Kidney and liver function tests
These include blood and urine tests, which are carried out regularly so any problems caused by lupus itself or by drug treatment can be recognized and dealt with quickly. A simple urine test can show if there's protein or blood in the urine. This test can help doctors recognize a problem in the kidneys at a very early stage. Further tests, such as kidney filtration tests, may be carried out if necessary. Those with kidney test abnormalities may be asked to have a biopsy which is the most accurate way of finding out how inflamed and damaged the kidneys are.
Blood cell counts
Haemoglobin, white and red blood cells and platelets are all made in the bone marrow, so blood cell counts can help to show whether the bone marrow is affected, either by the disease or the drugs you're using to treat it.
These tests can also be helpful in monitoring the condition after diagnosis – for example, a combination of higher levels of anti-dsDNA and falling complement levels (often accompanied by a high ESR test) is helpful in predicting a flare-up of lupus. If the C-reactive protein (CRP), another measure of inflammation, is raised, your doctor would also consider whether you have an infection.
A variety of tests are available to check how your heart, lungs, liver, and spleen are working. Depending on which organs your doctor thinks may be involved, you may have x-rays, an ultrasound scan, computerized tomography (CT) scan or a magnetic resonance imaging (MRI) scan.
A urine test can show if there's protein or blood in the urine. This can help doctors to recognize a problem in your kidneys at a very early stage. You may need further tests, such as kidney filtration tests.
If you have symptoms such as fever, weight loss and persistent swelling of the lymph glands, your doctor may take a biopsy of lymph gland tissue to rule out cancer, which can also cause these symptoms.