Autoimmune diseases present a special challenge for physicians. Many of the earliest symptoms—like fever and fatigue—are nonspecific, meaning they’re found in a variety of illnesses. Symptoms often come and go. A single autoimmune disease can show up in different ways in different people, or include features of other autoimmune diseases (called overlap).
For reasons like these, getting to a diagnosis can be a long and stressful journey for many families. But it’s important to remember that the difficulties are an unfortunate part of the process, not a sign that there’s something uniquely wrong with your child. And even when doctors aren’t 100 percent sure which specific autoimmune illness your child has, they often can learn enough from the diagnostic process to begin treatments to improve her health and quality of life.
Your child’s rheumatologist will first look at her full health history—including any family history of autoimmune disease—and conduct a thorough physical exam. If autoimmune disease is suspected, the doctor will gather more information through lab tests, including:
antinuclear antibody (ANA), which can detect certain abnormal proteins—called antinuclear antibodies—that the immune system makes when attacking the body’s own tissues.
- complete blood count (CBC), which is a collection of tests measuring the size, number and maturity of different blood cells in a specific amount of blood. Two important tests are:
- white blood cell count (WBC)—the number of white blood cells present. Low levels may point to a problem with the immune system; high levels, on the other hand, may indicate an infection.
hematocrit—the number of red blood cells present. Anemia, or low levels of red blood cells, is often a symptom of certain autoimmune diseases, including lupus and systemic juvenile idiopathic arthritis.|
complement, which measures the blood’s level of complement, a group of proteins that are part of the immune system. Low levels of complement may indicate an autoimmune problem.
C-reactive protein (CRP), which measures the amount of a special protein made in the liver. CRP levels tend to shoot upward when there’s severe inflammation—like the kind seen in autoimmune diseases—somewhere in the body.
erythrocyte sedimentation rate (ESR or sed rate), which measures how quickly red blood cells fall to the bottom of a test tube. If the cells to clump together and fall more rapidly than normal, it can signal there is inflammation in the body.
rheumatoid factor (RF), which, like ANA, can detect an abnormal protein that the immune system makes when attacking the body. It can be useful in classifying a certain kind of juvenile idiopathic arthritis (JIA). However, children with some non-autoimmune ailments may test positive for RF, and most kids who actually have arthritis may test negative.
- anti-cyclic citrullinated peptide (anti-CCP) antibody, a relatively new blood test that may be ordered along with an RF test to help characterize a certain kind of JIA.
Your child’s doctor may also want to take a closer look at her actual organs and tissues, to rule out things like infections, tumors and fractures. To do this, the doctor might use such imaging tests as:
- magnetic resonance imaging (MRI), which uses a combination of large magnets, radiofrequencies and a computer to produce detailed pictures of the body’s organs, bones and tissues. Because children have to lie very still for an MRI, which can last half an hour or more, some may need general anesthesia or a sedative.
- ultrasound, also known as sonography or ultrasonography, which uses high-frequency sound waves to create pictures of internal structures. Though ultrasound shows less detail than an MRI, it’s very fast and doesn’t require a child to be sedated.
- x-rays, which are good for seeing breaks or other damage to bones, but are less useful in showing soft tissues, like organs.
In some cases, your child’s doctor will actually take a sample of your child’s tissues—called a biopsy—to help identify the disease or to get an idea of how it’s progressing.
Overall, today’s diagnostic tools can help physicians home in on autoimmune disease, but can’t do much to differentiate one illness from another. To solve that problem, many researchers are now working on identifying biomarkers—things that the body is doing or making that point to a specific illness—for autoimmune diseases. Such biomarkers could allow doctors to make faster, more accurate diagnoses, and get started on treatment that much sooner.
Useful medical terms
Antibody: A protein molecule made by the immune system in response to a foreign invader (antigen), like bacteria or a virus. The antibody binds itself to the antigen and either kills it or marks it for attack by other cells.
Antigen: A substance or organism, like a virus, that the immune system recognizes and tries to eliminate.
Anti-inflammatory: Capable of reducing inflammation, an immune system reaction to infection and foreign substances.
Autoantibody: An antibody that reacts against a person’s own cells and tissues.
Autoimmune disease: An illness that results when the immune system mistakenly attacks healthy tissues.
Biologics: A relatively new class of medications based on compounds made by living cells. These compounds “block” specific actions of the immune system that fuel inflammation and tissue destruction.
Biomarkers: Biologic molecules that can indicate if a particular illness is present, and/or how it’s progressing.
Chronic: Long-lasting; without a cure or a definite endpoint.
DMARDs (disease-modifying anti-rheumatic drugs): A class of medications that can slow or potentially stop the activity of autoimmune disease, often by suppressing the overactive immune system.
Flare: When symptoms of a disease suddenly reappear or worsen.
Immune system:The body’s network of cells, tissues and organs that provides immunity, or protection, against foreign organisms.
Immunosuppressant: Describes a kind of medication that reduces the activity of the immune system.
Inflammation: An immune system reaction to infection and foreign substances, marked by swelling, heat, redness and pain.
NSAIDs (nonsteroidal anti-inflammatory drugs): A class of medications that work to reduce pain, fever and inflammation by blocking certain enzymes and proteins in the body.
Remission: When symptoms of a disease decrease or disappear.
Systemic: Involving the whole body.