AUTOIMMUNE DISEASES

Autoimmune diseases occur when the body’s immune system attacks parts of the body itself as if they are foreign. Antibodies and white blood cells are directed against body tissue, resulting in inflammation, injury, and, ultimately, scarring. Almost any part of the body can be affected by autoimmune disease. Some of the most common are the thyroid (Hashimoto’s thyroiditis), the pancreas (type I diabetes), the peripheral nervous system (Guillain-Barre disease), the skin (psoriasis), muscles (myasthenia gravis), and the small intestine (celiac sprue). Multiple sclerosis, rheumatoid arthritis, and lupus are three chronic, potentially debilitating autoimmune diseases that are frequently confused with each other.

In multiple sclerosis (MS), antibodies are directed against the myelin sheath – the fatty insulator surrounding nerves in the brain and spinal cord. This leads to multiple areas of scarring or sclerosis, producing slowing of the nerve signals that control muscle coordination, strength, sensation and vision. Most people with MS develop symptoms between ages 20 and 40. Depending on the location of affected nerve fibers, symptoms may vary but often include fatigue, numbness or weakness in one or two limbs on the same side of the body, visual blurring or blindness, tremor, or difficulties with coordination and balance. MS is most commonly characterized by flare-ups which may appear suddenly and gradually disappear after a few weeks or months. More than half of these people eventually enter a period of continuous deterioration. The trigger for the autoimmune attack in MS is not well-understood. Some researchers believe that there is a link with the Epstein-Barr virus which causes infectious mononucleosis. Others have noticed a geographical factor with high frequencies in the northern United States but rare incidence in Africa. Other environmental factors might include smoking or even month of birth.

Lupus is often mistaken for MS because it can involve symptoms in a number of areas of the body. In lupus, the autoimmune process targets many different body systems – including joints, skin, kidneys, blood cells, heart, and lungs. As in MS, the disease is characterized by flare-ups and periods of remission. Most people develop symptoms between 20 and 40. Fatigue, muscle aches, fever, and weight loss are the most common symptoms. Joint pains are also common and frequently involve the hands. These pains typically do not involve joint swelling and so cannot be classified as arthritis. A classic rash shaped like a butterfly may appear on the face. Risk factors for developing lupus include being female, black or Asian race, excess sun exposure, certain prescription medications, infection with Epstein-Barr virus, and possibly exposure to certain chemicals including mercury and silica.

Rheumatoid arthritis (RA) is a form of arthritis that involves an autoimmune attack on the synovium or lining of the joints, causing joint swelling, pain, and ultimately deformity. As in MS and lupus, the disease may follow a pattern of relapses and remissions. Most commonly, it affects people between 30 and 55. The typical symptoms include morning joint stiffness that lasts at least 30 minutes, pain and swelling in multiple joints – usually the hands or wrists, and subcutaneous nodules or bumps just under the skin. Manifestations may occur outside of the joints – including anemia, fatigue, nerve damage, and heart or kidney disease. Risk factors for developing RA include cigarette smoking, possible infection with Epstein-Barr virus or other viruses called retroviruses, as well as occupational exposure to silica.

Treatments of these three autoimmune diseases have much in common. Systemic corticosteroids like prednisone can reduce inflammation and shorten the duration of flare-ups. However, these medications can have dangerous side effects including hypertension and osteoporosis and can only be used for short periods. Each of these diseases is typically treated by a class of drugs called disease-modifying medications that help to regulate the immune system. Other common treatments include physical and occupational therapy, stress reduction, and analgesics or painkillers.

Dr. McMahon, a graduate of Yale University and the University of Pittsburgh School of Medicine, is board certified in Internal Medicine. She is a member of the American College of Physicians and the Allegheny County and Pennsylvania Medical Societies. She is in solo practice in the North Hills of Pittsburgh.